Clay sedimentation along the southeastern Neo-Tethys margin during the oceanic convergence stage

Applied Clay Science 24 (2004) 287 – 298 www.elsevier.com/locate/clay

Clay sedimentation along the southeastern Neo-Tethys margin during the oceanic convergence stage S. Shoval Geology Group, Department of Natural Sciences, The Open University of Israel, 16, Klausner St., Tel Aviv 61392, Israel Received 30 May 2003; received in revised form 12 August 2003; accepted 19 August 2003

Abstract The marine sedimentation along the margin of the southeastern Neo-Tethys during the oceanic convergence stage between the Senonian and the Eocene took place on sea-bottom topography formed by the folding of the Syrian arc deformation belt. The clay mineral assemblage within the marine rocks of the synclinal basins of the Syrian arc deformation belt in the southeast of Israel is dominated by smectitic IS (interstratified illite/smectite rich in smectite layers) accompanied by kaolinite, palygorskite and occasional sepiolite. The smectitic IS originated by conversion of the smectite transported from the open marine environment to the synclinal basins. The conversion of the precursor smectite took place due to warm water and the higher salinity resulting from the development of stratified water bodies in the marine synclinal basins. The origin of authigenic palygorskite and occasional sepiolite is related to the conditions of hypersaline bottom waters due to accumulation of residual heavy brines, enriched by Mg. Detrital kaolinite and discrete illite accompanying the smectitic IS in the marine rocks were transported to the Tethyan margin from the continent. D 2004 Elsevier B.V. All rights reserved. Keywords: Clay; Illite/smectite; Illitization; Interstratification; Kaolinite; Neo-Tethys; Palygorskite; Synclinal basin

1. Introduction The sedimentary sequence of the Senonian to Eocene in Israel and the nearby area was deposited along the margin of the southeastern Neo-Tethys during the primary oceanic convergence stage, which began during the late Cretaceous (Garfunkel, 1988). In the eastern Mediterranean region, the tectonic activity resulted in the folding of the Syrian arc deformation belt (Bosworth et al., 1999). The fold topography of the Syrian arc was covered by a marine transgression that caused the sea to extend to 600 –1000 km southeast of E-mail address: [email protected] (S. Shoval). 0169-1317/$ - see front matter D 2004 Elsevier B.V. All rights reserved. doi:10.1016/j.clay.2003.08.010

the present coast (Garfunkel, 1988). Thus, the sedimentation along the Tethyan margin during the convergence stage took place on sea-bottom topography formed by the folding of the Syrian arc deformation belt (Bartov et al., 1972). According to Speijer (1994) in the Nahal Avdat (Negev, Israel) and the Abu Rudeis (Sinai, Egypt), the deposition took place in NE – SW trending basin, extending parallel to the Tethyan margin of the Arabo– Nubian Shield, at the paleodepth of 500– 700 m. This paper concentrates on the marine clay mineral assemblages within the Senonian to the Eocene formations deposited in the synclinal basins of the Syrian arc deformation belt in the southeast of Israel (Table 1).

288

S. Shoval / Applied Clay Science 24 (2004) 287–298

In comparison with the sedimentation in the northwest of Israel (Shoval, 2003), the sedimentation here took place through the side closer to the Arabo– Nubian continent. The sedimentation in the marine synclinal basins brought to the deposition of thicker units. Marine transgression during the Santonian and the Campanian brought in the southeast of Israel to the deposition of chalk of the Menuha Formation (up to 100 m) and the overlaying porcelanite, chert and phosphorite of the Upper Campanian Mishash Formation (up to 120 m) (Garfunkel, 1978; Goldberg et al., 1978). These formations consist mainly of smectite (montmorillonite) (Nathan, 1969). Corresponding to these formations, the En Zetim Formation and Say’yrim Formation were deposited in the north of Israel and in the Elat area, respectively. The overlaying marl of the Ghareb Formation (up to 163 m) was deposited in basins all over Israel during the Maastrichtian. This formation consists of smectite with variable amounts of kaolinite and discrete illite (Bentor et al., 1963; Bentor, 1966; Nathan, 1969). The area occupied by smectite-rich marine sediments greatly increased during the marine transgression of the Paleocene. The calcareous shale of the Danian and Landenian Taqiye Formation (up to 105 m) is exposed in Israel and Jordan. In the southeast of Israel, the sequence from the base of the Taqiye formation upwards shows a gradual change from a smectite (montmorillonite) – kaolinite assemblage through almost pure smectite to a smectite– palygorskite and sepiolite assemblage (Nathan, 1966; Arkin et al., 1972). According to Nathan (1969), the kaolinite is detrital, the smectite is partly detrital and partly neoformed, and the palygorskite and sepiolite are entirely Table 1 The studied Senonian to Eocene formations exposed in the southeast of Israel Time units Eocene Paleocene

