Provenance and distribution of tethyan pelagic and hemipelagic siliceous sediments, pindos mountains, Greece

Sedimentary Geology, 31 (1982) 63--88

63

Elsevier Scientific Publishing Company, Amsterdam -- Printed in The Netherlands

PROVENANCE AND DISTRIBUTION OF TETHYAN PELAGIC AND HEMIPELAGIC SILICEOUS SEDIMENTS, PINDOS MOUNTAINS, GREECE

MIRIAM BALTUCK

Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA 92093 (U.S.A ) (Accepted for publication May 26, 1981)

ABSTRACT Baltuck, M., 1982. Provenance and distribution of Tethyan pelagic and hemlpelagic siliceous sediments, Pindos Mountains, Greece Sediment Geol., 31.63--88. The broad range of tlme over which ribbon bedded cherts were deposited does not extend into the present marine environment, and no ribbon cherts have been recovered from the sea floor by the Deep Sea Drilling Project. The depositional environment of bedded cherts is difficultto determine, but extra-siliclcimpurities in the rock m a y offer clues about the provenance of the non-blogenlc component. T o test the usefulness of relatlve abundances of the extra siliciccomponents in extracting information on the depositional environment of the chert, I analyzed the major element chemistry of chert samples from a broad range of environments including ophiolite-associatedchert from the Franciscan Formation of California, deep-sea chert and porcellanlte from the northwest Pacific ( D S D P Leg 32), shallow pelagic shelf chert nodules from the Chalk of Britain, continental marginal basin chert from the Monterey Formation of California,and continental marginal basin chert from the Pindos Zone of Greece The ratios FeO/Al203, TIO2/AI203 and Al/ A I + F e + M n were considered in detail. The interpretative logic is simple but empirically supported by observations of these ratio values at different depositional environments in the Pacific Al ~s concentrated most highly in continental material while Fe and M n are more concentrated in pelagic sediments. FeO/Al203 can be used to differentiatebetween ophiollte associated chert and chert associated only with other sediments. TiO2/Al203 is not a useful indicator, possibly because of the equalizing effect of widespread eolian transport. The AI/AI+Fe+Mn ratio was measured in detail in one stratlgraphicsection in central continental Greece. This ratio varied with the type of sediment admixture, decreasing in value after the influx of ophiolite debris-bearingsediments, even w h e n their presence was undetectable in hand sample or under petrographic microscope. T o help clarify the paleogeography of the main study area, the Pindos Zone, and to Identify sources and dispersal patterns of extra-basinal materials, isopach maps of sedimentary facms of the Pindos were constructed. Superimposed directlyupon the seriesof imbricated thrust slices that comprise the Plndos Zone, the maps are at best compressed pictures of the Plndos Sea Floor. Persistent regional variation of facies thicknesses over tlme suggests the existence of several smaller depressions surrounded by submarine highs in the Plndos Basin.

0037-0738/82/0000--0000/$02.75 © 1982 Elsevier Scientific Publishing Company

64 INTRODUCTION

Bedded cherts are widely distributed m time and space and axe associated with a large variety of rock types, but the environments of deposition and the processes of silicificatlon are n o t completely understood. They range in t:me from Archean banded chert and iron formations of problematic origin {North America, Africa and Australia; Gross, 1965) to upper Miocene bedded diatomltes of nearly circum-Pacific chstribution (Ingle, 1980). Radiolarian cherts occur in all systems of the Phanerozoic from the Cambrian (Caledomdes and Austraha) to the Eocene--Upper Oligocene (Colombia), including two spectacular intervals of Late Jurassic and Late Cretaceous age in the Tethyan belt (Grunau, 1965). On the other hand, the formation of bedded chert is not well documented m the marine enwronment. The absence of bedded chert from Recent sediment is understandable as their formation through the diagenesis of sihceous oozes requires several million years (Keene, 1975; Kastner et al., 1977), but no ribbon bedded cherts of any age have been recovered by the Deep Sea Drilling Project either because of technological problems m sampling or because they do not exist m sea floor sediments (Wmterer and Jenkyns, 1979). It :s frequently difficult to determine the depositlonal environment of bedded cherts. Ophiolite associated chert is usually indistinguishable in the held or under the microscope from cherts associated only with other sedimentary facies (Parea, 1970). Many cherts, however, are rich :n impurities wh:ch might provide environmental clues m determining the provenance of the non-biogenic component of the sediments. A direct and quantitative identification of the mineralogy of these extra-siliclc components is rarely possible because of the refractory nature of the mmro~rystalline quartz constituting the bulk of the chert. The most promising approach lies, therefore, in a determination of the geochemical properties of the chert. The rare-earth elemental composition of cherts was one tool of classification successfully applied by Shimizu and Masuda (1977) and by Steinberg et al. (1977). Steinberg and MpodozisMarm (1978) and Steinberg et al. (1977) approached the problem of characterizing the environment of chert formation by analyzing these rocks for their major and transition elemental composition (AI, Fe, Mg, Tl, V, Cr, Mn, Co, N1, Cu). They assumed the silica was mainly bmgenic in origin and thus only a dilutant of the other constituents of the sediment, i.e., of the component they wished to characterize. This approach dismissed any biogenic contribution of non-sihcic and non-carbonate material. To test the assumption that information on the depositional environment of chert can be extracted from the relative abundances of the extra-silicm components, I pursued the course essayed by Steinberg and his associates and analyzed the major element composition (A1, Fe, Mg, Ti, Mn, S:, P, K, Ca) of a number of chert samples from a broad range of environments which include ophiolite associated chert from the Franciscan Formation of California, deep-sea chert and

65

porcellanite from the northwest Pacific (DSDP Leg 32), shallow pelagic shelf chert nodules from the Chalk of Britain, continental marginal basin chert from the Monterey Formation of California, and continental marginal basin chert from the Pindos Zone of Greece. Since silica is the predominant constituent of the analyzed rocks it is preferable to characterize variations in extra4ilicic components by ratios of their concentrations rather than by their absolute concentrations. Aluminum, iron, titanium, and manganese have been used in other studies of siliceous sediments (e.g., Cressman, 1962; Audley-Charles, 1965; Bostrom, 1976; Steinberg and Mpodozis-Marin, 1978) as indicators of sedimentary source material. The interpretative logic is rather simple: aluminum is concentrated most highly in continental detrital material while iron and manganese are more concentrated in pelagic sediments. Several mechanisms have been suggested for the observed enrichment in Fe and Mn including differential transport of detrital material (Turekian, 1965), direct precipitation from sea water (Wedepohl, 1960, cited in Steinberg and Mpodozis-Marin, 1978), from hydrothermally recycled sea water (Corliss, 1971), from juvenile water (Bostrom et al., 1969), or through sea water alteration of oceanic crust (Hart, 1970). The titanium content of pelagic clays is fairly constant in Pacific pelagic sediments (Arrhenius, 1963; Bostrom, 1 9 7 6 ) a n d its absolute concentration is equivalent to that found m continental shale (Cressman, 1962). A higher concentration of titanium in pelagic sediments could be the result of an admixture of mafic pyroclastic (Goldberg and Arrhenius, 1958) or of biogenous titanium (Cressman, 1962), although the significance of the latter would be difficult to estimate. GEOLOGIC HISTORY OF THE PINDOS BASIN

Most of the samples analyzed in this paper come from stratigraphic sections measured throughout the Pindos Mountains, one of the Hellenide ranges in Greece. The Hellenides are an alpine-type mountain system composed of nappes resulting from the Cenozoic telescoping of a part of what had been the southern margin of the Tethys during Jurassic and Cretaceous time. Their present geographic configuration consists of imbricated tectonic units (see Fig. 1) which roughly correspond to former paleogeographic units that were arranged during most of Mesozoic time in a system of elongate basins separated by carbonate platforms. The Pindos Basin, the sediments of which are now preserved in the thrust slices of the Pmdos Mountains, was a site of fairly continuous deposition of pelagic siliceous and carbonate sediments over much of Jurassic and Cretaceous time (Aubouin, 1959; Steinberg and Mpodozis-Marin, 1978). They offer, therefore, the opportunity to test the usefulness of a geochemical stratigraphic investigation in discerning sediment sources and basin paleogeography. A better understanding of sediment sources, dipersal patterns, and paleo-

