Carbon and nitrogen diagenesis in deep sea sediments

Waples, Douglas; Sloan, Jon R.

doi:10.1016/0016-7037(80)90111-8

Cited by 71 publications

(62 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It is generally accepted that C/N values are higher for organic matter from a terrestrial rather than from a marine source (e.g., Calvert, 1983). However, modern marine sediments have C/N ratios in the range of 9 to 18 (Müller, 1977;Stevenson and Cheng, 1972) and diagenesis can alter C/N values (Müller, 1977;Waples and Sloan, 1980) which is in keeping with most of the C/N ratios observed at Site 797. Ratios outside this range at Site 797 are usually from sediments which are very low in nitrogen.…”

Section: Carbon Nitrogen and Sulfursupporting

confidence: 61%

Site 797

1990

Proceedings of the Ocean Drilling Program

View full text Add to dashboard Cite

1 Tamaki, K., Pisciotto, K., Allan, J., et al., 1990. Proc. ODP, Init. Repts., 127: College Station, TX (Ocean Drilling Program). Principal results: The objectives at Site 797, located in the southern Yamato Basin, were (1) to determine the age and nature of acoustic basement, (2) to measure the direction and magnitude of the present stress field, and (3) to characterize the sedimentation, subsidence, and oceanographic evolution of the area. The results at Site 797 are summarized below and in Figure 1. The principal results at Site 797 are as follows:1. Acoustic basement and an overlying seismic interval at this site comprise basalts and dolerites and interlayered volcaniclastic sandstones, siltstones, and silty claystones. The age of the sediments which overlie the shallowest basalt layer is estimated to be about 19 Ma. Based on paleodepth estimates using microfossils within these sediments and the sedimentologic interpretation of the underlying volcaniclastic sediments, this part of the Yamato Basin probably subsided rapidly during the early Miocene. The uppermost basalts most likely represent submarine lava flows, whereas the bulk of the underlying igneous units are sills and dikes. The upper nine units are high-Al basalt in composition, consistent with generation during the early stages of arc rifting. However, the units below these are mildly alkaline basalts and enriched tholeiites, which are unrelated to the overlying basalts and were probably derived from a different mantle source.2. The in-situ stress field could not be determined, because poor hole conditions precluded packer/hydro fracture tests. A borehole televiewer log over one basalt interval showed fractures but no borehole breakouts for stress directions.3. The lithologic and paleontological data indicate at least four principal stages in the evolution of this part of the Yamato Basin: (a) an early Miocene period of submarine basaltic volcanism and concomitant deposition of gravity-flow and current-reworked volcani- 323 SITE 797clastic sandstones and siltstones on a shelf or slope, probably outboard of a delta; (b) a late early to early middle Miocene phase of diminishing submarine volcanic activity, warm surface waters, and deposition of calcareous and slightly phosphatic hemipelagic claystones at lower middle bathyal depths (1500-2000 m) in a poorly oxygenated basin; (c) a late Miocene to late Pliocene cooling period beginning with an interval of anomalously slow sedimentation (5 m/m.y.) or a hiatus and characterized by dominant but variable diatomaceous sedimentation at lower middle bathyal depths (1500-2000 m); and (d) a latest Pliocene to Holocene stage during which diatomaceous sedimentation diminished volcanic-ash production and terrigenous input increased, subsidence continued, and climate oscillated to produce a sequence of interlayered light-and dark-colored silty clays having variable organic-carbon contents. In contrast with the more northern sites drilled during Leg 127, the sediments at Site 797 contain more carbonate suggesting ...

show abstract

Section: Carbon Nitrogen and Sulfursupporting

confidence: 61%

Site 797

1990

Proceedings of the Ocean Drilling Program

View full text Add to dashboard Cite

show abstract

“…Organic carbon contents are consistently higher than the average of 0.2% of most pelagic sediments (Degens and Mopper, 1976), which is surprising in view of the extensive bioturbation evident in cores from these holes. The increase in TOC from about 2% in late Miocene sediments to values between 3 and 6% in Pliocene and Pleistocene oozes parallels that reported for Site 362 by Erdman and Schorno (1978) and also that found at Site 530 (Table 2 and and Sloan (1980) present data from DSDP Leg 58 showing that, under uniform conditions of organic matter production and sedimentation, postdepositional degradation will decrease organic carbon concentrations to ca. 0.1% in 2 to 5 m.y.…”