Group

Formation

Lithology

Avedat

Mor

Mt. Scopus

Maastrichtian Campanian

Upper Taqiye Lower Taqiye Ghareb Mishash

Santonian

Menuha

Chalk, limestone Calcareous shale Calcareous shale Marl Porcelanite, flint, phosphorite Chalk

Lower Eocene Landenian Danian

Senonian

neoformed. The deposited sediments changed during the Lower Eocene and the chalk and limestone of the Mor Formations (up to 30 m) were formed in the southeast of Israel. Smectite and palygorskite are the major clay minerals in these formations (Nathan and Flexer, 1977). In this paper a novel point of view as to the origin of smectitic IS (interstratified illite/smectite rich in smectite layers) and palygorskite in the marine sediments deposited in synclinal basins along the Tethyan margin is suggested. Curve-fitted FT-IR spectra in the OH stretching region were first applied for quantitative determination of kaolinite relative to IS.

2. Materials and methods 2.1. Samples Marls and calcareous shales were collected from the Senonian to Eocene formations exposed in the southeast of Israel (central and northern Negev area). A list of the examined formations is given in Table 1. 2.2. Methods Bulk rocks, as well as their decalcified clay fractions, were investigated by the following methods: – X-ray diffracrometry (XRD) with a Philips PW3710 diffractometer using Cu Ka radiation 35 kV – 40 mA and a curved graphite monochromator. Oriented clay fractions, after carbonate removal with diluted HCl, decantation and glicolation (Eslinger and Pevear, 1988; Moore and Reynolds, 1997), were employed. – Infrared spectroscopy (FT-IR) using a Nicolet FTIR spectrometer and ‘‘Omnic’’ software. Bulk rock samples, after homogenization by grinding, were employed. The samples were recorded in KBr disks. – Scanning electron microscopy (SEM) and chemical analyses were obtained using a JEOL (JSM-840) instrument with an attached LINK EDS (Oxford ISIS). Calculations were made using the ZAF4/FLS program. – Transmission electron microscopy (TEM) using a JEM 100 CX apparatus.

S. Shoval / Applied Clay Science 24 (2004) 287–298

2.3. Curve-fitting The infrared spectra were analyzed with a peak fitting function in ‘‘Grams’’ software of the Galactic Industries. Lorentzian shapes were used for fitting the

289

sharp OH stretching bands of kaolinite (Shoval et al., 1999) and a Gaussian shape was used for fitting the broad OH stretching band of the smectitic IS in the FT-IR spectra. The center, area, intensities and width of the bands were selected by the software for best fit.

Fig. 1. X-ray diffractograms of the clay assemblages. (a) Smectitic IS – palygorskite assemblage. (b) Smectitic IS assemblage. (c) Smectitic IS – kaolinite assemblage. (IS = smectitic illite/smectite, P = palygorskite, K = kaolinite, DI = discrete illite, Q = quartz, OP = opal-CT, CP = clinoptilolite).

290

S. Shoval / Applied Clay Science 24 (2004) 287–298

3. Results 3.1. The clay mineral assemblages The clay mineral assemblage in the marine rocks was determined in the clay fractions according to the

X-ray diffraction data. In accordance with Nathan (1966, 1969) and Arkin et al. (1972), three types of clay assemblages were identified in the sediments of the marine synclinal basins in the southeast of Israel. A 1.7-nm smectitic IS of R = 0 type (randomly ordered IS, very rich in smectite layers) is defined here

Table 2 The mineralogical composition of the bulk rocks and the clay fractions in samples of the Senonian to the Eocene formations in the southeast of Israel (central and northern Negev area) Rock units

No.

Rock

Location

Bulk Rocka

Decalcified clay fractionb

Calcite versus IS versus IS or K P DI Others clay (%) K (%) S (%) (%) (%) (%) Lower Eocene Mor Fm.

80.58.9 80.58.8 80.58.2 – 62 80.58.1 – 94 Landenian Upper Taqiye Fm. 80.61.1 – 501 80.61.2 80.60.0 80.60.1 – 508 80.60.2 – 509 80.60.3 – 511 80.60.4 – 510 Danian Lower Taqiye Fm. 80.15.1 80.16.1 – 66 80.16.1 – 8 80.14.1 – 68 80.60.7 – 513 80.60.6 – 512 80.60.5 – 514 Maastrichtian Ghareb Fm. 80.62.2 – 515 80.62.1 – 516 80.61.3 – 517 80.63.2 – 518 80.63.1 Upper Campanian Mishash Fm. 80.32.4 80.32.3 – 558 80.32.2 – 557 80.30.6 – 551 80.30.5 80.11.2 – 53 Santonian – Campanian Menuha Fm. 80.30.2 80.30.3 – 506 80.30.4 – 507 80.29.1 80.29.2

Limestone Limestone Chalk Chalk Calc. shale Calc. shale Calc. shale Calc. shale Calc. shale Calc. shale Calc. shale Calc. shale Calc. shale Calc. shale Calc. shale Calc. shale Calc. shale Calc. shale Marl Marl Marl Marl Marl Phosphorite Porcelanite Porcelanite Porcelanite Porcelanite In chert Chalk Chalk Chalk Chalk Chalk