66 20 °

21 o

22 °

25 °

24 °

41 °

40 °

5 9°

58 ~

37 °

Fig. 1. Tectonic units of the Hellemdes, A = Athens, M = Metsovon, K = Karpemsion, P = Patras 1 = Pre-Apuhan Zone, 2 = Ioman Zone, 3 = Gavrovo Zone, 4 (stipple) = Pindos Zone, 5 = Parnassos Zone, 6 = Subpelagonian Zone, 7 = Pelagoman Zone, 8 = Vardar Zone, 9 = Serbo-Macedoman Massif, 1 0 = Attican Metamorphm System. After Auboum, 1977 g e o g r a p h i c r e l a t i o n s m t h e P m d o s Basra m a y b e p o s s i b l e t h r o u g h t h e s t u d y o f t h e d i s t r i b u t i o n o f s e d i m e n t a r y f a c i e s ' t h m k n e s s e s . F o r this p u r p o s e isop a c h m a p s o f s e d i m e n t a r y facies o f t h e P i n d o s B a s i n h a v e b e e n c o n s t r u c t e d o n t h e basis o f d a t a c o m p i l e d f r o m t h e l i t e r a t u r e , f r o m u n p u b l i s h e d t h e s e s , a n d f r o m n e w d a t a g a t h e r e d b y t h e a u t h o r i n t h e f i e l d * (Figs. 2, 3, 4 a n d 5). T h e m a p s are d r a w n d i r e c t l y u p o n t h e series o f i m b r i c a t e d , n o r t h t r e n d i n g thrust sheets attempting no palinspastic reconstruction. Thus the maps, at b e s t , r e p r e s e n t c o m p r e s s e d p i c t u r e s o f t h e P m d o s sea f l o o r . N e v e r t h e l e s s , a p e r s m t e n t a n d p r o n o u n c e d r e g i o n a l v a r i a t i o n o f t h i c k n e s s e s o f facies o v e r

* Isopach data were compiled from Celet, 1962, Loftus, 1966; Flament, 1973; Caron, 1975, Lecanu, 1976; Mpodozls-Marin, 1977, Lyberis, 1979 and from the author's 1978, 1979 and 1980 field notes.

67 20" ~0 s

21s

22*

23"

39'

38*

37'

Fig 2. Index map showing locations of columnar sections used m constructing the isopach maps. Letters identify references for stratigraphic thicknesses: C = C a r o n , 1975, JJF = Fleury, 1973; H = Lecanu, 1976, M = Mpodozis-Marln, 1977, L = Lyberis, 1979; W = Loftus, 1966, PC = Celet, 1962', F = Flament, 1973, B = Baltuck, this paper and unpubhshed field notes. Number subscripts following B's refer to the number designation of columnar sections used in F~g. 6.

time suggests t h e existence o f several sub-basinal paleographic features w i t h i n the P i n d o s Basin. T h e c h a n g i n g s e d i m e n t d i s t r i b u t i o n m a y reflect local tect o n i c events a n d / o r changes in c u r r e n t activity, a n d m a y be useful in distinguishing s e d i m e n t sources, e.g., distinguishing b e t w e e n pelagic " r a i n " o f sedim e n t s and a m o r e localized s o u r c e such as hemipelagic sediments f r o m a river m o u t h e m p t y i n g into the P i n d o s Basin. Events in the d e v e l o p m e n t o f the Pindos Basin reflect geologic events o f a m u c h b r o a d e r region, the T e t h y s Seaway. Figure 6 s h o w s several lithostratlgraphic c o l u m n s o f t h e Pindos Z o n e ( l o c a t i o n s are n o t e d in Fig. 1). The oldest s e d i m e n t a r y r o c k s in the Pindos section are m a r l y siltstone and sands t o n e o f Ladinian t o Carnian age, the e r o s i o n p r o d u c t s o f t h e rifting conti-

68 200

220

210

23"

60°~

' ', \\METS#VON~

\

" \,

\,

'\

39'

38"

\,

\

\, _

,oo\ l

\ 'k

% tl I

370

[

RADIOLARITE W AND KASTELLIMUDSTONE

',

"

~

Fig 3 I s o p a c h m a p o f R a d l o l a r l t e a n d K a s t e l h M u d s t o n e Dogger~ - - M , d d l e - L a t e M a i m L i n e s are d a s h e d w h e r e d a t a p o i n t s are far apart.

nental margin. These are followed by pelagm limestone and turbidltic hmestone containing Carnian and Norian debris. Sedimentation of carbonates was interrupted near the end of Triassic txme by an interlude of m u d d y siliceous sedimentation and then continued up through Liassic time with a mixture of micrite, siliceous carbonate and turbiditic carbonate as the tensional tectomc regime continued in the basin and pelagic conditions grew more widespread (Bernoulli and Jenkyns, 1974). By the end of Liassic time most of the Pindos sea floor has subsided below the calcite compensation depth, as evidenced by the widespread siliceous mudstones that have yielded a palynological assemblage similar to an assemblage in the Vicentinian Alps dated more precisely by Van Erve (1977) as Late Pliensbachian--Toarcian (Lyberis et al., 1980). Increasingly pelagic conditions prevailed, culminating between Bajocian and Tithonian times when the most siliceous sediments, the bedded radiolarian cherts, were deposited in the Pindos Basin as in m a n y

69

20 °

21° •

22°

\1

I

, \ M E TS.OVON. ~

'

',

230

\

\

,

~KARPFNINION

/

37 = CALPIONELLID LIMESTONE

\, ~

~.

Fig. 4. Isopach map of Calpmnelhd Limestone. T]thonmn/Berrmsian. Lines are dashed where data points are far apart.

places m the T e t h y s (Grunau, 1959, 1965; Parea, 1970). Depomtion of these sediments c o n t i n u e d m the Pmdos Basin until Tlthonian time when siliceous calpionellid-bearing pelagic carbonate sedimentation began. A b o u t this time (Thithonian--Berriasian), ophiolite debris-bearing sediments (the First Pindos Flysch) made their initial appearance in continental Greece and c o n t i n u e d as an admixture of smectite clays and chlorite in the lower and middle Cretaceous siliceous red marl t ha t overlies the calpionellid limestone. This clastic sedimentation c o n t i n u e d until Santonian time m Peloponnesian Pindos where ophiolite debris contaminates the thin-bedded middle to upper Cretaceous limestone. Elsewhere m continental Greece and m uch of the Peloponnesos this limestone is more purely pelagic. In Maastrichtian time compressive tectonics to the east of the Pindos Basin found expression in Pindos through the appearance of the Pindos Flysch, which is at first m t e r b e d d e d with marly Cretaceous limestone. By Paleogene time the transition to the

70

21° '\ ', '\1

20 ° ~0°~

\

220

23°

\W

.E'rs~ovo~ o

75 50

\

\

~'

""

39 ° -

< 38 ° -

370

-

RI AND Fli

Fig. 5 I s o p a c h m a p o f Red M a r l s t o n e a n d F i r s t P m d o s Flysch. T l t h o n l a n / B e r r l a m a n - T u r o m a n / C o m a c i a n Lines are d a s h e d w h e r e data p o i n t s are far a p a r t

calcareous sandstone and siltstone that comprise the Pindos Flysch was complete. The stratlgraphm nomenclature used m this paper Is d~rectly translated from French stratigraphic terms proposed mostly by Auboum {1959}, with further terminology proposed by Dercourt (1964). The First Pindos Flysch is the uppermost Jurassic--lower Cretaceous unit containing ophiolitic debris shed during tectonic closure of the small Vardar ocean basin to the northeast of the Pindos Basra (see Fig. 1) ; the Pmdos Flysch is the uppermost Cretaceo u s - l o w e r Cenozoic calcareous sandstone and slltstone formation that blankets the top of the stratigraphic section and signals the final infilhng of the Pindos Basin.