Section: Site 532-walvis Ridgesupporting

confidence: 85%

“…Values between 14 and 30 are charac-teristic of terrigenous material, whereas those between 4 and 8 typify marine organic matter (Goodell, 1972;Muller, 1977). Changes during diagenesis significantly affect the precise value of the C/N ratio and therefore may limit its utility (Muller, 1977;Waples and Sloan, 1980). During Deep Sea Drilling Project (DSDP), Leg 75, measurements of organic carbon content and of organic C/N ratios were done on sediment samples from two locations in the southeastern Atlantic Ocean (Fig.…”

Section: Introductionmentioning

confidence: 99%

Geochemistry of Organic Carbon in South Atlantic Sediments from Deep Sea Drilling Project Leg 75

Meyers¹,

Brassell²,

Hue³

1984

Initial Reports of the Deep Sea Drilling Project

View full text Add to dashboard Cite

CHN analyses of sediments and rocks sampled during DSDP Leg 75 in the South Atlantic have provided concentrations of organic carbon and atomic C/N ratios of organic matter from two sites. High values of organic carbon were measured in sediments deposited during Neogene and Cretaceous times at Site 530 in the Angola Basin; sediments deposited at other times contain less than 0.5% organic carbon. Development of the Benguela Current and associated upwelling-supported biological productivity is recorded in late Miocene to Holocene sediments which contain 1 to 7% organic carbon. These sediments include debris flows and turbidites composed of predominantly biogenic materials originally deposited on the Walvis Ridge and on the African continental margin. Organic-carbon-rich black shales containing up to 17% organic carbon occur in late Albian to Coniacian turbidite sequences. These Cretaceous black shale layers are commonly several centimeters thick and are separated by bioturbated fine-grained organic-carbon-poor turbidites which are usually much thicker. At Site 532 on the Walvis Ridge, biogenic sediments deposited between late Miocene and Holocene times contain 1 to 9% organic carbon. Fluctuations in the intensity of high biological productivity associated with the Benguela Current are preserved in alternating light and dark layers of sediments. C/N ratios of organic matter in sediments from both sites are typical of marine sources.

show abstract

“…The decrease in both organic carbon concentrations and C/N values observed over the upper 698 m of Site 603 (Meyers, this volume) is similar to decreases reported by Waples and Sloan (1980) in Neogene sediments from DSDP Leg 58 in the western North Pacific. They attribute these downhole decreases to continued, postburial microbial degradation of organic matter, with preferential losses occurring to carbon rather than to nitrogen.…”

Section: Unit I: Blake Ridge Formation (Eocene To Pleistocene)supporting

confidence: 85%

Synthesis of Organic Geochemical Studies, Deep Sea Drilling Project Leg 93, North American Continental Margin

Meyers¹

1987

Initial Reports of the Deep Sea Drilling Project

View full text Add to dashboard Cite

The results of organic geochemical studies of samples from Site 603 on the outer Hatteras Rise and from Sites 604 and 605 on the New Jersey continental slope are reviewed and integrated with lithostratigraphic information from those locations. Although most of the sediments and rocks encountered at all three sites contain little organic carbon, "black shales" enriched in organic matter were found in Cretaceous strata obtained from Hole 603B. These rocks exist as claystones in the Aptian to Turonian Hatteras Formation and as marlstones in the Neocomian Blake-Bahama Formation. Terrigenous organic matter predominates in these deposits, except in Cenomanian and Valanginian rocks, where marine material becomes dominant. Organic carbon concentrations in Cenomanian black claystones are higher than any previously reported from the western North Atlantic, but lower than the concentrations found in the eastern North Atlantic. Black shales at Site 603 appear to result from downslope transport and rapid reburial of coastal and ocean margin sediments by turbidity flows. Deep-basin anoxia is not a major factor. At Site 605, a well-defined Cretaceous/Tertiary boundary was obtained, and terrigenous components of the organic matter diminished in sediments deposited above this boundary. Organic matter in the sediments from all locations is thermally immature.

show abstract

Carbon and nitrogen diagenesis in deep sea sediments

Cited by 71 publications

References 8 publications

Site 797

Site 797

Geochemistry of Organic Carbon in South Atlantic Sediments from Deep Sea Drilling Project Leg 75

Synthesis of Organic Geochemical Studies, Deep Sea Drilling Project Leg 93, North American Continental Margin

Contact Info

Product

Resources

About