31. Chemostratigraphy of Madeira Abyssal Plain Miocene–Pleistocene Turbidites, Site 9501

Home , Madeira Abyssal Plain, Pelagic red clay

Weaver, P.P.E., Schmincke, H.-U., Firth, J.V., and Duffield, W. (Eds.), 1998 Proceedings of the Ocean Drilling Program, Scientific Results, Vol. 157

31. CHEMOSTRATIGRAPHY OF MADEIRA ABYSSAL PLAIN MIOCENE–PLEISTOCENE TURBIDITES, SITE 9501

Ian Jarvis,2 Jennifer Moreton,2 and Martine Gérard3

ABSTRACT

Miocene to Holocene sediments on the Madeira Abyssal Plain (MAP), northeast Atlantic, are dominated by thick-bedded distal mud turbidites. These turbidites record the history of sedimentary source areas and slope failure on the margins of the Canary Basin since ~15 Ma. Major elements and selected trace elements have been determined in 488 turbidite samples collected between 0 and 325 mbsf (Miocene–Pleistocene) at Site 950, on the western MAP. Carbonate and Ti/Al ratio data have been plotted against a detailed sedimentary log to demonstrate the distribution of turbidite chemofacies through the succession. Three major turbidite groups, recognized previously from Quaternary cores, are confirmed to continue through the older sediment record on the plain. Organic-rich, volcanic, and calcareous turbidites are clearly differentiated on chemostratigraphic logs. Organic-rich turbidites dominate both volumetrically and numerically. They have been deposited since the middle Miocene (~15 Ma) and may be subdivided into three geochemically distinct subgroups, the relative importance of which has changed through time. The oldest sediments are Al rich, reflecting more kaolinitic compositions; two K- and Mg-rich subgroups become dominant upward, implying a trend toward more chloritic and illitic clay-mineral assemblages. These changes indicate an increasing importance of northerly source areas on the northwest African continental slope, and/or climatic changes promoting mineralogical shifts in sediments on the margin. The onset of significant volcanic turbidite deposition occurred in the mid–late Miocene, ~14−16 Ma, with the deposition of low-Ti sediments derived from the vicinity of an evolved volcanic source, possibly the slopes of the Canary Islands off Lanzarote or Gomera. A major change toward more basaltic sources occurred in the late Pliocene (~3.5 Ma), possibly associated with the early development of La Palma. Wide ranges in trace-element compositions and a shift toward less Ti-rich compositions indicate the continued existence of multiple sources with increasing volcanic frac- tionation since that time. Calcareous turbidites have been deposited regularly since the Miocene, but underwent a major decrease in their volcaniclastic component ~3.5 Ma. This is interpreted to indicate the subsidence and draping of the seamount chains to the west of the MAP, which are believed to be the source area for these turbidites.

INTRODUCTION sands and silts (Units Tbcd of Bouma, 1962), but these units progressively disappear distally, leaving only wispy laminated silts and The Madeira Abyssal Plain (MAP) lies in the deepest part of the muds at the base (Units T3-5 of Stow and Shanmugam, 1980). Canary Basin at water depths of ~5.4 km. It consists of three linked Throughout the area, the bulk of each turbidite is typically composed sub-basins, which when combined occupy an area of approximately of Te (T6-8) ungraded muds. 68,000 km2 (Fig. 1). The morphology of the MAP is virtually flat, in- MAP Quaternary sequences have been dated using nannofossil terrupted only by small abyssal hills that rise a few hundred meters biostratigraphy of the pelagic marls and oozes. The turbidites them- above the plain. Quaternary sequences on the MAP represent one of 40û

the most comprehensively studied sedimentary records in the deep 2 Azores N 4 Iberia ocean (Weaver and Kuijpers, 1983; Colley et al., 1984, 1989; Colley MAR and Thomson, 1985, 1992; Kuijpers and Weaver, 1985; Wilson et al., 2 4 1985, 1986; Thomson et al., 1986, 1987, 1993; Weaver et al., 1986, 4 1992, 1994; Weaver, Buckley et al., 1989; Weaver, Thomson, et al., 2 4 1989; De Lange et al., 1987, 1989; Jarvis and Higgs, 1987; Kidd et

4 al., 1987; Searle, 1987; Weaver and Rothwell, 1987; Middelburg and

De Lange, 1988; Pearce, 1991; De Lange, 1992a, 1992b; Jones et al., 4 MAP 1992; McArthur et al., 1992; Middelburg, 1993; Pearce and Jarvis Calcareous Site 950 Organic 30û

1992a, 1992b, 1995; Rothwell et al., 1992; Weaver, 1993; Weaver

and Thomson, 1993). Sediments have been recovered primarily by piston cores to a Volcanic depth of up to 35 m, representing deposition since ~750 ka. More 4 than 160 cores have been collected from the plain, sequences typical- 6 ly comprising meter-thick, fine-grained distal turbidites, interbedded 2 with thin, centimeter to decimeter pelagic ooze, marl, or clay (Weav- Organic er et al., 1986; Weaver and Rothwell, 1987). Thicker turbidites may North Africa have a coarser basal facies (Rothwell et al., 1992), comprising thin 500 km 20û

30ûW20û 10û 1Weaver, P.P.E., Schmincke, H.-U., Firth, J.V., and Duffield, W. (Eds.), 1998. Proc. ODP, Sci. Results, 157: College Station, TX (Ocean Drilling Program). Figure 1. Location map for the Madeira Abyssal Plain (MAP) and ODP Site 2 School of Geological Sciences, Kingston University, Penrhyn Road, Kingston upon Thames, Surrey KT1 2EE, United Kingdom. [email protected] 950. MAR = Mid-Atlantic Ridge; bathymetry in kilometers; sediment trans- 3 Laboratoire Petrologie et Mineralogie, Orstom, 72 Route d’Aulnay, 93143 Bondy port pathways from Pearce and Jarvis (1995), gray arrows = organic-rich, Cedex, France. black = volcanic, white = calcareous turbidites.

535 I. JARVIS, J. MORETON, M. GÉRARD selves exhibit distinctive color and thickness variation, and yield MATERIALS unique mixed coccolith assemblages. By combining these data, individual turbidites have been successfully correlated between cores Site 950 is located in the southwestern part of the central MAP (Weaver and Kuijpers, 1983; Weaver et al., 1986; Weaver, Buckley (Fig. 1) at 31°9.01′N, 25°36.00′W, at a water depth of 5438 m. This et al., 1989; Weaver, Thomson, et al., 1989; Weaver, 1993). In addi- location is only 25 km west-southwest of the site of a 34-m-long giant tion, De Lange et al. (1987, 1989) studied the bulk-geochemical anal- piston core, MD10, which contains a complete turbidite sequence be- yses of turbidites from two representative MAP cores, and recog- ginning ~690 ka (isotope Stages 1 through 17). Core MD10 was nized three broad compositional groups: green organic-rich turbidites geochemically characterized by De Lange et al. (1987, 1989) and, − with 0.3% 2.5% organic carbon (Corg); gray “volcanic” turbidites along with Core D10688, was the first to be used to demonstrate the containing volcaniclastic debris and high concentrations of elements application of chemostratigraphic methods to sediment provenance such as Ti; and white calcareous turbidites with high CaCO3 (>75%) studies. The location of the site on the western margin of the plain en- contents. This work was extended by Pearce (1991) and Pearce and sures that it contains a relatively complete sediment record dominat- Jarvis (1992a, 1995), who used geochemical data for >500 samples ed by very distal facies, with little evidence of basal sand or silt de- from 23 cores, to demonstrate that individual MAP turbidites have velopment except in calcareous turbidites, which were derived from distinctive and consistent geochemical compositions over distances the west. These characteristics made the site the most appropriate of >500 km, which enable the chemostratigraphic correlation of se- choice for a chemostratigraphic type section. Shipboard (Schmincke, quences across the whole plain. Weaver, Firth, et al., 1995) and subsequent biostratigraphic data A combination of geochemical and sedimentological evidence (Howe and Sblendorio-Levy, Chap. 29, this volume) confirm that (De Lange et al., 1987, 1989; Jones, 1988; McCave and Jones, 1988; Site 950 exhibits a thick turbidite record down to the lowest middle Pearce, 1991; Pearce and Jarvis 1992a, 1995; Rothwell et al., 1992), Miocene. mineralogical data (Weaver and Rothwell, 1987; Pearce and Jarvis, An informal lithostratigraphy for Site 950 was proposed by 1992b), and geological arguments (Weaver, Buckley et al., 1989; Schmincke, Weaver, Firth, et al. (1995): Unit I (0−306 mbsf; meters Weaver, Thomson, et al., 1989; 1992, 1994), were employed by below seafloor), comprises thick (decimeter to meter) turbidite muds Pearce and Jarvis (1995) to demonstrate that the turbidite composi- separated by thin (centimeter) pelagic ooze, marl, or clay interbeds; tional groups represented deposition from flows derived from five Unit II (306−333 mbsf) consists of carbonate debris flows; Unit III distinct source areas. Organic-rich turbidites are sourced from the (333−370 mbsf) is predominantly pelagic red clay, with thin carbon- northwest African continental slope (Fig. 1), one subgroup being de- ate-rich turbidites and zeolitic ash bands; Unit IV (370−381 mbsf) rived from north of the Canaries, probably off the Moroccan coast; consists of volcaniclastic sandstones and siltstones. Unit I was divid- the second subgroup was derived from south of the Canaries, off ed (Schmincke, Weaver, Firth, et al., 1995) into Subunits Ia (0−150 Western Sahara. Volcanic turbidites originate from the slopes of the mbsf) and Ib (150−306 mbsf), on the basis that pelagic intervals be- Canary Islands, one subgroup coming largely from the western is- low 150 mbsf are clays rather than mixed lithologies (clays, clayey lands, the other being derived from the northern flanks of the central nannofossil mixed sediments, and nannofossil oozes). Following the and eastern islands. Calcareous turbidites are derived from the mar- work of De Lange et al. (1987, 1989) and Pearce and Jarvis (1992a, gins of the seamount chains lying to the west of the MAP. 1995), shipboard sedimentologists employed a genetic classification Despite their young age, minimal burial, and deep-water deposi- for MAP turbidites that included green (organic-rich), gray (volca- tional setting, MAP Quaternary turbidites display evidence of signif- nic-rich), and white (calcareous) turbidites. Other lithologies recog- icant early diagenetic modification. Many turbidites exhibit a distinc- nized (Schmincke, Weaver, Firth, et al., 1995) included gray-green tive two-tone coloration with decimeter-thick pale gray to brown-col- (intermediate-type), light brown or white nannofossil clay, and cal- ored tops, and thicker, darker, green lower portions. These ‘bleached’ careous turbidites with volcanic clasts. tops have been produced by the post-depositional oxidation of organ- In total, 488 10-mL sediment plug samples were collected from ic matter in the upper parts of the turbidites by oxygen diffusing into the mud portions of each turbidite >20 cm thick from 0–325 mbsf the sediment from bottom water (Colley et al., 1984; Colley and Th- (Cores 157-950A-1H to 36X); samples were taken from below redox omson, 1985; Wilson et al., 1985, 1986; Thomson et al., 1986, 1987, fronts and above any silty basal facies. Three equally spaced samples Chap. 32, this volume; Jarvis and Higgs, 1987; Weaver, Thomson, et were collected from turbidites >1 m thick, and one or two samples al., 1989). Oxidation proceeds by the downward migration of a sharp- from thinner beds. The aim was to adequately characterize the prima- ly defined redox boundary that remains active until the turbidite is cut ry geochemical composition of each major turbidite, and to use these off from its oxygen supply by the deposition of a subsequent flow, data to develop a chemostratigraphic framework, which could be generally within a few 10 k.y. The color change, which is caused by used to document changes in sediment composition and provenance the destruction of organic matter and oxidation of reduced transition- through the Miocene–Pleistocene. metal species, is particularly apparent in organic-rich (>0.3% organic carbon) turbidites. Many elements, (As, Cd, Co, Cu, Fe, Mn, Ni, S, Sb, Se, Tl, U, V, and Zn; Thomson et al., 1993, Chap. 32, this vol- ANALYTICAL METHODS ume) are mobilized and relocated in response to the changing redox conditions, but it is important to note that others, particularly Si, Ti, Sample preparation methods are described elsewhere (Jarvis, Al, Mg, K, and Zr (Jarvis and Higgs, 1987; Pearce and Jarvis 1995; 1992). Briefly, unwashed samples were freeze-dried, and ground by Thomson et al., Chap. 32, this volume), appear to be unaffected by hand to a fine powder in an agate mortar and pestle. Homogenized these early diagenetic processes. samples were redried overnight at 65°C; 0.250-g subsamples were Cores obtained during ODP Leg 157 provide the first opportunity fused with 1.250 g of lithium metaborate (LiBO2) at 1050°C, and the to study the pre-late Quaternary record on the MAP. In this paper, we melts dissolved in dilute HNO3. Final solutions were prepared in 250 have applied the methods of De Lange et al. (1987, 1989) and Pearce mL 0.5 M HNO3. and Jarvis (1992a, 1995) to sediments obtained at Site 950 to develop Geochemical data were obtained using a Jobin Yvon JY70 Plus a chemostratigraphic framework that will be used to document the ICP-AES at Kingston University. Analytical procedures and operat- history of turbidite sedimentation on the plain since the early middle ing conditions are listed in Jarvis and Jarvis (1992) and Totland et al. Miocene (~15 Ma). (1992). In this study, nine major elements (Si, Ti, Al, Fe, Mn, Mg, Ca,

536 CHEMOSTRATIGRAPHY OF MIOCENE–PLEISTOCENE TURBIDITES

Na, and K) and four trace elements (Ba, Cr, Sr, and Zr) were deter- groups were defined using a range of sedimentological and geochem- mined. Calibration of the ICP-AES was achieved using nine well- ical criteria, members of each group could be distinguished using characterized rock reference materials (RRMs) and a procedural only CaCO3 and Ti/Al data. Organic-rich turbidite muds (i.e., exclud- blank, selected to cover the range of elemental concentrations expect- ing basal sands and silts) have the lowest CaCO3 contents, typically ed in samples. Data are reported as weight percent oxides for Si, Ti, 45%–55% (a notable exception is turbidite a1, with 18%–32% Al, Fe, Mg Na, K, and P, and as µg/g (parts per million) for Ba, Cr, CaCO3), and low but constant Ti/Al ratios of ~0.05. Volcanic turbid- Sr, and Zr. Calcium data are also presented as CaCO3, since the bulk ite muds have intermediate carbonate contents, generally 55%–65%, of the Ca present occurs in the carbonate fraction. and high but variable Ti/Al ratios of 0.08−1.5, while calcareous tur- Analytical precision, reproducibility, and accuracy were deter- bidite muds were defined as having >75% CaCO3, and yielded mar- mined by replicate analyses of multiple digestions of four different ginally higher Ti/Al ratios than the organic-rich group, with values RRMs (Table 1) analyzed on a routine basis with each batch of un- ~0.06. knowns. Assessments were based on preparations and determinations The above criteria have been applied to turbidite geochemical made on a number of different days, over a period of 1 yr. Long-term data obtained from Site 950 (Table 2). Carbonate contents and Ti/Al reproducibility was generally better than 2% (with a short-term pre- ratios have been plotted against a detailed lithologic log for the inter- cision of 0.5% to 1%) for all elements present at or above shale-like val 0−325 mbsf (Fig. 2), to illustrate relationships between sediment concentrations, deteriorating to ~10% for elements at low concentra- type, bedding characteristics and geochemical composition. A num- tions in limestones. With reference to published data (Table 1), accu- ber of simplifications have been made in the construction of Figure racy is considered generally to lie within the range of the reproduc- 2. First, only turbidites are shown; pelagic sediments have been omit- ibility. ted for clarity, so beds are defined by the base of each turbidite. Sec- Data have been presented as absolute concentrations and as values ondly, the geochemical profiles assume constant or little composi- normalized to Al, the latter being used to exclude the masking affects tional variation within beds. This has been demonstrated to be the of high but variable CaCO3 contents in samples. The rationale for this case in the Quaternary of the MAP by Jarvis and Higgs, (1987), De procedure is that biogenic CaCO3 is relatively pure and free from oth- Lange et al. (1987, 1989), and Pearce and Jarvis (1992a, 1995). The er elements (Mg and Sr excepted), so differences in the bulk chemis- validity of the approach is confirmed by the close geochemical simi- try of the noncarbonate fraction are emphasized by relating values to larity of multiple samples from most beds (Fig. 2; Table 2); data are the Al contents of samples. In the absence of any evidence for pore- commonly within analytical error. Exceptions are generally confined water advection, significant import or export of Al ions is considered to the lower parts of what must be subtly graded beds. Where possi- unlikely for sediments of 50%–60% porosity buried to <400 m. ble, only unoxidized sediments from below fossil redox fronts were sampled from Site 950, so the geochemical profiles in Figure 2 reflect primary compositional variation within the sequence. Postdeposi- RESULTS AND DISCUSSION tional oxidation of organic matter in the bleached tops of organic-rich Chemostratigraphy turbidites leads to the dissolution of carbonate, producing character- istically stepped profiles for CaCO3 (Jarvis and Higgs, 1987; Thom- De Lange et al. (1987, 1989), Pearce (1991), and Pearce and son et al., Chap. 32, this volume); these tops are not represented in Jarvis (1995) demonstrated that, although their three major turbidite our data.

