Not logged in
PANGAEA.
Data Publisher for Earth & Environmental Science

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. 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

Always quote above citation when using data! You can download the citation in several formats below.

RIS CitationBibTeX CitationShow MapGoogle Earth

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):
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 * Device: Drilling/drill rig (DRILL) * Comment: 107 cores; 986.5 m cored; 9.5 m drilled; 62.6 % recovery
Parameter(s):
#NameShort NameUnitPrincipal InvestigatorMethodComment
1Sample code/labelSample labelDean, Walter EODP sample designation
2Depth, top/minDepth topmDean, Walter E
3Depth, bottom/maxDepth botmDean, Walter E
4DEPTH, sediment/rockDepthmGeocode
5RecoveryRecoverymDean, Walter E
6BedBed%Dean, Walter ECalculatedBlack shale
7BedBed%Dean, Walter ECalculatedRed shale
8BedBed%Dean, Walter ECalculatedGreen shale
9DurationDurationkaDean, Walter ECalculatedBased on average accumulation rates of 14.6 m/m.y. for Cores 87-94 and 9 m/m.y. for Cores 95-105
10ZincZn%Dean, Walter ECalculatedIn black shale beds, from Dean and Parduhn, 1984
11ChromiumCr%Dean, Walter ECalculatedIn black shale beds, from Dean and Parduhn, 1984
12NickelNi%Dean, Walter ECalculatedIn black shale beds, from Dean and Parduhn, 1984
13ZincZn%Dean, Walter ECalculatedIn red shale beds, from Dean and Parduhn, 1984
14ChromiumCr%Dean, Walter ECalculatedIn red shale beds, from Dean and Parduhn, 1984
15NickelNi%Dean, Walter ECalculatedIn red shale beds, from Dean and Parduhn, 1984
16ZincZn%Dean, Walter ECalculatedIn green shale beds, from Dean and Parduhn, 1984
17ChromiumCr%Dean, Walter ECalculatedIn green shale beds, from Dean and Parduhn, 1984
18NickelNi%Dean, Walter ECalculatedIn green shale beds, from Dean and Parduhn, 1984
19Accumulation rate, sediment, meanMARg/cm2/kaDean, Walter ECalculatedBulk 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
20Accumulation rate, sediment, meanMARg/cm2/kaDean, Walter ECalculatedBlack shale beds
21Accumulation rate, sediment, meanMARg/cm2/kaDean, Walter ECalculatedRed shale beds
22Accumulation rate, sediment, meanMARg/cm2/kaDean, Walter ECalculatedGreen shale beds
23Accumulation rate, total organic carbonAcc rate TOCg/cm2/kaDean, Walter ECalculatedMAR-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
24Accumulation rate, zincAcc rate Znmg/cm2/kaDean, Walter ECalculatedBlack shale beds, for Zn = (MAR of each colored shale bed) (% of trace element in each colored shale bed/100)
25Accumulation rate, chromAcc rate Crmg/cm2/kaDean, Walter ECalculatedBlack shale beds, for Cr = (MAR of each colored shale bed) (% of trace element in each colored shale bed/100)
26Accumulation rate, nickelAcc rate Nimg/cm2/kaDean, Walter ECalculatedBlack shale beds, for Ni = (MAR of each colored shale bed) (% of trace element in each colored shale bed/100)
27Accumulation rate, zincAcc rate Znmg/cm2/kaDean, Walter ECalculatedRed shale beds, for Zn = (MAR of each colored shale bed) (% of trace element in each colored shale bed/100)
28Accumulation rate, chromAcc rate Crmg/cm2/kaDean, Walter ECalculatedRed shale beds, for Cr = (MAR of each colored shale bed) (% of trace element in each colored shale bed/100)
29Accumulation rate, nickelAcc rate Nimg/cm2/kaDean, Walter ECalculatedRed shale beds, for Ni = (MAR of each colored shale bed) (% of trace element in each colored shale bed/100)
30Accumulation rate, zincAcc rate Znmg/cm2/kaDean, Walter ECalculatedGreen shale beds, for Zn = (MAR of each colored shale bed) (% of trace element in each colored shale bed/100)
31Accumulation rate, chromAcc rate Crmg/cm2/kaDean, Walter ECalculatedGreen shale beds, for Cr = (MAR of each colored shale bed) (% of trace element in each colored shale bed/100)
32Accumulation rate, nickelAcc rate Nimg/cm2/kaDean, Walter ECalculatedGreen shale beds, for Ni = (MAR of each colored shale bed) (% of trace element in each colored shale bed/100)
33Accumulation rate, zincAcc rate Znmg/cm2/kaDean, Walter ECalculatedTotal, Zn
34Accumulation rate, chromAcc rate Crmg/cm2/kaDean, Walter ECalculatedTotal, Cr
35Accumulation rate, nickelAcc rate Nimg/cm2/kaDean, Walter ECalculatedTotal, Ni
36ZincZn%Dean, Walter ECalculatedMAR-Zn in black shale bed as % MAR-Zn total
37ChromiumCr%Dean, Walter ECalculatedMAR-Cr in black shale bed as % MAR-Cr total
38NickelNi%Dean, Walter ECalculatedMAR-Ni in black shale bed as % MAR-Ni total
Size:
662 data points

Download Data

Download dataset as tab-delimited text (use the following character encoding: )

View dataset as HTML