71

PLATY LIMESTONE

(SAN TONIAN- MAASTRICHIAN)

L~ RED MARLSTONE (VALANGINIAN-CONIACIAN)

CALPIONELLID LIMESTONE

I

(TITHONIANIBERR)A$1A N)

]

B,i ,,,

i

L iU

4

....

~

KASTELL( MUDSTONE

UPPER DRIMOS L I M E S T O N E (LIASSlC AALENIAN?)

SlLJCEOUS PASS&GE ( R N E T I A N '))

LOWER ORIMOS LIMESTONE (CARNIAN-NORIAN)

Om D E T R I T A L TRIASSIC (LADINIAN-CARNIAN)

Fig. 6 Schematic columnar sectlon in the Pindos Zone showing stratigraphlc levels of Individual analyzed samples. See Fig. 2 for geographic locations of columns. ANALYTICAL PROCEDURES

Several sections in the Pindos Zone o f continental Greece and the Peloponnesos were sampled for study. Figure 1 shows the location of sections sampled and Fig. 6 the stratigraphic position of individual samples within a section. Rock samples were sawed into small cubes and polished with coarse carborundum grit to remove any metal traces left by the saw blade. The pieces were cleaned ultrasonically and crushed to gravel size using a tungsten-carbide mortar and piston. The gravel was then crushed and h o m o g e m z e d in a shaker mill to a free powder.

72 Fusion pellets were prepared for X-ray fluorescence analysis. 5.25 g of hthium metaborate (pre-heated at 400°C for several hours), 0.750 g of lanthanum oxide (pre-heated at 1000°C for 15 mm), and 0.900 g of rock powder (pre-heated at 120°C overmght) were desiccator-cooled, weighed out, then homogemzed together in a shaker mill. The mixture was fused m a covered graphite crucible at l l 0 0 ° C for 15 min. Upon removal from the oven the molten mixture was swirled, rapxdly transferred to a brass mold, pressed into disc shape, transferred to a cooling over set at 400°C, and slowly cooled to room temperature. Pellets were polished to a glassy fimsh (3 #m grit) and analyzed on a Phllips Automated X-ray Wavelength Spectrometer (AXS). A working curve was estabhshed using U.S.G.S. standards AGV-1A, W-l, PCC-1, G-2C, GSP-1, BR-M and BCR values as reported by Flanagan (1972). Because of some uncertainty regarding the apphcability of these standards (most of the samples to be analyzed had a higher SiO2 content than even the most sihceous standard on the working curve (U.S.G.S. G-2C, 69% SIO2), a pure silica (Spex Sihca 99.99% SIO2) pellet was analyzed as an u n k n o w n to check the accuracy of the curve at high silica values. As is shown m Table I the Spex sample was measured to have 101.45% SiO2, an error of less than 1.5%. Of the other oxide values sought m the spex sample, FeO had a measured percentage of 0.05%, MnO was detected at 0.01%, TiO~ at 0.01% and A1203 at 0.00%. Three samples and an mternal standard (U.S.G.S. BCR) constituted a single sample run in whmh Mg, Al, Si, P, K, Ca, Ti, Mn, and Fe contents were measured and reported as percent oxide (FeO as total iron oxide). Quahtatlve mineralogic content was determined on a select number of samples. These were first decarbonated in NaAc-buffered acetic acid. To reduce the quartz content of the rock powder and thus facilitate clay identification the setthng technique described by Jackson (1969) was apphed to separate the less-than-two-micron-size partmles. RESULTS AND DISCUSSION In Figs. 7 and 8, respectively, FeO (as total iron oxides) and TiO2 percentages of the samples are plotted against percent A1203. The cluster area of points for the Greek samples is lightly stippled, and best-fit linear regression curves are lightly drawn in for the individual localities. Also figured are the lines for average volcamc material and average continental material based on data presented in Krauskopf (1967) and Bostrom (1976). Table I lists sample locality and major element composition, Table II lists slope intercept and correlation coefficmnt for locahty sample clusters, Fig. 2 shows the geographic location of the sections and Fig. 6 shows the individual sample level in a section. Table I includes a calculated %CaCO3. This is computed assuming an average CaO/A1203 value m shales of 0.03% (Degens, 1965, p. 26) and attnb-

73

7 6

/

B

---- - • • • +

.

FRANCISCAN KARPENISION (B3) PLAKA (B8) TSIPIANA

5 ~

T

4

/

3

//=,

2

o

j

e

~,~.r t

0"

/.:" i.< /*l~'T ]i

"°

I

I

I

i

I

I

I

I

I

I

I

i

I

2

3

4

5

6

7

8

9

10

II

12

Fig. 7. Weight percent FeO number of samples permits ratios for East Pacific Rise (data for lines B and T f r o m

1:3

(as t o t a l iron oxides) vs AI:O 3 for samples analyzed. Where a regression line is drawn. Lines B and T represent average Basalt and average terrigenous detrsta] material, respectively Bostrom, 1976). Stipple encloses Greek sample points.

------• • • +

7

FRANCISCAN KARPENISION (B3) PLAKA (B8) TSIPIANA

6 B

5 o

4 3

/

jj--

2 I

I

2

3

4

5

6

7

8

i 9

i 10

ill

i 12

13

Fig. 8. Weight percdnt TIO2 vs. AI203 for samples analyzed. Lines B and T represent average ratios for East Pacific Rise Basalt and average terngenous detrital material, respectively (data for lines B and T f r o m B o s t r o m , 1976). Stipple encloses Greek sample points.

B786 B789 B7816 B7821 B7822 B7828 B7837 B7840 B7823a B7860 B7864 B7865 B7868 B7875 B7885 B7893 B7898 B78106 B78115 B78121 B78125b B78125d B78129 B78130 B78144 B78158 B78162

Karpenlsmn (B3)

Maroon mudstone Sihc m u d s t o n e Sihc. m u d s t o n e Silic. m u d s t o n e Sihc m u d s t o n e Slhc m u d s t o n e Red chert V silic, m u d s t o n e Red chert Vitreous chert Dark c h e r t Iron stained c h e r t Dark c h a r t Sllic l i m e s t o n e Red chert Sfllc'd l i m e s t o n e Sdm marl Silic marl Silic h m e s t o n e Silic m l c n t e Sdm'd hmestone Sdm h m e s t o n e Ophlolitic sandst Muddy limestone Maroon shale Red/gray mudstone Marly m u d s t o n e

Sample No and description

3 14 067 2 33 3 68 3.79 1.01 0 67 0.88 0 36 0.94 2.13 1 38 0 92 1.34 0 86 2 73 182 3 76 089 0 43 0,94 101 2 77 3.86 9.94 3 25 2 52

FeO

0.13 0.05 0 02 nd nd nd nd nd 0 01 0.08 0 03 nd 0.08 nd 0 08 0.18 0.21 007 0.17 0.05 0 13 nd 0 23 0.22 0 23 0.77 0 55

MnO

Compomtion

0 40 006 0 27 0.24 0 43 0.59 0.09 0 07 0.03 0.07 0 17 0 14 0.06 0 11 0.15 0 21 0.00 016 026 0 03 012 009 0 06 0 28 0 68 0.29 0 28

TiO2

6 29 0.45 0 48 0.41 0.57 0.17 0 15 0 21 2 11 0 07 0.15 0.22 0 24 15.07 0 27 21.24 26 30 17 49 42.53 18.47 804 7 50 43.16 20.33 1 22 30 16 35.37

