Miocene paleoenvironmental changes in the Solimões Basin, western Amazon, Brazil: A reconstruction based on palynofacies analysis

Journal Pre-proof Miocene paleoenvironmental changes in the Solimões Basin, western Amazon, Brazil: A reconstruction based on palynofacies analysis Natália de Paula Sá, Marcelo de Araujo Carvalho, Gabriel da Cunha Correia PII:

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https://doi.org/10.1016/j.palaeo.2019.109450

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PALAEO 109450

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Palaeogeography, Palaeoclimatology, Palaeoecology

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Please cite this article as: de Paula Sá, Natá., de Araujo Carvalho, M., da Cunha Correia, G., Miocene paleoenvironmental changes in the Solimões Basin, western Amazon, Brazil: A reconstruction based on palynofacies analysis, Palaeogeography, Palaeoclimatology, Palaeoecology (2019), doi: https:// doi.org/10.1016/j.palaeo.2019.109450. This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. © 2019 Published by Elsevier B.V.

1 1 Miocene paleoenvironmental changes in the Solimões Basin, western Amazon, Brazil: a 2 reconstruction based on palynofacies analysis 3 4

Natália de Paula Sá1,2; Marcelo de Araujo Carvalho1 and Gabriel da Cunha Correia1

5 6

1

7

Museu Nacional, Universidade Federal do Rio de Janeiro, Quinta da Boa Vista s/n, CEP:

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22040-040, São Cristóvão, Rio de Janeiro, Brazil.

9

2

Laboratório de Paleoecologia Vegetal, Departamento de Geologia e Paleontologia,

Programa de Pós-Graduação em Geologia, Departamento de Geologia,

10

Universidade Federal do Rio de Janeiro, Av. Athos da Silveira Ramos, 274, CEP: 21941-

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916, Ilha do Fundão, Rio de Janeiro, Brazil,

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Corresponding author: N.P. Sá, Departamento de Geologia e Paleontologia, Museu

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Nacional, Universidade Federal do Rio de Janeiro, Quinta da Boa Vista s/n, CEP: 22040-

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040, São Cristóvão, Rio de Janeiro, Brazil. ([email protected])

16 17

Abstract

18

We report palynofacies from two sections of Miocene Solimões Formation of the Solimões

19

Basin, western Amazon, Brazil to better understand paleoenvironmental evolution. Based

20

on cluster analysis, five palynofacies associations were recognized, dominated by either

21

opaque, non-opaque, algae, miospores and structureless/marine organic matter. The

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distribution of palynofacies associations reflects a complex depositional system with

23

fluvial, lacustrine, estuarine, and shallow marine environments. A high abundance of

24

woody material indicates a fluvial-lacustrine-dominated environment. Three marine

25

incursions were recognized, indicated by the presence of dinoflagellate cysts and

2 26

microforaminifera test linings. Marine influence was more evident during the late Middle-

27

Late Miocene interval, when transgressions occurred over a greater extent of the Amazon

28

region.

29 30

Keywords: sedimentary organic matter, marine incursion, depositional environments,

31

palynology, terrestrial facies.

32 33 34

1. Introduction In the Cenozoic, changes occurred in the physiography of northern region of South

35

America, especially in the Amazon region (Hoorn and Wesselingh, 2010c). In the Neogene

36

the following events occurred: the end of the Andean Orogeny and the beginning of the

37

present configuration of geo-hydrographic and phyto-physiognomic patterns in the

38

Amazonian landscape. As an isostatic response, the region subsided, accumulating cratonic

39

and Andean sediments (Hoorn and Wesselingh, 2010c).

40

The representative rock unit of this period corresponds to Solimões Formation in the

41

Solimões Basin. Its paleoenvironmental evolution involved three stages: an early Miocene

42

(23–16 Ma) lake system with fluvial and marginal marine influence; a middle Miocene

43

(16–10.5 Ma) system of extensive lakes, with marine influence; and a late Miocene (10.5–

44

5.3 Ma) complex system of rivers, deltas, and estuaries. During the Pliocene, the current

45

river drainage pattern was definitively set in the east, forested areas expanded, and the

46

Panama isthmus closed (Hoorn, 1993, 1994a, b, c; Hoorn et al., 1995; Wesselingh et al.,

47

2006; Hoorn et al., 2010a).

48

Several studies have used different indicators, such as sedimentology (Räsänen et al.,

49

1995; Latrubesse et al., 1997, 2007, 2010), ostracods (Linhares et al., 2011, 2017),

50

mollusks (Nuttall, 1990; Wesselingh et al., 2006), vertebrates (Cozzuol, 2006; Latrubesse

3 51

et al., 2010), and isotopes (Vonhof et al., 2003), to increase the knowledge on

52

paleoenvironmental history of the Solimões Basin over the last 23 My.

53

Among the paleontological studies, the palynology has been the most used tool to

54

understand the paleoenvironmental history of the Amazon. Sporomorphs (spores and

55

pollen grains) are especially important, as they indicate the diversity and richness of past

56

flora, and contribute to the paleoecological and paleoenvironmental inferences and

57

interpretations. Moreover, palynological studies reveal the biostratigraphic framework of

58

the region (Lorente, 1986; Hoorn, 1993, 1994c; Silva-Caminha et al., 2010, Hoorn et al.,

59

2010a, Silveira and Souza, 2015, 2016; Leite et al., 2016).

60

Due to the complexity of the depositional paleoenvironments of the Solimões

61

Formation, we use, for the first time, palynofacies analysis to interpret paleoenvironment.

62

Palynofacies analysis involves detailed investigation of the sedimentary organic matter

63

contained in the rocks or sediments. Changes in the depositional environments are

64

reflected in the distribution patterns of sedimentary organic matter. Furthermore, this

65

analysis is a useful to reconstruct complex paleoenvironments because it provides

66

information on the degree of continental influence (woody fragments, pollen grains) and

67

aquatic freshwater and marine influence (algae, dinocysts, microforaminifera test linings).

68

In the present study, quantitative analysis of the sedimentary organic matter supports

69

a discussion on the dynamics of sedimentation in the Amazon region during the Miocene.

70

An attempt has been made to integrate these investigations into a paleogeographical model

71

of the Miocene age in the Amazon region.

72 73 74 75

2. Geological setting The Solimões Basin is located in the western Amazon, between 2°–8°S and 62°– 72°W and is limited on the north by the Guiana Shield, on the south by the Brazilian

4 76

Shield, on the west by the Iquitos Arch, and on the east by the Purus Arch (Figure 1B)

77

(Wanderley Filho et al., 2007). It corresponds to a Paleozoic intracratonic depression,

78

which extends over an area of 1,180,000 km2 (Caputo, 2014), and is subdivided into Juruá

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Sub-basin to the east and Jandiatuba Sub-basin to the west by the Carauari Arch

80

(Wanderley Filho et al., 2007).

81

According to Eiras et al. (1994), the Solimões Basin contains two first-order

82

sedimentary sequences: Paleozoic and Meso-Cenozoic. The Meso-Cenozoic sequence is

83

represented by the Javari Group. The Cenozoic sequence is composed of the Solimões

84

(Neogene) and Içá (Pleistocene) formations (Eiras et al., 1994; Rossetti et al., 2005;

85

Wanderley Filho et al., 2007). The Içá Formation was designated by Maia et al. (1977) as a

86

discordant section, preserved on top of the Solimões Formation. It comprises friable

87

reddish-brown conglomerate to fine-grained sandstones or gray-variegated shales, and

88

possibly represents Pleistocene fluvial terraces.

89

The Solimões Formation, which forms the focus of this study, is recognized in Brazil

90

(Acre and Solimões basins), Peru (Marañon, Ucayali, Madre de Dios and Putumayo

91

basins), Colombia (Caqueta and Putumayo basins), and Ecuador (Napo Basin) (Caputo et

92

al., 1971; Maia et al., 1977; Eakin et al., 2014; Caputo, 2014). It comprises mudstones,

93

silty and sandy mudstones, clayey siltstones, and fine to medium-grained sandstones,

94

usually intercalated with lignite (rich in plant remains), carbonaceous clays, and limestones

95

(Maia et al., 1977; Eiras et al., 1994, Caputo 2014).

96

The age of the Solimões Formation was determined based on its abundant fossils that

97

includes fauna and flora, represented by the notable occurrence of sporomorphs (spores,

98

pollen grains), plant fragments (cuticles, leaves, woods), vertebrates, mollusks, and

99

ostracods. Based on palynological studies, Cruz (1984) determined that the Solimões

100

Formation belonged to the Neogene (Miocene–Pliocene: 23 to 2.6 Myr) and assigned three

5 101

palynological zones to the Brazilian territory: Miocene, Miocene-Pliocene and Pliocene.

102

Hoorn (1993, 1994b) recognized five palynozones in Solimões Formation:

103

Verrutricolporites-Retitricolporites (Early Miocene), Psiladiporites-Crototricolpites (Late

104

to early Middle Miocene), Crassoretitriletes (Middle Miocene), and Grimsdalea (Middle

105

Miocene to early Late Miocene). Other palynological studies refined the biostratigraphy of

106

the region by increasing the number of biozones (Kachniasz and Silva-Caminha, 2016;

107

Silveira and Souza, 2017; Leandro et al., 2018).

108

The paleoenvironmental interpretation of Solimões Formation is the focus of several

109

studies, and as yet, there is no consensus on the depositional environment(s). Several

110

hypotheses suggest different environments, which may or may not be co-existent during

111

the Neogene. Sedimentological and palynological studies indicated a fluvio-lacustrine

112

system, with meandering and anastomosed rivers, associated with flood plains, abandoned

113

meanders, and marshes (RADAM, 1977; Maia et al., 1977; Latrubesse et al., 2010; Silva-

114

Caminha et al., 2010; Gross et al., 2011; Nogueira et al., 2013; Leite et al.,2016).

115

Palynological studies have recorded marine dinoflagellate cysts, microforaminifera

116

test linings, mangrove pollen grains, and marshy vegetation spores, indicating marine

117

incursions during the Miocene times. Based on these records, the depositional environment

118

has been interpreted as a low salinity estuarine system, with varying marine coastal

119

conditions and high nutrient intake (e.g. Hoorn, 1993, 1994a, b, c, 2006; Hoorn et al.,

120

1995, 2010a, b; Boonstra et al., 2015; D'Apolito, 2016). Based on the occurrence of

121

ostracods and microforaminifera test linings, Linhares et al. (2011, 2017) suggested that

122

the marine transgressions during the Middle Miocene to the Late Miocene (16–11.3 Myr)

123

represented oligo-mesohaline environments, such as estuaries, mangroves, and brackish

124

marshes.

