Dean, Walter E; Arthur, Michael A; Stow, Dorrik A V (1984): (Table 4) Mass accumulation rates of selected components in red, green, and black lithologies at DSDP Hole 75-530A [dataset]. PANGAEA, https://doi.org/10.1594/PANGAEA.810117, Supplement to: Dean, WE et al. (1984): Origin and geochemistry of Cretaceous deep-sea black shales and multicolored claystones, with emphasis on Deep Sea Drilling Project Site 530, southern Angola Basin. In: Hay, WW; Sibuet, J-C; et al. (eds.), Initial Reports of the Deep Sea Drilling Project (U.S. Govt. Printing Office), 75, 819-844, https://doi.org/10.2973/dsdp.proc.75.121.1984
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Abstract:
Deep-water sedimentary sequences of mid-Cretaceous age, rich in organic carbon, have been recovered at many DSDP sites in the Atlantic Ocean. Most of these sequences have a marked cyclicity in amount of organic carbon resulting in interbedded multicolored shale, marlstone, and (or) limestone that have cycle periods of 20,000 to 100,000 years and average 40,000 to 50,000 years. These cycles may be related to some climatic control on influx of terrigenous organic matter and sediment, rates of upwelling and sea-surface production of organic matter, and preservation of organic matter related to deeper-water dissolved oxygen concentration. These variations in supply of organic matter had pronounced effects on the potential of the sediment for subsequent diagenetic changes and geochemical partitioning in adjacent beds.
Many trace elements are enriched in organic-carbon-rich lithologies relative to interbedded organic-carbon-poor lithologies. Elements that are most commonly enriched are Cr, Ni, V, Cu, Zn, and Mo. The association of high traceelement concentrations with organic matter may be the result of concentration of these elements by organisms or by chemical sorption and precipitation processes under anoxic conditions. Detailed trace-element profiles from organiccarbon- rich strata at Site 530 suggest that there may be differential mobility of trace elements, with diffusion of some elements over distances of at least tens of meters. The sequence of trace-element mobility, from highest to lowest, is approximately Ba, Mn, Pb, Ni, Co, Cr, Cu, Zn, V, Cd, and Mo. Slowly deposited, oxidized clays directly overlying some black shale sequences are enriched in some metals, particularly Fe, Mn, Zn, and Cu, relative to normal pelagic clays, and this enrichment may be the result of upward migration of metals in pore waters during compaction or diffusion from the underlying black shale.
Most depositional models that have been used to explain the accumulation of the organic-carbon-rich strata imply that reducing conditions in the sediments (and therefore the increased degree of preservation of organic matter) were the result of anoxic or near-anoxic conditions in oceanic bottom waters, or in a midwater oxygen-minimum zone. Evidence from several DSDP sites in the Atlantic, however, indicate that some of these middle Cretaceous "black shale" beds may be the result of variations in rate of supply of organic matter that produced anoxia or near-anoxia within midwater oxygen-minimum zones and possibly, under extreme conditions, throughout much of the bottomwater mass. Although bottom-water anoxia may have occurred during periods of organic-carbon-rich strata, it was not necessarily the only cause for accumulation of these strata. The main reason for the accumulation of organic-carbonrich strata was an increase in the relative amount of organic debris being deposited. Some of this organic debris was derived from continental-margin areas of increased production, accumulation, and preservation of organic matter from marine, terrestrial, or mixed sources and transported to slope and basinal sites by turbidity currents.