CaO

10.70 0.72 0 49 0.33 0.00 0.19 0.19 0.27 3 72 0 02 0.06 0.21 0.38 26.70 0 36 37.53 43 94 30 85 75 66 32.83 14 16 13.21 76.71 35 79 1 51 53.28 62 58

CaCO3

69 49 91 65 80.34 89 41 82 43 93 54 97 06 96.82 92 00 92 83 87.13 92.62 90 95 79.70 91 58 52.53 47 48 55 45 29 39 66.56 79 67 88 19 15 40 47 71 58.65 32.88 25.99

Sib2

9.27 150 6 76 7.33 12.81 2 17 1.42 1.90 0.74 1 90 3 74 3.48 0.87 2 38 2.23 5 12 5.38 523 0.84 0.86 284 265 2.07 7.44 12.36 7 66 7 02

A1203

C o m p o s i t i o n o f analyzed rocks in weight p e r c e n t a g e , e x p r e s s e d as o m d e s . See Figs 6 and 2 for s e c t i o n and individual sample ]ocahty n d = n o t d e t e r m i n e d See t e x t for calculation o f CaCO~

TABLE I

Black flint n o d u l e

Red c h e r t Orange/red chert

Silic'd calcaren. Sihc'd mlcrite

Red chert Muddy chert Red chert Silic m u d s t o n e Red/green chert

Nodular c h e r t Wavy b e d d e d c h e r t Red chert Silic. marl Silic. m u d s t o n e Sdic. m u d s t o n e

Marly m u d s t o n e Sihc m u d s t o n e

DSDP32-307-4-1-37 DSDP32-302-7-1 DSDP32-310A-17 c m DSDP32-307-11

North west Paczflc

B78604

Porcellamte Calc. Grey c h e r t Brown chert

Black/grey c h e r t

The Monterey Formation

Dover 34

The Chalk

B78194 B78200

Petralona (Bl o )

B78657 B78659

Anthusa (1[]2)

B78288 B78301 B78311 B78322 B78334

Tsipiana

B78341 B78344 B78348 B78354 B78357 B78363

Plaka (B8)

B78174 B78178

1 44 0.46 0.28 075

0.11

0.08

1.00 0.89

0.19 0.46

0.37 0.17 0.89 0.95 0.42

0 44 0 52 0.18 0.80 0 49 0 43

1.49 2.26

0.02 0.03 0.01 0.01

0.01

0.01

0.03 017

0.08 036

0.02 0.01 0.16 0.16 0 06

0.01 0 O2 0 02 0.17 OO2 0.09

011 0.06

0.07 0.06 0.01 002

0.02

0.02

0.09 0.06

002 0.04

0 02 0.02 005 0.09 0.04

0 04 0 03 0 03 0.06 0.05 0.06

0.10 018

4.94 4.81 0 20 0.22

0.17

0.35

031 9.89

5.34 34 92

5.78 0.33 9.86 0.35 6.74

0.18 0 02 147 47 73 041 0.41

41 49 16.06

8.76 8.52 0.36 0.38

0.30

0.62

0.44 17 56

9.48 62.08

10.27 0 59 17.50 0 52 11.95

0.27 0.00 2.60 84.85 0 69 068

73.65 28 32

84.36 87 44 94.24 93.21

93 49

93 82

88 21 79.39

87.33 39.60

86 76 95 34 78.99 90.57 89.06

94.29 94 07 93 11 15 73 93 11 92.61

22.65 60 39

067 075 0.00 0 26

0.00

0.00

2.16 0.92

031 0.15

037 0.00 0 97 1 94 0 90

0.96 0 93 0 40 2 00 078 0.95

3.80 500

0 44 3.08 0 12 2 58 2,61 1 05 0 05

Spex SIhca

FeO

0.01

0 12 0.03 0 01 1.27 1 29 0.37

MnO

Composition

The Franc~can Formahon Laytonville L i m e s t o n e L1 Red c h e r t F1 C h e r t n o d u l e f r o m Lay Q9 F r a n 791 Muddy chert Fran 791a Muddy chert F r a n 792 White c h e r t

Sample No. a n d d e s c r i p t i o n

TABLE I (continued)

0 01

0 01 0 18 0 00 0.28 0.28 0 09

T102

0 14

58 96 0 16 6.04 0.43 0.46 0.32

CaO

0.25

104 95 0.13 10 75 0 52 0,58 0.48

CaCO3

101.45

0 00 89 43 89.25 84 41 84.14 91 81

$102

0 00

0 00 2 99 0 00 4.61 4 43 1.70

A1203

-..1 O~

77 TABLE II Mineralogic content of selected samples, determined by X-ray diffraction. Silica and carbonates not recorded. XX = relatively abundant, X = present Sample No.

Smectlte

Chlorite

Ilhte

Kaolinite

Hematite

Plagioclase

B78 6 B78 9 B78 21 B78 64 B78 106 B78 144 B78 162 B78 189 Franciscan F1

X XX X X XX XX

XX X

X

X X XX XX XX XX X

X X XX X

X

XX XX X X

XX XX XX X XX XX XX X

XX

X

XX

X

XX

u t i n g all excess CaO t o c a l c i u m c a r b o n a t e in t h e e q u a t i o n : %CaCO3 = 1.78(%CAO - - 0.03%A1203) In p e t r o g r a p h i c thin sections a n d in h a n d s a m p l e CaCO3 is o b s e r v e d b o t h as a d e t r i t a l c o n s t i t u e n t (e.g., r e d e p o s i t e d oolites, fossil f r a g m e n t s a n d in h e m i p e l a g i c marls) a n d a pelagic c o m p o n e n t (e.g., micritic t e x t u r e , u n b r o k e n pelagm c a l p i o n e l l e d fossils) t h u s t h e g e o c h e m i c a l c o n c e n t r a t i o n o f CaO c a n n o t be u s e d a l o n e as an i n d i c a t o r o f d e t r i t a l s e d i m e n t a t i o n , especially w h e r e evidence o f silica r e p l a c e m e n t o f original m a t e r i a l a d d s f u r t h e r c o m p l i cation. As p o i n t e d o u t in t h e i n t r o d u c t i o n 1 t h e r a t i o s o f non-silicic c o m p o n e n t s in a s a m p l e are b e t t e r i n d i c a t o r s o f s e d i m e n t a r y source m a t e r i a l t h a n their a b s o lute c o n c e n t r a t i o n s . I f a l u m i n u m is m o r e c o n c e n t r a t e d in c o n t i n e n t a l d e t r i t a l m a t e r i a l a n d iron a n d m a n g a n e s e are m o r e c o n c e n t r a t e d in pelagic s e d i m e n t s , t h e n a s t e e p e r FeO/A1203 slope is i n t e r p r e t e d t o r e p r e s e n t an e n v i r o n m e n t m o r e distal f r o m c o n t i n e n t a l sources and e n r i c h e d in pelagic material. T h e i m p l i c a t i o n s o f this s i m p l e i n t e r p r e t a t i v e m o d e l are b o r n e o u t b y r e l a t i o n s in t h e areas u n d e r s t u d y here: t h e F r a n c i s c a n F o r m a t i o n r a d i o l a r i a n cherts o f C a l i f o r n i a rest, in t h e area s a m p l e d , o n o p h i o l i t e a n d are c o n s i d e r e d distal f r o m c o n t i n e n t a l s o u r c e m a t e r i a l (Bailey et al.1 1 9 7 0 ; Wachs a n d H e i n , 1 9 7 5 ; H o p s o n e t al., 1981). T h e slope f o r t h e F r a n c i s c a n s a m p l e s is i n d e e d closest t o t h a t o f average v o l c a n o g e n i c m a t e r i a l . In p a l e o g e o g r a p h i c r e c o n s t r u c t i o n s f o r Jurassic and Early C r e t a c e o u s t i m e o f the T e t h y s (Biju-Duval et al., 1 9 7 7 ; A u b o u i n , 1 9 7 7 ; Channell et al., 1 9 7 9 ) , t h e s o u t h o f G r e e c e was f a r t h e r f r o m sources o f c o n t i n e n t a l d e t r i t u s t h a n c e n t r a l a n d n o r t h e r n G r e e c e . In C r e t e t h e P i n d o s Z o n e b e c o m e s increasingly m o r e neritic ( A u b o u i n et al., 1 9 7 6 ) a n d to t h e n o r t h in A l b a n i a a n d Yugoslavia, P i n d o s Z o n e s e d i m e n t s b e c o m e