Table 1. Results obtained for rock reference materials used to assess analytical data quality.

Material Element Mean SD Reference Material Mean SD Reference

MAG-1 marine mud* NIST 88b dolomitic limestone† Major element (wt%) SiO2 50.6 0.3 50.36 1.14 0.13 1.13 TiO2 0.756 0.005 0.751 0.0180 0.0023 0.016 Al2O3 16.3 0.1 16.37 0.369 0.031 0.36 Fe2O3 6.87 0.05 6.80 0.293 0.018 0.28 MnO 0.0981 0.0009 0.098 0.0153 0.0004 0.016 MgO 3.06 0.03 3.00 21.3 0.2 21.03 CaO 1.54 0.07 1.37 30.1 0.2 30.12 Na2O 3.84 0.04 3.83 0.04 0.03 0.03 K2O 3.55 0.06 3.55 0.11 0.02 0.10 Trace elements (µg/g) Ba 479 3 479 <10 4 ND Cr 95 2 97 22 5 ND Sr 147 1 146 63 1 64 Zr 128 2 126 17 4 ND SCo-1 Cody Shale* CCH-1 limestone** Major element (wt%) SiO2 62.7 0.8 62.78 0.92 0.17 0.97 TiO2 0.621 0.009 0.628 0.0161 0.0034 0.017 Al2O3 13.7 0.2 13.67 0.314 0.055 0.3 Fe2O3 5.06 0.07 5.14 0.180 0.021 0.17 MnO 0.0512 0.0005 0.053 0.0058 0.0005 0.007 MgO 2.72 0.04 2.72 2.81 0.03 2.91 CaO 2.66 0.05 2.62 51.4 0.5 52.12 Na2O 0.92 0.03 0.90 0.05 0.04 0.048 K2O 2.77 0.02 2.77 0.07 0.01 0.082 Trace elements (µg/g) Ba 566 5 570 <10 4 6.6 Cr 72 1 68 20 5 7.4 Sr 172 3 174 282 3 284 Zr 169 3 160 16 4 8

Notes: Originators: * = U.S. Geological Survey; † = National Institute of Standards and Technology, U.S.A.; ** = University of Liège, Belgium. Reference values from Govindaraju σ (1994); number of determinations = 14; SD = standard deviation ( n). Total iron expressed as Fe2O3. ND = no data available.

537 I. JARVIS, J. MORETON, M. GÉRARD c f j t r s e k d h q u l1 l3 s1 s2 b g n o p Gray Gray Gray Green White White Green White - White Green - Green White - White Green - Green - Green - - Green - White Pale green -

3 (wt%) CaCO g/g) µ O Ba Cr Sr Zr Ti/Al Group Color 2 OK 2 Table 2. Geochemical composition of turbidites, Site 950. Table MnO MgO CaO Na 3 O 2 Major (wt%)Major elements ( elements Trace Fe 3 O 2 Al 2 TiO 2 SiO Depth (mbsf) interval (cm) Core, section, 1H-3, 113-115 4.03 29.4 0.540 10.3 3.71 0.0683 2.81 22.5 2.17 2.08 408 86 780 98 40.1 0.0595 o 1H-3, 18-20 3.08 16.6 0.308 5.45 2.15 0.0737 1.28 36.1 2.17 1.00 240 47 1160 81 64.3 0.0641 o 1H-2, 63-651H-2, 101-1031H-2, 136-138 2.03 2.41 2.76 20.7 20.5 19.9 0.908 0.873 0.654 6.75 6.71 6.60 3.90 3.82 3.40 0.110 0.115 0.105 2.20 2.17 1.91 30.8 31.1 32.2 2.78 2.93 2.53 1.15 1.19 1.17 332 343 289 57 40 44 1150 1160 1150 124 120 104 55.0 55.4 57.5 0.152 0.147 0.112 v v v Gray - 1H-4, 130-1321H-5, 64-661H-6, 63-652H-1, 79-81 5.702H-2, 79-812H-3, 79-81 6.54 21.82H-4, 98-100 8.032H-5, 104-106 9.60 22.1 11.012H-6, 78-80 0.433 22.6 12.492H-6, 89-91 14.19 24.4 15.752H-6, 96-98 0.441 7.56 26.22H-7, 4-6 0.453 25.7 18.1 16.982H-7, 11-13 7.38 0.366 18.2 0.384 2.76 17.092H-7, 35-37 7.31 0.374 17.162H-CC, 10-12 7.32 0.617 25.2 2.77 7.51 0.619 0.06213H-1, 40-42 25.3 17.73 2.77 7.33 17.80 6.03 24.9 2.66 0.429 6.15 2.06 0.0618 18.04 18.17 2.78 0.434 0.0653 2.80 6.08 2.02 0.432 8.26 2.90 0.0471 5.41 18.81 2.82 0.0501 29.2 30.1 25.1 2.04 8.31 0.0508 0.110 8.40 1.72 0.0975 0.0949 3.02 1.78 0.112 29.5 23.8 0.515 2.42 0.455 1.83 3.05 1.76 29.6 2.05 1.63 3.05 11.6 0.0630 27.1 10.1 2.09 0.410 1.58 27.4 1.58 0.0633 2.35 0.794 27.3 0.887 1.92 0.0637 34.0 8.67 2.04 1.44 3.95 2.12 1.94 0.119 34.1 3.54 0.125 1.49 1.90 2.20 2.84 27.0 476 1.17 3.35 0.0482 0.0534 1.24 0.651 2.37 27.2 0.628 1.22 27.0 474 1.92 1.74 1.12 0.0797 1.70 48.1 442 47.7 49 1.79 1.17 582 1.79 2.25 563 1.38 21.7 24.6 48 1.88 559 1120 1.39 1.34 306 45 1.43 29.1 308 60 1.75 1100 1.89 72 0.41 0.34 1090 442 72 83 36 1.49 430 1.64 1020 993 1.35 43 421 87 53.7 990 1240 199 90 172 69 1.90 1240 74 79 91 0.0648 52.7 662 550 94 149 52.8 990 90 24 15 150 0.0676 993 273 48.4 49.0 o 0.0703 111 978 60.7 90 1520 1490 48.6 94 0.0567 0.0579 60.9 o 98 75 0.116 o 842 0.0578 933 98 0.114 24 48.2 o o 31 1030 48.6 o v 94 0.0588 48.2 85.9 v 86 Green - 85.1 0.0592 66 0.0583 0.0604 38.8 o 0.0609 43.9 o Green - 0.0503 52.0 o Gray - c 0.0509 c 0.0536 o o Green - o White - Green - 3H-1, 98-100 19.39 25.7 0.466 9.59 3.59 0.0783 2.39 26.8 1.43 2.18 273 60 948 78 47.9 0.0551 o 3H-3, 23-253H-3, 50-523H-4, 25-273H-4, 74-76 20.433H-5, 12-14 20.703H-6, 32-34 21.793H-6, 70-72 16.2 22.283H-7, 42-44 16.2 23.15 17.8 0.629 24.85 18.7 0.575 25.23 17.3 0.639 5.54 26.45 16.9 0.654 5.60 16.3 5.90 0.629 2.99 0.755 5.89 9.08 2.87 0.698 5.85 3.10 0.113 5.67 0.168 3.64 0.108 5.47 2.70 0.104 2.90 1.65 3.05 0.110 1.62 2.91 0.121 1.56 1.30 0.126 34.9 1.71 0.110 35.2 1.58 0.0633 34.8 1.81 2.28 33.2 1.71 2.20 0.767 34.9 2.18 1.05 35.6 2.56 1.08 35.6 45.0 2.34 1.09 2.65 1.13 2.40 1.40 348 1.09 359 0.99 351 0.90 0.64 348 47 323 25 335 32 1260 321 197 52 1260 33 1270 49 1220 90 36 1270 84 3 123 1310 129 62.3 1320 1430 118 62.8 62.1 0.129 99 59.2 0.116 95 0.123 62.3 47 0.126 63.6 v 0.122 63.6 v 80.4 v 0.151 v 0.145 0.0659 v v Gray - v c Gray - Gray - 3H-7, 140-1423H-CC, 20-224H-1, 18-20 27.434H-1, 77-79 27.724H-1, 97-994H-1, 142-144 5.08 28.094H-2, 21-23 25.6 28.664H-2, 80-82 0.100 28.85 29.294H-3, 26-28 22.9 0.4664H-3, 66-68 28.5 1.62 29.574H-3, 147-149 26.4 0.420 7.55 30.15 8.444H-4, 66-68 0.512 31.084H-4, 112-114 0.70 26.1 0.131 7.56 0.370 31.47 32.264H-5, 50-52 10.6 26.3 3.184H-5, 122-124 0.0792 28.5 0.359 2.30 6.90 32.94 33.394H-6, 81-83 3.05 29.3 24.1 0.0841 0.3654H-6, 129-131 3.44 0.566 34.95 6.74 0.412 34.254H-7, 18-20 0.799 2.63 0.0582 24.8 2.42 0.420 6.70 0.323 9.104H-7, 39-41 0.0548 48.1 8.26 0.0959 36.01 36.485H-1, 21-23 25.0 2.49 2.25 0.0481 25.3 8.22 0.157 0.346 6.60 28.15H-1, 55-57 2.56 2.72 0.656 1.20 36.865H-1, 76-78 3.10 1.92 0.0476 26.8 32.7 0.356 0.353 2.80 6.94 28.7 37.065H-1, 142-144 3.03 2.49 0.0525 1.73 37.62 23.2 46.85H-2, 8-10 1.85 0.33 0.0491 7.10 7.04 0.511 0.535 4.59 37.95 27.65H-2, 47-49 1.03 1.85 2.59 1.93 0.0515 0.0611 4.75 38.15 38.80 1.915H-3, 18.9 39-41 1.52 1.95 1.30 11.4 0.088 9.03 27.3 3.445H-3, 117-119 2.65 1.94 1.69 1.86 0.0879 0.0567 20.2 1.50 0.0908 29.0 1325H-4, 41-43 18.7 38.96 25.9 0.680 2.48 1.58 0.44 24.5 39.34 0.05875H-4, 142-144 1.90 1.62 3.80 0.759 1.72 4.84 0.0572 629 40.72 0.713 1.31 24.6 29.9 41.495H-5, 72-74 1.91 6.21 0.626 0.489 25.2 1.735H-6, 67-69 0.603 1.72 1.86 0.0729 0.0607 25.2 45.0 615 2 1.19 6.44 0.648 28.1 42.20 43.195H-7, 17.5 54-56 1.92 1.97 17.5 465 216 1.22 5.85 9.20 54 0.0803 3.166H-1, 95-97 0.480 2.41 2.78 0.0795 630 28.1 1.32 0.481 1.39 28.0 43.97 14306H-2, 23-25 3.50 1.90 18.6 0.844 48 1.31 0.474 0.834 1.22 9.50 45.39 0.1056H-2, 84-86 8.99 3.48 3.30 0.519 601 973 69 19 8.91 25.2 46.73 19.7 1.77 1.88 0.52 0.115 25.1 552 5.57 51 0.830 1.20 5.49 0.172 49.9 47.84 1100 34 0.107 0.0606 25.4 48.3 653 1.77 3.27 48.21 1480 3.23 1.79 1.55 26.4 792 615 739 1.23 60 1.25 0.515 5.70 1.89 3.09 92 48.80 3.55 3.65 1.05 2.34 29.5 949 62 85.9 0.520 1.85 1.31 0.0600 195 33.5 85 0.0613 15.9 713 74 0.543 8.68 1.97 2.41 0.106 35 3.81 1.25 0.101 28.2 31.6 50.2 943 87 76 56 0.0700 0.530 8.55 2.36 0.32 26.1 685 2.32 0.36 31.7 991 719 2.56 92 51.3 8.14 0.493 18 3.15 11.1 0.0995 0.0815 0.0625 879 1.94 54 83.6 0.474 2.70 2.03 1090 41.3 3.10 1.61 c 25.6 882 792 537 89 0.0629 5.31 2.81 25.5 1.20 49.3 3.05 2.04 0.759 0.0523 1480 159 66 96 65 0.0643 9.26 1030 149 o 34.7 0.0547 1.17 3.75 0.0587 33.4 82 2.03 1.88 66 0.0607 48.7 o 1.10 2.58 2.31 1.82 0.0568 44.2 93 66 92 1010 32.9 1010 51.8 3.63 2.29 c 0.0513 2.06 335 40 29 o 2.72 75 0.0603 28 43.8 1.81 2.27 0.0794 53.4 1.78 o 1.05 26.8 330 0.0618 43.8 2.74 2.33 0.0404 937 666 425 27.0 307 1620 80 0.89 69 0.0565 80.3 1.57 0.91 1580 Green - 0.0555 50.2 o 26.7 39 0.0579 2.22 1.72 0.55 o 0.94 23.2 421 43 0.0635 1.94 405 50.2 97 86 71 0.0565 50.0 o 35.5 1290 40 30 1.82 o 248 29 o 1.84 22.8 242 1.51 1250 0.0569 0.0568 1.70 c 130 66 45.0 35.1 o 2.31 1240 238 951 69 89.0 1.59 151 Green - 86.2 2.43 2.48 54 o 152 58 0.0642 0.0532 o 487 0.0632 0.99 Green - 943 132 22 0.0636 937 466 59.7 93 57 1.54 1290 459 1240 56.3 o o c 436 1440 0.124 70 56.6 c 1230 97 46.6 176 97 76 0.126 Green 104 103 551 67 0.121 1000 0.0602 v 89 106 45 45.8 1030 45.6 61.9 51 59.6 v 970 White 81 0.0605 v o 93 0.0611 58.6 78.8 822 0.172 0.172 1250 98 110 0.165 0.0629 o 873 47.9 o v 92 48.2 v 71 0.0673 47.7 Gray c v 97 0.0689 41.4 Pale green 0.0756 63.4 o 0.0541 40.6 o 0.105 o 0.0580 Gray o v o Green 157-950A-

538 CHEMOSTRATIGRAPHY OF MIOCENE–PLEISTOCENE TURBIDITES Gray Gray Gray Gray Gray White White White Green White White White White Green White Green Pale green Pale