125

6 126 127

3. Studied sections In this paper, we study successions in two wells (1-AS-37-AM and 1AS-46-AM)

128

assigned to the Solimões Formation. The sections were selected because of their low and

129

deep depositional setting within the Solimões Basin. They are separated by a distance of

130

~130 km from each other (Figure 1C). The wells are located on an S–N axis, extending

131

from the Remanso locality (1-AS-37-AM, 03°30′S and 68°51′W) to the Esperança locality

132

(1-AS-46-AM, 02°23′ S/68°28′ W), both in Amazonas State. Well 1-AS-37-AM (Figure 2)

133

reaches a depth of 237.75 m and it is composed primarily of massive mudstones, shales,

134

and fine-grained sandstones, with lignite layers. Maia et al. (1977) assigned the Neogene

135

age to the section. Well 1-AS-46-AM is 200.9 m deep (Figure 3) with a similar lithological

136

composition to that of the well 1-AS-37-AM. In this study, the ages assigned to the

137

sections were according to Jaramillo et al. (2011). Three biozones were recognized: T14-

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Grimsdalea magnaclavata and T15-Crassoretitriletesvanraadshooveni, whose age varies

139

from ?16.1–12.7 My (Middle Miocene) and biozone T16-Fenestritesspinosus, from 12.7–

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?7.1 My (Late Middle-Late Miocene).

141 142

4. Methods

143 144 145

4.1. Sampling and preparation The sections were examined for lithological changes and any evidence of

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stratigraphic discontinuities. A total of 170 core samples (80 samples from 1-AS-37-AM

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and 90 samples from 1-AS-46-AM) were selected. All the samples were processed for

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palynofacies investigation by non-oxidative technique proposed by Tyson (1995) and

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Mendonça Filho et al. (2010) in the Laboratório de Paleoecologia Vegetal of Museu

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Nacional, Universidade Federal do Rio de Janeiro. It includes destruction of all mineral

7 151

constituents using hydrochloric acid (HCl) (32%) and cold hydrofluoric acid (HF) (40%).

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The remaining organic matter was separated using the panning method (Oliveira et al.,

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2004) prior to slide mounting. The slides are stored at Laboratório de Paleoecologia

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Vegetal of Museu Nacional, Universidade Federal do Rio de Janeiro (Rio de Janeiro,

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Brazil).

156 157 158

4.2. Palynofacies analysis The slides were analyzed using transmitted light and fluorescence microscopy. At

159

least 200 particles were counted and classified into three main kerogen categories:

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amorphous, phytoclasts, and palynomorphs. The classification used herein is according to

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Mendonça Filho et al. (2011). However, for a detailed paleoenvironmental interpretation,

162

an extensive description of sedimentary organic matter was used (e.g., Boulter and

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Riddick, 1986; Steffen and Gorin, 1993a, 1993b; Tyson, 1995; Batten, 1996; Oboh-

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Ikuenobe et al., 2005; Carvalho et al., 2006, 2013; Mendonça Filho et al., 2010).

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For detailed environmental analyses, several kerogen distribution trends, especially

166

of the three main groups (amorphous, phytoclasts, and palynomorphs), and parameters

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were used (cf., Tyson, 1993, 1995; Tyson and Follows, 2000; Carvalho et al., 2006, 2013).

168 169 170

4.2.1. Significance of amorphous organic matter (AOM) A large quantity of AOM results from a combination of high preservation rate and

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low-energy environment (Carvalho et al., 2006). The Amorphous Group is mainly

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composed of the AOM stricto sensu derived from phytoplankton and bacteria, and the

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pseudoamorphous matter derived from macrophyte tissues (Mendonça Filho et al., 2011).

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The preservation of this material is directly related to dysoxic conditions (e.g. distal

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suboxic-anoxic and carbonate shelf and restricted marine or lagoon). The terrestrially

8 176

derived AOM, herein named as pseudoamorphous organic matter (pseudoAOM), is the

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result of microbiologic reworking (by heterotrophic bacteria) in reducing conditions

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(Mendonça Filho et al, 2011).

179 180 181

4.2.2. Significance of phytoclasts The Phytoclast Group is basically composed of two main categories: non-opaques

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(non-biostructured, biostructured, cuticles) and opaques. Phytoclasts are mostly transported

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the same way as silt or sand, and are thus preferentially deposited in sediments, e.g.:

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nearshore, higher energy, or turbidites (Mendonça Filho et al., 2011). Therefore, the main

185

controlling factor is the short transport of the particles.

186 187 188

4.2.3. Significance of palynomorphs The Palynomorph Group is, in general, the least abundant of the three main groups;

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therefore, its occurrence is controlled by AOM and phytoclast dilution (Tyson, 1993;

190

Carvalho et al., 2006; Mendonça Filho et al., 2011). The group is subdivided into three

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main subgroups: sporomorphs, microplankton (freshwater and marine), and zoomorphs

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(e.g., marine). Paleoenvironmental inferences, based on this group, depend on the origin of

193

the palynomorphs. Sporomorph dominance shows that the paleoenvironment could be

194

oxidizing and moderately proximal to a fluvio-deltaic source. The relative abundance of

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microplankton is inversely related to that of the sporomorphs (Tyson, 1993). Depending on

196

the type of microplankton, the ratio of sporomorphs to phytoplankton reflects the

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proximal–distal trend (Carvalho et al., 2006).

198 199

4.2.4. Ratio of opaque to non-opaque phytoclasts (Op:NOp)

9 200

According to Tyson (1993), opaque phytoclast particles are primarily derived from

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the oxidation of translucent (non-opaque) material that has been transported over a

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prolonged period of time. In contrast, non-opaque particles are deposited in nearshore

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environments without a prolonged transport. Therefore, the ratio of these two categories

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could reflect the proximal–distal trend (Steffen and Gorin, 1993a; Tyson, 1993; Carvalho,

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2006, 2013).

206 207 208

4.2.5. Data representation In palynofacies, data representation facilitates the interpretation of

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paleoenvironments. One of the effective ways is to plot the percentage data using ternary

210

diagrams (Tyson, 1995). In this study, we used three types of ternary diagrams: 1) APP

211

(AOM-Phytoclast-Palynomorph) (Tyson, 1995, Mendonça Filho et al., 2011), in which the

212

most proximal component is plotted at the top (Phytoclasts) and the reducing condition at

213

the left hand corner (AOM) (Mendonça Filho et al, 2011); 2) the diagram of continental

214

palynomorph assemblage SFP (Spore-Freshwater-Pollen), in which the aquatic

215

autochthonous is plotted at the top (Freshwater) and the most proximal component at the

216

left hand corner (Spores); and 3) PAOM/AOM-P-B (PseudoAOM/AOM-Pediastrum-

217

Botryococcus) indicates the salinity/brackishness and oligotrophic conditions

218

(Botryococcus) at the left corner, and freshwater and eutrophic conditions (Pediastrum) at

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the right corner.

220 221 222

4.3. Statistical analysis Statistical analyses were employed based on the count of the sedimentary organic

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particles. Cluster analysis was employed based on the abundance and composition of

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sedimentary organic matter using the Ward method with Pearson-r similarity measure

10 225

(program STATISTICA), to establish grouping and to recognize relationships between

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kerogens. The cluster analysis results in discrete grouping based on abundances of the

227

objects. The results are displayed in dendrograms. To establish the grouping of samples

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(intervals), an agglomerative, hierarchical clustering and stratigraphically constrained

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cluster analysis (CONISS) was employed (Grimm, 1987).

230

Principal Component Analysis (PCA) was performed using PAST software (Hammer

231

et al., 2001). This technique was chosen to highlight and explain the variation of

232

sedimentary organic matter in each section.

233 234

5. Results

235

Samples from the two studied sections yielded abundant and diversified sedimentary

236

organic matter. Three main groups and their subgroups were identified: Amorphous Group

237

(AOM, pseudoAOM and resin), Phytoclast Group (opaques, biostructured and non-

238

biostructured non-opaques, and cuticles), and Palynomorph Group (fern spores, pollen

239

grains, Botryococcus and Pediastrum algae, dinoflagellate cysts and microforaminifera test

240

linings) (Figure 4).

241

In both sections, the Phytoclast Group showed the highest abundance (Table 1),

242

highlighting the non-opaque-non-biostructured phytoclasts (NOp-NBio) (Appendices 1

243

and 2). NOp-NBio range of well 1-AS-37-AM was 9.3% to 94.3% (Appendix 1) and that

244

of well 1-AS-46-AM was 0% to 95.1% (Appendix 2).

245

The Palynomorph Group showed the second highest abundance (Table 1). The pollen

246

grains showed the highest abundance. They constitute up to 94.7% of the total kerogens in

247

section 1-AS-46-AM (135.19 m). Aquatic palynomorphs (marine and freshwater) are also

248

represented, particularly by freshwater/brackish algae Botryococcus, marine dinoflagellate

249

cysts (dinocysts), and microforaminifera test linings. The last two confirm the marine

11 250

incursion in the region. Massulae of Salviniaceae was identified in few samples of both

251

wells (Appendices 1 and 2). These are classified as spores; however, due to Salviniaceae

252

aquatic habitat, these can be interpreted as non-terrestrial palynomorphs, which helps in

253

understanding the deposition site.

254

The Amorphous Group showed the least abundance (Table 1). The analyzed AOM

255

presented varied sizes and diffused contours, without inclusion of palynomorphs or pyrite.

256

AOM shows medium to intense fluorescence. Their records were sporadic in well1-AS-37-

257

AM. However, in well 1-AS-46-AM, it showed the second highest percentage of total

258

sedimentary organic matter (88%) at a depth of 158 m (Appendix 2).

259 260 261

5.1. Palynofacies associations Five palynofacies associations were recognized in the two studied sections, viz.,

262

Opaque; Non-opaque; Algae, Miospores and Structureless/Marine. These were

263

distinguished using cluster analysis (Figure 5). The two main groups,

264

continental/terrigenous sedimentary organic matter and aquatic (freshwater/brackish and

265

marine) sedimentary organic matter (Table 2), are related to the origin of the material.

266

All the associations occur in the two wells studied, but in different proportions and

267

stratigraphic distributions. The most significant palynofacies associations were Non-

268

opaque and Opaque in 1-AS-37-AM; and Algae, Miospores and Structureless/Marine in 1-

269

AS-46-AM (Table 3).

270 271 272

5.1.1. Opaque palynofacies This palynofacies association contains only opaque particles (Figure 4e–f), which are

273

lath and equidimensional, with varied sizes. The opaques are derived mainly from the

274

oxidation or charcoalification of translucent woody material. Their general average (both

12 275

sections) is 2.8% and they are more abundant in well 1-AS-37-AM than in well 1-AS-46-

276

AM (Table 3).

277

5.1.2. Non-opaque palynofacies

278

Similar to the previous association (Opaques), this palynofacies association is

279

composed of only one type of particle, non-opaques (Figure 4a). This type of particle

280

conspicuously showed the highest abundance in both sections. The Non-Opaque

281

palynofacies is typically from wood tissues material, which encompasses non-biostructured

282

and biostructured (visible internal structures: striped, pitted) matter, and cuticles. Their

283

general average (both sections) is 77.4 % and they are more abundant in well 1-AS-37-AM

284

than in well 1-AS-46-AM (Table 3).