Nahal Zin Nahal Zin Nahal Zin Nahal Zin Arod Arod Nahal Zin Nahal Zin Nahal Zin Nahal Zin Nahal Zin Arad Oron Oron Yerocham Nahal Zin Nahal Zin Nahal Zin Arod Arod Arod Nahal Zin Nahal Zin Arod Arod Arod Arod Arod Zavoa Arod Arod Arod Nahal Zin Nahal Zin

95/5 95/5 70/30 75/25 85/15 85/15 85/15 85/15 95/5 95/5 95/5 60/40 60/40 50/50 45/55 50/50 70/30 55/45 95/5 90/10 90/10 90/10 95/5 ** *** *** *** *** 85/15 95/5 95/5 95/5 95/5 95/5

100* 100* 100* 100* 100* 100* 100* 100* 100 100 97/3 80/20* 75/25* 85/15* 80/20* 70/30 85/15 75/25 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100

70 70 65 60 10 20 75 85 95 95 90 60 60 65 60 60 70 60 95 95 95 95 95 95 100 100 100 100 95 95 95 90 95 90

0 0 0 0 0 0 0 0 1 1 5 30 30 25 30 35 25 35 0 0 0 0 0 0 0 0 0 0 1 1 1 5 1 5

30 30 35 40 90 80 20 10 0 0 0 5 5 5 5 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

0 0 0 0 0 0 <5 <5 <5 <5 <5 <5 <5 <5 <5 <5 <5 <5 <5 <5 <5 <5 <5 <5 0 0 0 <5 <5 <5 <5 <5 <5 <5

OP, CP OP, CP OP OP, CP OP OP OP Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q OP OP OP OP Q Q Q Q Q Q

IS = illite/smectite, S = smectite, K = kaolinite, P = palygorskite, DI = discrete illite, Q = quartz, OP = opal-CT, CP = clinoptilolite, Calc. shale = calcareous shale. a FT-IR spectroscopy data. b XRD data. * The smectite is accompanying by palygorskite. ** The sample is rich in apatite. *** The sample is rich in opal-CT.

S. Shoval / Applied Clay Science 24 (2004) 287–298

291

Fig. 2. Curve fitted FT-IR spectra in the OH stretching region recorded in bulk rocks containing: (a) IS, without kaolinite. (b) 90% IS and 10% kaolinite. (c) 75% IS and 25% kaolinite. (IS = smectitic illite/smectite, K = kaolinite).

292

S. Shoval / Applied Clay Science 24 (2004) 287–298

as the principle clay mineral of these assemblages (instead of montmorillonite defined in previous works). Representative X-ray diffractograms of the clay assemblages are shown in Fig. 1. – Smectitic IS –palygorskite assemblage: is prevalent in the calcareous shale of the Landenian part of the Taqiye Formation and within the limestone of the Lower Eocene Mor and Adulam Formations. In this assemblage, the IS is accompanied by palygorskite (Fig. 1a) and occasional sepiolite. Opal-CT (diagenetic opal with weak and diffuse diffraction, indicating cristobalite– tridymite like groupings in the mineral) is present. Kaolinite, quartz and discrete illite are absent or appear in very low amounts. – Smectitic IS assemblage: is prevalent in the marl of the Maastrichtian Ghareb Formation. In this assemblage, the IS is almost the only clay mineral (Fig. 1b). Zeolite – clinoptilolite is frequently found in association with the IS. Minor amounts of kaolinite, palygorskite, discrete illite and quartz may be present. – Smectitic IS– kaolinite assemblage: is prevalent in the calcareous shale of the Danian part of the Taqiye Formation. In this assemblage, the IS is accompanied by kaolinite (Fig. 1c). Discrete illite is present. Palygorskite is absent or appear in very low amounts. Quartz appears as an accessory mineral.

the synclinal basins in the southeast of Israel is dominated by smectitic IS accompanied by kaolinite, palygorskite and occasional sepiolite. 3.2.2. The bulk rock The relative amount of smectitic IS versus kaolinite in the bulk rocks were determined according to FT-IR spectroscopy data using curve-fitting technique (Shoval, 2000). The results are summarized in Table 2. The data was obtained according to the curve-fitted FT-IR spectra of the samples in the OH stretching region (Fig. 2). In the spectra of sample containing IS, without kaolinite, a broad OH stretching band appears at 3628 cm 1 (Fig. 2a). In that containing mixtures of IS and kaolinite, the sharp OH stretching band of the kaolinite at 3621 cm 1 overlays the broad OH stretching band of the IS at

In addition to these smectitic IS assemblages, smectite is common within the chalk of the Santonian – Campanian Menuha Formation and in the porcelanite and the phosphorite of the Upper Campanian Mishash Formation. These formations were deposited predominantly in open sea water conditions. 3.2. The relative amount of the clays 3.2.1. The clay fraction The relative amount of smectitic IS, kaolinite, palygorskite and discrete illite in the clay fractions were determined according to the X-ray diffraction data. The results are summarized in Table 2. XRD diffractograms and calibration curves were used for this determination. The results demonstrate that the clay mineral assemblage within the marine rocks of

Fig. 3. FT-IR spectra in the range of the main CO3 and Si – O bands recorded in bulk rocks containing: (a) 50% calcite, (b) 80% calcite.