3 (wt%) CaCO g/g) µ O Ba Cr Sr Zr Ti/Al Group Color 2 OK 2 Table 2 (continued). MnO MgO CaO Na 3 O 2 Major (wt%)Major elements ( elements Trace Fe 3 O 2 Al 2 TiO 2 SiO Depth (mbsf) interval (cm) Core, section, 6H-6, 19-216H-6, 59-616H-6, 76-786H-CC, 13-15 54.126H-CC, 42-44 54.516H-CC, 95-96 54.67 55.527H-1, 22-24 4.43 55.807H-1, 37-39 31.6 56.287H-1, 98-100 11.5 0.0741 4.567H-1, 108-110 0.554 56.63 3.617H-1, 128-130 1.54 28.65 0.203 56.78 0.08427H-2, 67-69 11.7 57.39 57.49 0.07257H-3, 63-65 28.00 0.497 1.48 3.79 0.460 57.697H-4, 62-64 28.00 1.24 29.17H-5, 90-92 0.471 4.51 0.0684 27.8 9.98 58.58 0.5837H-6, 52-54 1.42 0.477 60.04 5.85 0.5387H-7, 42-44 0.497 9.51 0.461 0.0509 0.0630 0.477 61.53 3.617H-7, 60-62 9.60 0.0487 26.5 0.0645 10.3 0.110 63.128H-1, 107-109 2.89 14.1 48.7 0.471 3.88 9.84 64.23 0.03808H-2, 81-83 0.901 15.4 0.395 0.477 3.52 2.00 65.458H-2, 140-142 15.3 49.0 0.229 3.91 1.51 0.0408 20.7 65.57 66.58 2.018H-3, 122-124 3.76 16.2 42.9 50.5 9.78 0.240 0.04348H-4, 114-116 0.809 23.1 0.241 4.60 1.88 0.0674 67.80 68.39 0.918H-5, 88-90 1.74 0.36 0.0564 22.4 21.8 23.8 0.247 4.66 1.89 1.31 0.0631 69.71 0.668H-6, 58-60 3.38 4.76 0.438 2.71 71.138H-7, 36-38 1.70 2.56 16.7 23.1 15.7 0.31 0.429 4.96 2.99 0.436 0.577 1.888H-CC, 3-5 1.72 0.74 0.0464 24.6 16.3 0.23 8.38 72.36 1159H-1, 6-8 1.74 0.0688 24.3 25.0 8.16 0.718 1.66 0.615 7.67 73.56 23.8 48.59H-1, 72-74 1.85 2.56 0.0620 1.51 1.50 0.722 74.87 1249H-1, 117-119 3.01 1.10 0.0657 25.9 403 5.36 1.37 5.17 0.461 75.15 1219H-2, 39-41 14 2.95 1.50 1.14 3.22 1.33 1.05 0.0615 25.3 88 5.35 25.79H-2, 62-64 1.15 1.45 0.0475 17.5 0.469 8.63 39.9 75.47 76.12 76.56 5839H-2, 126-128 2.45 3.09 1.13 2.77 0.0461 35 0.0673 1620 17.8 84 0.454 2.25 0.40 36.39H-3, 26-28 1.38 2.11 2.89 19 37 8.35 0.276 38.5 77.26 5819H-3, 112-114 2.04 1.26 2.93 1.95 0.0740 0.0754 16.5 27.3 1560 7.97 103 3.43 36.6 77.49 78.12 580 0.2769H-4, 18-20 1.53 0.0724 752 1640 27 2.42 5.86 30.1 1420 3879H-4, 95-97 2.91 1.33 1.67 1.53 0.0550 14.4 370 0.258 0.82 0.493 0.0673 29.8 78.61 31.3 79.45 5.83 819H-5, 57-59 94 2.75 1.24 1.69 12.7 29.1 921 100 0.89 319H-5, 121-123 86.9 10.0 2.25 1.12 1.34 2.41 0.0545 93 5.48 0.89 0.538 24 35.6 80.00 36.29H-5, 139-141 57 82 1.34 1.32 0.0463 365 2.26 71 0.96 0.487 0.497 4.98 4.13 80.75 34.8 8879H-6, 66-68 18 0.0546 2.41 103 0.0422 87.5 354 937 82.48 4.73 1.77 0.458 81.85 28.49H-6, 119-121 36.9 2.11 3.75 2.30 2.14 10.3 1.74 18.4 90.0 389 0.0458 76.6 1.71 0.0898 4.29 0.0819 1.68 82.65 8719H-6, 133-135 1.50 1.88 0.0592 0.0643 17.9 371 1560 843 101 77 c 27.6 42.59H-7, 28.0 14-16 102 0.0537 1.68 2.36 1.38 1.39 0.0458 0.0607 0.0662 17.8 432 1.47 46 0.0608 0.890 1.05 1.08 27.3 83.41 83.939H-7, 40-42 2.11 3.82 0.457 28.4 413 41 0.911 1.04 0.0565 35.4 84.06 c 9H-CC, 8-10 83 41.3 1.40 1.32 2.75 0.0579 919 392 460 0.504 45 84 29 44.0 5.52 o 0.887 0.719 1.86 0.618 1470 c 36.710H-1, 89-91 1.35 c 0.0625 0.0561 29.7 50.7 46 5.54 0.508 4.77 84.37 1300 10.410H-2, 42-44 0.0561 1.36 1.37 0.0503 0.0827 29.3 215 198 o 77 0.0563 43.4 1.76 5.87 35.9 24.8 84.62 138010H-2, 78-80 42.4 86.5 3.93 1.24 10.4 2.84 233 1.29 84.82 83 72 65 1.69 0.0828 0.485 1.06 131010H-4, 21-23 58 3.75 0.507 0.464 25.3 85.80 401 0.0548 o 1.02 0.481 37.8 1150 3.6910H-4, 79-81 64 0.0549 0.0623 1.36 1.56 3.23 o 1.29 0.0890 26.2 86.83 65 54 White 9.79 39.7 23.6 1.04 1120 1180 26.310H-4, 105-107 62 45.9 3.76 0.21 0.109 87.19 49.4 50.9 392 66 71.2 0.479 9.76 26.3 0.056310H-4, 133-135 67 o 1.94 1.78 0.141 88.27 386 75 64.8 1.00 2.45 0.423 0.654 o c 27.3 1320 132010H-5, 138-140 90 0.0553 1.75 3.87 1.23 0.0561 89.11 88.85 536 0.430 106 0.0563 68.8 9.66 1.93 0.98 1.01 27.7 1300 2.8010H-6, 2-4 88 0.430 4.09 0.0841 89.36 494 78 0.0583 65.4 0.96 8.73 1.82 34.0 1070 Green 10H-6, 58-60 0.504 2.83 0.0369 8.28 90.91 86 8.79 68 0.0575 53.8 o 0.85 2.52 16.0 16.010H-6, 100-102 93 81 55.8 0.512 8.61 o 3.31 0.33 0.505 0.29 0.0385 31.0 456 320 24.1 61 0.0566 53.2 10.1 15.9 102010H-6, 121-123 78 0.183 o 2.04 3.49 2.13 32.5 0.0593 Gray 66 24.9 23.8 3.6210H-7, 23-25 96 0.0644 9.71 o 0.686 0.709 2.12 0.0489 91.05 92.03 91.61 49.2 993 194 22 0.0596 63.6 64.6 3.54 2.05 1340 1.2410H-7, 32-34 0.657 3.00 o 0.0419 92.24 204 342 57 108 90 62.1 0.99 3.45 1.97 23.0 112 0.0461 139010H-7, 81-83 5.37 0.468 5.37 o 2.55 1.26 62 0.152 0.135 50.6 3.54 o 1.04 0.0541 24.3 16.8 27.2 22.8 1680 109 5.28 o 1.00 1.81 92.76 2.30 54 0.153 1.24 0.0555 17.6 1320 1.82 61 49.3 9.26 1.07 1.41 92.85 899 34 75 0.0605 2.89 2.87 1.79 2.50 0.0551 23.0 15 0.458 0.361 0.504 0.33 1.47 62 93.34 188 12 48.6 2.78 v 2.64 v 0.115 27.4 24.8 1370 21 0.0636 Gray 0.388 25.7 63.2 10.2 3.12 2.57 v 1.69 0.0955 0.0911 26.6 186 1470 59 323 8.84 5.97 1.08 o 26.8 830 1720 87 0.0646 1.76 0.0959 24.7 65.5 186 1570 Green 6.20 0.522 0.785 1.26 25.1 335 90 0.0534 90.5 o 1.47 1.47 0.0477 136 1.33 86 0.519 24.8 64.0 3.01 10.3 2.48 3.44 1.46 2.30 1.42 0.0536 91 73 44.3 o 0.471 44.4 75 747 85 28 0.0679 Gray 2.71 10.2 2.34 1.44 1.45 1300 87 27 o 37.2 36.5 759 1.50 0.0534 76 67.5 1.23 0.0479 0.0909 0.0455 15 0.0556 9.04 1.46 36.8 1200 o 7 6H-3, 8-106H-3, 53-556H-4, 29-316H-4, 97-996H-5, 91-93 49.60 50.04 51.27 29.2 51.94 29.2 53.35 22.2 0.484 23.1 0.483 19.7 0.388 9.45 9.39 0.404 0.481 7.89 8.04 3.68 3.70 7.08 2.73 0.0442 2.86 0.0431 2.70 0.0569 2.06 2.08 0.0562 2.05 0.0611 2.17 23.5 23.3 2.09 28.3 1.59 29.1 1.57 33.2 1.44 1.59 1.63 1.70 1.46 1.73 1.77 1.47 566 571 394 406 84 393 77 66 60 892 881 74 1030 1040 104 1240 105 73 76 41.9 41.5 88 50.4 0.0580 0.0583 51.9 0.0558 59.2 0.0569 o o 0.0769 o o o Green Gray

539 I. JARVIS, J. MORETON, M. GÉRARD Gray Gray Green Green Green Green Green Green Green Green Green Green White White Dark green

3 (wt%) CaCO g/g) µ O Ba Cr Sr Zr Ti/Al Group Color 2 OK 2 Table 2 (continued). MnO MgO CaO Na 3 O 2 Major (wt%)Major elements ( elements Trace Fe 3 O 2 Al 2 TiO 2 SiO Depth (mbsf) interval (cm) Core, section, 11H-4, 70-7211H-4, 90-9211H-4, 8-1011H-5, 61-6311H-5, 99.52 75-7711H-5, 99.71 15-1711H-6, 100.38 100.90 50-5211H-6, 2.92 101.05 121-12311H-6, 3.09 19.1 101.90 29-3111H-7, 0.0870 29.6 102.24 102.94 4-611H-CC, 0.0938 29.3 1.0412H-1, 120-122 0.449 16.8 0.546 1.08 103.5112H-2, 19-21 16.7 25.1 0.548 105.07 103.8512H-2, 58-60 10.9 6.98 0.506 0.85312H-2, 104-106 0.511 11.0 30.2 0.825 0.476 0.0791 105.5412H-3, 60-62 27.4 26.0 5.71 2.58 0.0849 106.37 105.9212H-3, 119-121 3.93 5.54 0.548 0.390 9.2112H-4, 30-32 3.98 26.3 0.502 0.383 0.0515 107.97 107.40 0.48012H-4, 96-98 3.14 11.1 0.0435 20.8 24.7 51.912H-5, 26-28 3.18 3.24 0.0454 9.58 1.95 0.481 51.0 108.56 9.8512H-5, 90-92 3.00 0.102 24.2 24.7 0.457 0.427 109.2012H-5, 110-112 3.85 3.03 0.88 0.103 0.0484 9.05 109.9812H-6, 27-29 3.45 0.85 24.9 33.4 3.45 7.32 9.05 0.447 1.67 0.457 22.2 110.60 110.7912H-6, 100-102 2.66 0.0403 26.1 1.68 0.23 22.312H-7, 30-32 3.40 0.0466 27.5 0.0452 9.05 0.457 9.08 1.10 0.21 112.15 111.4413H-1, 88-90 3.02 3.31 1.19 3.00 27.5 35.1 28.3 0.471 26.613H-2, 49-51 2.67 1.17 0.0450 35.3 2.56 0.473 9.21 112.9313H-2, 138-140 3.05 1.50 3.38 0.0761 0.0899 31.3 2.62 8.09 0.493 1.82 0.501 4.49 22.0 74 114.1913H-3, 81-83 2.56 1.07 7.40 1.85 2.52 25.5 75 116.19 115.30 25.913H-4, 4-6 3.15 2.03 2.86 0.0528 0.0522 0.0939 0.577 9.82 9.85 5.5913H-4, 52-54 1.08 3.10 1.27 30.5 2.12 26.4 370 117.1213H-4, 136-138 18 1.02 2.68 1.57 2.53 1.11 2.57 11.4 0.0573 30.0 30.1 331 1.22 0.115 32.1 28.013H-CC, 15-17 16 3.58 3.37 0.0657 323 0.497 2.50 117.85 119.16 118.3314H-1, 32-34 2.59 1.13 0.0642 29.6 1670 2.10 0.480 0.487 1.96 0.632 27.6 27.8 185 2.19 119.8714H-1, 75-77 57 10.3 3.89 1.20 1.01 2.49 0.0506 0.0501 1620 324 77 16914H-1, 140-142 2.32 10.1 0.0704 30.9 22.0 21.9 73 0.465 9.90 1.99 27.9 123.2314H-2, 59-61 0.737 2.87 1.14 2.90 1.15 0.0397 1310 307 20.6 23 101 1.66 2.12 27.8 124.31 123.6614H-2, 137-139 3.84 0.530 824 336 350 21 69 0.549 1.26 9.46 1.24 0.0637 27.214H-3, 77-79 80 3.56 3.67 3.03 1.13 27.0 843 1.89 2.00 125.78 24.6 24.9 125.00 1340 0.38414H-4, 10-12 92.6 1.18 11.3 0.0314 26.4 28.6 50.6 318 74 83 0.59314H-4, 58-60 91.0 7.39 7.34 3.60 1.20 0.0329 0.0315 1330 413 293 934 93 79 2.04 0.494 65 21.1 126.68 7.4114H-4, 90-92 0.0952 2.01 1.16 1.14 28.0 25.7 93 0.482 0.517 1.91 0.86 127.51 49.214H-5, 15-17 90 0.0985 59.5 3.78 1.93 1.98 0.0389 335 847 333 75 4.42 1.77 9.99 4.10 127.9914H-6, 7-9 39.6 10.3 1.17 27.6 962 2.51 973 86 50 64 77 0.516 9.38 0.459 2.38 2.37 c 22.4 128.3114H-6, 134-136 0.0728 39.8 1.85 0.29 0.89 0.0584 26.6 334 62.6 c 0.0809 0.0964 23.7 22.3 129.0615H-1, 7-9 0.0567 3.79 15.8 976 312 0.0508 99 70 71 9.85 0.505 9.26 2.50 131.73 115015H-1, 50-52 0.0567 62.9 47.5 2.98 3.26 3.84 1.34 16.6 947 302 90 0.169 2.17 o 0.476 2.08 0.36 83 130.48 25.315H-1, 88-90 1.28 1.34 0.0494 14.6 347 357 1.87 78 o 0.939 9.42 1020 103015H-1, 130-132 0.169 0.0585 39.2 3.78 3.30 0.0557 0.0497 15.4 62 90 101 58 o 0.965 8.80 1.59 22.1 132.48 132.9115H-2, 54-55 45.4 2.63 1.27 15.0 46.2 28.7 30.8 390 White 73 47 5.46 v 0.721 1.54 1.60 133.71 133.29 1040 33.115H-2, 58-59 0.056 3.50 2.52 2.72 0.0494 0.0503 75 80 0.716 5.62 o 6715H-2, 69-70 78 80 0.0594 47.0 57.3 v 1.17 3.19 0.0552 22.1 21.9 956 20 0.782 5.04 2.39 1.52 2.36 24.4 134.4415H-2, 120-122 50.0 3.52 2.69 2.75 0.0507 26.0 21.3 904 464 1.04 95 5.22 27.5 24.7 134.4815H-3, 4-6 80 0.0602 0.0708 o 3.71 0.0562 877 480 461 881 Green 49.2 49.7 5.26 2.51 0.356 o 0.352 135.11 134.59 1610 o 15H-3, 62-64 22 0.0535 1.17 2.59 2.60 1.25 1.11 0.0942 45.3 96 0.516 0.347 26.2 28.4 1.6015H-3, 70-72 105 110 2.49 1.12 1.12 2.44 0.0978 44.5 783 471 0.0560 0.0571 49.7 7.56 7.51 o o 15H-4, 51-53 Gray 2.61 10.1 1.64 0.0920 45.7 1540 80 88 99 98 o 0.943 7.35 2.20 4.13 135.45 25.5 136.0315H-4, 62-64 24 49.7 1.13 1.71 1.07 0.105 322 0.0562 48.5 1.98 2.22 0.933 28.3 136.11 163 878 15715H-4, 95-97 102 3.56 20.4 3.11 o o 1.28 0.104 338 99 0.0911 0.955 35.7 137.4215H-5, 114-116 0.0660 43.9 44.5 20.0 3.45 2.71 1.06 25.9 909 862 28 0.0724 90.3 2.13 1.21 2.15 4.52 36.7 137.53 1.54 o 20.5 1.11 0.0457 0.0478 25.8 308 Green 89 113 37.6 1.26 38.8 137.86 139.55 54 47 0.0569 0.0576 6.53 2.07 0.0659 0.0498 23.8 273 293 945 0.0677 0.115 o 2.22 0.485 59 111 111 87.9 1.46 o 6.51 1.42 2.06 37.9 23.5 0.0576 0.488 0.729 2.01 40.0 6.77 2.84 1.39 1.73 0.0445 37.6 27.9 23.8 821 321 1210 307 1140 67 1.52 o 0.93 1.12 9.12 o 1207 115 0.0663 c 0.0450 0.0869 65 74 42.2 39.7 9.34 1.67 0.91 1.09 31.2 31.4 0.0547 o 1.70 0.0462 308 1.71 0.528 0.658 1.02 25.6 31.3 129 138 112 0.761 8.42 3.26 1.66 0.454 897 280 75 74 0.0550 0.0547 45.1 c Green 1.15 1.01 8.3510.6 3.26 1.13 1.69 67 997 911 117 8.94 o 0.0924 1.06 1.12 1.12 0.0502 4.48 50.3 114 Green 61 0.0556 39.4 51.1 55.0 4.62 1030 o o 0.0501 4.34 972 195 82 72 1.28 0.473 1.33 4.61 59.0 3.63 3.39 1.36 2.82 4.34 84 85 38 0.0551 0.194 0.191 2.34 1.18 0.8 10H-7, 98-10010H-7, 124-126 43-4511H-1, 93.51 112-11411H-1, 93.77 55-5711H-2, 30-3211H-3, 24.9 94.83 95.51 24.5 60-6211H-3, 11-1311H-4, 96.42 0.477 25.2 25.4 0.470 97.65 97.95 9.16 25.7 0.479 8.93 0.481 98.94 2.71 8.56 0.464 8.22 3.25 2.77 3.18 27.2 0.0534 0.0519 7.82 0.0605 0.986 3.13 3.03 0.0602 0.544 0.958 2.55 2.960.430 10.0 2.50 0.0623 0.0643 0.420 0.0647 2.51 2.44 0.0613 28.0 0.0577 27.5 3.62 0.397 2.29 0.376 1.45 28.1 28.6 1.20 0.0408 51.5 28.0 50.8 1.31 2.68 2.08 1.25 1.91 0.97 1.22 0.89 1.86 1.72 25.1 0.17 330 323 1.82 0.17 1.22 304 307 65 68 2.37 68 287 62 1020 70 66 1010 15 320 56 1020 1020 13 82 82 1700 970 1710 72 90 94 50.o 49.1 19 102 0.0590 885 18 0.0596 50.1 51.0 92.0 0.0634 0.0663 49.9 o 90.6 o 90 0.0614 0.0672 0.0614 o o 44.8 c o c Green 0.0616 o Green White