285 286 287

5.1.3 Algae palynofacies In Algae palynofacies, Botryococcus and Pediastrum are the two main components

288

of the total kerogens. The stratigraphic distribution of the Algae palynofacies exceeds 20%

289

and 45% in wells 1-AS-37-AM and 1-AS-46-AM, respectively. Their general average

290

(both sections) is 5.9% and they are more abundant in well 1-AS-46-AM than in well 1-

291

AS-37-AM (Table 3).

292 293 294

5.1.4 Miospores palynofacies The Miospores palynofacies contains a high proportion (average 7.8%) of terrestrial

295

plant pollen grains, fern spores, resins, and aquatic Salviniaceae massulae. The proportions

296

of Miospores palynofacies are up to 40% and 100% of the total kerogens in well 1-AS-37-

297

AM and well 1-AS-46-AM, respectively. The pollen grains and fern spores are

298

conspicuously the most abundant (~80%). Resins and Salviniaceae massulae show an

13 299

average of 10% and ~1%, respectively. The Miospores palynofacies are slightly more

300

abundant in well 1-AS-46-AM than in well 1-AS-37-AM (Table 3).

301 302 303

5.1.5 Structureless/marine palynofacies This palynofacies association includes amorphous products: AOM, PseudoAOM,

304

and marine elements (dinocysts and microforaminifera test linings). The

305

Structureless/Marine palynofacies constitute, on an average, 6.1% of the total kerogens.

306

This palynofacies is present in ~80% of the samples from both the sections, and is

307

significantly high at the top of 1-AS-37-AM and at the base of 1-AS-46-AM. Although

308

restricted in some intervals, the presence of dinocysts and microforaminifera test linings

309

confirms the marine influence on both sections. This palynofacies is more abundant in well

310

1-AS-46-AM than in well 1-AS-37-AM (Table 3).

311 312 313

5.2. Intervals based on palynofacies associations The Miocene succession of the Solimões Basin is characterized by a continuous

314

terrigenous input, mainly indicated by high abundance of non-opaque particles. Thus, it is

315

reasonable to assume that the phytoclast richness indicates environments with high

316

oxygenation, which was especially observed in 1-AS-37-AM. This was confirmed by the

317

ternary APP, which shows most of the samples plotted near the top (Phytoclasts) (Figure

318

6A). However, the presence of Algae palynofacies and Structureless/Marine palynofacies,

319

which are indicative of an aquatic origin, are present especially in 1-AS-46-AM. In the

320

ternary diagram, (Figure 6B) the samples are not very concentrated at the top, reflecting a

321

low oxygenation condition.

14 322

The distribution patterns of palynofacies associations were evaluated by the

323

agglomerative, hierarchical clustering and stratigraphically constrained cluster analysis

324

(CONISS) (Grimm, 1987), which revealed depositional intervals for each well.

325 326 327

5.2.1. Intervals of 1-AS-37-AM The organic sedimentation in 1-AS-37-AM is characterized by high input of

328

phytoclasts, especially of non-opaque particles. The cluster analysis based on palynofacies

329

association revealed five intervals (A37–E37) for 1-AS-37-AM.

330

Interval A37 (234.17–196.35 m)–This interval is characterized by high contents of

331

Non-opaque palynofacies (Figure 6), which was confirmed in the ternary diagram (Figure

332

6a). However, this palynofacies decreases significantly in the upward samples. The

333

Miospores palynofacies reached 40%, followed by Algae palynofacies with 10%. The

334

presence of dinocysts (e.g. Spiniferites) confirms marine incursion in the area. In the

335

middle part of the interval, the Miospores and Algae palynofacies increase remarkably,

336

reflecting high abundance of sporomorphs and Pediastrum, respectively (Figure 7). The

337

increase in Opaque palynofacies was accompanied by a decrease in Miospores and Algae

338

(Figure 7).

339

Interval B37 (192.13–162.31 m)–The increase in Opaque palynofacies from previous

340

intervals reached its apex (~40%) in the lower part of interval B37, i.e., it decreased

341

upwards from 191.56 m (Figure 7). The Algae palynofacies, constituted only by

342

Botryococcus and Miospores palynofacies together reached 20% of the total sedimentary

343

organic matter (Appendix 1). This interval is also characterized by an increase in Non-

344

opaque palynofacies until the top of the interval. The others palynofacies showed a slight

345

increase in the upward samples, except the Opaque palynofacies (Figure 7).

15 346

Interval C37 (162.31–125.53 m)–The increase Opaque palynofacies continued,

347

accompanied by an increase in Algae and Miospores palynofacies. A remarkable decrease

348

in Non-opaque palynofacies is observed in this zone at 135.10 m (Figure 7). However, the

349

Non-opaque and Algae palynofacies reassumed an increasing trend accompanied by the

350

decrease of the other palynofacies.

351

Interval D37 (124.26–86.22 m)–Non-opaque palynofacies declined and Opaque

352

palynofacies showed small peaks at the beginning. The Structureless/Marine palynofacies

353

increased remarkably showing a maximum at the very top of the interval. In this interval,

354

all palynofacies showed a wide oscillation, except Opaque palynofacies, which remained

355

low (Figure 7).

356

Interval E37 (85.28–31.83 m)–At the beginning of the interval the previous

357

conditions continued, i.e., the Non-opaque palynofacies showed a trend that was inverse to

358

that of other palynofacies (Figure 7). The Non-opaque palynofacies returned with higher

359

values around the middle of the interval, accompanied by a decreasing trend of the other

360

palynofacies, especially of Structureless/Marine palynofacies.

361 362

5.2.2. Intervals of 1-AS-46-AM

363 364

Characteristics of 1-AS-46-AM were similar to those of 1-AS-37-AM, with

365

continuous input of phytoclasts, represented by Non-opaque palynofacies (Figure 8).

366

However, the palynofacies distributions showed wider oscillation than in 1-AS-37-AM,

367

which was caused by the conspicuous peaks of Algae, Miospores and Structureless/Marine

368

palynofacies (Figure 8). This was confirmed by the ternary diagram in which the plot

369

shifted to right hand corner (Figure 6b).

16 370

Interval A46 (200.70–189.18 m)–The interval is characterized by an increase in

371

Algae and Miospores palynofacies accompanied by a decrease in Non-opaque

372

palynofacies. Pediastrum showed a spectacular increase reaching ~40% of total

373

sedimentary organic matter. All the others palynofacies showed unexpressive values

374

(Figure 8).

375

Interval B46 (188.65–161.01 m)–The increasing trend of Algae palynofacies

376

continued in this interval accompanied by a decrease in Miospores and Non-opaque

377

palynofacies that recorded a unique disappearance in the two studied sections (Figure 8).

378

An increase in Structureless/Marine palynofacies was observed, showing a trend that was

379

inverse to that of others palynofacies, particularly Non-opaque that remained low

380

throughout the interval. Notably amongst the Structureless/Marine palynofacies, a high

381

content of AOM and marine elements (Figure 8), dinocysts (Spiniferites and Lejeunecysta)

382

and microforaminifera test linings, was observed.

383

Interval C46 (160.97–138.38 m)–The interval started with a conspicuous decrease of

384

Non-opaque palynofacies. However, this increased remarkably around (153.44 m) the

385

middle of the interval. The Non-opaque and Structureless/Marine palynofacies showed

386

inverse trends throughout the interval. After the decrease of Structureless/Marine

387

palynofacies at the top of the previous interval, they showed an increasing trend in this

388

interval. The Algae palynofacies continued to record an increasing trend with respect to

389

Botryococcus (Figure 8).

390

Interval D46 (137.08–134.26 m)–This interval is characterized by remarkable

391

increase of Miospores palynofacies, due to a spectacular increase of Salviniaceae massulae

392

accompanied by small peaks of Algae palynofacies (Figure 8). The increase of

393

Salviniaceae massulae seems to have forced the drastic decrease of Non-opaque

394

palynofacies (0.7% at 134.26 m).

17 395

Interval E46 (130.53–85.61 m)–The interval starts with maintaining the conditions

396

similar to those of previous interval, i.e. increasing trend of Structureless/Marine

397

palynofacies, particularly those associated with lignite levels. However, this was followed

398

by low levels of palynofacies in the interval. The Algae palynofacies showed the same

399

pattern, i.e., it began with higher values and then decrease upwards. The Opaque

400

palynofacies were abundant in this interval showing a maximum value at 119.52 m. In

401

general, opaque and non-opaque particles showed opposite trends. Non-opaque, Algae and

402

Miospores palynofacies showed remarkable peaks around the top of the interval. One of

403

the highlights of this interval is the conspicuous peaks of cuticles (Non-opaque

404

palynofacies), which reached 16% of the total sedimentary organic matter in this interval

405

(Appendix 2).

406

Interval F46 (85.17–41.73 m)–This interval began with a drastic drop of Non-

407

Opaque palynofacies abundance (at the 85.17 m), compared to the detriment of the notable

408

peak of Pediastrum and Botryococcus (Algae palynofacies), whichconstituted~90% of the

409

total sedimentary organic matter. After that, all the palynofacies oscillated, except Non-

410

opaque palynofacies, which remained high (Figure 8).

411 412 413

6. Paleoenvironmental interpretation The paleoenvironment was interpreted based on not only the stratigraphic

414

distribution of palynofacies association, but also the trends in environmentally significant

415

elements, i.e., autochthonous (Botryococcus, Pediastrum and Salviniaceae) and marine

416

elements (dinocysts and microforaminifera test linings), and Op:NOp ratio.

417 418

In general, the dominance of Phytoclast group, especially by non-opaques in Solimões Formation, indicates a complex depositional system (e.g., fluvial, estuarine,

18 419

lakes, marine), with high input of terrigenous material. This is more evident in 1-AS-37-

420

AM than in 1-AS-46-AM (Figure 6).

421 422

6.1. Fluvial-dominated environment based on palynofacies associations

423 424

A fluvio-dominated environment is suggested in this study by the very low or no

425

recovery of sedimentary organic matter. When present, the sedimentary organic matter is

426

characterized by high contents of phytoclasts and AOM, poor content of algal elements,

427

and no marine elements. In fluvial environments, the phytoclasts can reach high values in

428

non-oxidized floodplain (Oboh-Ikuenobe et al., 2005). In this study, the fluvial-dominated

429

environment was recognized in both sections, which showed high abundance of Non-

430

opaque and Opaque palynofacies that were eventually associated with Algae palynofacies.

431

Therefore, it is interpreted as a non-oxidized floodplain. Despite the freshwater influx, low

432

energy deposition predominated, which was corroborated by the presence of massive

433

mudstone layers (see figures 2–3). Gastaldo and Huc (1992) associated this lithology with

434

marshy areas, rich in plant fragments (e.g., non-opaque biostructured phytoclasts).

435

Conversely, the absence of sedimentary organic matter is associated with the occurrence of

436

sandstones layers (e.g. intervals E37, E46).

437 438 439

6.2. Lake-dominated environment based on palynofacies associations A lake-dominated environment is characterized by the predominance of Algae

440

palynofacies. The predominance alternated between Botryococcus and Pediastrum,

441

indicating oligotrophic and eutrophic conditions, respectively. The lacustrine-dominated

442

environment was also confirmed by the decrease in abundance of non-opaque particles.