78 increasingly of shallow water aspect, with nentm facies present (Cadet, 1976). The central Pindos Zone, 1.e. southern continental Greece and the Peloponnesos, was the most removed from land. The line slopes in Table II may reflect this environmental transition. The line for the southern Pindos section of Plaka is closer to the Franciscan basaltic material lines than is the line for the Karpenision section of central continental Greece, though the difference may not be statistically s,gnificant because of the small number of samples used in calculating some of the values. Several FeO/A1203 curves intersect the abscissa above the origin, which would not be the case if all iron present were associated with clay minerals. Table II presents the mineral content of a select number of samples, and several of these contain hematite. The source of this hematite could be dehydrat m n transformation of authlgenic ferric hydroxides (Van Houton, 1968}, of ferric hydroxides derived from the alteration of illite {Steinberg et al., 1977) or from adsorption onto and transport by clay particles, particularly kaolinite or halloysite {Carroll, 1958}. Petrographic sections of these rocks, particularly those of radlolarian "sands", contain abundant opaque stringers of iron oxide. Other authors (Audley-Charles, 1965; Grunau, 1965; Barrett, 1979} report c o m m o n occurrences of mmro-particles of iron oxides and of pyrite, although this mineral was not detected m the Pmdos samples. The slope of the Franciscan line is steeper than the lines for the collective Greek samples, both for FeO/AI203 and for TiO2/AI203. However, the difference in TiO2/AI203 between the Franciscan and the terrigenous material average ~s very slight, and the stippled area encompassing the Greek points almost includes the Franciscan line. The proximity of the TiO2/A1203 Franciscan hne to the average terrigenous material line could be due to sedimentation of continental material, reflecting an eolian contribution, or may reflect some more felsic volcanic material such as the tuff and dacite that underlie some of the Franciscan cherts in sections reported by Hopson et al., 1981, but not observed in the Franciscan localities sampled for this study. A look at the change in A1/A1 + Fe + Mn values m one locality (Fig. 9, Karpenismn section of central Greece} shows the variation over time in a single area. This ratio is another index of continental provenance. Typical continental material has a value of 0.619 (average shale composition} while marine biogenous material has a value of 0.391. Basalt,c material from the East Pacific Rise has the low value of 0.00815 (Bostrom, 1976). The prevailing values in the section hover close to that of average continental material (Krauskopf, 1967; Bostrom, 1976). A sharp decrease m values occurs in a sandy horizon containing ophiolite debris, reflecting the higher basic igneous c o m p o n e n t in the sediment. Samples from one bed overlying this horizon continue to reflect an admixture of volcanic material by their lower A1/A1 + Fe + Mn value. Several of the samples analyzed were nodular chert associated with limestone rather than the bedded cherts constituting the greater portion of the rocks {Table I: Dover 34 from the Chalk, several DSDP samples, Q9 from

79 AI/AI+Mn #'Fe 03

05

04

06

452 RED MARLSTONE AND FIRST FLYSCH PINDOS 554 517 644

5,, 350

o

\

~

e

•

.J

/

~o

481 55l 545

~k e \

CALPIONELLID LIMESTONE

,l/

\

/

617

'

56O

,o

541 559

RADIOLARITE

576

662

e~o

585

o/

586

I

~o

658

/

e~

565 609

I

SCALE I0 METERS

~o

? KASTELLI MUDSTONE

Fig. 9. Al/Al + Fe + Mn variation in one locality (section B3, Karpenis]on, central cont m e n t a l Greece). Prevailing ratio is close to the average ratio for terrigenous material (from B o s t r o m , 1976, and references therein), but influx of ophiolite debris-bearing sedim e n t lowers the ratio, bringing it closer to that for volcanic material (see t e x t for further discussion).

the Franciscan melange). Many of these show very low percentages of extrasilicic material. This may reflect the original host rock composition (compare L1, the Laytonville Limestone sample with Q9, a nodule from the same formation), but it may also relate to cation exclusion processes during silifica-

80

tion. If exclusion of impurities (i.e. of any non-siliclc element) dunng sihcification of nodules does occur it could fractionate the original sediment composition. Thus the ratio techniques applied in this study to bedded siliceous sediments may not be useful for chert nodules m limestone. In general the mineral assemblage observed in the Pindos samples (see Table III) is very similar to that found by Steinberg et al., (1977) for the Pindos Zone in northern continental Greece except that albite is much rarer in the samples examined here. They concluded that the non-silica component of the sediments was largely detrital since, as in the sections discussed here: (1) the mineralogic assemblage does not change much qualitatively during the Late Triassic and the entire Jurassic, despite changes in the major (biogenic) sedimentary components; and (2) the illite--chlorite assemblage is one that could be derived from erosion of the Hercynian rocks believed to have formed much of the surrounding land mass during this time. But the illite--chlorite assemblage is also increasingly c o m m o n in increasingly older sedimentary rocks (Blatt et al., 1972) and thus is not conclusive. The constancy of the mineralogic assemblage over time through changing proportions of silica and carbonate (i.e., changing types of biogenic input) is also indicative of the small importance, except for silica and calcium carbonate, of biologic material in the final bulk composition of the rocks. The major elemental composition of siliceous micro-orgamsms has been measured m partial or complete analyses in other studies (Martin and Knauer, 1973; Van Bennekom and Van der Gaast, 1976; Kastner, 1980); these studies have shown that the non-silicic elements consitute only a small percentage of the total composition of the organisms, which may, however, have played a significant role as agents of sedimentation through the ingestion of particles in the water column and excretion of particle agglomerates in the form of fecal pellets (e.g., Schrader, 1971; Roth et al., 1975).

T A B L E lII Statistmal data for localltms f e a t u r e d in Figs. 7 and 8 Section

No samples

Y-m tercep t

Slope

Correlation coeffmient

A. F e O vs. A1203 K a r p e n i s l o n (B3) Tsipiana Plaka (Bs) Franciscan

29 5 7 5

0 080 0.216 0.151 0.350

0.47 0.41 0 33 0 59

0.829 0.877 0.933 0 898

B. TIO2 vs Al203 Karpension (B3) Tsipiana Plaka (Bs) Franciscan

29 5 7 5

0 013 0.012 0.032 0.001

0.042 0.039 0.014 0.060

0 931 0 975 0.589 0 998

81

The presence of kaolinite is n o t surprising in a tropical or equatorial area (0--20 ° paleolatitude; Biju-Duval et al., 1977; Channell et al., 1979). The extreme weathering that results in an iron- and kaolinite-bearing sediment has been invoked for Tethys sediments b y Grunau (1965) and b y Hs~i (1976). Smectite is ubiquitous, and is certainly in part of volcanic origin. Beds of tuff in the Jurassic in the north of Greece (Lecanu, 1976) demonstrate that some volcanic ash was supplied to this part of the Tethys, probably from the subduction zone that was operating to the northeast at this time in the nearby Vardar ocean (Aubouin, 1977; Le Pichon and Blanchet, 1978). ISOPACH MAPS OF SEDIMENTARY