540 CHEMOSTRATIGRAPHY OF MIOCENE–PLEISTOCENE TURBIDITES Gray Gray Gray Gray Gray White White White

3 (wt%) CaCO g/g) µ O Ba Cr Sr Zr Ti/Al Group Color 2 OK 2 Table 2 (continued). MnO MgO CaO Na 3 O 2 Major (wt%)Major elements ( elements Trace Fe 3 O 2 Al 2 TiO 2 SiO Depth (mbsf) interval (cm) Core, section, 16H-3, 8-1016H-3, 68-7016H-3, 117-11916H-4, 6-8 144.88 145.46 145.9316H-4, 29-3116H-4, 46-48 28.616H-4, 117-119 28.3 28.8 146.31 146.5316H-5, 2-5 147.38 146.6916H-5, 21-23 0.530 0.523 0.53316H-5, 87-89 46.3 44.6 10.916H-5, 117-119 10.5 10.3 46.1 5.24 147.72 147.9016H-6, 2-4 0.988 0.956 148.54 148.8316H-6, 60-62 3.74 0.126 0.99216H-6, 70-72 21.4 20.8 4.01 3.71 30.3 2.0416H-6, 136-138 21.5 19.3 19.7 1.87 0.0633 149.17 149.7316H-7, 71-73 0.0639 0.0676 0.0725 0.577 150.46 149.8316H-CC, 11-13 6.68 7.07 2.60 0.907 0.91417H-1, 48-50 0.714 0.824 6.64 2.53 2.50 11.8 30.8 20.4 151.20 151.3317H-1, 69-71 0.0387 0.0344 18.8 20.3 6.54 6.79 0.099017H-2, 50-52 0.388 0.0385 23.0 0.564 0.384 22.7 24.2 151.5917H-2, 63-65 1.71 4.46 1.64 19.3 18.6 0.415 0.384 0.542 0.0635 151.7817H-3, 26-28 3.42 3.33 1.68 11.8 1.14 7.73 152.0617H-3, 35-37 1.10 1.14 0.0700 30.4 0.444 7.09 7.70 0.464 49.9 152.17 0.43317H-3, 122-123 0.102 0.113 3.93 30.7 3.77 152.6517H-3, 130-131 2.38 3.88 2.63 3.32 23.0 4.09 6.92 2.35 0.550 2.28 51.0 153.43 152.73 6.7117H-3, 138-139 1.30 2.69 2.62 1.29 0.95 24.6 0.564 1.52 1.58 153.5017H-4, 14-16 1.28 11.3 0.0684 0.0690 0.426 2.97 20.7 153.5717H-4, 60-62 2.65 1.11 11.3 0.0858 0.0744 41.5 2.60 2.22 2.18 0.459 0.37 3.54 32717H-CC, 22-24 2.86 1.74 40.8 31.0 32.8 308 315 0.0721 8.63 2.21 153.7818X-1, 111-113 4.06 1.90 1.77 1.09 0.103 41.4 0.104 0.14 0.879 0.0826 8.81 154.35 154.1518X-1, 128-130 1.10 4.11 0.863 1.98 2.05 21.4 32.6 154.6518X-1, 143-145 71 18.3 1.20 3.09 0.0554 44.1 358 356 74 64 0.873 1.84 2.97 33.3 32.2 154.82 38 1.8118X-2, 47-49 18.0 3.32 27.6 0.0568 27.4 359 0.570 154.9718X-2, 94-96 1.09 1.46 18.2 1.50 1.06 2.93 0.0587 28.1 0.931 0.699 863 1618X-2, 118-120 173 164 5.60 2.92 1.09 1.03 0.06380.115 28.1 34.2 830 901 33.3 0.492 0.497 155.5018X-CC, 10-12 18 170 5.57 19.2 2.52 0.108 15.4 244 2.66 1.72 0.503 21.2 155.97 156.2118X-CC, 37-39 10.1 5.69 2.74 0.023 9.51 0.501 1.09 1.58 1.60 0.367 22.1 247 262 261 239 1.09 157.0119X-1, 70-72 93 0.0233 28.1 1460 94 3 97 0.283 9.59 0.421 29.4 251 157.2819X-1, 87-89 6.35 1.16 0.0236 27.6 28.0 76 9.42 1.70 29.450.819X-1, 135-137 3.40 1.62 3.55 1.67 1.14 1.45 311 311 28.0 171 164 41.1 5.83 0.506 51.1 160.84 106019X-2, 15-17 19 20 40.5 43.2 1.70 3.97 0.98 0.0256 260 301 27.4 34 173 0.496 0.503 2.51 161.49 161.0119X-2, 40-42 0.0559 3.52 10.3 1.000.79 0.0542 727 0.0551 2.51 9.06 0.52019X-2, 66-68 0.0564 0.0584 1.97 1.79 0.88 0.0574 8.97 13.8 1240 1170 85 54 7.02 6.73 9.88 9.89 2.17 161.72 263 0.508 24919X-2, 103-105 20 2.72 89.1 2.72 0.0585 9.12 15.3 10.3 51 46 7.29 1.17 2.120.21 8.69 161.9719X-2, 141-143 131 0.0522 0.0520 o 1.17 3.68 2.78 0.0832 315 o 0.258 o 0.23 162.60 162.23 9.98 117019X-3, 38-40 194 178 0.0761 0.0524 4.64 2.79 3.49 1.35 8.27 771 299 91.0 0.321 0.279 24.3 8.79 25.0 162.98 1270 117019X-3, 118-120 48 1.98 1.35 52 0.0589 262 3.52 36.9 o 1.93 5.09 o 9.43 24.819X-4, 39-41 1.33 0.0622 0.0632 27.4 253 3.52 84 0.115 55.3 58.6 3.15 2.00 0.330 4.99 o c 3.13 25.1 163.45 164.25 3219X-4, 127-129 74 1.06 1.08 2.86 1300 0.0473 1280 99 82 0.0555 0.362 3.02 38.4 3319X-5, 27-29 77 75 1.74 2.79 2.77 1.07 0.0486 73 0.157 0.152 Gray 0.0875 0.503 3.23 2.11 165.84 164.96 36219X-5, 61-63 1.39 1.16 1.76 23.8 355 772 2.60 68 2.13 58.2 2.22 0.0647 3.45 c 3.44 24.019X-5, 93-95 20 38.3 1.07 10.3 o 0.96 0.0585 810 373 2.57 Dark green 84 59.4 57.5 2.31 83 23.6 24.9 166.34 101019X-5, 144-146 15 1.06 1.31 0.0822 0.0620 26.7 24.3 137 0.0562 v 2.19 0.0855 v 0.437 166.68 1020 24.419X-6, 28-30 100 135 0.0544 1.36 1.20 1.07 1570 378 0.0663 0.0565 1.11 0.491 167.51 167.00 24.4 103 137 61.0 1.18 3.73 0.90 1.07 1.29 1.06 287 0.0849 31.4 59.5 290 1610 0.461 8.63 0.440 0.460 70 o 0.0754 0.0838 33.2 429 317 1.09 White 37.8 o 2.50 40.0 167.85 425 80 168 0.0727 o o 0.89 0.0799 0.0767 0.0731 20.2 32.8 297 1.06 20 39.4 7.60 2.36 0.564 8.44 0.511 2.33 45.1 39.3 432 3.08 0.394 0.94 335 83 78 24 0.0551 52.4 Gray 0.597 2.27 148 3.58 0.93 0.384 11.1 0.0685 20.4 145 70 0.0564 52.4 o 0.394 0.590 44.7 415 o 2.30 90.7 2.81 1.15 3.06 1.04 11.6 0.0551 51.2 306 154 65 0.0559 44.1 91.2 o 0.412 11.6 857 51.7 916 290 300 52 0.0590 16.2 7.16 0.99 0.399 24.2 0.0744 16.0 Gray o 4.78 2.66 1.26 0.0732 0.0591 857 300 165 0.68 0.99 0.80 0.0783 16.3 o 4.36 1.40 50.9 861 288 73 Gray/green 0.0544 7.11 0.80 1360 0.0543 2.86 3.89 2.80 o 1.02 2.76 0.0274 97 93 68 68 0.71 c 28.7 0.0542 14.8 0.26 0.0296 245 99 0.74 0.80 c 75 101 o 2.86 2.14 0.25 0.0852 0.0293 136 838 236 o 2.58 68 28.2 27.9 Green 43.4 58 0.0549 44.7 2.23 1.08 818 860 o 44.3 2.83 2.21 0.27 0.0844 140 858 40 44.8 19.7 Green 0.0586 0.0557 1.27 1.07 46 142 849 95 27 44 68.6 1.91 o 20.8 0.0594 2.78 246 43 White 95 98 0.0602 33.2 20.1 1410 1.23 22 0.0549 o o 1.71 1.88 98 1560 1320 42.8 1.25 46 24 o 96 32.2 9 42.1 44.4 o 0.96 1.21 268 Dark green 75 1.71 1560 54 15H-5, 118-12015H-6, 34-36 139.5915H-6, 67-6915H-6, 116-118 140.2515H-CC, 9-11 24.3 140.58 141.0716H-1, 10-1216H-1, 66-68 24.5 141.23 0.67516H-1, 117-119 24.2 34.8 142.0116H-2, 28-30 8.74 0.454 142.55 143.04 34.816H-2, 45-47 0.441 0.63816H-2, 102-104 35.4 9.11 143.62 13.5 3.33 34.7 34.4 0.640 8.88 144.32 143.79 0.632 13.5 3.27 0.0926 27.9 0.604 0.600 13.0 3.22 5.09 28.3 28.1 12.3 12.2 1.97 0.0841 0.528 6.11 0.0908 0.0390 0.510 0.532 10.3 4.90 2.50 28.9 0.0396 10.3 10.4 5.97 2.45 4.51 2.12 0.0382 28.2 2.13 3.76 1.35 0.0373 0.0372 28.5 16.1 3.96 3.86 2.14 2.02 2.00 1.04 0.0691 16.2 1.96 1.05 1.30 0.106 0.0665 16.8 3.06 2.09 17.0 17.9 1.32 3.12 2.20 3.12 1.92 1.30 292 23.0 1.28 1.27 1.95 23.1 24.4 308 1.90 1.12 304 482 62 1.96 1.97 1.15 1.05 491 62 2.47 1080 132 467 70 2.52 2.44 458 455 129 1030 116 1010 670 121 274 114 111 273 675 263 75 51.6 119 701 74 68 684 711 0.0876 119 67 50.3 73 28.8 125 50.8 815 129 132 0.0565 v 28.9 0.0534 808 0.0562 831 30.0 0.0537 30.4 32.0 o 85 o 0.0551 o 87 83 0.0556 0.0557 o Gray 41.1 o 41.3 43.6 o o Gray/green 0.0583 0.0582 0.0563 o Dark green o o Green

541 I. JARVIS, J. MORETON, M. GÉRARD Gray Gray Gray Green Green White Green Pale gray Pale

3 (wt%) CaCO g/g) µ O Ba Cr Sr Zr Ti/Al Group Color 2 OK 2 Table 2 (continued). MnO MgO CaO Na 3 O 2 Major (wt%)Major elements ( elements Trace Fe 3 O 2 Al 2 TiO 2 SiO Depth (mbsf) interval (cm) Core, section, 20X-1, 126-12820X-2, 97-99 170.9120X-2, 115-11720X-3, 5-7 172.12 171.9620X-3, 23-25 13.520X-3, 46-48 20X-3, 106-108 26.3 26.3 0.781 172.48 172.6420X-4, 41-43 172.84 173.3820X-4, 64-66 4.78 0.490 0.48120X-4, 109-111 23.2 23.3 174.1320X-5, 24.2 8-10 10.0 9.61 3.16 174.33 174.7320X-5, 49-51 2.24 1.31 1.3220X-5, 110-112 1.37 0.088 8.9420X-6, 39-41 3.34 3.20 0.108 17.9 175.17 8.81 175.52 176.0720X-6, 112-114 7.98 8.02 1.03 0.288 8.4320X-CC, 21-23 0.0622 0.0533 0.290 1.24 0.309 38.4 177.42 176.7721X-1, 81-83 39.3 40.0 4.91 3.11 4.85 178.2421X-1, 109-110 0.470 2.28 2.22 4.83 3.05 6.4321X-2, 39-41 0.763 21.9 39.2 21.9 0.774 0.793 0.115 0.0860 0.115 179.55 179.2721X-2, 107-109 1.40 23.9 0.0978 16.1 29.2 27.321X-3, 40-42 16.2 1.40 2.16 16.6 0.406 1.67 0.409 0.600 181.00 180.3321X-3, 124-126 2.25 2.25 0.101 15.4 15.5 2.27 0.43621X-4, 6-8 1.10 1.15 0.109 0.0660 5.40 8.09 8.10 50.8 182.67 181.8421X-4, 62-64 0.99 5.38 5.30 24.1 23.9 0.280 0.283 0.910 28.2 28.2 7.7921X-4, 119-121 26.6 1.25 0.870 2.12 2.03 0.027721X-4, 145-147 2.86 2.92 1.03 0.0281 0.0287 32.5 24.8 5.53 0.444 0.439 5.60 182.99 44.6 183.55 184.1121X-5, 19-21 2.38 2.40 2.83 2.48 1.82 45.1 35.6 184.37 20621X-5, 88-90 1.85 1.84 0.0741 0.0703 0.564 0.446 8.38 8.45 0.2421X-5, 103-105 1.84 1.87 1.21 33.1 34.6 28.4 259 265 0.0710 1.26 1.30 184.61 1.3921X-5, 125-127 2.17 1.19 2.13 1.14 11.6 30.5 11.2 8.16 185.44 185.29 11.5 11.021X-6, 4-6 25 3.29 3.05 0.0628 0.0613 2.20 0.575 0.595 0.504 0.67 185.6621X-6, 89-91 26.6 68 62 0.67 0.536 1.35 1.06 31.0 31.4 4121X-6, 142-144 12.1 3.99 2.95 1.29 10.5 1.28 1.29 1.33 11.6 0.0853 0.0778 19.3 17.1 204 1360 206 225 29.821X-CC, 7-9 10.9 0.516 5.31 185.95 187.32 186.79 106022X-1, 62-64 1.86 2.37 2.37 1.07 1.06 0.0374 0.0875 988 162 0.328 0.284 1.90 1.90 38.1 39.222X-1, 84-86 10 4.18 4.05 3.53 161 356 1.09 44 99 42 0.125 9.79 39 187.9722X-2, 3-5 3.89 1.98 2.28 14.1 13.8 108 6.75 5.95 1.73 1.77 3.74 29.0 29.4 188.8122X-2, 48-50 1.10 1.04 0.0410 0.0446 0.0622 1100 92 24 1.84 1070 189.02 1070 530 1.7122X-2, 87-89 1030 70.0 3.30 0.0656 543 506 15.0 28 50 0.098 0.281 0.277 18.9 29.222X-3, 26-28 52.2 2.00 2.55 2.26 2.06 2.38 1.06 1.03 1.02 0.97 189.69 8.91 190.12 157022X-3, 98-100 0.185 48.8 0.766 2.49 0.0696 276 285 167 23 170 129 1.29 5.07 5.02 8.58 190.50 1600 168 1290 0.30022X-4, 37-39 130 134 0.0553 1.16 1.11 0.0647 0.0791 265 1.84 1.76 0.203 0.134 19.4 20.3 25.2 191.3722X-5, 58-60 0.0568 2.92 26.9 25.8 192.07 0.217 26.2 5.1122X-6, 92-94 54 50.4 90.7 50.4 0.573 v 1.84 1.84 1.37 1.24 26.4 502 284 300 47.4 61 60 1.73 1.74 3.05 o 192.93 510 49622X-CC, 24-26 52 61 1.20 0.533 1.26 1.12 20.5 0.481 2.88 o 0.457 0.139 55 26.6 19.9 194.5923X-1, 14-16 0.185 0.0966 0.186 1.18 0.0835 0.0726 309 319 0.184 1.79 79.6 0.469 36.8 38.1 196.39 1100 1110 197.6623X-1, 36-38 137 1.26 23.7 50.2 140 53 144 52 80.5 63.6 9.62 1.66 1.76 0.401 9.16 2.27 103023X-2, 8-10 0.437 1.18 1.12 1.16 0.385 1.12 20.7 470 315 0.0856 0.105 9.40 2.43 c 197.9523X-2, 55-57 Gray v v 1.01 0.90 0.141 20.7 v 23.8 Green 65 70 0.108 0.0544 20.0 0.433 7.72 1.09 198.17 1330 138023X-2, 142-144 78 80 20.5 19.7 3.30 7.47 3.28 0.143 52.1 1.11 2.38 0.401 41.3 40.623X-3, 26-28 107 3.07 91 199.35 25.6 460 467 342 66 0.0538 8.60 1.21 1.10 0.402 0.738 c 200.69 199.82 1010 1020 0.46523X-3, 119-121 0.0542 0.0543 0.39 o 2.72 0.0466 0.0497 27.8 355 55.4 56.0 0.98 7.57 0.788 2.65 c 40.223X-4, 35-37 62 61 1.05 1.12 0.0542 Dark gray 0.501 7.53 53.1 46.0 201.03 201.96 1000 709 7.6323X-4, 114-116 108 109 1.68 o 3.06 1.64 0.0728 4.23 13.9 275 77 0.0568 0.0571 o 0.530 o 0.0692 4.53 46.423X-5, 71-73 86 85 0.27 2.73 1.66 357 323 1.03 79 68.1 70.0 1.01 7.67 0.98 0.0634 203.41 202.6223X-5, 95-97 0.119 2.73 1.89 0.92 0.0785 12.9 26.3 60 2.92 124 0.375 0.158 7.52 1.86 27.6 27.2 726 76223X-5, 144-146 91 o o 1.07 0.0684 900 76 0.0574 0.0572 51.8 52.4 Gray 28.7 204.48 1.0023X-6, 28-30 1.46 2.96 2.10 0.0703 28.4 28.0 925 o 0.0820 Dark green 59 55 4.920.381 1.51 0.485 0.60 34.4 205.21 204.7223X-CC, 10-12 33.7 1.09 2.93 1.94 1.08 33.4 53 243 243 124 129 26 0.0601 0.0589 52.1 0.5824X-2, 40-42 o o 1.14 1.92 0.0847 888 1.99 90 0.671 4.68 0.495 9.95 0.508 4.29 30.7 205.55 1310 1310 205.9024X-3, 54-56 0.0552 2.19 0.742 1.10 0.0819 15.2 245 98 0.0619 1.37 1.34 0.99 3.53 33.6 1500 34.5 36.3 o o 10.1 2.01 0.0919 25 49 48 9.57 1.37 0.0992 0.0785 33.4 209.40 53 32.1 Green 44.9 1.90 3.12 1.00 2.00 0.0833 25.8 87 0.294 o 1.58 0.0846 56 211.02 4.85 Pale green 71 62 0.0562 0.0556 46.8 0.451 o 1.53 1.06 1.60 0.511 46 30.6 1520 1440 1430 34 0.0543 3.25 1.24 3.42 1.21 1.02 0.0893 0.0481 35.6 372 357 1.06 5.80 1.83 0.471 28.7 0.126 31 0.0556 47.5 50.7 26.4 363 65.6 68.1 o o 1.60 0.654 50.4 1410 31 1.14 1.64 1.08 0.0515 0.0544 244 89.5 0.644 9.89 o 1.60 0.566 41.0 243 1.66 1.73 29 66 64 0.0597 1.91 1.15 0.126 1360 89 84 0.0551 0.0541 o 0.99 0.844 Green 12.8 1 19X-6, 62-6419X-CC, 9-1119X-CC, 43-45 168.1920X-1, 20-22 168.47 168.8120X-1, 61-6320X-1, 93-95 22.6 169.97 23.1 22.3 170.34 0.431 170.62 23.8 0.427 0.412 23.8 7.13 15.8 8.60 0.444 8.31 0.448 2.90 0.496 8.38 2.93 5.05 8.47 0.0870 5.55 0.0682 3.60 0.0704 2.92 2.87 2.58 2.28 0.0743 2.42 0.0714 30.8 2.49 0.130 29.0 27.9 2.37 1.06 1.21 28.6 1.01 1.02 29.1 1.71 1.13 38.5 1.91 1.85 1.08 1.27 1.92 245 1.91 275 258 1.16 261 48 60 252 57 184 1010 1030 56 995 57 1010 29 75 81 1030 80 1350 55.0 86 51.7 91 49.9 0.0685 108 0.0562 51.0 0.0562 52.0 o 0.0600 68.8 o 0.0598 o 0.101 o Gray/green o v Green