443

Despite the lower concentration of non-opaques, a moderate abundance of cuticles and

19 444

pollen grains can be found in the sediments. The remarkable presence of cuticle may be

445

related to high content of pseudoAOM, which reflects a process of degradation that may be

446

related to oxidizing conditions during transport (Carvalho et al., 2013).

447

The oligotrophic lake-dominated environment was recognized in parts of the

448

intervals, A37, B37, C37, and D37 (1-AS-37-AM) and those of intervals, B46 and F46 (1-

449

AS-46-AM) (figures 9–10). The oligotrophic condition was assigned based on high

450

abundance of Botryococcus. The genus occurs predominantly in clear epilimnia of deeply

451

mixed meso-eutrophic lakes (e.g. Reynolds et al., 2002, Rull et al., 2008; Padisák et al.,

452

2009). Peaks of Pediastrum were also recorded (figures 9–10); however, these usually

453

occur in a trend inverse to that of Botryococcus. In fact, despite showing distinct behaviors,

454

the genera were recorded in co-occurrence in several studies (e.g. Tyson, 1995; Rull et al.,

455

2008; Chagas et al., 2009; Mendonça Filho et al., 2011). Their proportions were used to

456

distinguish the oligotrophic (Botryococcus) and eutrophic (Pediastrum) environments.

457

The eutrophic lake-dominated environment was recognized in parts of intervals B37

458

and E37 (1-AS-37-AM) and that of interval A46 (1-AS-46-AM) (figures 9–10). The Algae

459

palynofacies, represented almost exclusively by Pediastrum, reach a maximum of 42% of

460

the total sedimentary organic matter (A46) (Figure 10). The eutrophic condition was

461

assigned based on high abundance of Pediastrum. As previously mentioned, species of

462

Pediastrum occur in shallow, mixed, and highly enriched systems (including many low-

463

gradient rivers) (Reynolds et al. 2002, Rull et al., 2008; Padisák et al., 2009).

464

Occurrence of Pediastrum is also associated with Salviniaceae, showing similar

465

trends at times (e.g., intervals B37, E37) (Figure 9), with the latter suggesting reducing

466

conditions.

467 468

6.3. Estuarine-dominated environment based on palynofacies associations

20 469

The palynofacies association present during the sedimentation of the sections is

470

controlled by marine incursions as well as the local environment. The incursions were

471

caused by subsidence of orogenesis of Andes in Amazonian basins (Shephard et al., 2010,

472

Jaramillo et al., 2017). The interpretation of an estuarine environment for the Solimões

473

Formation was based on sedimentological and paleontological aspects (e.g. Hoorn et al.,

474

2010a; Jaramillo et al., 2017).

475

Estuarine-dominated environment was recognized in the both sections based on low

476

to moderate input of phytoclasts represented by Non-opaque palynofacies mixture with

477

marine elements (dinocysts and microforaminifera test linings) and amorphous products.

478

These conditions reflect estuarine mesohaline conditions (5–18 psu) (McLusky, 1989;

479

Dalrymple et al., 1992; Day-Jr et al., 2013).

480

The presence of Structureless/Marine palynofacies in clayey sand layers, suggests

481

large distance from river sources or lower river discharge. The presence of AOM and

482

pseudoAOM is associated with dinocysts of Spiniferites (Interval A37), which reinforces

483

the evidence suggesting marine influence. The genus is typically cosmopolitan and is

484

distributed in a wide range of temperatures and environments (e.g. Wall et al., 1977;

485

Harland, 1983; Vink et al., 2000; Zonneveld et al., 2013). However, in general, they occur

486

in normal marine conditions. Co-occurrence of dinocysts (e.g., Spiniferites) and

487

Botryococcus was also recorded. It reflects that the environment was at least brackish,

488

when Botryococcus can be recorded in these conditions (Batten and Grenfell, 1996).

489 490 491

6.4. Marine-dominated environment based on palynofacies associations The marine-dominated environment was recognized only in 1-AS-46-AM. A distinct

492

interval (B46) of high abundance of dinocysts and amorphous material associated with

493

lower values of terrigenous material (non-opaque phytoclasts and miospores) reflects the

21 494

most prominent marine incursion in the sections studied (Figure 10). The marine elements

495

reached ~5% of total organic matter between 175.28 and 176.33 m (Figure 10). The

496

dinocysts were represented by Spiniferites and Lejeunecysta. Spiniferites distribution can

497

be seen in sediments in nearshore and open marine settings (Wall et al., 1977; Harland,

498

1983; Vink et al., 2000; Zonneveld et al., 2013); therefore, it has little paleoenvironmental

499

significance. However, the Spiniferites occurred in association with cosmopolitan genus

500

Lejeunecysta (Zonneveld et al., 2013), which, although occurring in varied environments,

501

are usually associated with a marine environment rich in nutrients (Kurita and Obuse,

502

2003). This condition is corroborated by the presence of microforaminifera test lining that

503

occurs preferentially in the same conditions.

504 505 506

6.5. Temporal distribution of the paleoenvironments Biostratigraphic data provides insights into the paleoenvironmental evolution of the

507

study area. Changes were indicated throughout the two studied sections, suggesting links to

508

broader changes in shoreline shifts and flooding, which impacted the depositional facies of

509

the Solimões Formation.

510

The correlation between 1-AS-37-AM and 1-AS-46-AM was evaluated using

511

Principal Components Analysis (PCA). Component-1 for both sections corresponds to the

512

dominant Non-opaque palynofacies, which explain 98% of the total variance in 1-AS-37-

513

AM and 89% of that in 1-AS-46-AM. Component-1 was herein named Fluvial-component.

514

The maxima of the non-opaques were inversely correlated with autochthonous and marine

515

elements, especially in 1-AS-46-AM (figures 8 and 9). Therefore, the Non-opaque

516

palynofacies, in this study is linked to fluvial-dominated environment.

517 518

The marine incursions were recognized once in the Middle Miocene (1-AS-37-AM) and twice in the late Middle-Late Miocene (1-AS-37-AM and 1-AS-46-AM) (figures 9–

22 519

10). This assumption is corroborated by the palynological investigations that suggested an

520

estuarine system, with low salinities, and varying marine coastal conditions and nutrients

521

supply (Hoorn, 1993; D’Apolito, 2016). In fact, the marine influence was more intense

522

during the interval of 12.7–?7.1 Ma, especially in the northwestern portion of the Solimões

523

Formation. In this interval, inner neritic conditions were established. The extension of

524

marine influence is still controversial, but is confirmed in other regions. In the Pebas and

525

Ipururo formations (Peru, correlatable to the Solimões Formation), the marine incursions

526

during the Burdigal-Tortonian, influenced the fluvio-lacustrine environment, generating

527

mixohaline and brackish conditions that are typically seen in oligo/mesohaline estuaries

528

and coastal plains (Nuttall, 1990; Vonhof et al., 2003; Boonstra et al., 2015; Antoine et al.,

529

2016). This was similar to the “Terciário Inferior Amazônico” (Pebas Formation,

530

Colombia) and Yecua Formation (Bolivia) (Hoorn, 1994b, 2006; Uba et al., 2005; Antoine

531

et al., 2016; Jaramillo et al., 2017). The marine influence recorded in the studied sections,

532

came from the sea-way through Caribbean and was recognized in Llanos Basin (Colombia)

533

(e.g., Nuttall, 1990; Hoorn, 1993, 1994b; Vonhof et al., 2003; Hovikoski et al., 2007, 2010;

534

Boonstra et al., 2015; D’Apolito, 2016; Jaramillo et al., 2017; Linhares et al., 2017).

535

1-AS-37-AM and 1-AS-46-AM have the same sequences, which correspond to the

536

Middle Miocene, but their paleoenvironments are slightly different, with 1-AS-37-AM

537

showing less waterlogged conditions than 1-AS-46-AM. In fact, the ternary diagram in

538

Figure 11 shows that the Middle Miocene samples of 1-AS-46-AM are more concentrated

539

in the freshwater corner than those of 1-AS-37-AM. Moreover, flooding was confirmed in

540

1-AS-46-AM by a more eutrophic condition as indicated by higher number of samples

541

plotted in the “Pediastrum corner” (Figure 11).

542 543

The palynofacies associations recorded in the Middle Miocene are related to the changes in sedimentary organic matter, reflecting a fluvio-lacustrine system (Figure 12A)

23 544

with marine incursion (Figure 12B). This incursion was recorded only in 1-AS-37-AM,

545

which probably corresponds to the second transgression recorded by Jaramillo et al. (2017)

546

ca. 13.7 Ma.

547

This complex scenario with estuaries, marshes, marine coasts, and large lakes, during

548

the end of Middle Miocene in the Solimões Formation, was extended mainly on the

549

western Amazon (Figure 12B-C). The origin is linked to the greater subsidence in isostatic

550

response to the upwelling of the Andes, and lower supply of cratonic sediments and high

551

precipitation (Hoorn et al., 2010a, b; Shephard et al., 2010, Jaramillo et al., 2017).

552

In the late Middle Miocene-Late Miocene, the marine incursions were more

553

effective, especially on 1-AS-46-AM area. In fact, the waterlogging intensified as

554

demonstrated in the ternary diagram for both sections (Figure 11). The marine influence is

555

confirmed by presence of marine elements (Spiniferites, Lejeunecysta and

556

microforaminifera test linings), together with high concentration of plotted samples in the

557

PAOM/AOM, and Botryococcus corners (Figure 11).

558

After orogenic quiescence in the Late Miocene (~9.0 Ma) (Hoorn et al., 2017), no

559

marine incursions were recorded. The current physiographic configuration of the region

560

was established, forming a new drainage pattern for the Amazon River; the sedimentary

561

filling of the Solimões Basin came predominantly from the Andean origin (Hoorn et al.,

562

2010c; Hoorn et al., 2017). The younger intervals of the studied sections (E37 and F46) do

563

not record any marine elements, reflecting a fluvio-lacustrine environment indicated by the

564

terrigenous input in aquatic bodies (e.g. lakes, ponds), and confirmed by the presence of

565

algae (Figure 11).

566 567

7. Conclusions

24 568

The sedimentary organic matter of the Miocene succession of the Solimões Basin is

569

marked by high content of phytoclasts, especially non-opaque material. The succession is

570

strongly controlled by marine incursions that changed the paleoenvironmental

571

configuration in the western Amazon region.

572

•

main groups and their subgroups, dominated by non-opaque phytoclast particles.

573 574

The sedimentary organic matter recorded in the studied wells contains the three

•

Results from cluster analysis indicate five palynofacies associations with distinct

575

origin and depositional preferences, viz, the Opaque, Non-opaque, Algae,

576

Miospores, Structureless/Marine associations.

577

•

Middle-Late Miocene–Late Miocene.

578 579

•

582

The palynofacies associations indicate that the marine incursions in the MiddleLate Miocene–Late Miocene were more significative.

580 581

Three marine incursions were recorded, one in the Middle Miocene and two in the

•

The palynofacies associations indicate fluvial, lacustrine, estuarine, and shallow marine environments.