F A C I E S IN T H E P I N D O S B A S I N

Sediment dispersal, even from a localized source such as a river m o u t h or submarine channel, does n o t necessarily follow a linear thickness gradient. Current flow and thus sediment transport will be influenced by sea floor relief and ultimately can change the geography of the sea floor. To help clarify the paleogeography of the Pindos Basin, identify sources and distribution patterns of pelagic and extra-basinally derived sediments and to observe the interactions of these two influences, lsopach maps of sedimentary facies of the Pindos Zone have been constructed (Figs. 2, 3, 4 and 5). The maps do n o t a t t e m p t any palinspastic reconstruction of the basin b u t are contoured around points drawn directly u p o n a base map of present day Greece witho u t consideration of the underlying series of imbricated north--south trending thrust sheets. At best the maps represent an east--west compressed picture of the Pindos sea floor. There is a consistent pattern of facies thicknesses over time that suggests the long term existence of smaller depressions surrounded by relative (sub~narine) highs within the Pindos Basin, b u t there are also thickness patterns that change from one map to the next. These may be interpreted as reflecting local tectonic events, changes in current activity, perturbations in the calcite compensation depth, slumping, or other redeposition of sediments. The maps in Figs. 3, 4, and 5 and the accompanying descriptions are based on a b o u t sixty data points, the actual number varying with the facies mapped. The locations of sections used in the construction of the maps are shown in Fig. 2. Data were compiled from the author's field notes and from theses and published literature (see Introduction for citations). Radiolarite plus underlying Kastelli Muds t one (Dogger ? - - Middle.Late Maim)

Several features stand o u t in the map (Fig. 3). The sections thicken southward as far as central continental Greece north of Karpenision (the Agrapha region), where a thinning extends NE--SW across the Pindos Zone. South o f this area the section thickens again. In the Peloponnesos (fewer data points) this southward thickening blends with an eastward thickening, outlining a loosely defined broad sedimentary wedge of siliceous sediments.

82

Calplonelhd Ltmestone ( Tzthon~an/Bernaszan ) Some of the earlier features persist in this map of the subsequent sedimentary facies, but in contrast to the previous map there is an abrupt thickening southward from nor t he r n continental Greece, then a gradual thinning of section still farther southward (Fig. 4). As with the Radmlarite and Kastelh Mudstone, the throning occurs in a broad cross-area north of Karpemsmn. There is a slight thickening southward of Karpenislon, the the section wedges out altogether in most of the Peloponnesos. In sout hernm ost Peloponnesos the limestone may be represented in a muddier form difficult to distinguish fr o m the overlying Red Marlstone.

Red Marlstone and first Pindos Flysch ( Ti thontan/Berriastan--Turonian/Contactan ) Certain features of previous maps can still be f o u n d m this map (Fig. 5). The throning over the broad cross-area m central Greece persists here, though its trend has shifted toward NNE--SSW. There is a new area of thin sedimentary section in n o r t he r n continental Greece, as well as a gradual eastward thinning in central Peloponnesos of a nearly N--S trend. To the west of this thinnest area in the Peloponnesos the section thickens rather abruptly. DISCUSSION OF PINDOS BASIN ISOPACH MAPS If thin sedgnentary section can be interpreted as shallower parts of basin floor then the Plndos Basra would appear to have been subdivided into at least two smaller basins by a central NE-trendmg shallow block of sea floor t h r o u g h o u t Middle Jurassic to Middle Cretaceous time. The abrupt thickness changes th at define broad sub-regions of the Plndos Zone are suggestive o f a faulted, horst-and-graben relief which would reflect the tensional tectonic regime o f that time. The thickness variation is usually on the order of only a few tens of meters at most, which may be rather a small difference to attribute to currently active, large scale structurally defined relief, even when compaction o f original sediment is considered. The observed sediment patterns may be inherited from topographic features dating back to the Permo?Triassic break up of the continental margin. Certain of the formations (particularly the Radlolarite and Kastelli Mudstone) are thickened locally by redeposited limestone beds bearing oolitic or oncohtic material like that o c c u r n n g in the platform carbonates of Liassic age in the Subpelagonian Zone to the east of Pindos. Sedimentary rocks of Jurassm and Early Cretaceous age are r e por t ed in only a few places in the Gavrovo Zone (paleogeographically a carbonate platform defmmg the western edge of the Pindos Basin). The Gavrovo was doubtless the source of some of the redeposited carbonates, particularly in western central Pelopon-

83 nesos where the section is dominated by thick layers of calcareous microbreccia. Despite the apparent derivation of some of the redeposited beds from the west, the section thickens generally to the east in the Peloponnesos and in northern continental Greece, a pattern attributable to redeposited carbonates from the Subpelagonian and Parnassos Zones (Aubouin, 1959; Johns, 1979). The maps of radiolarite and siliceous mudstone thickness do n o t show any relationship between enrichment in detrital material and proximity to margin source, and thickness variations may be related more to sea floor relief and redistribution of an essentially homogeneous mixture of sediments than to proximity to source material. The CalpioneUid Limestone map (Fig. 4) most resembles the Radiolarite and Kastelli Mudstone map (Fig. 3). The pelagic nature of the sediments should lead to similar map patterns if other factors are unchanged. In northern continental Greece the radiolarite facies includes much unsilicified micritic carbonate as well as the redeposited limestone beds mentioned earlier. The micrite may represent a facies transition from the neritic facies in Yugoslavian Pindos to the deeper water radlolarite facies farther south. Subsequent widespread deposition of pelagic carbonate sediments in Tithonian/ Berriaslan time is nearly a Tethys-wide event (Bernoulli and Jenkyns, 1974) and may be related to an evolutionary burst of the coccolithophorids (Garrison and Fisher, 1969) or to a regional oceanographic event (Winterer and Bossellini, 1981}. The disappearance of this facies in southern continental Greece and most of the Peloponnesos during Tithonian/Berriasian time, on the other hand, may be because the central part of the basin was below the calcite compensation depth. This region which is geographically farthest removed from the neritic facies and carbonate platforms, shows some of the -most silica-rich radiolarite facies, and (see Fig. 7) may be the most "pelagic" chemically. The time of most pronounced reorientation of isopachs in the central elevated area in the Pindos Basin (compare Fig. 5 to Figs. 3 and 4) is coincident with the time of compressional tectonics and westward obduction of ophiolites in the Vardar Zone to the east (Le Pichon and Blancher, 1978). The First Pindos Flysch, featured in Fig. 5, heralds this change of the tectonic regime. Kligfield (1979) discusses reactivation of tensional features in the Tethys in places of weakened continental crust, where shear zones may form when compressional tectonics begin. It is tempting to speculate that oceanic closing in the Vardar Zone found expression in the Pindos structurally as well as through deposition of the First Pmdos Flysch. CONCLUSIONS Major element ratios and mineralogic assemblages of ancient siliceous sediments from environments well characterized geologically were studied in comparison with modern Pacific pelagic sediments. The FeO/AI:O3 ratio of