S. Shoval / Applied Clay Science 24 (2004) 287–298

3628 cm 1, whereas the kaolinite bands at 3696 cm 1 remained undistorted (Fig. 2b). With increase amounts of the kaolinite the undistorted kaolinite bands at 3696 cm 1 become stronger relatively to the combined IS-kaolinite band at 3628 cm 1 (Fig. 2c). Thus, the area-ratios of the illite – smectite component at 3628 cm 1 relative to the kaolinite band at 3696 cm 1 constitute the relative amounts of these clays. Calibration curve was prepared using mixtures of kaolinite and smectitic IS with different ratios. To receive a reliable calibration curve, local deposits of kaolinite (Ramon kaolinite) and smectitic IS (Ramon bentonite; Bentor, 1966) after purification were used. The spectra of mixtures containing up to 50% kaolinite in interval range of 5% were recorded. The linearity of area-ratios in the calibration curve enables quantitative determination of the kaolinite relative to the smectitic IS. Although the FT-IR results are in correlation to that observed by the XRD method, greater amounts of IS were observed by the former method. It seems that the lower amount of smectitic IS detected by the XRD

293

method is due to the low intensity of the diffraction peaks as a result of poorly crystallized structure and the broad diffraction peaks of the interstratified IS. 3.3. The amount of calcite The relative amounts of calcite versus clay minerals in the bulk rocks according to FT-IR spectroscopy data are summarized in Table 2. These amounts were calculated according to the intensities of the main CO3 band of calcite at about 1430 cm 1 relative to the main Si– O band of the clays at about 1030 cm 1 (Fig. 3) Curve-fitted FT-IR spectra and calibration curves were used for this determination. The results demonstrate that the marine rocks contain pronounced amounts of calcite. 3.4. The composition of the clays The major element compositions of the clay fractions in representative samples are summarized in Table 3. In clay fractions containing smectitic IS

Table 3 The major element composition of the clay fractions in representative samples of the Senonian to the Eocene formations in the southeast of Israel (central and northern Negev area) Rock units

No.

SiO2

Al2O3

MgO

FeO

TiO2

K2 0

Na2O

CaO

Lower Eocene Mor Fm.

80.58.2 – 62 80.58.1 – 94 80.61.1 – 501 80.60.1 – 508 80.60.2 – 509 80.60.3 – 511 80.60.4 – 510 80.16.1 – 66 80.16.1 – 8 80.14.1 – 68 80.60.7 – 513 80.60.6 – 512 80.60.5 – 514 80.62.2 – 515 80.62.1 – 516 80.61.3 – 517 80.63.2 – 518 80.32.3 – 558 80.32.2 – 557 80.30.6 – 551 80.11.2 – 53 80.30.3 – 506 80.30.4 – 507

73.69 78.39 54.42 64.84 62.25 61.55 60.86 59.24 61.04 60.29 59.34 61.04 58.61 62.30 59.92 61.31 60.59 80.73 84.65 95.65 64.95 63.32 57.76

12.22 9.85 17.82 19.56 19.24 19.72 20.14 25.31 25.16 26.88 26.18 23.72 27.53 18.50 17.47 19.05 11.69 8.13 10.58 3.10 19.55 22.40 27.03

4.87 3.96 4.86 4.20 3.91 3.82 3.93 2.71 2.55 1.97 2.50 2.35 1.76 3.90 3.40 4.01 2.22 4.70 1.32 0.29 2.55 2.62 1.80

5.73 4.16 14.67 6.83 9.15 10.56 11.14 6.91 7.21 6.77 9.03 7.83 7.53 11.34 15.19 12.39 19.84 4.51 2.04 0.73 8.00 9.54 8.46

0.69 0.75 2.06 1.14 0.98 0.54 0.71 1.53 1.01 0.80 0.95 1.23 1.11 0.58 0.67 0.76 0.77 0.56 0.47 0.28 1.28 0.85 1.11

1.57 1.41 5.25 2.31 2.41 2.15 1.60 1.54 1.60 1.48 1.62 2.98 2.33 1.76 1.81 1.61 1.28 0.47 0.37 0.12 1.04 0.45 0.93

0.62 0.17 0.28 0.22 0.33 0.29 0.32 0.81 0.42 0.46 0.17 0.31 0.15 0.00 0.26 0.22 0.17 0.04 0.09 0.04 0.30 0.21 0.00

0.16 0.29 0.18 0.74 1.56 1.71 1.03 0.81 0.93 0.99 0.27 0.70 0.86 1.61 0.75 1.02 2.17 0.77 0.44 0.00 1.93 0.44 2.26

Landenian Upper Taqiye Fm.