583 584 585 586

Acknowledgments

587

We express our thanks to the Companhia de Pesquisa de Recursos Minerais (CPRM)

588

Manaus/AM and Departamento Nacional de Produção Mineral (DNPM) for giving N.P. Sá

589

the opportunity to study the material. We thank Prof. Dr. Emílio Alberto Amaral Soares

590

from the Universidade Federal do Amazonas for help to select the material and the

591

sections. This study was supported by the Conselho Nacional de Desenvolvimento

25 592

Científico e Tecnológico (CNPq) scholarship to N.P. Sá, and grant no. 303390/2016-6 to

593

M. Carvalho. We also thank the anonymous reviewer for helpful suggestions.

594 595

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equatorial Atlantic surface sediments, distributions and their relation to environment.

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821

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822

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823

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824

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825

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826

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827

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828

dinoflagellate cyst distribution based on 2405 data points. Review of Palaeobotany

829

and Palynology 191, 1–197.

830 831

FIGURE CAPTIONS

832

Figure 1. Maps showing the location of the studied wells. A) Regional map (modified from

833

Linhares et al., 2017); B) Solimões Basin with isopach thickness lines (modified

834

from Hoorn et al., 2010a); C) Detailed map showing the studied wells (modified

835

from RADAM, 1977).

35 836 837 838 839

Figure 2. Lithological profile of the well 1-AS-37-AM. Legend: Mdst= mudstones; Wkst= wackestones; Pkst= packstones; Grst= grainstones. Figure 3. Lithological profile of the well 1-AS-46-AM. Legend: Mdst= mudstones; Wkst= wackestones; Pkst= packstones; Grst= grainstones

840

Figure 4. Palynofacies components. A) Phytoclast non-opaque/non-biostructured. B-C)

841

Cuticles. D) Phytoclast non-opaque-biostructured (stripped). E) Phytoclast opaque

842

equidimensional F) Phytoclast opaque-lath. G) Trilete spore. H) Bissacate pollen

843

grain. I) Dinoflagellate cyst (Lejeunecysta). J) Salviniaceae massulae. K)

844

Dinoflagellate cyst (Spiniferites). L) Botryococcus. M-N) Pseudoamorphous. O)

845

Pediastrum. P) Microforaminifera test lining. Q-R) Amorphous organic matter. Scale

846

bar 20 µm for all figures.

847

Figure 5. Ward dendrogram (r-mode) of 13 sedimentary organic matter from the studied

848

sections showing the five palynofacies associations. Legend: Op-la= opaque lath;

849

Op-eq= opaque equidimensional; Forams= microforaminifera test linings; AOM=

850

amorphous organic matter; PseudoAOM= pseudoamorphous.

851

Figure 6. Ternary diagrams (AOM-Phytoclast-Palynomorph) for wells 1-AS-37-AM and

852

Well1-AS-46-AM (plotted using the scheme modified from Tyson, 1989, 1995;

853

Mendonça Filho et al., 2011).Palynofacies fields: I- Highly proximal shelf or basin;

854

II- Marginal, dysoxic-anoxic basin; III- Heterolithic oxic shelf (proximal shelf); IVa-

855

shelf to basin transition with dysoxic-suboxic and IVb-suboxic-anoxic (IVb)

856

conditions; V- Mud-dominated oxic shelf; VI- Proximal suboxic-anoxic shelf; VII-

857

Distal dysoxic-anoxic “shelf”; VIII-Distal dysoxic-oxic shelf; IX- Distal suboxic-

858

anoxic shelf, carbonate shelf, restricted marine (proximal) or lagoon.

859 860

Figure 7. Stratigraphic distribution of palynofacies associations in the 1-AS-37-AM well (Figure 3).

36 861 862

Figure 8. Stratigraphic distribution of palynofacies associations in the 1-AS-46-AM well (Figure 4)

863

Figure 9. Stratigraphic distribution of fluvial component (from PCA analysis), parameters

864

in palynofacies associations and the inferred curve of water (freshwater and marine)

865

of the 1-AS-37-AM. The red dotted line represents 12.7 Ma.

866

Figure 10. Stratigraphic distribution of fluvial component (from PCA analysis), parameters

867

in palynofacies associations and the inferred curve of water (freshwater and marine)

868

of the 1-AS-46-AM. The red dotted line represents 12.7 Ma.

869

Figure

11.

Ternary

diagrams:

Pediastrum-PseudoAOM/AOM-Botryococcus

and

870

Freshwater-Spore-Pollen of Middle Miocene and Middle—Late Miocene for the two

871

studied sections.

872

Figure 12. Schematic reconstruction of the paleoenvironmental evolution. A) Middle

873

Miocene - Permanently waterlogged conditions B) Middle—Late Miocene – Marine

874

incursion on waterlogged area. C) Middle—Late Miocene - Fluvial system with

875

waterlogged area. Image by Manoel Magalhães.

876 877

TABLE CAPTIONS

878 879 880

Table 1. Mean percentages of sedimentary organic matter of1-AS-37-AM. Legend:

881

tAOM=total of the AOM; PMOA= PseudoAOM; tPhyto= total of Phytoclast; Op-

882

Eq= Opaque equidimensional; Op-la= opaque lath; Cut= Cuticle; NOpBio= Non-

883

opaque biostructured; NBio= Non-opaque non-biostructured; tPalyno= total of

884

Palynomorphs;

PG=

pollen

grain;

Spor=

spores;

Salv=Salviniaceae;

37 885

Bot=Botryococcus; Ped=Pediastrum; Dino= Dinocysts; mfl= microforaminifera test

886

linings.

887

Table 2. Origin and association interpretation for each palynofacies association.

888

Table 3. Mean percentage of palynofacies associations for each well. In bold the values

889

above of the general average.

1

2

Appendix 1- Percentage of the sedimentary organic matter of the 1-AS-37-AM. Sample

Depth (m)

PAOM

AOM

Res

Op-equi

Op-lath

Cut

Nop-Bio

Nop-Nbio

Poll

Spore

Salv

Botry

Pediast

Dino

Foram

373

31.83

0.9

1.4

0.0

0.5

0.9

3.3

64.7

22.8

2.3

1.4

0.0

1.4

0.5

0.0

0.0

374

31.91

2.9

0.0

0.0

0.0

0.0

3.9

44.1

44.1

2.5

1.0

0.0

1.0

0.5

0.0

0.0

375

32.13

6.5

0.0

0.9

12.4

10.6

5.5

27.6

31.8

2.3

2.3

0.0

0.0

0.0

0.0

0.0

376

35.08

0.5

0.0

0.0

0.0

0.0

1.9

86.0

9.3

0.5

0.9

0.0

0.9

0.0

0.0

0.0

378

35.32

0.5

0.0

0.0

2.3

1.8

5.0

48.4

29.0

5.9

5.0

0.0

2.3

0.0

0.0

0.0

379

36.08

1.0

0.0

0.0

0.0

0.0

5.8

56.5

15.9

9.7

6.8

2.4

0.5

1.4

0.0

0.0

380

37.43

0.4

0.0

0.0

0.0

0.0

3.4

74.2

22.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

382

38.42

0.5

0.0

0.0

0.0

0.0

1.4

48.6

44.4

2.3

0.9

0.0

0.0

1.9

0.0

0.0

384

49.13

0.0

0.0

0.0

0.0

0.0

2.2

63.9

28.6

1.8

2.2

0.9

0.4

0.0

0.0

0.0

385

49.20

0.0

0.0

0.0

0.0

0.0

4.8

16.3

63.9

1.8

4.0

8.8

0.4

0.0

0.0

0.0

386

49.28

0.0

0.0

0.0

0.0

0.0

2.9

54.3

34.1

0.0

5.8

0.0

1.9

1.0

0.0

0.0

388

50.13

0.0

0.0

0.0

0.0

0.0

1.1

38.7

49.8

1.1

1.5

0.0

0.4

7.3

0.0

0.0

390

51.16

0.4

0.0

0.0

0.0

0.0

4.2

64.6

18.3

1.3

1.3

0.0

1.3

8.8

0.0

0.0

392

53.46

2.0

0.0

0.0

0.0

0.0

2.0

23.1

59.0

0.8

10.0

0.0

1.2

2.0

0.0

0.0

394

53.81

10.6

0.0

0.0

0.0

0.0

3.3

24.4

44.7

0.8

2.0

0.0

8.1

6.1

0.0

0.0

396

54.12

2.5

0.0

0.0

0.0

0.0

6.9

49.3

37.4

3.0

1.0

0.0

0.0

0.0

0.0

0.0

398

54.80

3.7

0.0

0.0

0.0

0.0

2.8

40.5

42.3

4.7

4.7

0.0

0.0

1.4

0.0

0.0

404

56.28

15.5

0.0

1.4

0.0

0.0

1.4

58.7

12.7

2.3

2.3

0.0

0.0

5.6

0.0

0.0

405

76.82

3.5

0.0

0.0

0.4

0.0

3.9

32.9

39.0

3.5

16.2

0.0

0.4

0.0

0.0

0.0

406

77.78

11.7

0.0

0.0

1.0

2.0

1.0

37.6

38.5

2.0

5.9

0.0

0.5

0.0

0.0

0.0

407

78.32

3.9

0.0

0.0

2.5

1.0

0.0

34.5

52.2

3.0

2.0

0.0

0.5

0.5

0.0

0.0

411

83.80

0.0

0.0

0.0

8.7

4.1

2.9

46.5

18.6

4.1

6.4

0.0

5.8

2.9

0.0

0.0

415

85.28

31.4

0.5

0.0

0.0

0.0

0.0

37.1

27.1

0.5

0.5

0.0

1.4

1.4

0.0

0.0

416

86.22

3.1

0.0

0.0

0.0

0.4

0.9

39.6

48.5

1.8

1.8

0.0

1.8

2.2

0.0

0.0

417

86.30

1.0

0.0

0.5

0.0

0.5

0.5

32.5

56.0

1.0

3.5

0.0

1.0

3.0

0.5

0.0

421

87.35

13.3

0.4

0.0

0.0

0.0

1.8

15.0

68.6

0.4

0.4

0.0

0.0

0.0

0.0

0.0

3

Continued. Sample

Depth (m)