84 cherts can be sensitive enough environmental discriminators to permit the distinction of ophiolite-associated bedded cherts from bedded cherts associated only with other non-volcanic sedimentary facies. Calculations of FeO/A120~ slopes for individual locahties indicate that geographm variation within a sedimentary setting may be detectable, but these data are n o t sufficmnt to be statistically significant. The TiO:/A1203 ratio does not show sufficient variation to be a useful environmental mdicator. This is possibly because of the equahzing effect of eohan sedimentation of continental TiO2 and Al:O3 in a pelagm setting (Cressman, 1962; Griffin et al., 1968; Bostrom, 1976). A1/A1 + Fe + Mn variation was studied m detail in one stratlgraphic section. Changes in the non-biogenic sedimentary c o m p o n e n t were documentable, the section beginning with essentially average continental material and progressing through intervals of obvious volcanm admixture (volcanogenic minerals visible in hand sample) to intervals of volcanic and continental mixtures n o t easily distinguished in the field from the continental detritus below. Chemical data cor r obor a t e mineralogic data in indmating a predominantly sialic or "average continental material" origm for the non-blogenous components in the Pindos sediments {Steinberg et al., 1977; and this paper) up until earhest Cretaceous time, when subaerial erosion of freshly obduct ed ophiolitic material cropping out to the northeast of the Pindos introduced an " o c e a n i c " c o m p o n e n t (First Pindos Flysch) to the basin sediments. Use o f elemental ratms appears feasible as an environmental interpretative tool for bedded cherts. Cautmn must be used in applying this t e c h m q u e to chert nodules in limestone until further work can be done to characterize elemental fractionation during silicificatmn. Fractionation or cation exclusion varmtion as a f u n c t m n of the host rock may hold the key to solution of the origin of bedded versus nodular chert. The dlstributmn of sediments in the Pindos Basra reflects their sources and processes of sedimentatmn. The accumulation of redeposited platform sediments derived f r om the carbonate banks that flank the basra resulted in thickened sedimentary sections toward the basra edges. Differences in distrlbution patterns of Pmdos pelagnc sediments may be due to dissolution of the carbonate fraction at depth, to changes m currents on the sea floor, to local tectonic changes m sea floor relief, or to combinations of these. Persistent lsopach patterns suggest that the Pindos Basin was subdivided into several smaller depressions surrounded by submarine highs. ACKNOWLEDGEMENTS This paper has benefited considerably from revmws by Drs. Yaacov K. Bentor, R o b er t E. Garrison, M m a m Kastner, and E.L. Winterer. Sherman Bloomer, Cynthia Evans, Ron T. La Borde and John Melchior offered cheerful advice and instruction in X R F sample preparation and analysis. M. Beach

85

typed the manuscript. The author gives warm thanks for these contributions, and thanks Dr. J. Aubouin and numerous other colleagues in France for the kind assistance and hospitality shown her during her sojourn at the University of Paris. Appreciation is extended toward P.A. Baker, K. Grieg, J. Ogg, and Dr. E.L. Winterer for their assistance in the field during the author's three field seasons (1978, 1979, 1980). Fmld work during 1978 was supported by the Centre National de la Recherche Scientifique (France), account 6510041. Subsequent study was funded by the National Science Foundation, grant number EAR78-10786.

REFERENCES Arrhemus, G.O., 1963. Pelagm sediments. In: M N. Hill (Editor), The Sea. Wiley, New York, N.Y., 3" 655--727. Auboum, J., 1959 Contribution fi l'~tude g~ologique de la Grace Septentionale: les Confins de l'Epire et de la Thessalie. Ann. G~ol. Pays Hell., X 1--525. Aubouin, J., 1977. Br~ve presentation de la g~ologie de la Grace. Bull Soc. G~ol France, 7, XIX 6--10. Aubouin, J., Bonneau, M., Davidson, J., Le Boulenger, P., Matesco, S. and Zambetakls, A.. 1976. Esquisse structurale de l'Arc Eg~en externe: des Dinarides aux Taurldes Bull. Soc. G~ol. Fr., 7, XVIII: 327--336. Audley-Charles, M G , 1965. Some aspects of the chemistry of Cretaceous sihceous sedimentary rocks from eastern Timor. Geochim. Cosmochlm. Acta, 29: 1175--1192. Barley, E H., Irwin, W.P and Jones, D.L., 1970. Franciscan and related rocks, and their significance in the geology of western California Calif. Div. Mines Geol , Bull., 183: C70--C81. Barrett, T.J., 1979 Origin of Bedded Cherts Overlying Ophlohtic Rocks m the Itahan North Appemnes, and Implicahons of the Ophiohte--Pelagic Sediment Sequences for Seafloor Processes. D. Phil. Thesis, University of Oxford, 268 pp. Bernoulli, D. and Jenkyns, H.C., 1974. Alpine, Mediterranean, and Central Atlantic Mesozoic facies in relation to the early evoluhon of the Tethys In: R.H. Dott and R.H. Shaver (Editors), Modern and Ancient Geosynclinal Sedimentation. Soc. Econ Paleontol. Mineral., Spec Publ., 19: 129--160. Bernoulli, D. and Laubscher, H., 1972 The pahnspastm problem of the Hellenides. Eclogae Geol. Helv., 65. 107--118. Buu-Duval, B , Dercourt, J. and Le Pichon, X , 1977, From the Tethys Ocean to the Mediterranean Seas: a tectonic model of the evolution of the western Alpine system. In: B. Bi]u-Duval and L. Montadert (Editors), International Symposium on the Structural History of the Mediterranean Basins, Split. Ed. Techmp, Pans, pp. 143--164. Biscaye, P.E., 1968. Mineralogy and sedimentation of Recent deep-sea clay m the Atlantic Ocean and adjacent seas and oceans. Geol. Soc. Am. Bull., 7 6 : 8 0 3 - - 8 3 2 Blatt, H., Mlddleton, G and Murray, R , 1972. Origin of Sedimentary Rocks. PrenticeHall, Englewood Cliffs, N . J , 634 pp, Bostrom, K., 1976. Partmulate and d~ssolved matter as sources for pelagic sediments. Stockholm Contrib. Geol , 30: 16--79. Bostrom, K , Peterson, M.N , Joensuu, O. and Fisher, D., 1969. The origin of A1 poor ferromangoan sediments in areas of high heat flow m the East Pacific Rise. Mar. Geol , 7 : 427--447 Bostrom, K., Kraemer, T. and Gartner, S , 1973 Provenance and accumulatmn rates of opaline silica, AI, Ti, Fe, Mn, Cu, Ni, and Co in Paclfm pelagic sediment. Chem Geol., 1 1 123--148