Danian Lower Taqiye Fm.

Maastrichtian Ghareb Fm.

Upper Campanian Mishash Fm.

Santonian – Campanian Menuha Fm.

294

S. Shoval / Applied Clay Science 24 (2004) 287–298

(without palygorskite or kaolinite), the Al2O3, FeO and MgO contents are characteristic of dioctahedral IS rich in iron and magnesium. The Al2O3 and MgO content increases in samples containing kaolinite and palygorskite, respectively. The SiO2 content increases in samples containing opal-CT. The K2O content reflects the presence of IS. 3.5. The micromorphology and crystallinity of the clay SEM and TEM micrographs of the smectitic IS – palygorskite assemblage are shown in Fig. 4. The palygorskite have elongated euhedral crystals (Fig. 4a), which are characteristic of authigenic origin. The size of the palygorskite needles reaches 3 Am (Fig. 4b).

Fig. 4. Micrographs of the smectitic IS – palygorskite assemblage. (a) SEM Micrographs of palygorskite crystals in the bulk rock. (b) TEM Micrographs of palygorskite needles in the clay fraction (  15 000).

4. Discussion The marine sedimentation along the margin of the southeastern Neo-Tethys during the oceanic convergence stage between the Senonian and the Eocene took place contemporaneously with main folding of the Syrian arc deformation belt. The clay mineral assemblage within the marine rocks of the synclinal basins in the southeast of Israel is dominated by smectitic IS accompanied by kaolinite, palygorskite and occasional sepiolite. 4.1. The origin of the smectitic IS Several types of genesis have been related to the formation of interstratified IS, particularly on deep burial diagenesis, by degradation of illites, by transformation from precursor smectite or by illitization of detrital IS (Inoue et al., 1987; Elliott et al., 1999). For the Albian and the Cenomanian marine rocks of the Judea Group exposed in the Jerusalem Hills, Taitel-Goldman et al. (1995) rejected possible neoformation of orderly interstratified IS on deep burial diagenesis. The arguments are: the burial depth of the sediments was far less than the minimum depth of approximately 3000 m required for ordering; random interstratification is found in rock units underlying those with ordered interstratification; ordered or slight interstratification was observed in rock units deposited in parallel and buried at similar depths. In accordance, Sandler et al. (2002) found that the Middle Albian to the Turonian sequences in the Makhtesh Ramon and Makhtesh Hatira were not subjected to deep burial or to thermal events since K – Ar dating of clay separates yielded ages corresponding to the stratigraphic ages or up to 80% older. Following these observations, it seems that deep burial diagenesis did not take place in the sedimentary rocks of the Senonian to Eocene formations which are younger and buried shallower. An IS origin in a marine environment, by illitization of precursor smectite of volcanic origin, was suggested by Nadeau and Reynolds (1981). Deconinck et al. (1988, 2001) found that illitic minerals were formed at low temperature (surface temperature) in Purbekian sediments exposed in the Jura Mountains. Kirsimae et al. (1999) found that diagenetic formation of IS in shallow marine sediments can

S. Shoval / Applied Clay Science 24 (2004) 287–298

occur in warm marine water ( f 35 jC), given enough time for the process to take place. Based on this observation, it seems that the smectite transported from the open marine environment to the synclinal basins along the Tethyan margin was converted to IS (Shoval, 2001a, 2002). The conversion of the precursor smectite probably took place due to the warm water and the higher salinity resulting from the development of stratified water bodies in the marine synclinal basins. Residual heavy brines, enriched by K and Mg might reflux from the extending lagoon or sabkha and accumulate on the bottom in the synclinal basins in which the conversion of the precursor smectite to smectitic IS took place. Existence of warm sea water environment is indicated by the arid climatic conditions expanded on the coastal region of the southeastern Tethys margin during the Upper Paleocene (Bolle et al., 2000) and by the warm climate conditions during the Early Eocene (Robert and Chamley, 1991). Deposition in hypersaline and stagnant water is indicated by the presence of marcasite, barite and celestite concretions, some gypsum and bituminous material in the marl and calcareous shale of the Ghareb and the Taqiye Formations. The observation that IS was formed under surface temperature conditions along the margin of the southeastern Neo-Tethys (Shoval, 2001a, 2002) are supported by later work of Sandler et al. (2002). By K – Ar dating of fine fractions rich with randomly ordered IS separate from the Upper Albian to Turonian rocks exposed in the southeast of Israel, Sandler et al. found that some clay separates yielded ages corresponding to the stratigraphic ages. The rest yielded ages up to 80% older, much younger than the assumed continental provenance ages that are three to five times older. They concluded that illitization acts on detrital IS at ambient temperatures and, in contrast to deep-sea recent sediments, these clays do not fully retain the provenance signature as they are partially reset in environments of oscillating shallow waters where evaporation might produce K-rich brines. 4.2. The origin of the palygorskite Smectitic IS –palygorskite assemblage with occasional sepiolite is prominent in the calcareous shale of the Landenian part of the Taqiye Formation and within the limestone of the Lower Eocene Mor