PAOM

AOM

Res

Op-equi

Op-lath

Cut

Nop-Bio

Nop-Nbio

Poll

Spore

Salv

Botry

Pediast

Dino

Foram

422

87.39

5.7

0.0

0.0

0.0

0.0

6.2

37.8

42.5

0.0

7.8

0.0

0.0

0.0

0.0

0.0

427

89.85

5.0

0.0

0.0

0.0

0.0

1.0

15.3

71.8

1.5

2.0

0.0

1.5

1.0

1.0

0.0

428

92.72

1.0

0.0

0.0

0.0

0.5

2.0

30.2

62.3

2.5

0.0

0.0

0.5

1.0

0.0

0.0

429

92.83

0.5

0.0

0.0

0.0

0.0

0.5

33.5

54.1

3.6

6.7

0.0

0.0

0.0

1.0

0.0

439

96.83

14.9

0.5

0.0

0.0

0.0

3.1

29.2

52.3

0.0

0.0

0.0

0.0

0.0

0.0

0.0

441

99.25

7.7

1.8

0.0

0.0

0.0

0.9

21.6

59.0

2.7

2.3

0.0

1.8

2.3

0.0

0.0

447

103.91

3.4

0.0

0.0

0.0

0.0

2.4

6.7

84.1

1.0

1.4

0.0

0.5

0.5

0.0

0.0

449

106.86

4.9

0.0

0.0

0.0

0.4

2.2

23.2

65.2

2.7

0.4

0.0

0.9

0.0

0.0

0.0

450

106.95

10.0

1.0

0.0

0.0

0.0

2.9

21.9

60.0

3.3

0.5

0.0

0.0

0.5

0.0

0.0

451

107.60

12.2

0.0

0.0

1.0

0.0

0.0

19.4

65.3

0.5

0.5

0.0

0.5

0.5

0.0

0.0

453

108.32

3.4

0.0

0.0

3.4

4.3

1.4

7.7

75.0

2.4

1.9

0.0

0.5

0.0

0.0

0.0

455

108.96

1.3

0.0

0.0

1.3

0.4

2.2

25.6

55.1

6.2

4.4

0.0

2.2

1.3

0.0

0.0

464

115.29

2.2

0.0

0.0

1.3

1.3

3.1

21.6

47.1

8.8

7.9

0.0

3.1

3.5

0.0

0.0

467

116.02

7.5

0.5

0.0

0.0

0.0

0.0

45.5

46.0

0.0

0.0

0.0

0.5

0.0

0.0

0.0

469

117.85

10.8

0.0

0.0

0.0

0.0

1.0

23.2

62.6

0.0

1.0

0.0

1.0

0.5

0.0

0.0

475

121.02

0.3

0.0

0.0

1.7

1.3

0.3

1.7

91.3

1.7

1.7

0.0

0.0

0.0

0.0

0.0

477

121.67

0.0

0.0

0.0

5.3

2.4

1.9

13.6

73.8

2.4

0.0

0.0

0.5

0.0

0.0

0.0

478

121.93

0.0

0.0

0.0

7.9

4.2

4.2

11.6

67.9

1.9

0.9

0.0

1.4

0.0

0.0

0.0

481

122.64

0.0

0.0

0.0

4.6

4.1

0.5

9.1

77.6

1.4

1.4

0.0

1.4

0.0

0.0

0.0

483

122.88

0.0

0.0

0.0

4.3

1.4

2.9

3.3

83.7

2.4

1.4

0.0

0.5

0.0

0.0

0.0

485

124.02

5.7

0.4

0.0

1.3

1.8

0.4

17.6

67.4

1.3

0.9

0.0

1.3

1.8

0.0

0.0

487

124.26

23.2

0.0

0.0

0.0

0.0

5.3

42.5

26.3

0.0

0.9

0.0

0.0

1.8

0.0

0.0

491

125.53

1.8

0.0

0.0

0.0

0.0

3.2

31.7

57.5

0.9

2.7

0.0

1.8

0.5

0.0

0.0

492

125.62

4.7

0.0

0.0

0.0

0.0

5.2

39.6

40.6

4.7

2.4

0.0

0.9

1.9

0.0

0.0

493

126.03

0.0

0.0

0.0

0.0

0.0

0.0

17.1

80.6

0.0

1.4

0.0

0.5

0.5

0.0

0.0

499

130.20

0.0

0.0

0.0

4.1

2.7

0.5

18.3

66.2

0.5

2.3

0.0

4.1

1.4

0.0

0.0

4

Continued. Sample

Depth (m)

PAOM

AOM

Res

Op-equi

Op-lath

Cut

Nop-Bio

Nop-Nbio

Poll

Spore

Salv

Botry

Pediast

Dino

Foram

501

132.21

1.9

0.0

0.0

0.0

0.5

4.9

4.9

80.1

2.4

2.9

0.0

0.5

1.9

0.0

0.0

503

132.73

1.3

0.0

0.0

1.0

2.3

1.3

1.0

90.0

1.3

0.7

0.0

1.0

0.0

0.0

0.0

505

135.10

0.0

1.0

0.0

13.3

8.4

0.0

5.9

42.4

10.8

4.4

0.0

7.4

6.4

0.0

0.0

511

162.93

1.4

0.0

0.0

6.8

2.3

0.9

16.7

65.3

3.6

0.5

0.0

2.3

0.5

0.0

0.0

513

163.31

4.1

0.0

0.0

1.8

1.4

3.2

23.7

55.7

2.7

0.9

0.0

4.1

2.3

0.0

0.0

514

163.49

1.4

0.0

0.0

0.0

0.0

9.0

14.9

58.1

3.2

3.6

7.2

0.5

2.3

0.0

0.0

515

164.05

5.4

0.0

0.0

0.0

0.0

0.8

12.8

69.4

1.7

0.4

0.0

4.5

5.0

0.0

0.0

517

164.39

0.3

0.0

0.0

0.0

0.0

1.7

0.0

94.3

1.0

1.0

0.0

1.3

0.3

0.0

0.0

519

169.61

0.7

0.0

0.0

0.0

0.0

2.0

0.7

90.7

2.0

1.0

0.0

2.7

0.3

0.0

0.0

521

171.21

0.0

0.0

0.5

0.5

1.4

1.9

23.8

64.3

4.3

3.3

0.0

0.0

0.0

0.0

0.0

523

185.19

0.0

0.0

0.0

1.4

2.4

11.0

11.9

59.5

7.6

2.4

0.0

3.3

0.5

0.0

0.0

524

185.33

5.4

0.0

0.0

0.7

1.1

2.5

6.4

55.4

3.9

3.6

0.0

16.1

5.0

0.0

0.0

526

188.45

0.0

0.0

0.0

3.3

2.1

3.8

7.9

67.9

6.3

0.8

0.0

2.9

5.0

0.0

0.0

528

189.19

0.0

0.0

0.0

0.0

2.3

1.4

6.8

75.0

5.5

7.7

0.0

1.4

0.0

0.0

0.0

531

190.24

0.0

0.0

0.0

7.0

11.0

2.0

8.5

70.0

1.5

0.0

0.0

0.0

0.0

0.0

0.0

532

190.29

0.0

0.0

0.0

5.4

6.3

2.1

11.7

59.2

1.7

1.7

0.0

10.4

1.7

0.0

0.0

533

191.16

8.9

0.0

0.0

2.7

3.5

6.6

11.6

50.2

8.9

1.9

0.0

3.1

2.7

0.0

0.0

535

191.56

1.4

0.0

0.0

0.5

0.0

48.2

13.8

22.9

9.6

1.8

0.0

1.8

0.0

0.0

0.0

537

192.13

0.0

0.0

0.5

19.2

26.4

1.9

7.2

40.9

1.4

1.0

0.0

1.4

0.0

0.0

0.0

541

196.35

0.0

0.0

0.0

0.0

0.0

4.1

13.1

70.7

5.9

1.8

0.0

4.5

0.0

0.0

0.0

543

196.74

0.5

0.0

0.0

4.2

0.9

1.4

23.6

60.6

3.2

1.9

0.0

3.2

0.5

0.0

0.0

551

207.28

0.0

0.0

0.0

4.6

6.9

2.3

20.7

53.9

4.1

2.3

0.0

3.2

1.8

0.0

0.0

555

215.94

0.0

0.0

0.0

0.5

0.5

2.4

20.8

56.1

9.9

9.4

0.0

0.5

0.0

0.0

0.0

556

218.28

0.0

0.0

0.0

0.5

4.4

30.1

12.6

12.6

31.1

8.7

0.0

0.0

0.0

0.0

0.0

557

219.05

0.0

0.0

0.0

0.0

0.4

5.9

9.2

58.6

11.3

3.8

0.0

2.5

8.4

0.0

0.0

561

220.66

1.4

0.0

0.0

0.0

1.4

4.7

13.0

68.4

10.2

0.9

0.0

0.0

0.0

0.0

0.0

5

6 7 8

Continued. Sample

Depth (m)

573

229.44

PAOM

AOM

Res

Op-equi

Op-lath

Cut

Nop-Bio

Nop-Nbio

Poll

Spore

Salv

Botry

Pediast

Dino

Foram

11.6 0.0 0.0 0.4 0.4 4.0 17.3 54.7 4.9 1.3 4.4 0.0 0.0 0.9 0.0 575 234.17 5.2 0.0 0.0 0.5 0.0 6.2 14.7 63.0 2.8 3.3 0.0 0.0 4.3 0.0 0.0 Legend: PAOM = pseudoamorphous; AOM = amorphous orgnica matter; Op-equi = opaque equidimensional; Op-lath = opaque lath; Cut = cuticle; Nop-Bio = non-opaque biostructured; Nop-Nbio = non-opaque non-biosctructured; Poll= pollen; Salv = Salviniaceae; Botry = Botryococcus; Pediast = Pediastrum; Dino = dinocyst; Foram = microforaminifera test lining.

1

Appendix 2. Percentage of the sedimentary organic matter of the 1-AS-46-AM. Sample Depth (m) PAOM AOM Res Op-equi Op-lath Cut Nop-Bio Nop-Nbio Poll Spore Salv Botry Pediast Dino Foram 580