86 Bostrom, K., Joensuu, O. and Brohm, I., 1974 Plankton: its chemmal composition and its significance as a source of pelagic sediments. Chem Geol., 14 256--271 Cadet, J . P , 1976. Contribution ~ l'Etude G~ologique des Dinarides. les Confins de la Bosnie--Herzogovme et due Montenegro, Essai sur l'Evolution Alpine d'une Pal~omarge Continental. Th~se du Doctorat d'Etat et des Sciences Naturelles, Universit~ d'Orl~ans, 181 pp. Caron, D , 1975..Sur la Gdologie du Prude M~rldional les Monts Lakmon (Epire, Grace) La S~rle des Radiolarites. Th4se du Troisi~me Cycle, Unlverslt~ Pans VI, 119 pp Carroll, D L., 1958. Role of clay minerals in the transportation of iron. Geochim. Cosmochim. Acta, 14 1--27. Celet, P , 1962. Contribution ~ l'Etude G~ologlque du Parnasse--Klona et d'une Partle des Regions Meridionales de la Grace Contmentale. Ann Gdol Pays Hell., 1, XIII_ 1--446 Channell, J E T , d'Argenlo, B and Horvath, F , 1979 Adna, the African promontory, in Mesozom Mediterranean paleogeography Earth Scl. Rev., 15 213--292 Corhss, J.B , 1971. The origin of metal bearing hydrothermal solutions J Geophys. Res , 68 8128--8138. Cressman, E R., 1962 Data of geochemistry non-detntal siliceous sediments U.S. Geol. Surv, Prof. Pap., 440 T 1--22. Cronan, D.S., 1974 Authigenic minerals m deep-sea sediments. In. E D Goldberg (Editor), The Sea. Wiley, New York, N.Y., 5 491--525 Degens, E.T., 1965 Geochemistry of Sediments a Brief Survey. Prentme-Hall, Englewood Cliffs, New Jersey, N.J., 342 pp. Dercourt, J., 1964. Contribution ~ l'Etude G~ologlque d'un Secteur de Pdloponndse Septentrionale. Ann G~ol. Pays. Hell., XV: 1--417 Flament, J . M , 1973. De l'Olonos au Chelmos Etude G~ologique d'un Secteur de la Nappe du Pmde--Olonos Th/~se du Troisi~me Cycle, Universit~ de Lille. Flanagan, F.J., 1972. Values for international geochemical reference samples. Geochlm Cosmochim. Acta, 3 7 : 1 1 8 9 - - 1 2 0 0 Fleury, J.J., 1973 Pr~cisions sur la S~rie de la Nappe du Pinde l'Age des "Radiolarites" (Dogger--Maim) et des Marnes Rouges a Radiolalres Premier Flysch (Eocr~tac@-S~nonian) Basal, Gr4ce C R Acad. Sci , 298 (D) 201--204. Fleury, J.J., 1977. De Lamia ~ Messolonghi. La Nappe du Pinde--Olonos et l'Unlt~ du Megdovas Bull Soc G~ol Fr., 7, XIX 53--60 Garrison, R.E. and Fisher, A G , 1969_ Deep-water limestones and radlolarites of the Alpine Jurassic. In' G.M Friedman (Editor), Depositional Environments m Carbonate Rock, a Symposmm. Tulsa, Oklahoma. Soc Econ Paleontol. Mineral., Spec. P u b l , 14 20--56. Goldberg, E.D. and Arrhenms, G O., 1958. Chemistry of Paclhc pelagic sediments. Geochim. Cosmochim. Acta, 13 153--212 Griffin, J.J., Wmdom, H. and Goldberg, E.D., 1968 The distribution of clay minerals in the world ocean Deep-Sea Res., 15' 433--459 Gross, G.A , 1965. Geology of iron deposits in Canada, I_ General geology and evaluation of iron deposits. Geol, Surv. Can Econ Geol R e p , 22" 1--258 Grunau, H.R., 1959. Mikrofazies und Schmhtung Ausgewahlter, Jungmesozoischer, Radiolarit-Fuhrender Sedimentserien der Zentral-Alpen. E J. Brlll, Leiden, 179 pp Grunau, H.R., 1965. Radiolarian cherts and associated rocks m space and time. Eclogae Geol. Helv , 58: 157--208. Hart, R., 1970 Chemical exchange between seawater and deep-ocean basalts Earth Planet ScI Lett., 9" 269--279 Hopson, C.A., Mattinson, J . M , Pessagno, E A , 1981 Coast range Ophio]ite, western Califorma In W.G. Earnst (Editor), Geotectonic Development of California. PrenticeHall, Englewood Cliffs, N J , pp 232--248 Hsi~, K.J., 1976. Paleoceanography of the Mesozoic Alpine Tethys Geol. Soc. Am. Spec Pap., 1 7 0 40 pp.

87 Hurd, D.C., 1973. Interachons of bLogemc opal, sediment, and seawater in the Central Equatorial Pacific. Geochim Cosmochim. Acta, 37- 2257--2282. Ingle, J C., 1980. Depositional history and significance of Neogene diatomites from the Pacific Rim. 26th Int. Geol. Congr., II: p. 487 (abstracts). Jackson, M.L., 1969. Soil Chemical Analysis--Advanced Course. Department of Soil Science, Umverslty of Wisconsin, Madison, Wis., 895 pp. Johns, D . R , 1979. Mesozoic carbonates and associated deposits from central Greece Sedimentology, 25' 561--574. Kastner, M., 1980. Authlgemc silicates in deep-sea sediments: formation and diagenesis. In: C. Emiliani (Editor), The Sea, 7. in press. Kastner, M., Keene, J B. and Gieskes, J M , 1977 Diagenesls of siliceous oozes -- chemical controls on the rate of opal-A to opal CT tranformation an experimental study. Geochlm Cosmochim. Acta, 41: 1041--1059. Keene, J B., 1975 The Distribution, Mineralogy, and Petrography of Blogenic and Authigenic Silica from the Pacific Basra. D. Phil Thesis, Univ. Cahf., San D~ego, 280 pp. Khgfield, R., 1979 The Northern Appenines as a colllslonal orogen Am. J. Scl., 279. 676--691. Krauskopf, K., 1967. Introduction to Geochemistry. McGraw-Hill, New York, N.Y., 706 PPLe Plchon, X. and Blanchet, R., 1978. Where are the passLve margins of the western Tethys Ocean? Geology, 6: 597--600. Lecanu, H , 1976. Contribution ~ l'Etude G~ologlque des Hell~nides La r~glon du Haut PenCe. Th~se du Trolsi~me Cycle. Umversit~ Paris, VI, 166 pp. Loftus, D L., 1966. The Geology of the Pindos Zone in the Navpaktos--Thermon Region, Western Greece D. Phil. Thesis Imperial College, 268 pp. Lyberls, N., 1978. Etude G~ologique de la Pattie Meridionale des Montagnes d'Agrapha (Evritanie, Grace). Th~se du Troisi~me Cycle Umverslt~ Paris, VI, 145 pp. Lyberis, N., Chotin, P and Doubinger, J , 1980. Pr~clsions stratigraphiques sur la S~rie du Prude (Grace). la Dur~e de s~dimentation des radlolarites. C.R. Acad. Sci., 290 (D): 1513--1516. Martin, J H. and Knauer, G.A , 1973. The elemental composition of plankton Geochim. Cosmochim. Acta, 37: 1639--1653. Mpodoz,s-Marm, C., 1977 Etude G~ologlque de la R~gion d'Agrapha (Zone du Pinde, Evntame, Grace) Essai de Classification G~ochimique des Sediments Hypersllicleux Matins Th~se du Troisi~me Cycle Universit~ Paris, VI, 245 pp. Paten, G C , 197(}. Rlcherche sulla genesl delle rocce slllcee non detritiche Mere. Soc. Geol. Italia, 9 665--707. Roth, P H., Mull,n, M.M. and Berger, W.H., 1975. Coccohth sedimentation by fecal pellets laboratory and field observations. Geol. Soc. Am. Bull., 8 6 1079--1084. Schrader, J H , 1971 Fecal pellets: role in sedimentation of pelagic diatoms. Science, 174" 55--57 Shlmizu, H. and Masuda, A., 1977. Cerium in chert as an indicator of marine environment of Its format,on. Nature, 226: 346--348. Steinberg, M., Despralrles, A , Fogelgesang, J F., Martin, A., Caron, D. and Blanchet, R., 1977. Radiolarites eL sediments hypersilicieux oceaniques: une camparaison. Sedimentology, 24: 547--563. Steinberg, M. and MpodozLs-Marin, C., 1978 Classification g~ochlmlques des radiolarites et des sediments silicleux oceaniques, s,gniflcation paleo-oceanographique Oceanol. Acta, 1: 37--49. Tureklan, K.K., 1965. Some aspects of the geochemistry of marine sediments In: J P. Riley and G Skirrow (Editors), Chemical Oceanography, 2 Academic Press, London, pp. 81--126. Van Bennekon, A.J. and Van der Gaast, S.J., 1976. Possible clay structures m frustules of hwng diatoms. Geochim. Cosmochlm. Acta, 40 1149--1152. -

-

88 Van Erve, A.W., 1977 Palynologlcal investigation m the Lower Jurassic of the Vicentmlan Alps (northeastern Italy) Rev. Palaeobot. Palynol , 23_ 1--117. Van Houton, F.B., 1968. Iron oxides m red beds Geol Soc. Am. Bull., 79: 399--416. Wachs, D. and Hein, J.R., 1975. Franciscan limestones and their environments of deposition. Geology, 3: 29--33. Winterer, E.L. and Boselhnl, A , 1981. Subsidence and sedimentation on a Jurassic passtve continental margin (southern Alps, Italy) Bull. Am. Assoc. Pet. G e o l , 65: 394--421. Winterer, E.L. "and Jenkyns, H.C., 1979. Radiolarians, dtatoms, and the origin of Mesozoic ribbon chert Geol. Soc. Am., 11' 542--543 (abstract)