542 CHEMOSTRATIGRAPHY OF MIOCENE–PLEISTOCENE TURBIDITES Gray Gray Gray Green White Green White White Green White Brown Brown Brown Pale gray Pale Pale green Pale Gray/brown

3 (wt%) CaCO g/g) µ O Ba Cr Sr Zr Ti/Al Group Color 2 OK 2 Table 2 (continued). MnO MgO CaO Na 3 O 2 Major (wt%)Major elements ( elements Trace Fe 3 O 2 Al 2 TiO 2 SiO Depth (mbsf) interval (cm) Core, section, 24X-6, 17-1924X-6, 39-4124X-6, 71-73 215.1124X-6, 111-113 215.3324X-CC, 20-22 215.65 216.0525X-1, 49-51 25.1 217.0025X-1, 89-91 4.1325X-1, 123-125 19.1 0.513 5.76 217.6225X-1, 146-148 26.3 0.119 218.36 218.0225X-2, 54-56 0.161 0.694 7.93 218.5925X-2, 111-113 34.9 1.51 1.4525X-3, 5-7 17.9 35.4 2.10 6.96 219.74 219.1725X-3, 90-92 2.61 16.1 0.62525X-4, 9-11 0.672 8.70 0.483 0.64525X-4, 37-39 13.0 0.942 3.21 0.0810 15.7 16.5 0.460 0.189 220.18 221.0325X-4, 80-82 13.6 6.57 0.184 6.7025X-4, 107-109 1.67 0.111 221.72 5.87 0.567 0.576 222.0025X-5, 13-15 3.81 0.439 15.9 19.5 222.70 222.43 0.18525X-5, 30-32 2.82 4.56 0.542 5.26 5.61 1.46 34.3 30.625X-5, 97-100 2.56 0.0454 33.1 49.5 0.577 0.358 223.2625X-5, 134-137 0.170 0.0944 31.7 33.6 49.2 3.12 223.4325X-6, 25-27 0.614 2.88 3.02 2.09 0.97 0.191 33.8 224.10 5.32 0.590 7.40 0.85 224.4725X-6, 74-76 3.02 12.4 0.535 1.51 0.568 0.85 4.44 24.225X-6, 135-137 12.0 0.141 0.139 1.39 1.36 1.84 4.6641.2 18.9 224.8825X-CC, 29-31 2.74 0.32 2.48 11.1 11.8 41.0 0.126 17.3 225.98 225.3726X-1, 36-38 0.40 35.6 1.94 4.38 1.56 0.132 1.60 226.4226X-1, 121-123 0.738 4.26 1.50 1.17 0.143 0.0932 38.4 40.5 0.728 1.4826X-2, 22-24 7.96 4.21 1.09 34.8 41.3 270 1.00 1.5415.7 0.0729 227.90 227.05 1.7826X-2, 141-143 15.3 1.37 0.0702 38.2 37.9 33 26.1 1.56 1.02 1.90 0.70726X-3, 17-19 0.746 0.0354 0.0376 39 2.62 0.626 0.726 2.87 229.60 228.41 12526X-3, 61-63 1.48 14.6 0.790 2.54 24.3 25.7 55 5.31 0.96 1.02 0.163 34.4 0.47026X-3, 134-135 1.36 13.2 15.2 6.13 1.90 2.01 37.4 218 17 0.161 229.8626X-3, 140-141 19.3 26.6 24.8 372 19 0.448 0.463 0.0295 19.4 231.02 230.30 1050 9.4026X-3, 146-147 38 1.13 1.27 6.80 0.463 0.88 0.0315 267 1.06 17.4 18.9 231.08 175 144026X-4, 79-81 4.50 5.33 0.471 26.7 1.12 0.500 8.75 9.11 0.457 2.21 61 231.14 160 146026X-5, 19-21 115 2.19 1.23 0.0318 37.9 26.9 50.3 1210 3.59 108 1.3726X-5, 64-66 1.19 1.09 1.16 0.0944 0.0335 38.5 49.8 91 9.79 0.500 8.99 231.98 149 13926X-5, 145-147 49 30 2.70 3.07 3.59 2.09 37.6 10.7 0.141 807 0.688 2.57 0.502 0.86 232.88 729 11.026X-6, 28-30 46 39 140 54.7 2.65 2.06 1.70 0.696 9.72 1.89 0.83 234.14 233.3326X-6, 88-90 14.2 3.57 3.13 0.0962 0.127 10.8 1210 644 245 88.3 0.682 9.68 1.25 10.8 165 1.8126X-CC, 3-5 41 44 0.0733 14.5 0.33 1.28 185 34.0 1290 114 87.8 60.3 18.2 234.47 275 11.227X-1, 12-14 14.1 3.59 1.65 0.33 0.0974 0.101 38.3 29.6 280 0.0893 0.257 1.74 235.0727X-1, 42-44 101 114 4.87 2.16 3.68 1.22 415 410 1140 1130 27.4 65 0.0867 0.113 0.611 2.08 o 43.2 235.7227X-1, 103-105 44 33.8 4.99 2.65 1.11 1.17 0.104 38.0 99 0.712 3.83 0.543 1.67 29.8 236.6327X-1, 135-137 80 13.0 4.98 c 0.0790 0.114 28.7 51.4 49 80 63.6 31.0 2.09 0.189 237.51 236.92 1260 1.0427X-2, 21-23 109 0.0546 112 15.0 c 11.4 0.0755 49 1110 37.6 92 95 2.94 0.710 2.69 2.17 v 26.2 237.82 55127X-2, 80-82 68.5 1.69 2.16 1.03 0.0728 38.5 30.2 527 0.0832 0.0539 1.05 0.956 2.71 71127X-3, 14-16 14.9 5.43 2.20 50.4 37.9 727 2.06 23 o 238.15 672 730 v 0.69327X-3, 60-62 75 0.0888 68.1 67.7 4.73 0.97 19.1 3.69 2.14 0.239 49.0 26.4 489 93 21132 1.92 0.717 1.04 15.0 238.7327X-3, 98-100 130 v 2.12 o 0.206 26.3 314 482 14.0 115 1.07 0.712 14.3 239.55 1530 White 27X-3, 134-136 0.122 0.117 111 14.3 5.14 0.0850 0.119 109 61.4 111 v 2.45 1.04 0.908 1.01 7.34 15.0 239.99 1520 23827X-4, 50-52 126 66.8 1.17 1.94 14.5 7.53 39.6 240.36 466 22.9 2.60 1.00 240.71 47327X-4, 110-112 128 34.4 2.47 1.18 0.0959 33.5 258 4.77 88 0.0547 34.7 22.3 0.19 2.30 43.0 Gray 24727X-5, 42-44 29 0.123 31.1 33.7 v 2.43 v 4.91 1.19 0.103 37.2 2.03 0.731 37.3 241.36 241.94 45627X-5, 72-74 129 29 0.0562 2.44 4.99 2.45 66 18.7 256 0.101 130 0.0555 2.04 0.599 6.87 8.85 14.3 256 47127X-5, 100-102 0.0547 0.0544 2.60 o 1.18 15.5 0.101 23.6 681 61 89.7 Gray 6.70 2.00 0.644 3.36 242.7527X-5, 138-140 62 v 12.9 0.640 0.123 32.0 50.3 134 19.1 88.8 o 0.196 1.10 0.0355 14.8 243.31 243.04 255 2.47 96627X-6, 7-9 19.6 o 1.22 13.5 432 68 135 0.0961 o 0.73 1.29 2.49 o 1.01 13.4 0.0344 243.68 1080 25227X-6, 120-122 108 60 6.35 50.8 1020 414 0.0532 0.0970 3.11 0.600 1.74 2.49 1.07 1.0927X-7, 37-39 0.0540 19.3 3.05 5.32 1.16 50.1 51.8 416 15.0 3.29 1.68 101 0.324 244.9727X-CC, 14-16 127 70 20.0 2.59 4.64 c 11.8 0.404 41.6 15.3 901 1090 32.4 1.10 23.0 1.47 4.54 243.8728X-1, 21-23 99 101 130 69 0.0548 Gray 1.38 o c 0.377 15.2 Dark green o 3.25 1.06 1.10 0.67 245.62 52 1.32 245.85 129 0.0543 Gray 0.639 0.0899 48.9 0.0537 0.696 22.8 1.22 2.87 0.0822 1.67 5.38 595 897 270 100 4.29 5.31 0.400 41.7 348 86 53.3 51.3 22.0 22.6 2.31 7.19 o 1.30 1.20 246.22 572 892 295 14.5 2.08 0.0567 43.3 46.8 3.03 43.1 o 1.25 0.123 2.07 597 32 o 2.77 0.277 12.2 343 0.0580 0.0576 119 53.9 0.701 6.07 0.772 0.0404 White 88 84 46.8 2.13 2.91 17.8 40.3 124 88 0.720 1.87 6.19 6.33 0.97 15.6 346 o 0.706 89 74 14.6 2.11 5.48 15.8 1240 124 0.0577 3.05 1.55 1.23 0.0188 45.2 349 0.0578 26.7 o o 15.7 15.3 Dark green 89 24X-4, 86-8824X-5, 15-1724X-5, 112-114 212.83 213.61 214.58 29.3 31.4 16.8 0.983 0.995 0.454 9.91 10.6 6.09 4.63 4.84 2.49 0.178 0.149 0.231 2.23 2.34 1.20 24.1 22.1 37.7 1.59 1.61 1.12 2.24 2.37 1.47 228 206 171 55 57 38 860 1250 812 218 133 227 43.1 67.3 39.5 0.112 0.0846 0.106 v v v Gray

543 I. JARVIS, J. MORETON, M. GÉRARD Green White White White White White Green White Green White White Green White Dark gray Dark green Dark green Dark green Dark green Dark green Dark green Dark green Dark green Dark green Dark green Dark green Dark green Dark green Dark green Dark green Dark green Dark green Dark green Dark green Dark green Dark green Dark brown Dark Green/brown Green/brown Green/brown Green/brown