295

Formation in the southeast of Israel. Palygorskite is indicative of Mg-rich environments. Several types of genesis have been related to the formation of palygorskite, particularly on evaporative pedogenic and lacustrine environments (Singer, 1984) and in perimarine alkaline basins (Weaver and Beck, 1977). The genesis of palygorskite in marine sediments is explained either by diagenesis (a change of degraded smectite) or by neoformation (chemical precipitation) from the water in the presence of magnesium and silica (Arkin et al., 1972). An authigenic, entirely neoformed origin, has been related to the palygorskite in the Taqiye Formation (Nathan, 1966, 1969). The formation of authigenic palygorskite requires appropriate inputs of Mg2 + and SiO2 taken from a solution, which in many sedimentary basins are severely restricted (Zhou et al., 1999). According to Thiry and Jacquin (1993), the formation of palygorskite in Cretaceous marine sediments is diagnostic of magnesian-rich environments and is indicative of warm and hypersaline bottom waters. Based on these observations, Shoval (2001b) related the origin of the authigenic palygorskite and occasional sepiolite deposited along the Tethyan margin to the conditions of hypersaline bottom waters. These conditions were formed due to the development of stratified water bodies in the marine synclinal basins and the accumulation of residual heavy brines, enriched by Mg, on the bottom in which the formation of the authigenic palygorskite took place. The existence of a magnesian-rich environment is also indicated by the precipitation of sepiolite. The deposition of the authigenic palygorskite in the Taqiye and Mor Formation is associated with the presence of opal-CT (Table 2). In these samples significant amounts of SiO2 are presence (Table 3). Opal-CT is generally related to an abundance of biogenic silica from diatoms and radiolarians due to high organic productivity during period of strong marginal upwelling currents (Steinberg, 1981; Leinen et al., 1986). The closely related distribution pattern of the authigenic palygorskite and opal-CT (Table 2) indicates that the SiO2 requires for the formation of the palygorskite was supplied by the marginal upwelling currents. Indeed, greater amounts of palygorskite and opal-CT are found in the marine rocks of the synclinal basins in the northwest of Israel, through the side turning to the upwelling currents (Shoval, 2003).

296

S. Shoval / Applied Clay Science 24 (2004) 287–298

According to Bolle et al. (2000), arid climatic conditions during the Landenian are progressively indicated by the gradual disappearance of the detrital kaolinite and the increased abundance of palygorskite and sepiolite in the Taqiye Formation. The assumption that input of detritus from palygorskitic soils is the source of the palygorskite in the Landenian part of the Taqiye Formation is rejected for the following reasons: The euhedral shape of the palygorskite crystals (Fig. 4) is characteristic of authigenic origin within the marine basin, not in accordance with the shape of detrital particles. The shore of the exposed continent was located far away, several hundreds to thousands of kilometers southeast of the depositional environment (Garfunkel, 1988). The amounts of palygorskite and opal-CT in the Upper Taqiye Formation increase in the dipper marine environment of deposition of the northwest of Israel (Shoval, 2003), not in accordance with transportation from land. The appearance of palygorskite is not particular of the Landenian part of the Taqiye Formation; in the northwest of Israel it is characteristic of the Maastrichtian Ghareb Formation, the Danian and Landenian parts of the Taqiye Formation and the lower Eocene Adulam Formations (Shoval, 2003). Thiry and Jacquin (1993) also reported that palygorskite is common in Cretaceous oceanic sediments, but never within their correlative continental deposits.

tropical conditions. According to Arkin et al. (1972), the source of the kaolinite in the Taqiye formation was situated on a land mass, located to the east and southeast, which had a moderate relief and a well developed kaolinitic soil cover.

5. Conclusion The folding of the Syrian arc deformation belt along the margin of the southeastern Neo-Tethys during the oceanic convergence stage brought to the formation of marine synclinal basins. The smectitic IS was formed by conversion of precursor smectite due to warm water and the higher salinity resulting from the development of stratified water bodies in the synclinal basins. The palygorskite was formed in conditions of hypersaline bottom waters due to accumulation of residual heavy brines enriched by Mg. The SiO2 requires for the formation of the palygorskite was supplied by the marginal upwelling currents.

Acknowledgements This work was supported by The Open University of Israel Research Fund. This support is gratefully acknowledged.