41.73

65.2

16.4

0.3

5.4

1.0

0.0

0.0

9.0

2.0

0.7

0.0

0.0

0.0

0.0

0.0

584

48.88

4.7

0.7

0.0

1.3

0.0

1.7

0.0

91.7

0.0

0.0

0.0

0.0

0.0

0.0

0.0

585

51.8

2.0

0.3

0.0

0.3

1.7

95.0

0.0

0.7

0.0

0.0

0.0

0.0

0.0

0.0

0.0

587

54.5

10.6

0.9

0.0

0.0

0.0

3.7

0.0

81.0

0.3

0.0

0.0

0.0

3.4

0.0

0.0

588

55.1

1.8

0.0

1.0

0.0

0.0

1.8

0.0

58.9

6.0

11.2

0.0

4.9

14.3

0.0

0.0

589

57.59

5.3

0.0

8.3

19.8

0.0

0.0

0.0

44.6

14.2

6.9

0.0

1.0

0.0

0.0

0.0

590

79.57

4.5

0.3

0.3

0.0

0.0

3.2

0.0

80.6

4.8

3.2

0.0

1.0

1.9

0.0

0.0

592

80.61

7.4

0.0

0.3

0.0

0.0

2.9

0.0

80.1

2.6

4.2

0.0

1.6

1.0

0.0

0.0

595

81.16

3.5

0.0

0.3

0.5

0.3

5.7

0.0

69.3

0.8

1.6

0.0

12.0

6.0

0.0

0.0

597

81.66

4.6

0.7

0.0

0.7

0.3

3.3

0.0

89.5

0.3

0.0

0.0

0.7

0.0

0.0

0.0

601

82.88

0.0

0.0

1.3

0.0

0.3

8.9

0.0

78.5

3.3

3.6

0.3

3.0

0.7

0.0

0.0

602

83.26

0.0

0.0

2.3

0.7

0.0

2.3

0.0

80.4

5.9

7.8

0.0

0.7

0.0

0.0

0.0

603

85.17

0.0

0.0

0.0

0.0

0.0

1.6

0.0

4.6

2.9

2.3

0.0

40.7

47.9

0.0

0.0

605

85.61

0.0

0.0

3.3

5.2

0.7

2.3

0.0

68.5

5.6

6.6

0.0

6.2

1.6

0.0

0.0

608

86.38

0.3

0.0

0.3

0.0

0.3

16.2

0.0

71.7

3.8

5.4

0.0

1.9

0.0

0.0

0.0

610

86.99

0.6

0.0

2.1

0.3

0.9

4.7

8.9

70.3

1.5

0.6

0.0

3.9

6.2

0.0

0.0

611

87.81

0.9

0.0

1.9

0.6

3.1

2.2

2.8

76.9

0.9

3.4

0.0

2.8

4.6

0.0

0.0

613

88.53

3.2

1.0

0.3

1.0

0.0

1.0

2.2

86.6

1.0

0.6

0.0

2.6

0.6

0.0

0.0

616

89.66

2.3

0.0

0.6

0.3

0.0

1.3

0.3

92.6

0.3

0.0

0.0

1.3

1.0

0.0

0.0

618

90.51

2.6

0.0

0.0

0.6

1.3

0.0

6.8

83.1

1.3

1.6

0.0

1.9

0.6

0.0

0.0

619

90.7

0.7

0.3

1.7

1.0

0.3

3.3

1.7

82.5

7.0

1.7

0.0

0.0

0.0

0.0

0.0

622

91.61

1.6

0.6

6.4

0.0

0.0

1.6

0.3

82.4

1.6

1.6

0.0

1.9

1.9

0.0

0.0

625

92.86

1.0

0.0

0.3

0.3

0.0

1.6

0.3

93.8

0.6

0.3

0.0

1.6

0.0

0.0

0.0

627

93.6

2.5

0.0

0.6

0.9

3.1

0.6

0.0

86.5

0.3

2.2

0.0

2.5

0.6

0.0

0.0

629

93.98

0.0

0.0

0.0

0.9

1.2

2.2

0.0

86.5

0.9

3.4

0.0

4.0

0.9

0.0

0.0

631

94.31

0.3

0.0

0.3

1.6

0.0

2.8

0.9

87.8

0.3

1.3

0.0

2.8

1.9

0.0

0.0

632

94.56

1.9

0.0

0.0

0.6

0.6

1.3

1.0

91.4

0.0

1.0

0.0

1.9

0.3

0.0

0.0

633

94.61

1.6

0.0

0.0

0.7

0.7

2.9

1.6

89.6

0.3

0.3

0.0

2.0

0.3

0.0

0.0

2

Continued. Sample Depth (m) PAOM AOM Res Op-equi Op-lath Cut Nop-Bio Nop-Nbio Poll Spore Salv Botry Pediast Dino Foram

3

635

95.01

1.3

0.0

0.0

0.3

0.3

3.2

0.0

89.2

1.0

1.6

0.0

3.2

0.0

0.0

0.0

637

96.13

2.2

0.3

0.0

1.9

0.0

1.9

0.6

87.8

1.6

1.3

0.0

1.3

1.3

0.0

0.0

640

117.43

1.5

0.0

0.0

0.3

0.6

1.5

0.9

83.0

4.0

2.2

0.0

4.6

1.2

0.0

0.0

641

118.34

0.6

0.0

0.9

0.3

0.0

0.6

0.0

81.0

1.8

5.4

0.0

3.6

5.4

0.3

0.3

642

119.52

2.3

0.5

0.0

14.5

22.9

2.8

2.3

43.5

1.9

1.4

0.0

7.5

0.0

0.5

0.0

643

120.13

7.7

1.0

1.9

3.5

0.0

2.2

4.8

70.2

1.9

6.1

0.0

0.6

0.0

0.0

0.0

644

120.18

0.9

0.0

1.6

5.6

0.9

2.2

0.0

80.7

0.9

5.0

0.0

0.9

1.2

0.0

0.0

647

122.32

0.3

0.0

1.3

3.3

4.9

3.6

0.0

71.9

5.2

4.6

0.0

4.2

0.7

0.0

0.0

648

122.83

2.6

0.0

3.2

2.3

4.9

4.9

0.0

58.4

4.9

4.5

1.0

13.0

0.3

0.0

0.0

651

124.03

0.3

0.0

3.6

2.9

0.7

7.5

0.0

70.7

3.9

2.9

0.0

7.5

0.0

0.0

0.0

652

124.06

0.3

0.3

1.3

1.7

0.0

4.7

0.0

75.7

4.0

5.3

0.0

6.7

0.0

0.0

0.0

654

124.6

3.3

0.0

0.0

0.7

0.0

0.0

0.0

93.7

0.7

1.3

0.0

0.3

0.0

0.0

0.0

655

124.96

1.0

0.0

0.0

0.3

6.6

0.7

0.0

79.7

3.7

8.0

0.0

0.0

0.0

0.0

0.0

657

125.68

2.9

0.0

2.9

1.0

0.7

0.7

0.0

87.0

2.6

2.3

0.0

0.0

0.0

0.0

0.0

658

127.82

0.3

0.7

3.3

2.6

3.3

1.6

0.0

68.8

8.2

10.2

0.0

1.0

0.0

0.0

0.0

660

129.37

1.0

0.0

1.0

1.2

0.2

2.9

0.0

66.3

0.7

2.5

0.0

0.0

23.8

0.2

0.0

663

129.83

0.9

0.0

0.0

0.9

0.3

0.9

0.0

91.6

0.6

0.9

0.0

1.9

1.2

0.6

0.0

664

129.86

9.2

10.5

0.0

1.3

0.7

2.6

0.0

70.6

3.3

1.6

0.0

0.3

0.0

0.0

0.0

665

130.31

4.7

4.3

0.7

0.3

1.3

3.3

0.0

61.7

2.0

2.3

0.0

19.3

0.0

0.0

0.0

666

130.4

0.3

0.0

0.3

2.4

2.1

2.4

0.0

82.6

0.6

0.0

0.0

8.8

0.6

0.0

0.0

667

130.53

7.6

0.7

0.0

0.7

0.0

3.0

0.0

84.9

1.6

1.3

0.0

0.3

0.0

0.0

0.0

669

134.26

2.0

0.0

0.7

0.0

0.0

0.0

0.0

0.7

92.8

1.3

0.0

1.6

1.0

0.0

0.0

670

134.3

2.0

0.0

0.7

1.6

0.0

1.3

0.0

81.8

6.2

6.5

0.0

0.0

0.0

0.0

0.0

671

134.83

0.3

0.0

1.1

0.5

1.6

1.9

0.5

43.2

6.3

15.3

11.2

17.2

0.8

0.0

0.0

672

135

1.2

0.0

5.0

2.5

0.2

3.5

0.5

52.5

2.2

8.2

1.0

23.3

0.0

0.0

0.0

673

135.19

0.3

0.0

0.0

2.0

0.0

0.0

0.0

1.7

94.7

0.7

0.0

0.7

0.0

0.0

0.0

675

137.08

0.0

0.0

0.3

1.3

0.3

1.0

0.0

93.3

1.0

2.7

0.0

0.0

0.0

0.0

0.0

4

Continued. Sample Depth (m) PAOM AOM Res Op-equi Op-lath Cut Nop-Bio Nop-Nbio Poll Spore Salv Botry Pediast Dino Foram 678 680

138.38

2.8

3.2

0.0

0.6

0.0

0.6

0.0

86.1

0.0

0.3

0.0

6.3

0.0

0.0

0.0

140.17

1.0

1.6

0.3

0.6

0.0

3.2

0.0

81.1

1.9

2.2

0.0

7.7

0.3

0.0

0.0

682

140.77

4.4

8.2

0.0

0.0

0.0

0.6

0.0

77.6

0.3

0.0

0.6

8.1

0.0

0.0

0.0

684

141.91

8.8

65.3

0.0

0.0

0.0

0.3

0.0

22.1

0.3

0.0

0.0

1.9

0.0

1.3

0.0

686

142.61

1.0

0.0

1.3

0.3

3.3

3.3

0.0

83.7

2.7

4.0

0.0

0.3

0.0

0.0

0.0

687

143.14

0.0

0.0

0.3

0.0

0.0

2.6

0.0

87.4

2.9

6.8

0.0

0.0

0.0

0.0

0.0

689

143.57

0.0

0.0

1.3

4.3

3.7

2.0

0.0

87.3

0.0

1.3

0.0

0.0

0.0

0.0

0.0

691

144.86

0.0

0.0

0.0

0.0

0.0

0.6

0.0

90.5

0.6

1.8

0.0

2.5

4.0

0.0

0.0

692

145.55

0.0

0.0

0.0

0.3

0.0

2.6

0.0

93.5

0.0

1.3

0.0

1.0

1.3

0.0

0.0

693

146.41

0.7

0.0

0.0

0.0

0.7

2.3

0.0

95.1

1.0

0.0

0.0

0.3

0.0

0.0

0.0

695

146.89

0.3

0.0

0.0

1.7

0.7

1.4

16.9

67.8

2.7

1.4

0.3

2.0

4.7

0.0

0.0

696

147.12

1.0

0.0

0.3

0.0

0.0

2.2

1.6

89.5

0.0

1.6

0.0

0.3

3.5

0.0

0.0

698

152.45

2.1

0.0

0.9

0.9

0.0

0.0

0.0

91.9

0.4

0.0

0.0

0.4

3.4

0.0

0.0

700

153.44

1.0

0.0

0.7

0.7

0.0

2.3

0.0

93.8

0.0

0.7

0.0

0.3

0.7

0.0

0.0

702

153.84

3.3

4.8

0.5

1.0

1.9

2.4

2.9

73.7

1.9

2.4

0.5

2.4

0.0

0.0

2.4

703

155.3

3.5

2.5

0.0

2.5

3.0

2.5

5.0

55.5

2.0

2.5

0.0

21.0

0.0

0.0

0.0

706

158

1.4

88.0

0.0

0.0

0.0

0.0

0.0

8.6

0.0

0.0

0.0

1.9

0.0

0.0

0.0

708

160.97

20.1

8.4

0.0

0.0

0.0

1.1

0.0

44.9

0.3

0.3

0.0

25.1

0.0

0.0

0.0

709

161.01

1.3

0.0

0.0

0.0

0.0

0.3

0.0

76.0

0.0

0.0

0.0

22.5

0.0

0.0

0.0

713

165.31

2.3

38.4

0.0

0.0

0.0

0.5

0.9

54.6

0.0

0.5

0.0

2.3

0.0

0.0

0.5

722

175.28

0.0

86.2

0.0

0.0

0.0

0.0

0.0

0.0

6.2

0.5

0.0

2.9

0.0

0.0

4.3

723

176.33

14.4

31.1

0.0

0.5

1.0

0.5

1.4

37.3

1.9

0.0

0.0

6.7

0.0

4.8

0.5

725

181.07

3.4

1.3

0.0

0.0

0.4

3.0

3.9

64.7

0.4

2.2

0.0

19.0

0.0

1.7

0.0

730

183

1.9

57.9

0.0

0.5

0.5

0.0

3.7

6.5

1.4

0.0

0.0

27.8

0.0

0.0

0.0

731

184.14

1.4

6.6

0.0

0.0

0.5

1.9

1.4

29.6

6.6

0.5

0.0

51.6

0.0

0.0

0.0

734

187.65

0.0

0.0

0.0

0.0

0.0

0.0

0.0

79.2

2.2

1.1

0.0

12.6

4.9

0.0

0.0

735

188.65

0.3

0.0

0.3

4.1

0.5

0.5

0.0

47.8

19.2

11.0

0.0

15.4

0.8

0.0

0.0

5

Continued. Sample Depth (m) PAOM AOM Res Op-equi Op-lath Cut Nop-Bio Nop-Nbio Poll Spore Salv Botry Pediast Dino Foram