3 (wt%) CaCO g/g) µ O Ba Cr Sr Zr Ti/Al Group Color 2 OK 2 Table 2 (continued). MnO MgO CaO Na 3 O 2 Major elements (wt%) elements Major ( elements Trace Fe 3 O 2 Al 2 TiO 2 SiO Depth (mbsf) interval (cm) interval Core, section, 28X-1, 42-4428X-1, 123-12528X-2, 11-13 246.43 247.2428X-2, 76-78 247.62 39.4 37.0 248.27 37.1 0.649 0.707 40.1 13.9 14.2 0.709 0.637 14.1 6.16 13.6 4.64 4.56 0.0766 0.131 5.24 2.22 0.135 2.43 0.111 2.42 11.1 15.9 2.20 1.28 16.1 1.11 13.7 1.11 2.25 2.93 1.23 2.99 2.21 383 364 375 121 397 84 432 84 120 596 120 599 552 143 19.7 149 120 28.3 0.0531 0.0566 28.8 24.5 o 0.0570 0.0531 o o o Dark green Dark green 28X-3, 10-1228X-3, 45-4728X-CC, 7-9 249.1128X-CC, 36-38 249.4629X-1, 88-90 249.64 249.9329X-1, 134-136 40.229X-2, 22-24 40.3 256.59 257.0529X-2, 54-56 41.4 40.3 0.67229X-2, 109-111 0.668 257.4329X-3, 34-36 15.1 42.9 48.3 257.75 258.30 0.662 0.69029X-3, 73-75 14.229X-3, 146-148 41.2 13.9 14.7 0.756 0.984 259.0529X-4, 36-38 5.49 5.03 5.19 259.44 260.1729X-4, 78-80 5.61 15.9 22.2 0.79529X-5, 23-25 0.149 42.7 5.49 5.69 0.124 0.143 260.5629X-5, 57-59 16.2 0.104 51.7 7.01 260.9829X-5, 116-118 5.84 6.77 0.112 0.157 0.773 2.07 1.76 1.77 261.9329X-5, 140-142 43.7 0.185 2.21 1.17 262.27 262.8629X-6, 27-29 6.36 16.7 0.109 0.0332 49.8 263.10 2.18 2.2029X-6, 78-80 0.963 0.858 51.3 12.7 0.774 2.46 22.029X-6, 131-133 2.02 0.309 49.5 12.2 50.3 0.965 2.19 0.448 0.340 263.4829X-CC, 28-30 5.45 16.7 51.0 12.4 12.1 1.10 1.23 263.99 264.5230X-1, 25-27 1.05 21.5 0.920 1.20 2.46 1.06 5.89 265.1330X-1, 99-101 0.488 0.58 0.137 0.65 23.5 1.12 5.53 9.32 1.24 1.2230X-1, 147-149 2.14 5.57 19.8 0.564 21.9 0.0561 5.36 5.75 265.5430X-2, 44-46 2.10 6.74 1.31 49.0 266.26 11.5 51.8 0.164 1.27 2.18 17.3 48.4 266.7430X-2, 115-117 0.163 2.18 2.29 0.148 5.91 0.600 0.151 1.9130X-2, 144-146 6.64 0.0713 1.15 1.83 0.84 6.09 2.14 44.6 7.23 267.21 267.92 427 1.0130X-3, 49-51 2.23 1.17 50.0 2.40 1.75 1.87 6.81 0.0192 47.2 9.93 268.21 38730X-3, 118-120 2.10 0.225 0.190 0.0690 0.64 21.1 349 35630X-4, 66-68 0.749 3.32 0.866 0.33 39.7 47.8 120 1.18 1.90 0.913 0.38 0.206 268.76 269.4530X-4, 115-117 0.99 0.942 0.937 431 132 2.65 2.26 15.3 1.13 1.96 0.266 9.12 7.30 37730X-5, 77-79 20.4 1.17 0.661 0.830 133 132 0.285 0.289 270.43 270.92 6.0930X-5, 123-125 2.33 2.99 32.9 38.4 524 1.23 0.46 0.163 0.38 38830X-6, 20-22 174 1.28 1.14 0.521 13.5 17.0 2.14 488 88 139 5.56 1.35 1.59 272.04 272.50 85 0.18530X-6, 73-75 0.500 6.08 0.488 33.4 34.4 489 492 1.27 0.660 0.616 2.3030X-CC, 22-24 111 2.33 0.203 49.2 1.12 1.26 2.37 1.17 0.0593 272.97 409 13631X-1, 58-60 123 93 4.94 6.04 12.5 0.0213 43.5 49.0 46.1 49.0 407 2.21 19 0.725 9.72 0.757 273.50 49 326 274.1731X-2, 41-43 17 2.41 1.60 1.00 132 119 22.6 2.66 0.610 0.9631X-2, 127-129 2.56 12.5 2.25 12.4 2.28 0.0981 0.0509 45.0 146 152 21.8 0.752 0.93 0.714 0.88 275.49 505 415 147031X-3, 27-30 134 4.86 3.32 0.252 40.0 348 1190 41.0 0.60 0.0506 165 3.14 22.0 47.5 21.5 276.82 277.6831X-3, 66-68 23 14.4 2.67 0.39 2.79 14.1 0.0532 0.704 8.74 28531X-3, 102-104 4.20 0.32 4.15 0.36 0.0622 0.0736 43.2 0.57 444 1.22 142 150 16.6 1.16 0.599 0.587 0.0541 0.0533 278.19 543 319 0.58631X-3, 138-140 30 172 o 1.04 14.2 52.8 36.8 1400 141 30 1.29 12.1 278.58 278.9431X-4, 36-38 0.0503 6.73 12.0 o 2.73 2.06 1.37 6.05 0.0861 0.0902 5.51 246 11.6 198 0.0540 0.700 48.4 279.30 125 2.3831X-4, 108-110 134 20.5 37.8 437 o o 187 168 87.4 0.953 0.42 0.513 160 163 10731X-4, 146-148 201 86.4 1.20 2.47 2.25 1.46 5.48 14.4 2.26 0.0499 0.0506 35 o 2.22 5.68 14.9 22.8 279.78 7.77 280.5031X-5, 30-32 0.0557 5.00 18.1 o 0.94 10.6 47.1 154 5.05 93 0.0801 17.7 0.497 280.8831X-5, 63-65 132 24 0.0919 2.82 2.96 0.0486 173 180 241 155 0.143 2.09 2.23 0.206 19.3 19.331X-CC, 19-21 21 18 84.2 1.14 1.27 1.17 5.10 10.1 0.0649 35.9 170 0.0658 0.0524 o 0.721 0.49 7.41 281.22 46332X-1, 16-18 186 5.79 2.96 4.38 c 39.3 169 1400 345 0.0600 16.3 1.69 2.32 c 281.55 282.4032X-1, 108-110 152 184 0.0850 1.11 2.67 1.17 14.1 175 0.0556 7.90 9.13 1510 1570 2.50 2.09 0.171 1.95 1.77 0.52932X-2, 58-60 o 3.92 0.0263 0.0660 39.1 344 341 130 30 0.0524 0.584 284.97 285.8832X-2, 123-125 212 0.0510 169 0.68 1.35 0.693 2.77 o 1.47 0.860 11.0 9.14 120 35.8 36 2.16 2.49 2.35 c 14.0 6.32 14.0 13332X-3, 8-10 2.41 2.84 2.69 2.37 6.50 0.0635 11.7 Brown 34 0.0531 33 0.578 0.271 0.256 286.86 287.50 149032X-4, 9-11 125 143 o 1.48 38.4 42.9 404 443 340 White 0.0526 0.0547 0.136 1.88 o 2.10 10.2 139 0.48032X-4, 38-40 2.00 87.8 1.32 0.816 2.26 4.07 11.7 0.126 1.26 30 179 18.432X-4, 88-90 87.5 87.5 o 0.485 4.47 0.597 43.4 2.32 46.5 287.85 466 428 10.2 0.0730 0.502 1.90 2.14 0.483 0.299 508 30032X-5, 31-33 147 40 109 0.102 o 1.36 o 0.0828 289.33 62 166 1.94 3.14 17.4 289.61 1520 1.9332X-5, 104-106 0.0956 0.0911 1.59 4.40 10.7 1.25 0.0806 49.1 46.8 437 324 0.468 0.506 9.80 45.1 1.07 290.1032X-6, 14-16 0.715 0.561 o 2.60 4.13 79 132 162 83 15.6 84.8 1.87 54.2 291.04 291.76 62032X-6, 102-104 1.26 10.3 2.67 c 0.0798 0.0541 51.9 844 309 1.02 2.07 0.95 9.43 1.61 1.00 c c 0.379 8.04 128 44 127 0.512 4.03 3.86 51.9 48.4 405 0.0781 403 0.0553 0.0949 18.3 292.34 293.20 0.0508 21.6 0.822 2.66 49.2 50.1 792 782 125 9.84 0.853 10.6 1.64 1.83 16.0 o 145 127 0.34 0.807 4.19 4.13 0.46 0.0803 0.0658 344 2.57 86.4 0.874 0.96 16.7 345 405 0.0553 0.0553 113 17.1 o 1.29 c 107 46.3 280 366 0.506 0.487 o 15.8 9.97 130 137 26.6 2.70 17.2 1.36 1.68 2.57 0.0589 0.0667 48.8 0.0806 40.7 4.75 403 17.7 128 0.47 10.1 363 153 142 0.218 5.63 o o 0.546 9.77 1.57 569 157 141 5

544 CHEMOSTRATIGRAPHY OF MIOCENE–PLEISTOCENE TURBIDITES Gray Gray White White Dark gray Dark gray Dark gray Dark gray Dark gray Dark gray Dark gray Dark gray Dark green Dark green Green/brown Green/brown

3 (wt%) CaCO = organic-rich and other turbidites; sst = organic-rich = volcaniclastic sandstone. g/g) µ O Ba Cr Sr Zr Ti/Al Group Color 7), Weaver, Buckley et al., 1989, and Weaver, Thomson, et al., 1989; bed divisions Buckley are indicated et al., by 1989, horizontal and Weaver, 7), Weaver, 2 OK 2 Table 2 (continued). MnO MgO CaO Na 3 O 2 Major (wt%)Major elements ( elements Trace Fe 3 O 2 Al 2 TiO 2 calculated from CaO data, assuming that all Ca is present as carbonate. Lithologic groups are: c = calcareous; v = volcanic; o 3 SiO ; CaCO 3 O 2 Depth (mbsf) interval (cm) Core, section, 32X-CC, 16-18 294.26 50.3 0.675 13.6 5.72 0.0342 2.81 5.72 1.62 1.73 629 122 314 146 10.2 0.0565 o 33X-1, 76-7833X-1, 133-13533X-2, 44-46 295.63 295.0833X-2, 98-10033X-2, 138-140 296.3133X-3, 62-64 53.4 53.4 296.84 297.2333X-3, 143-14633X-4, 34-36 53.6 0.796 0.786 34.7 298.75 297.9633X-4, 56-58 35.033X-4, 145-147 16.2 16.5 0.703 299.1533X-5, 55-57 0.702 54.5 48.4 0.773 300.24 299.3733X-5, 127-129 15.2 10.933X-6, 22-24 10.9 5.91 5.73 52.2 0.736 0.649 301.54 300.8333X-7, 27-29 53.8 54.733X-CC, 28-30 15.4 13.6 6.07 0.0282 0.0245 0.786 4.09 301.9834X-1, 79-81 4.14 54.1 55.3 1.28 0.885 303.51 303.9934X-1, 104-106 16.5 3.60 3.50 0.0469 0.088734X-2, 16-18 18.1 6.00 5.58 0.0923 52.7 0.845 15.0 1.18 305.07 304.8234X-2, 33-35 4.05 50.8 53.1 2.5034X-2, 44-46 17.9 5.60 2.44 0.0522 0.0528 1.18 0.76 0.979 16.2 305.6734X-2, 60-62 6.04 43.3 43.6 8.50 1.21 305.84 1.1034X-2, 95-97 1.66 19.7 3.73 3.56 1.67 0.0196 1.56 19.6 20.2 305.9534X-CC, 27-29 5.86 0.0277 39.6 0.783 0.997 16.4 7.21 0.104 306.11 15.635X-1, 71-73 3.38 1.81 33.3 2.33 2.22 1.21 306.46 306.7835X-CC, 36-37 1.29 13.3 13.9 5.62 3.43 0.0213 2.06 7.40 15.8 0.571 0.040836X-1, 91-93 3.55 2.36 0.564 6.64 6.30 314.32 7.37 314.80 3.25 1.66 1.54 2.02 11.9 0.0172 0.84 2.03 0.359 3.41 4.21 2.49 5.15 5.51 1.15 323 465 9.62 0.213 0.0306 324.05 0.0478 1.73 2.93 1.42 58.8 2.29 2.19 0.147 4.59 6.83 0.0983 4.93 1.63 0.0420 0.0418 1.01 412 1.87 3.23 1.27 478 3.55 144 153 1.80 3.94 502 0.766 2.06 0.174 1.21 0.85 1.08 1.52 2.07 2.87 2.85 0.0369 0.75 2.18 1.77 162 0.806 0.0664 340 409 0.320 2.71 1.95 0.0319 4.46 169 169 1.21 94 0.531 2.92 1.53 0.173 5.47 93 2.06 0.244 10.0 0.128 2.86 0.287 2.26 9.39 592 1.59 0.219 165 1.73 151 138 0.712 359 150 153 2.11 1.45 14.0 816 2.33 1.08 1.50 1.54 0.124 819 365 0.999 0.123 23.1 166 2.87 0.987 721 2.35 132 0.179 178 341 259 0.538 163 1.50 38.4 51.4 108 2.11 1.36 1.90 2.02 48.2 124 117 1.15 1.17 49.9 337 181 154 0.0556 0.0541 0.863 1.20 139 125 2.79 1.42 0.78 196 488 0.41 213 99 35.0 0.68 36.0 1.31 0.65 47.6 182 157 0.0524 53.0 456 453 138 o o 169 13.5 0.0731 13.2 0.73 0.12 150 134 0.0808 3.68 0.37 146 188 0.79 0.25 534 158 o 0.80 183 131 139 0.0542 0.0540 450 1.12 154 1.50 v v 271 169 196 2.05 0.34 176 138 0.0541 0.06 31 183 2.53 o o 70 438 423 1.08 0.0555 43 99 1.80 152 0.0970 159 2.27 o 491 55 0.0536 123 140 1.33 o 30 44 28 0.0827 Gray 573 292 33 v 4 0.0563 7.96 2.16 100 o 658 17.9 16.8 565 0.0837 v 0.0797 621 126 34 123 572 o 29 0.0666 0.0814 25.0 77 v v 41.1 Dark gray 32 405 260 43 0.0543 43 v v 439 0.0664 68.5 91.8 86.0 o 421 88 89.1 0.0886 26 c 0.146 0.130 Dark gray 0.137 24.1 85.0 c 94.5 0.223 c 0.101 c c 0.126 sst c c White to brown Italicized letters in the Color column are Quaternary turbidite identifiers of Weaver andItalicized letters Kuijpers in the Color (1983), column De Langeare Quaternary et al. turbidite (198 identifiers of Weaver lines. Notes: Total iron expressed as Fe iron expressed Total Notes:

545 I. JARVIS, J. MORETON, M. GÉRARD

A CaCO3 (wt %) Ti/Al ratio 0 255075100 0.04 0.12 0.20 Series Core Samples Recovery/ lithology Unit

c d 1H

e1 10

!+,-.89:f 2H _`k

h l j k

l1 l 3 20 n

q Unit I/1

Depth (mbsf) r Pleistocene '4 +,-78+,67s s1 ;< !*+,-78 *+ s2 30 t u 4H

,-789 *+6 ,-78

Figure 2. A–G. Carbonate and Ti/Al ratio profiles plotted against lithology for Site 950. Only turbidite data are plotted; pelagic intervals are excluded. Turbidite

classification: (a) calcareous turbidites, >75% CaCO3 (calculated from CaO data); (b) volcanic turbidites, Ti/Al >0.8 and CaCO3 <75%; (c) organic-rich and other turbidites. Turbidite lettering in Sections 157-950A-1H through 4H after Weaver and Kuijpers (1983) and Weaver et al. (1989a, 1989b); series boundaries derived from Howe and Sblendorio-Levy (Chap. 29, this volume).

546 CHEMOSTRATIGRAPHY OF MIOCENE–PLEISTOCENE TURBIDITES

B CaCO3 (wt %) Ti/Al ratio 0 255075100 0.04 0.12 0.20 Series Core Samples Recovery/ lithology 50 Unit 6H

60 7H Pleistocene

<=34:; !"*+12

'ST_ 70 8H

Unit I/1 Depth (mbsf)

80 9H

"*+123:!

90 Upper Pliocene 10H

5=>tPQ

100 11H

Figure 2 (continued).

=34:;<

547 I. JARVIS, J. MORETON, M. GÉRARD

C CaCO3 (wt %) Ti/Al ratio 0 255075100 0.04 0.12 0.20 Series Core Samples Recovery/ lithology 100 Unit

110 $

'FGRS 13H 12H Unit I/1

120 Upper Pliocene Depth (mbsf)

$, 14H

130

089

15H

140

-.6hiu Unit I/2 Lower Pliocene

?$ .5678>?" 16H

150

Figure 2 (continued).

548

.567>??.567=> CHEMOSTRATIGRAPHY OF MIOCENE–PLEISTOCENE TURBIDITES

D CaCO3 (wt %) Ti/Al ratio 0 255075100 0.04 0.12 0.20 Series Core Samples Recovery/ lithology 150 Unit 17H 18X

160

! 19X

DE23:dopqz{|W Lower Pliocene 170

20X Unit I/2 Depth (mbsf)

!" ! "* 180 21X

190 22X Upper Miocene

"*+,23 !

200

Figure 2 (continued).

549 I. JARVIS, J. MORETON, M. GÉRARD

E / CaCO3 (wt %) Ti/Al ratio 0 255075100 0.04 0.12 0.20 Series Samples Core lithology Recovery Unit 200

23X

$ABCN

210

24X

Unit I/3a

220

25X

$+,-.456=" $*+,3 ! Depth (mbsf) Upper Miocene

230 26X

*2bco

240

>?,-456=>?-45< Unit I/3b 27X 28X 250

Figure 2 (continued).

550

6=>?$+,3

CHEMOSTRATIGRAPHY OF MIOCENE–PLEISTOCENE TURBIDITES

F CaCO3 (wt %) Ti/Al ratio 0 255075100 0.04 0.12 0.20 Series Core Samples Recovery/ lithology 250 Unit

Unit I/3b Upper Miocene 260 29X

$,Z[9:zUVW

270 30X Depth (mbsf) 31X 280 Unit I/4 Middle Miocene 32X 290

29:;{|VWX

Unit I/5

300 33X

Figure 2 (continued).

551

=> I. JARVIS, J. MORETON, M. GÉRARD

G CaCO3 (wt %) Ti/Al ratio 0 255075100 0.04 0.12 0.20 Series Core Samples Recovery/ lithology 300 Unit

Unit I/5

34X

*/0

&'- ./0&',-. $/

35X Depth (mbsf) Unit II

320 $345<=>GF Lower Miocene 36X

white mud/sand turbidites calcareous turbidites

gray mud turbidites volcanic turbidites

green mud turbidites organic-rich and other turbidites

brown - green/brown mud turbidites volcaniclastic sandstone

gray sandstone sample position

no core recovery geochemical data point

no lithological data

Figure 2 (continued).