4.3. The origin of the kaolinite Smectitic IS– kaolinite assemblage is prevalent in the marl of the Maastrichtian Ghareb Formation and in the calcareous shale of the Danian part of the Taqiye Formation in the southeast of Israel (Table 2). In marine sediments, kaolinite is considered to be detrital mineral, transported from the continent (Griffin et al., 1968; Robert and Kennett, 1992, 1994; Chamley, 1998). In accordance, greater amounts of kaolinite are present within the marine rocks deposited the southeast of Israel (Table 2), through the side closer to the Arabo –Nubian continent, relative to that deposited in the northwest of Israel, through the side turning to the open Tethys Ocean (Shoval, 2003). Kaolinite is generally formed on land in a warm, humid climate, under acid weathering conditions and effective leaching (Robert and Chamley, 1991). Kaolinitic soils are common in equatorial to

References Arkin, Y., Nathan, Y., Starinsky, A., 1972. Paleocene – early Eocene environment of deposition in the northern Negev (southern Israel). Bull.-Isr. Geol. Surv. 56/72 (17 pp.). Bartov, J., Eyal, Y., Garfunkel, Z., Steinitz, G., 1972. Late Cretaceous and Tertiary stratigraphy and paleogeography of southern Israel. Isr. J. Earth-Sci. 21, 69 – 97. Bentor, Y.K., 1966. The clays of Israel: guidebook to the excursion. Int. Clay Conf. Jerusalem, Israel. Isr. Progr. for Sci. Transl., Jerusalem. 121 pp. Bentor, Y.K., Bodenheimer, W., Heller, L., 1963. A reconnaissance survey of the relationship between clay mineralogy and geological environment in the Negev. J. Sediment. Petrol. 33, 874 – 903. Bolle, M.P., Pardo, A., Adatte, T., Von Salis, K., Burns, S., 2000. Climatic evolution on the southeastern margin of the Tethys (Negev, Israel) from the Paleocene to the early Eocene: focus on the late Paleocene thermal maximum. J. Geol. Soc. (Lond.) 157, 929 – 941.

S. Shoval / Applied Clay Science 24 (2004) 287–298 Bosworth, W., Guiraud, R., Kessler II, L.G., 1999. Late Cretaceous (ca. 84 Ma) compressive deformation of the stable platform of northeast Africa (Egypt): far-field stress effects of the ‘‘Santonian event’’ and origin of the Syrian arc deformation belt. Geology 27, 633 – 636. Chamley, H., 1998. Clay mineral sedimentation in the ocean. In: Paquet, N., Clauer, N. (Eds.), Soils and sediments (mineralogy and geochemistry). Springer, Berlin, pp. 269 – 302. Deconinck, J.F., Strasser, A., Debrabant, P., 1988. Formation of illitic minerals at surface temperatures in Purbekin sediments (Lower Berriasian Swiss and French Jura). Clay Miner. 23, 91 – 103. Deconinck, J.F., Gillot, P.Y., Steinberg, M., Strasser, A., 2001. Syndepositional, low temperature illite formation at the Jurassic – Cretaceous boundary (Purbeckain) in the Jura mountains (Switzerland and France): K/Ar and d18O evidence. Bull. Soc. Ge´ol. Fr. 172, 343 – 348. Elliott, W.C., Edenfield, A.M., Marion Wampler, J., Matisoff, G., Long, P.E., 1999. The kinetics of the smectite to illite transformation in Cretaceous bentonites, Cerro Negro, New Mexico. Clays Clay Miner. 47, 286 – 296. Eslinger, E., Pevear, D., 1988. Clay minerals for petroleum geologists and engineers. Short course notes no. 22. Soc. Econ. Paleontol. Mineral. (SEPM) (233 pp.). Garfunkel, Z., 1978. The Negev-regional synthesis of the sedimentary basins. Sedimentology in Israel, Cyprus and Turkey. Guidebook, Part I: Proc. Tenth Int. Congress on Sedimentology. IAS, Jerusalem, pp. 35 – 110. Garfunkel, Z., 1988. The pre-quaternary geology of Israel. In: YomTov, Y., Tchernov, E. (Eds.), The Zoogeography of Israel. Dr. W. Junk Publishers, Dordrecht, pp. 7 – 33. Goldberg, M., Druckman, Y., Buchbinder, B., Goldbery, R., 1978. Continental to marine environments in the Negev. Guidebook, Tenth Int. Congress on Sedimentology. IAS, Jerusalem, pp. 35 – 110. Griffin, J.J., Windom, H., Goldberg, E.D., 1968. The distribution of clay minerals in the world ocean. Deep-Sea Res. 15, 433 – 459. Inoue, A., Kohyama, N., Kitagawa, R., Watanabe, T., 1987. Chemical and morphological evidence for the conversion of smectite to illite. Clays Clay Miner. 35, 11 – 120. Kirsimae, K., Jorgensen, P., Kalm, V., 1999. Low-temperature diagenetic illite – smectite in Lower Cambrian clays in North Estonia. Clay Miner. 34, 151 – 163. Leinen, M., Cwienk, D., Heath, G.R., Biscaye, P.E., Kolla, V., Thiede, J., Dauphin, J., 1986. Distribution of biogenic silica and quartz in recent deep-sea sediments. Geology 14, 199 – 203. Moore, D.M., Reynolds Jr., R.C., 1997. X-ray Diffraction and the Identification and Analysis of Clay Minerals. Oxford Univ. Press, Oxford. Nathan, Y., 1966. The clay mineralogy of the Upper Cretaceous sediments in the northern Negev. In: Heller, L., Weiss, A. (Eds.), Proc. Int. Clay Conf. Jerusalem, Isr., vol. 1. Isr. Progr. for Sci. Transl., Jerusalem, pp. 147 – 159. Nathan, Y., 1969. Studies on palygorskite. PhD thesis. Heb. Univ. Jerusalem. 153 pp. (Hebrew). Nathan, Y., Flexer, A., 1977. Clinoptilolite, paragenesis and stratigraphy. Sedimentology 24, 845 – 855.