Related to:
Dean, Walter E; Parduhn, Nancy L (1984): Inorganic geochemistry of sediments and rocks recovered from the southern Angola Basin and Adjacent Walvis Ridge, Sites 530 and 532, Deep Sea Drilling Project Leg 75. In: Hay, WW; Sibuet, J-C; et al. (eds.), Initial Reports of the Deep Sea Drilling Project (U.S. Govt. Printing Office), 75, 923-958, https://doi.org/10.2973/dsdp.proc.75.127.1984
Meyers, Philip A; Brassell, Simon C; Huc, Alain Y (1984): Geochemistry of organic carbon in South Atlantic sediments from Deep Sea Drilling Project Leg 75. In: Hay, WW; Sibuet, J-C; et al. (eds.), Initial Reports of the Deep Sea Drilling Project (U.S. Govt. Printing Office), 75, 967-981, https://doi.org/10.2973/dsdp.proc.75.129.1984
Project(s):
Deep Sea Drilling Project (DSDP)
Coverage:
Latitude: -19.187700 * Longitude: 9.385800
Date/Time Start: 1980-07-29T00:00:00 * Date/Time End: 1980-07-29T00:00:00
Minimum DEPTH, sediment/rock: 944.5 m * Maximum DEPTH, sediment/rock: 1098.5 m
Event(s):
75-530A * Latitude: -19.187700 * Longitude: 9.385800 * Date/Time: 1980-07-29T00:00:00 * Elevation: -4629.0 m * Penetration: 1121 m * Recovery: 617.5 m * Location: South Atlantic/RIDGE * Campaign: Leg75 * Basis: Glomar Challenger * Method/Device: Drilling/drill rig (DRILL) * Comment: 107 cores; 986.5 m cored; 9.5 m drilled; 62.6 % recovery
Parameter(s):
| # | Name | Short Name | Unit | Principal Investigator | Method/Device | Comment |
|---|---|---|---|---|---|---|
| 1 | Sample code/label | Sample label | Dean, Walter E | DSDP/ODP/IODP sample designation | ||
| 2 | Depth, top/min | Depth top | m | Dean, Walter E | ||
| 3 | Depth, bottom/max | Depth bot | m | Dean, Walter E | ||
| 4 | DEPTH, sediment/rock | Depth sed | m | Geocode | ||
| 5 | Recovery | Recovery | m | Dean, Walter E | ||
| 6 | Bed | Bed | % | Dean, Walter E | Calculated | Black shale |
| 7 | Bed | Bed | % | Dean, Walter E | Calculated | Red shale |
| 8 | Bed | Bed | % | Dean, Walter E | Calculated | Green shale |
| 9 | Duration | Duration | ka | Dean, Walter E | Calculated | Based on average accumulation rates of 14.6 m/m.y. for Cores 87-94 and 9 m/m.y. for Cores 95-105 |
| 10 | Zinc | Zn | % | Dean, Walter E | Calculated | In black shale beds, from Dean and Parduhn, 1984 |
| 11 | Chromium | Cr | % | Dean, Walter E | Calculated | In black shale beds, from Dean and Parduhn, 1984 |
| 12 | Nickel | Ni | % | Dean, Walter E | Calculated | In black shale beds, from Dean and Parduhn, 1984 |
| 13 | Zinc | Zn | % | Dean, Walter E | Calculated | In red shale beds, from Dean and Parduhn, 1984 |
| 14 | Chromium | Cr | % | Dean, Walter E | Calculated | In red shale beds, from Dean and Parduhn, 1984 |
| 15 | Nickel | Ni | % | Dean, Walter E | Calculated | In red shale beds, from Dean and Parduhn, 1984 |
| 16 | Zinc | Zn | % | Dean, Walter E | Calculated | In green shale beds, from Dean and Parduhn, 1984 |
| 17 | Chromium | Cr | % | Dean, Walter E | Calculated | In green shale beds, from Dean and Parduhn, 1984 |
| 18 | Nickel | Ni | % | Dean, Walter E | Calculated | In green shale beds, from Dean and Parduhn, 1984 |