Figure 2 demonstrates that shipboard identification of all gray tur- values of ~0.2 toward the base of the unit. There is a suggestion that bidites as being members of the ‘volcanic’ group was erroneous, and the high-Ti (turbidites b, p; Fig. 2) and low-Ti (g, o) subgroups de- $*+FGPQR that the frequency of volcanic turbidite deposition is much lower than fined by Pearce and Jarvis (1995) in the Quaternary sediments, con- originally thought. The detailed log (Fig. 2), combined with summary tinue downcore with a trend toward increasing Ti/Al ratios in both geochemical profiles (Fig. 3) for CaCO3 and Ti/Al ratios through groups. shipboard lithostratigraphic Unit I (Schmincke, Weaver, Firth, et al., Carbonate contents of both the volcanic and calcareous turbidites 1995), enable five new subdivisions to be designated here (defined also generally increase downward through this interval. Ti/Al ratios here as chemostratigraphic Units I/1 through I/5): of the organic-rich turbidites are remarkably consistent throughout the section, with small excursions toward higher values being caused Unit I/1, 0−134 mbsf (upper Pliocene–Pleistocene) by samples from the lower portions of beds, which commonly contain a proportion of entrained volcaniclastic grains (Pearce and The pattern of turbidite deposition seen in the upper Pleistocene– Jarvis, 1992a, 1992b, 1995). A thick gray turbidite at 59−65 mbsf, Holocene, continues down to ~134 mbsf (low–upper Pliocene). Tur- originally assigned to the volcanic group (Schmincke, Weaver, Firth, bidites in this interval fall clearly into one of the three previously de- et al., 1995), contains a high carbonate content of 68%, but a low Ti/ fined turbidite groups. Ti/Al ratios for the volcanic turbidites form a Al ratio of 0.057 (Figs. 2B, 3). A sample (157-950A-7H-3, 78−79 broad array with increasing values downward, attaining maximum cm; 61.68 mbsf) from this turbidite analyzed for Corg aboard ship,

552 CHEMOSTRATIGRAPHY OF MIOCENE–PLEISTOCENE TURBIDITES

CaCO3 (wt%) Ti/Al ratio Series 0 50 100 0.04 0.12 0.20 Unit 0 Pleistocene I/1

100 Upper Pliocene

volcanic turbidites I/2 Lower Pliocene

Depth (mbsf) organic-rich and other 200 turbidites a

I/3 Upper b Miocene

Figure 3. Geochemical variation in turbidite carbonate I/4 contents and Ti/Al ratios, Unit I, Site 950. Note the clear

calcareous Middle 300 I/5 Miocene distinction between volcanic (solid circles; 71 data turbidites points), calcareous (open circles; 70 points), organic-rich Site 950 II L. and other (shaded area and continuous line; 338 analy- Mio. ses) turbidites in Unit I/1. yielded 0.51% (Schmincke, Weaver, Firth, et al., 1995), indicating Ti/Al ratio profile (Fig. 3), a characteristic that continues down that despite its color, the turbidite belongs to the organic-rich group. through to the remainder of Unit I. Indeed, two gray calcareous tur- The clear distinction between volcanic and other turbidites is bidites within this interval (at 161 and 174 mbsf), have carbonate shown by data for other elements known to be enriched in the volca- contents of 80%, but high Ti/Al ratios of ~0.11. niclastic fraction (De Lange et al., 1987, 1989), particularly Fe/Al, Despite the occurrence of a few dark green turbidites with very Cr/Al, and Zr/Al (Fig. 4). Fe/Al ratios, are also lowest in the organic- low carbonate contents, there is a general downward increase in the rich turbidites, occur at intermediate levels in the calcareous turbid- carbonate contents of the nonvolcanic turbidites through Unit I/2; ites, and are highest in the volcanic category. Chromium contents CaCO3 contents attain a maximum in a series of three thick, gray tur- overlap between the organic-rich and volcanic groups, but trend to bidites with low Ti/Al ratios (Fig. 2D) at 199 mbsf. The bottom of the highest values in the latter category. Zirconium contents are in- Unit I/2 is defined by this shift in the carbonate profile (Fig. 3); cal- variably highest in volcanic turbidites. Unlike Ti, only Cr/Al displays careous turbidites also attain their highest CaCO3 contents of >90% a clear downhole increase within the volcanic group of Unit I/1, and toward the base of the unit. Shipboard Corg determination in this case a maximum is reached in a turbidite at 102 mbsf, some (Schmincke, Weaver, Firth, et al., 1995) of a sample (157-950A- distance above the base of the unit. 23X-1, 11−12 cm; 197.91 mbsf) taken from one of the thick, gray Pearce and Jarvis (1995) recognized two subgroups within Qua- nonvolcanic beds at the base of Unit I/2, gave a low value of 0.19%. ternary organic-rich turbidites, based largely on potassium contents. Given the considerable thickness (>5 m) of this turbidite, it is unlike- Such a distinction is apparent in the K/Al ratios of the green turbidites ly that it represents an oxidized member of the organic-rich group. in Unit I/1 at Site 950 (Fig. 5), with high-K examples being charac- This points to a different provenance for this, and possibly the other terized by ratios of >0.3, and a second subgroup having ratios of 0.2− thick, gray nonvolcanic beds; additional organic carbon and other 0.3; however, separation between the fields of the two subgroups be- geochemical data are required to test this hypothesis. comes less clear in the mid-Pleistocene. A similar pattern is shown A number of high-Ti volcanic turbidites continue to occur in Unit by Mg/Al (Fig. 6), with organic-rich turbidites at 18 (turbidite k), 56, I/2, and also have high Fe and Zr, but low Cr contents (Fig. 4). Occa- 84, 85, 115, and 133 mbsf, in particular, displaying markedly K- and sional high Fe values in samples from organic-rich turbidites are at- Mg-depleted compositions. Si/Al ratios vary considerably in the or- tributed to the occurrence of scattered pyrite in the deeper turbidites. ganic-rich turbidites of Unit I/1 (Fig. 7), but show no clear strati- The two subgroups of organic-rich turbidites identified in Unit I/1 graphic trends. Volcanic and calcareous turbidites display much less continue through Unit I/2, and display even clearer separation on K variation, with overlapping arrays on K, Mg, and Si plots, and little and Mg profiles (Figs. 5, 6). The low-carbonate organic-rich turbid- distinction between beds. ites that first appear in Unit I/2 are also distinguished by having the lowest K/Al (<0.2), Mg/Al, and Si/Al ratios in the sequence (Figs. 5 Unit I/2, 134−199 mbsf (uppermost Miocene–lower Pliocene) through 7), forming a distinctive third compositional subgroup on the geochemical profiles. A transition toward increased proportions of thin-bedded turbidites ~134 mbsf (Fig. 2C), is accompanied by the appearance of low- Unit I/3, 199−265 mbsf (uppermost middle Miocene–upper carbonate (<10% CaCO3) dark-green organic-rich turbidites, gray Miocene) volcanic turbidites with low Ti/Al ratios (~0.09), and calcareous turbidites with high Ti/Al ratios of >0.07 (Fig. 3). Samples from calcar- Turbidites below 199 mbsf generally display declining CaCO3 eous turbidites with the highest Ti/Al ratios (up to 0.12) are generally contents, reaching a minimum in a sequence of thin-bedded dark- from the lower portions of beds. Together, these changes produce green turbidites at the base (Fig. 2E–G), which contains no signifi- overlap between the calcareous and volcanic turbidite fields on the cant carbonate. Even the calcareous turbidites become increasingly

553 I. JARVIS, J. MORETON, M. GÉRARD

Fe/Al ratio Cr/Al ratio (x103) Zr/Al ratio (x103) Series 0.3 0.7 1.1 0.5 2.0 3.5 1.0 3.5 6.0 Unit 0 Pleistocene I/1

100

volcanic Upper turbidites Pliocene

I/2 Lower Pliocene Depth (mbsf) 200 a

I/3 Upper organic-rich b Miocene calcareous and other turbidites turbidites

I/4 Middle

300 I/5 Miocene

Site 950 II L. Mio.

Figure 4. Geochemical variation in turbidite Fe/Al, Cr/Al, and Zr/Al ratios, Unit I, Site 950. Volcanic (solid circles), calcareous (open circles), organic-rich and other (shaded area and continuous line) turbidites follow discrete trends similar to those displayed by Ti/Al ratio plots (Fig. 3). Calcareous turbidites have been omitted from the Cr/Al and Zr/Al plots because scattering produced by poor analytical reproducibility masks any geochemical trends.

K/Al ratio K/Al ratio K/Al ratio Series 0 0.25 0.50 0 0.25 0.50 0 0.25 0.50 Unit 0 Pleistocene I/1

100 Upper Pliocene

intermediate

I/2 Lower Pliocene Depth (mbsf)

200 low high a

I/3 Upper b Miocene

I/4 Middle

300 I/5 Miocene

Volcanic and calcareous Organic-rich Other II

turbidites turbidites turbidites L. Mio.

Figure 5. Stratigraphic variation in turbidite K/Al ratios, Unit I, Site 950. Volcanic (solid circles) and calcareous (open circles) turbidites have similar ratios, typically >0.25. Green organic-rich turbidites (filled squares; 229 analyses) display three distinct compositional arrays (shaded): with high (>0.3), intermediate (0.2–0.3) and low (<0.2) K/Al ratios. Gray nonvolcanic (open squares; 60 data points) and other (open triangles; 48 analyses) turbidites fall mostly within the field (outlined) of the high K/Al organic-rich group, except near the base on Unit I.

554 CHEMOSTRATIGRAPHY OF MIOCENE–PLEISTOCENE TURBIDITES

Mg/Al ratio Mg/Al ratio Series 0 0.4 0.8 0 0.4 0.8 Unit 0 Pleistocene I/1

100 Upper Pliocene

I/2 Lower Pliocene Depth (mbsf) 200 a

I/3 Upper b Miocene

I/4 Middle

300 I/5 Miocene

Volcanic and calcareous Organic-rich and other II Figure 6. Stratigraphic variation in turbidite Mg/Al turbidites turbidites L. Mio. ratios, Unit I, Site 950. Symbols as in Figure 5.

Si/Al ratio Si/Al ratio Series 1 3 5 1 3 5 Unit 0 Pleistocene I/1

100 Upper Pliocene

I/2 Lower Pliocene Depth (mbsf) 200 a

I/3 Upper b Miocene

I/4 Middle

300 I/5 Miocene

Volcanic and calcareous Organic-rich and other II Figure 7. Stratigraphic variation in turbidite Si/Al turbidites turbidites L. Mio. ratios, Unit I, Site 950. Symbols as in Figure 5. impure through this interval (Fig. 3). The last thick, gray volcanic tur- However, there is a general shift toward lower Mg contents through bidites occur ~221 mbsf, and these, with one exception (at 217 mbsf), Unit I/3, a consequence of declining carbonate, which contains sig- are characterized by low Ti/Al ratios of ≤0.12. There is a noticeable nificant Mg. The Mg/Al minimum, therefore, corresponds to the car- overall decrease in bed thickness below 231 mbsf (Fig. 2E), with old- bonate minimum at the base of Unit I/3; K and Si profiles remain un- er turbidites typically <2 m thick. This change in bedding style and affected. lithology is used to subdivide the unit into I/3a (above) and I/3b (below). Unit I/4, 265−294 mbsf (mid- to high middle Miocene) Organic-rich turbidites in Unit I/3 display an increasing dominance of the intermediate K subgroup (K/Al ratios, 0.2−0.3) toward Unit I/4 is dominated by thinly bedded green and green/brown the base, with common low K (K/Al ratios, <0.2) examples in Sub- turbidites (Fig. 2; Table 2), with low and variable CaCO3 contents of unit I/3b (Fig. 5). Separation between the subgroups is also seen on 0% to 34%. Calcareous turbidites have moderate carbonate contents the Mg/Al (Fig. 6), and to a lesser extent the Si/Al (Fig. 7) profiles. (87%) and high Ti/Al ratios of ~0.09. The oldest dark-green high K

555 I. JARVIS, J. MORETON, M. GÉRARD organic-rich turbidite occurs toward the top of Unit I/4 at 247 mbsf (6−11 Ma), with a progressive increase in bed thicknesses and car- (Fig. 5), although brown turbidites with similar compositions occur bonate contents, and a shift toward the deposition of turbidites con- below, at 257 and 263 mbsf. taining higher K/Al and Mg/Al ratios. Carbonate contents generally All turbidite groups display increasing Si/Al ratios downward fell slightly through the latest Miocene to latest early Pliocene (3.5− through Unit I/4, with the highest Si/Al ratios occurring in a unique 6 Ma), a trend accompanied by decreasing bed thicknesses and an in- suite of green/brown turbidites between 286 and 294 mbsf (Figs. 2, creasing dominance of high-K over medium-K sediments, but with 7; Table 2), at the very base of the unit. the continued intermittent influx of flows with very low carbonate, K-depleted compositions. The low-K source switched off in the latest Unit I/5, 294−306 mbsf (low middle Miocene) early Pliocene, and deposition during the last 3.5 m.y. has been remarkably uniform, with deposition being dominated by thick-bed- The oldest beds in Unit I consist of a thin-bedded sequence of ded, high-carbonate, high-K organic-rich turbidites, accompanied by dark-gray turbidites (Unit I/5; Fig. 2), with variable Ti/Al ratios and the occasional input of medium-K beds. low carbonate contents. Many have Ti/Al ratios of >0.08, and so are Preliminary interpretation of these trends is that, since the latest assigned to the volcanic group, but they are lithologically and Miocene, organic-rich turbidites have originated predominantly from geochemically distinct from younger members of the group, which a chlorite- and illite-rich sediment source area on the northwest Afri- only appear above 221 mbsf, in the upper Miocene. Despite their Ti- can continental slope off Morocco (Fig. 1), but with regular input of enriched signatures (Fig. 3), these middle Miocene volcanic turbid- more kaolinitic sediment from a southerly source area, probably off ites have lower Zr contents (Fig. 4), than other volcanic turbidites in Western Sahara. A third source, possibly a high-productivity area lo- the core; they are further distinguished by having low Mg and K, and cated even further to the south, was particularly active during the ear- high Si to Al ratios. Organic-rich and other turbidites in this interval ly late Miocene and mid-Pliocene. The less potassic sediments that are all medium to low K/Al varieties (Fig. 5), with relatively high Si dominate the middle and upper Miocene may be a consequence of the contents (Fig. 7) and no clear separation between subgroups. No cal- increased importance of the southerly source area, and/or climate careous turbidites occur in Unit I/5. change, promoting mineralogical changes in the northern source. Di- agenetic processes are not considered to be a likely cause of the ob- Unit II, 306−333 mbsf (lower Miocene–lowest middle Miocene) served geochemical trends, because pore-water profiles (Schmincke, Weaver, Firth, et al., 1995) demonstrate minor uptake rather than the Unit II is characterized by very poor core recovery; only a few loss of potassium from deeper sediments at Site 950. sections of carbonate sand and gravel were obtained. Downhole logs indicate that three coarse-grained carbonate units occur in Unit II (Schmincke, Weaver, Firth, et al., 1995), and that its base coincides Volcanic Turbidites with the base of the nonrecovered interval (top of Core 157-950A- 37X). A unique feature in this sequence is the occurrence at its top of Pearce and Jarvis (1995) concluded that during the late Quaterna- a hybrid turbidite, which grades upward from carbonate sands and ry, high-Ti volcanic turbidites on the MAP were derived from the gravels containing 90% CaCO3, at its base (Fig. 2), to brown muds younger western Canary Islands (Fig. 1), or possibly the basaltic with 40% CaCO3 at its summit. High Ti/Al ratios of 0.14 in the coars- complexes of Tenerife, whereas the low-Ti subgroup reflected a er lower part of the turbidite reflect a high proportion of volcaniclas- more fractionated volcanic source, and probably originated from the tic material, dominantly zeolitic vitric tuff and basaltic rock frag- northern flanks of the central and eastern Canary Islands. ments with occasional glass shards and mineral crystals; this fraction The oldest members of the volcanic turbidite group at Site 950 are is diluted by increasing proportions of clay minerals upward, and at confined to the early middle Miocene, ~14−16 Ma. These thin-bed- the top of the bed the Ti/Al ratio is only 0.07. ded, dark-gray turbidites are lithologically quite distinct from young- A sample of a thinner calcareous turbidite sand at 324 mbsf (Sec- er members of the group and have trace-element–depleted signatures. tion 157-950A-36X-1, 91−93 cm; Fig. 2G; Table 2) also has a very Their origin is currently uncertain. high Ti/Al ratio of 0.13, suggesting a similar source to the thick hy- The first thick-bedded, gray volcanic turbidites were deposited in brid turbidite. A gray volcaniclastic sandstone at 315 mbsf (Section the mid-late Miocene, ~6.5 Ma. This corresponds to volcanic hiatuses 157-950A-35X-CC, 36−37 cm; Fig. 2G; Table 2), displays the high- on Gran Canaria and Fuerteventura, and the early submarine stage of est Ti/Al ratios measured, at 0.22. Both of these sediments have mod- Tenerife (Schmincke, 1976, 1982, 1994). It has been demonstrated erate Fe but very high Cr and Zr contents. Very high Mg/Al ratios that Gran Canaria was supplying very little sediment to the deep characterize the carbonate sediments within this interval, attaining a ocean at that time (Schmincke, Weaver, Firth, et al., 1995). Low Ti, value of 3.4 in the turbidite sand at 324 mbsf. The volcaniclastic Fe, and Cr, and moderate Zr concentrations predominate in the late sandstone, on the other hand, displays low Mg but high Si to Al ra- Miocene turbidites, pointing toward an evolved volcanic source area, tios. probably the slopes of Lanzarote or Gomera. However, an increasing proportion of Ti-rich turbidites were deposited during the early Turbidite Provenance Pliocene, Organic-Rich Turbidites A major change in volcanic turbidite geochemistry occurred at the beginning of the late Pliocene, ~3.5 Ma, with the disappearance of The deposition of organic-rich turbidites at Site 950 began in the low-Ti sediments and an influx of common turbidites with very high early middle Miocene (~15 Ma), with the first dark-green turbidite, Ti/Al and Fe/Al ratios. This points to a major shift toward a more ba- now at 296 mbsf (two thin, green turbidites occur below this, ~324 saltic source area. The island of La Palma was initiated around this mbsf, but these contain negligible Corg). Organic-rich turbidites have time (Schmincke, 1994), while activity had ceased on Gomera and a dominated deposition on the MAP since that time. volcanic hiatus was occurring on Tenerife. Gran Canaria was under- Organic-rich turbidites display major changes in carbonate con- going the development of a large stratocone, with the eruption of al- tents and other geochemical parameters through the sequence. Depo- kali basalt, trachyte, basanite, and phonolitic lavas and pyroclastics. sition on the plain during the middle Miocene was predominantly It is speculated that the development of the La Palma Shield may thin-bedded, low-carbonate sediments with low to medium K/Al and have caused sediment instability on the slopes of the western Canary high Si/Al ratios. Major changes occurred during the late Miocene Islands, providing a significant sediment source at that time.