6 7 8

736

189.18

0.0

0.0

1.1

0.0

0.3

0.3

0.0

61.9

8.6

15.2

0.3

1.1

11.3

0.0

0.0

738

189.34

0.6

0.0

0.9

0.0

1.2

20.2

0.0

65.3

7.1

3.7

0.0

0.9

0.0

0.0

0.0

740

189.95

0.0

0.0

3.5

0.0

0.0

0.7

0.0

44.7

20.1

12.9

0.0

5.0

13.2

0.0

0.0

743

190.58

8.0

0.0

1.3

1.0

0.0

0.6

0.0

84.4

0.6

1.6

0.0

0.6

1.9

0.0

0.0

746

192.16

3.2

2.2

1.9

1.6

1.6

2.9

0.0

24.3

13.1

2.6

0.0

4.8

41.9

0.0

0.0

749

195.7

0.0

0.0

0.9

0.3

0.3

1.4

0.0

80.7

0.9

2.9

0.0

5.8

6.9

0.0

0.0

752

196.14

0.0

0.0

1.3

0.0

0.0

0.5

0.0

69.1

4.0

6.6

0.0

8.0

10.4

0.0

0.0

755 200.7 0.0 0.0 0.0 0.0 0.5 1.3 0.0 74.8 5.6 4.2 0.0 0.0 0.0 11.1 2.4 Legend: PAOM = pseudoamorphous; AOM = amorphous orgnica matter; Op-equi = opaque equidimensional; Op-lath = opaque lath; Cut = cuticle; Nop-Bio = non-opaque biostructured; Nop-Nbio = non-opaque non-biosctructured; Poll= pollen; Salv = Salviniaceae; Botry = Botryococcus; Pediast = Pediastrum; Dino = dinocyst; Foram = microforaminifera test lining.

Table 1. Mean percentages of sedimentary organic matter of 1-AS-37-AM. Amorphous Group

Phytoclast Group

Palynomorph Group

37

3.6

0.1

3.7

Op- OpNOptPhyto PG Spor Salv Boty Ped Dino mfl tPalyno Cut NOpBio Eq la NBio 1.7 1.7 3.6 25.9 54 86.7 3 2.7 0.2 1.7 1.4 >1.0 0 9.6

46

3

5.8

8.9

1.3

Wells PAOM AOM tAOM

1

3.3

0.8

68

74.5

4.9

3

0.2

5.7

2.7

0.1

0.1

Legend = tAOM = total of the AOM; PMOA = PseudoAOM; tPhyto = total of Phytoclast; OpEq = Opaque equidimensional; Op-la = opaque lath; Cut = Cuticle; NOpBio = Non-opaque biostructured; NBio = Non-opaque non-biostructured; tPalyno = total of Palynomorphs; PG = pollen grain; Spor = spores; Salv = Salviniaceae; Bot = Botryococcus; Ped = Pediastrum; Dino = Dinocysts; mfl = microforaminifera test linings.

16.6

Table 2. Origin and association interpretation for each palynofacies association.

Palynofacies Associations

Components

Origin/Association interpretation

Opaques

Op-lath and Op-equidimensional.

Non-opaques

Non-opaques.

Miospores

Resin, spores, Salviniaceae and pollen grains.

Algae

Botryococcus and Pediastrum.

Continental/ Freshwaterbrackish

Structureless/Marine

Pseudoamorphous, amorphous organic matter, microforaminifera test linings and dinocysts.

Continental-marine/Marine

Continental/Terrigenous

Table 3. Mean percentage of palynofacies associations for each well. In bold the values above of the general average. Wells 1-AS-37-AM 1-AS-46-AM Average

Opaque 3.4 2.3 2.8

Non-opaque 83.3 72.2 77.4

Algae 3.2 8.4 5.9

Miospores 6.4 8.9 7.8

Structureless/Marine 3.7 8.2 6.1

1-AS-46-AM

Lithostratigraphy/ Depth(m) Age 40

Fluvial component

Op/Non-opaque

Marine elements

Autochthonous elements

Botryococcus

Pediastrum

Salviniaceae

Inferred Freshwater level

Intervals

50 60

F46

70 80

100

Late Miocene

Solimões Formation

90

E46

110 120 130

D46

140

C46

150 160 170

B46

180 190

Middle Miocene

A46

200 -300 -200 -100

0

1000.0

0.3

0.60.0

2.5

Frenquency (n)

Figure 11

5.0 0

150

Frenquency (n)

300 0

75

Frenquency (n)

150 0

75

Frenquency (n)

150 0

24

Frenquency (n)

48

-

+

Middle-Late Miocene

Middle Miocene Pediastrum (freshwatet/Eutrophic)

AOM/AOM (saline/anoxic)

Pediastrum (freshwatet/Eutrophic)

Botryococcus (freshwater/brackish/oligotrophic)

AOM/AOM (saline/anoxic)

Freshwater Micro

Botryococcus (freshwater/brackish/oligotrophic)

Freshwater Micro

37 Marine incursion -37 46 Marine incursion -46

Spores

Pollen

Spores

Pollen

Figure 12

N A 3746

Middle Miocene

Figure 13

B

C

3746

37

Middle-Late Miocene

46

A

Coarse tuff stone Pyroclastic breccia Pkst

Grst Boundstone

0.062 0.125 0.25 0.5 1 2 4 64 256

Mudstone Sandstone Conglomerate

clay

Fossils

Mdst Wkst

Sedimentary Structures

Lapill

0.004

Depth (meters)

Formation

Epoch

Samples

Fine tuff

Grain size mm

silt vf f m c vc gr pe co bo

28.6 40 50 60 70 80

100 110

Solimões Formation

Late Miocene

90

120

130

140

150

160

170

Middle Miocene

180

190 200 210

220

230 237.8

SITE NAME Well 1−AS−37−AM Scale 1: 1000 Author: Natália de Paula Sá printed by SDAR, Ortiz J. et al. 2015

LEGEND Lithology

Fossils

mudstone

Covered Area

mollusks

siltstone

Rock Sample

gastropods

Location Latitude: −3.3 Longitude: −68.51 Elevation: 60 meters

lignite sandstone

Sedimentary structures

wood

planar lamination

Figure 3.

Mdst Wkst

Pkst

Grst Boundstone

0.004

0.062 0.125 0.25 0.5 1 2 4 64 256

Mudstone SandstoneConglomerate

clay

Sedimentary Structures

Lapill Coarse tuff stone Pyroclastic breccia

Fossils

Depth (meters)

Formation

Epoch

Samples

Fine tuff

Grain size mm

silt vf f m c vc gr pe co bo

39.2

55

65

75

85

Solimões Formation

Late Miocene

95

105

115

125

135

145

155

165

175

MM

185

195 200.9

SITE NAME Well 1−AS−46−AM Scale 1: 1000 Author: Natália de Paula Sá printed by SDAR, Ortiz J. et al. 2015

Location Latitude: −2.23 Longitude: −68.28 Elevation: 101 meters

LEGEND Lithology mudstone siltstone

MM Middle Miocene Covered Area

mollusks

Rock Sample

gastropods

shale lignite

Fossils

Sedimentary structures

wood

planar lamination

sandstone

Figure 4.

Figure 5

Figure 6 Opaque N-Op Algae Miospores

PseudoAOM

1.8

AOM

Forams

Dinocysts

Resin

Spores

Salvinaceae

Pollen

Botryococcus

Pediastrum

Non-opaque

Op-eq

Op-la

Linkage distance 2.0

Ward’s method 1-Pearson r

1.6

1.4

1.2

1.0

0.8

0.6

0.4

0.2

Structureless/Marine

1-AS-37-AM

1-AS-46-AM

Phytoclasts

Phytoclasts

I

I

II

II IVa

VI

III

IVa VI

IVb

IVb

V IX

V

VII

IX

VIII AOM

III

VII VIII

Palynomorphs

AOM

Palynomorphs

high terrestrial/freshwater influx proximal

oxic

distal anoxic low terrestrial/freshwater influx

Figure 7

Depth (m)

St ru ct ur el es s/ M ar in e

at er al ga e Fr es hw

M io sp or es

O

pa qu es

N on -o pa qu e

1-AS-37-AM

30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120 125 130 135 140 145 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235

CONISS

Intervals

E37

D37

C37

B37

A37

20

40

60

80 100

100

200

300

20

40

60

Frequency (n)

Figure 8

80

20

40

60

20

40

60

2

4

Within-cluster sum of squares

6

ru ct

ur el

er al g Fr es hw at

M io sp or es

Zone

St

N

O pa qu es

on -o pa qu e

ae

es s/ M ar in e

1-AS-46-AM

40

CONISS

45 50 55 60

F46

65 70 75 80 85 90 95 100

Depth (m)

105

E46

110 115 120 125 130

D46

135 140 145

C46

150 155 160 165 170

B46

175 180 185 190

A46

195 200 205

20

40

60

80

100

200

300

100

200

300

Frequency (n)

Figure 9

100

200

300

100

200

300

2

4

6

8

10

12

14

Within-cluster sum of squares

16

1-AS-37-AM

Fluvial component

Lithostratigraphy/ Depth (m) Age

Op/Non-opaque

Marine elements

Autochthonous elements

Inferred Botryococcus Pediastrum Salviniaceae Freshwater Intervals level

30 40 50

E37

60

Late Miocene

80 90

D37

100 110 120 130

C37

140 150 160 170

Middle Miocene

Solimões Formation

70

B37

180 190 200 210

A37

220 230 -120

-40

40

1200.0

0.3

0.50.0

1.0 Frequency (n)

Figure 10

2.0 0

30 Frequency (n)

60 0

30 Frequency (n)

0

-

30 0

Frequency (n)

Frequency (n)

+

HIGHLIGHTS •

Palynofacies are reported for Miocene rocks of Amazon Region.

•

Findings indicated fluvial, lacustrine, estuarine, and marine environments predominate

•

Three marine incursions are identified: one in the Middle Miocene and two in the Middle–Late Miocene.