| 19 | Accumulation rate, mass | MAR | g/cm2/ka | Dean, Walter E | Calculated | Bulk sediment = [(accumulation rate) 100 (1 - porosity/100) grain density] (Thiede and Rea, 1981), where accumulation rate = 14.6 m/m.y. for Cores 87-94 and 9.0 m/m.y. for Cores 95-105; porosity = 33% for all cores, and grain density is assumed to be 2.7 g/cm**3 |
| 20 | Accumulation rate, mass | MAR | g/cm2/ka | Dean, Walter E | Calculated | Black shale beds |
| 21 | Accumulation rate, mass | MAR | g/cm2/ka | Dean, Walter E | Calculated | Red shale beds |
| 22 | Accumulation rate, mass | MAR | g/cm2/ka | Dean, Walter E | Calculated | Green shale beds |
| 23 | Accumulation rate, total organic carbon | Acc rate TOC | g/cm2/ka | Dean, Walter E | Calculated | MAR-Corg= (MAR of black shale beds) (5.4/100), where 5.4 is the grand average concentration of organic carbon in black shale-shale samples analyzed by Meyers, Brassell, and Hue, 1984 |
| 24 | Accumulation rate, zinc | Acc rate Zn | mg/cm2/ka | Dean, Walter E | Calculated | Black shale beds, for Zn = (MAR of each colored shale bed) (% of trace element in each colored shale bed/100) |
| 25 | Accumulation rate, chrom | Acc rate Cr | mg/cm2/ka | Dean, Walter E | Calculated | Black shale beds, for Cr = (MAR of each colored shale bed) (% of trace element in each colored shale bed/100) |
| 26 | Accumulation rate, nickel | Acc rate Ni | mg/cm2/ka | Dean, Walter E | Calculated | Black shale beds, for Ni = (MAR of each colored shale bed) (% of trace element in each colored shale bed/100) |
| 27 | Accumulation rate, zinc | Acc rate Zn | mg/cm2/ka | Dean, Walter E | Calculated | Red shale beds, for Zn = (MAR of each colored shale bed) (% of trace element in each colored shale bed/100) |
| 28 | Accumulation rate, chrom | Acc rate Cr | mg/cm2/ka | Dean, Walter E | Calculated | Red shale beds, for Cr = (MAR of each colored shale bed) (% of trace element in each colored shale bed/100) |
| 29 | Accumulation rate, nickel | Acc rate Ni | mg/cm2/ka | Dean, Walter E | Calculated | Red shale beds, for Ni = (MAR of each colored shale bed) (% of trace element in each colored shale bed/100) |
| 30 | Accumulation rate, zinc | Acc rate Zn | mg/cm2/ka | Dean, Walter E | Calculated | Green shale beds, for Zn = (MAR of each colored shale bed) (% of trace element in each colored shale bed/100) |
| 31 | Accumulation rate, chrom | Acc rate Cr | mg/cm2/ka | Dean, Walter E | Calculated | Green shale beds, for Cr = (MAR of each colored shale bed) (% of trace element in each colored shale bed/100) |
| 32 | Accumulation rate, nickel | Acc rate Ni | mg/cm2/ka | Dean, Walter E | Calculated | Green shale beds, for Ni = (MAR of each colored shale bed) (% of trace element in each colored shale bed/100) |
| 33 | Accumulation rate, zinc | Acc rate Zn | mg/cm2/ka | Dean, Walter E | Calculated | Total, Zn |
| 34 | Accumulation rate, chrom | Acc rate Cr | mg/cm2/ka | Dean, Walter E | Calculated | Total, Cr |
| 35 | Accumulation rate, nickel | Acc rate Ni | mg/cm2/ka | Dean, Walter E | Calculated | Total, Ni |
| 36 | Zinc | Zn | % | Dean, Walter E | Calculated | MAR-Zn in black shale bed as % MAR-Zn total |
| 37 | Chromium | Cr | % | Dean, Walter E | Calculated | MAR-Cr in black shale bed as % MAR-Cr total |
| 38 | Nickel | Ni | % | Dean, Walter E | Calculated | MAR-Ni in black shale bed as % MAR-Ni total |
License:
Creative Commons Attribution 3.0 Unported (CC-BY-3.0)
Size:
662 data points