556 CHEMOSTRATIGRAPHY OF MIOCENE–PLEISTOCENE TURBIDITES

There is a decline in Ti/Al and Fe/Al and a general increase in Zr/ rich), carbonate-poor turbidites. The high-K subgroup probably orig- Al ratios through the subsequent 3.5 m.y., indicating increasing input inated principally from a northern source area on the upper continen- of sediment from areas having more evolved volcanic compositions. tal slope off Morocco, whereas high-Al sediments were derived from La Palma, Tenerife, and, more recently, Hierro, seem likely sources the south, off Western Sahara. Climatic changes are also likely to for the more basic material, with Gran Canaria, Lanzarote, and Fu- have modified sediment mineralogy in the competing sources areas. erteventura providing a more fractionated volcaniclastic component. Volcanic turbidites are volumetrically the second most important sediment type through most of the sequence, although carbonate tur- Calcareous Turbidites bidites are more frequent. A thin package of thinly bedded dark gray volcanic turbidites with distinctive trace-element–depleted geochem- The deposition of thin calcareous turbidites on the MAP has oc- ical signatures was deposited during the early–middle Miocene (14− curred since at least the late Eocene. They occur regularly through the 16 Ma). These are of uncertain affinity. The first typical thick-bed- middle Miocene to Pleistocene record. Prior to the late Pliocene (~3.5 ded, Ti-, Fe-, and Zr-rich volcaniclastic turbidites were deposited on Ma), geochemical evidence indicates that calcareous turbidites en- the MAP in the mid-late Miocene, ~6.5 Ma, and probably originated trained significant amounts of basaltic volcaniclastic debris, imply- from the Canary Island slopes of Lanzarote or Gomera. A major ing the active erosion of the westerly seamount chains (Fig. 1), which change to turbidites with very high Ti and Fe contents occurred are believed to have acted as their source area. Younger turbidites around the beginning of the late Pliocene (~3.5 Ma), possibly associ- contain little volcaniclastic material, indicating that the seamounts ated with sediment failure during the early growth of La Palma. have been covered by a pelagic drape since that time. Younger volcanic turbidites display a clear trend toward progressively more fractionated volcanic sources since 3.5 Ma, although their Other Turbidites wide range of trace-element compositions indicate continued supply from a variety of different source areas on the Canary Island slopes. A number of turbidites that do not fall clearly into any of the Thin-bedded calcareous turbidites occur throughout the sequence. above groups have been observed at Site 950. Many of these are thin, They originated predominantly from the seamount chains to the west gray turbidites that probably represent the now completely oxidized of the MAP and, up until the latest early Pliocene, incorporated a sig- members of the organic-rich group. Such turbidites fall entirely with- nificant proportion of basaltic material derived from erosion of the in the geochemical compositional arrays defined by green turbidites. exposed volcanic edifices. Since ~3.5 Ma, these seamounts have been A smaller number of beds fall between the main arrays and may have largely covered by a pelagic sediment drape, which now provides the mixed compositions. The source area of several thick, gray turbidites main sediment source for calcareous turbidites on the plain. with nonvolcanic signatures remain uncertain, and the distinctive package of middle Miocene green/brown Si-rich turbidites also mer- its further investigation. ACKNOWLEDGMENTS Thick, carbonate-debris flows and calcareous turbidites deposited during the early Miocene have distinctive trace-element–enriched We thank the crew, marine technicians, and fellow scientists of geochemical signatures, reflecting the inclusion of a high proportion Leg 157 for their help and enthusiasm. In particular, Sten Lindblom, of basaltic and other volcaniclastic debris. In the absence of dolomite, Anne Pimmel, and Robert Kemp managed to survive the shipboard high Mg/Al ratios point to the inclusion of high-Mg calcite in the car- geochemical program. Erinn McCarty remained jovial despite our re- bonate-sand fraction. The latter is consistent with a shallow-water or- quests for difficult samples. Meryl Batchelder provided valuable igin for these sediments. They probably originated from the upper technical assistance in the initial stages of this project. Constructive flanks of the Cruiser/Hyères/Great Meteor Seamount chain, which reviews were provided by Gert De Lange, Tim Pearce, Guy Roth- may have been emergent at that time. well, and Phil Weaver. We gratefully acknowledge support of this work through NERC ODP grant GST/02/1097.

CONCLUSIONS REFERENCES

Significant turbidite deposition on the MAP at Site 950 began in Bouma, A.H., 1962. Sedimentology of Some Flysch Deposits: A Graphic the early Miocene with the deposition of thin, carbonate-sand turbid- Approach to Facies Interpretation: Amsterdam (Elsevier). ites and three thick carbonate-debris flows. These beds have distinc- Colley, S., and Thomson, J., 1985. Recurrent uranium relocations in distal tive geochemical signatures, reflecting the incorporation of signifi- turbidites emplaced in pelagic conditions. Geochim. Cosmochim. Acta, cant amounts of basaltic material and shallow-water carbonate grains 49:2339−2348. derived from the erosion of seamounts lying to the west of the plain. ————, 1992. Behavior and mobility of U-series radionuclides in Madeira Abyssal Plain turbidites over the past 750,000 years. Mar. Geol., The middle Miocene to Pleistocene was dominated by the deposition − of distal mud turbidites, beginning at ~15 Ma. Three major turbidite 109:141 158. Colley, S., Thomson, J., and Toole, J., 1989. Uranium relocations and deriva- compositional groups (organic-rich, volcanic, and calcareous), origi- tion of quasi-isochrons for a turbidite/pelagic sequence in the Northeast nally defined in the Quaternary of the MAP, have been recognized in Atlantic. Geochim. Cosmochim. Acta, 53:1223−1234. the older sedimentary record on the plain. Geochemical data define Colley, S., Thomson, J., Wilson, T.R.S., and Higgs, N.C., 1984. Post-deposi- five chemostratigraphic units within the turbidite succession, reflect- tional migration of elements during diagenesis in brown clay and turbid- ing sediment evolution in turbidite source areas and changes in prov- ite sequences in the North East Atlantic. Geochim. Cosmochim. Acta, enance during the history of deposition on the plain. 48:1223−1235. Organic-rich turbidites dominate the sedimentary record, and be- De Lange, G.J., 1992a. Distribution of exchangeable, fixed, organic and total nitrogen in interbedded turbiditic/pelagic sediments of the Madeira abys- come progressively more K and Mg rich with time. Three subgroups − are evident from the geochemical data, indicating significant changes sal plain, eastern North Atlantic. Mar. Geol., 109:95 114. − ————, 1992b. Distribution of various extracted phosphorus compounds in sediment sources, particularly during the early late Miocene (10 in the interbedded turbiditic/pelagic sediments of the Madeira Abyssal 11 Ma), with a shift toward more potassic- (illitic and chloritic) and Plain, eastern North Atlantic. Mar. Geol., 109:115−139. carbonate-rich compositions, and during the latest early Pliocene De Lange, G.J., Jarvis, I., and Kuijpers, A., 1987. Geochemical characteris- (~3.5 Ma) with the final disappearance of very low-K (kaolinite- tics and provenance of late Quaternary sediments from the Madeira

557 I. JARVIS, J. MORETON, M. GÉRARD

Abyssal Plain, North Atlantic. In Weaver, P.P.E., and Thomson, J. (Eds.), Schmincke, H.-U., Weaver, P.P.E., Firth, J.V., et al., 1995. Proc. ODP, Init. Geology and Geochemistry of Abyssal Plains. Geol. Soc. Spec. Publ. Repts., 157: College Station, TX (Ocean Drilling Program). London, 31:147−165. Searle, R.C., 1987. Regional setting and geophysical characterization of the De Lange, G.J., Middelburg, J.J., Jarvis, I., and Kuijpers, A., 1989. Great Meteor East area in the Madeira Abyssal Plain. In Weaver, P.P.E., Geochemical characteristics and provenance of late Quaternary sedi- and Thomson, J. (Eds.), Geology and Geochemistry of Abyssal Plains. ments from the Madeira and southern Nares Abyssal Plains (North Atlan- Geol. Soc. Spec. Publ. London, 31:49−70. tic). In Schuttenhelm, R.T.E., Auffret, G.A., Buckley, D.E., Cranston, Stow, D.A.V., and Shanmugam, G., 1980. Sequences of structures in fine- R.E., Murray, C.N., Shephard, L.E., and Spijkstra, A.E. (Eds.), Geo- grained turbidites: comparison of recent deep-sea and ancient flysch sed- science Investigations of Two North Atlantic Abyssal Plain—The ESOPE iments. Sediment. Geol., 25:23−42. International Expedition: Luxembourg (Commission of the European Thomson, J., Colley, S., Higgs, N.C., Hydes, D.J., Wilson T.R.S., and Community), 2:785−851. Sorensen, J., 1987. Geochemical oxidation fronts in NE Atlantic distal Govindaraju, K., 1994. 1994 compilation of working values and sample turbidites and their effects in the sedimentary record. In Weaver, P.P.E., description for 383 geostandards. Geostand. Newsl., 18 (spec. iss.). and Thomson, J. (Eds.), Geology and Geochemistry of Abyssal Plains. Jarvis, I., 1992. Sample preparation for ICP-MS. In Jarvis, K.E., Gray, A.L., Geol. Soc. Spec. Publ. London, 31:167−177. and Houk, R.S. (Eds.), Handbook of Inductively Coupled Plasma Mass Thomson, J., Higgs, N.C., Croudace, I.W., Colley, S., and Hydes, D.J., 1993. Spectrometry: Glasgow (Blackie), 172−224. Redox zonation of elements at an oxic/post-oxic boundary in deep-sea Jarvis, I., and Higgs, N., 1987. Trace-element mobility during early diagene- sediments. Geochim. Cosmochim. Acta, 57:579−595. sis in distal turbidites: late Quaternary of the Madeira Abyssal Plain, N Thomson, J., Higgs, N.C., Jarvis, I., Hydes, D.J., Colley, S., and Wilson, Atlantic. In Weaver, P.P.E., and Thomson J. (Eds.), Geology and T.R.S., 1986. The behaviour of manganese in Atlantic carbonate sedi- Geochemistry of Abyssal Plains. Geol. Soc. Spec. Publ. London, 31:179− ments. Geochim. Cosmochim. Acta, 50:1807−1818. 214. Totland, M.M., Jarvis, I., and Jarvis, K.E., 1992. An assessment of dissolu- Jarvis, I., and Jarvis, K.E., 1992. Inductively coupled plasma-atomic emis- tion techniques for the analysis of geological samples by plasma spec- sion spectrometry in exploration geochemistry. In Hall, G.E.M. (Ed.), J. trometry. Chem. Geol., 95:35−62. Geochem. Expl., 44:139−200. Weaver, P.P.E., 1993. High resolution stratigraphy of marine Quaternary Jones, K.P.N., 1988. Studies of fine-grained, deep-sea sediments [Ph.D. the- sequences. In Hailwood, E.A., and Kidd, R.B. (Eds.), High Resolution sis]. Univ. of Cambridge, UK. Stratigraphy. Geol. Soc. Spec. Publ. London, 70:137−153. Jones, K.P.N., McCave, I.N., and Weaver, P.P.E., 1992. Textural and dispersal Weaver, P.P.E., Buckley, D.E., and Kuijpers, A., 1989. Geological investiga- patterns of thick mud turbidites from the Madeira Abyssal Plain. Mar. tions of ESOPE cores from the Madeira Abyssal Plain. In Schuttenhelm, Geol., 107:149−173. R.T.E., Auffret, G.A., Buckley, D.E., Cranston, R.E., Murray, C.N., Kidd, R.B., Hunter, P.M., and Simm, R.W., 1987. Turbidity-current and Shephard, L.E., and Spijkstra, A.E. (Eds.), Geoscience Investigations of debris-flow pathways to the Cape Verde Basin: status of long-range side- Two North Atlantic Abyssal Plains: The ESOPE International Expedi- scan sonar (GLORIA) surveys. In Weaver, P.P.E., and Thomson, J. (Eds.), tion: Luxembourg (Commission of the European Community), 1:535− Geology and Geochemistry of Abyssal Plains. Geol. Soc. Spec. Publ. 555. London, 31:33−48. Weaver, P.P.E., and Kuijpers, A., 1983. Climatic control of turbidite deposi- Kuijpers, A., and Weaver, P.P.E., 1985. Deep-sea turbidites from the north- tion on the Madeira Abyssal Plain. Nature, 306:360−363. west African continental margin. Dtsch. Hydrogr. Z., 38:147−164. Weaver, P.P.E., Masson, D.G., and Kidd, R.B., 1994. Slumps, slides and tur- McArthur, J.M., Tyson, R.V., Thomson, J., and Mattey, D., 1992. Early bidity currents: sea-level change and sedimentation in the Canary Basin. diagenesis of marine organic matter: alteration of the carbon isotopic Geoscientist, 4:14−16. composition. Mar. Geol., 105:51−61. Weaver, P.P.E., and Rothwell, R.G., 1987. Sedimentation on the Madeira McCave, I.N., and Jones, K.P.N., 1988. Deposition of ungraded muds from Abyssal Plain over the last 300,000 years. In Weaver, P.P.E., and Thom- high-density non-turbulent turbidity currents. Nature, 333:250−252. son, J. (Eds.), Geology and Geochemistry of Abyssal Plains. Geol. Soc. Middelburg, J.J., 1993. Turbidites provide a unique opportunity to study Spec. Publ. London, 31:71−86. diagenetic processes. Geol. Mijnbouw, 72:15−21. Weaver, P.P.E., Rothwell, R.G., Ebbing, J., Gunn, D., and Hunter, P.M., 1992. Middelburg, J.J., and De Lange, G.J., 1988. Geochemical characteristics as Correlation, frequency of emplacement and source directions of megatur- indicators of the provenance of Madeira Abyssal Plain turbidites: a statis- bidites on the Madeira Abyssal Plain. Mar. Geol., 109:1−20. tical approach. Oceanol. Acta, 11:159−165. Weaver, P.P.E., Searle, R.C., and Kuijpers, A., 1986. Turbidite deposition and Pearce, T.J., 1991. The geology, geochemistry, sedimentology and prove- the origin of the Madeira Abyssal Plain. In Summerhayes, C.P., and nance of Late Quaternary turbidites, Madeira Abyssal Plain [Ph.D. the- Shackleton, N.J. (Eds.), North Atlantic Palaeoceanography. Spec. Publ. sis]. CNAA, Kingston Polytechnic. Geol. Soc. London, 21:131−143. Pearce, T.J., and Jarvis, I., 1992a. Applications of geochemical data to mod- Weaver, P.P.E., and Thomson, J., 1993. Calculation erosion by deep-sea tur- elling sediment dispersal patterns in distal turbidites: Late Quaternary of bidity currents during initiation and flow. Nature, 364:136−138. the Madeira Abyssal Plain. J. Sediment. Petrol., 62:1112−1129. Weaver, P.P.E., Thomson, J., and Jarvis, I. 1989. The geology and geochem- ————, 1992b. Composition and provenance of turbidite sands: Late Qua- istry of Madeira Abyssal Plain sediments: a review. In Freeman, T.J. ternary, Madeira Abyssal Plain. Mar. Geol., 109:21−53. (Ed.), Advances in Underwater Technology, Ocean Science and Offshore ————, 1995. High-resolution chemostratigraphy of Quaternary distal Engineering (Vol. 18): London (Graham and Trotman), 51−78. turbidites: a case study of new methods for the analysis and correlation of Wilson, T.R.S., Thomson, J., Colley, S., Hydes, D.J., Higgs, N.C., and barren sequences. In Dunay, R.E., and Hailwood, E.A. (Eds.), Non-bios- Sorensen, J., 1985. Early organic diagenesis: the significance of progres- tratigraphical Methods of Dating and Correlation. Geol. Soc. Spec. Publ. sive subsurface oxidation fronts in pelagic sediments. Geochim. Cosmo- London, 89:107−143. chim. Acta., 49:811−822. Rothwell, R.G., Pearce, T.J., and Weaver, P.P.E., 1992. Late Quaternary evo- Wilson, T.R.S, Thomson, J., Hydes, D.J., Colley, S., Culkin, F., and lution of the Madeira Abyssal Plain, Canary Basin, NE Atlantic. Basin Sørensen, J., 1986. Oxidation fronts in pelagic sediments: diagenetic for- Res., 4:103−131. mation of metal-rich layers. Science, 232:972−975. Schmincke, H.-U., 1976. The geology of the Canary Islands. In Kunkel, G. (Ed.), Biogeography and Ecology in the Canary Islands: The Hague (W. Junk), 67−184. ————, 1982. Volcanic and chemical evolution of the Canary Islands. In von Rad, U., Hinz, K., Sarnthein, M., and Seibold, E. (Eds.), Geology of the Northwest African Continental Margin: Berlin (Springer), 273−306. Date of initial receipt: 8 July 1996 ————, 1994. Geological Field Guide: Gran Canaria (6th ed.): Kiel, Ger- Date of acceptance: 8 January 1997 many (Pluto Press). Ms 157SR-129

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