297

Nadeau, P.H., Reynolds Jr., R.C., 1981. Volcanic components in politic sediments. Nature 294, 72 – 74. Robert, C., Chamley, H., 1991. Development of early Eocene worm climates, as inferred from clay mineral variations in oceanic sediments. Palaeogeogr. Palaeoclimatol. Palaeoecol. 89, 315 – 332. Robert, C., Kennett, J.P., 1992. Paleocene and Eocene kaolinite distribution in the South Atlantic and Southern Ocean: Antartic climate and paleoceanographic implications. Mar. Geol. 103, 9 – 110. Robert, C., Kennett, J.P., 1994. Antartic subtropical humid episode at the Paleocene – Eocene boundary: clay mineral evidence. Geology 22, 211 – 214. Sandler, A., Harlavan, Y., Steinitz, G., 2002. K – Ar and Ar – Ar dating of edimentary K-bearing minerals, Mesozoic sequences, Southern Israel. Geol. Surv. Isr., Report GSI/18/ 2002. 82 pp. Shoval, S., 2000. Quantitative estimation of kaolinite relative to smectite or illite in sediments and soils by curve fitting of infrared spectra. Ma’alot Meeting Proc. Israel Geological Society, Jerusalem, p. 118. Shoval, S., 2001a. The Jurassic and the Cretaceous shallow-shelf platform along the Tethyan margin of the Arabo – Nubian shield; an environment of conversion from smectite to interstratified Illite/Smectite. Elat Meeting Proc. Israel Geological Society, Jerusalem, p. 112. Shoval, S., 2001b. Accumulation of bottom brines in Syncline basins; a precipitation environment of the palygorskite in the Paleocene Taqiye formation. Elat Meeting Proc. Israel Geological Society, Jerusalem, p. 113. Shoval, S., 2002. Various types of interstratified illite/smectite along the stratigraphic section of Israel. Maagan Meeting Proc. Israel Geological Society, Jerusalem, p. 114. Shoval, S., 2004. Deposition of volcanogenic smectite along the southeastern Neo-Tethys margin during the oceanic convergence stage. Appl. Clay Sci. 24, 299 – 311, this issue. Shoval, S., Yariv, S., Boudeulle, M., Panczer, G., 1999. MicroRaman and FTIR spectroscopic study of Jurassic pisolitic laterite and flint clay, Makhtesh Ramon, Israel. In: Kodama, H., Mermut, A., Torrance, J.K. (Eds.), Proc. Int. Clay Conf., Clays for our Future. ICC 97 Organizing Committee, 1997, Ottawa, Canada, pp. 623 – 630. Singer, A., 1984. Pedogenic palygorskite in arid environment. In: Singer, A., Galan, E. (Eds.), Palygorskite-Sepiolite Occurrences, Genesis and Uses. Development in Sedimentology, vol. 37. Elsevier, New York, pp. 169 – 176. Speijer, R.P., 1994. Extinction and recovery patterns in benthic foraminiferal paleocommunities across the Cretaceous/Paleogene and Paleocene/Eocene boundaries. PhD thesis. Universiteit Utrecht. Geologia Ultraiectina, No. 124. 191 pp. Steinberg, M., 1981. Biosiliceous sedimentation, radiolarite periods and silica budget fluctuation. Oceanologica Acta 4, 149 – 154 (S. Issue). Taitel-Goldman, N., Heller-Kallai, L., Sass, E., 1995. Clay minerals and feldspars in argillaceous strata of the Judea Group in the Jerusalem Hills. Isr. J. Earth-Sci. 44, 71 – 79. Thiry, M., Jacquin, T., 1993. Clay minerals distribution related to

298

S. Shoval / Applied Clay Science 24 (2004) 287–298

rift activity, sea-level changes and palaeoceanography in the Cretaceous of the Atlantic Ocean. Clay Miner. 28, 61 – 84. Weaver, C.E., Beck, K.C., 1977. Miocene of the United States: a model for chemical sedimentation in peri-marine environment. Sediment. Geol. 17 (234 pp.).

Zhou, H., Murray, H.H., Harvey, C.C., 1999. Formation of the Guanshan palygorskite, Anhui Province, P.R. China. In: Kodama, H., Mermut, A., Torrance, J.K. (Eds.), Proc. Int. Clay Conf., Clays for Our Future. ICC 97 Organizing Committee, 1997, Ottawa, Canada, pp. 89 – 96.