scholarly journals Driving mechanisms of organic carbon burial in the Early Cretaceous South Atlantic Cape Basin (DSDP Site 361)

2021 ◽  
Vol 17 (1) ◽  
pp. 469-490
Author(s):  
Wolf Dummann ◽  
Sebastian Steinig ◽  
Peter Hofmann ◽  
Matthias Lenz ◽  
Stephanie Kusch ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Black Shale ◽  
South Atlantic ◽  
African Continent ◽  
Short Term ◽  
Driving Mechanisms ◽  
Carbon Burial ◽  
Organic Carbon Burial ◽  
Cape Basin ◽  
Dsdp Site

Abstract. Extensive black shale deposits formed in the Early Cretaceous South Atlantic, supporting the notion that this emerging ocean basin was a globally important site of organic carbon burial. The magnitude of organic carbon burial in marine basins is known to be controlled by various tectonic, oceanographic, hydrological, and climatic processes acting on different temporal and spatial scales, the nature and relative importance of which are poorly understood for the young South Atlantic. Here we present new bulk and molecular geochemical data from an Aptian–Albian sediment record recovered from the deep Cape Basin at Deep Sea Drilling Project (DSDP) Site 361, which we combine with general circulation model results to identify driving mechanisms of organic carbon burial. A multimillion-year decrease (i.e., Early Aptian–Albian) in organic carbon burial, reflected in a lithological succession of black shale, gray shale, and red beds, was caused by increasing bottom water oxygenation due to abating hydrographic restriction via South Atlantic–Southern Ocean gateways. These results emphasize basin evolution and ocean gateway development as a decisive primary control on enhanced organic carbon preservation in the Cape Basin at geological timescales (> 1 Myr). The Early Aptian black shale sequence comprises alternations of shales with high (> 6 %) and relatively low (∼ 3.5 %) organic carbon content of marine sources, the former being deposited during the global Oceanic Anoxic Event (OAE) 1a, as well as during repetitive intervals before and after OAE 1a. In all cases, these short-term intervals of enhanced organic carbon burial coincided with strong influxes of sediments derived from the proximal African continent, indicating closely coupled climate–land–ocean interactions. Supported by our model results, we show that fluctuations in weathering-derived nutrient input from the southern African continent, linked to changes in orbitally driven humidity and aridity, were the underlying drivers of repetitive episodes of enhanced organic carbon burial in the deep Cape Basin. These results suggest that deep marine environments of emerging ocean basins responded sensitively and directly to short-term fluctuations in riverine nutrient fluxes. We explain this relationship using the lack of wide and mature continental shelf seas that could have acted as a barrier or filter for nutrient transfer from the continent into the deep ocean.

scholarly journals Driving mechanisms of organic carbon burial in the Early Cretaceous South Atlantic Cape Basin (DSDP Site 361)

2020 ◽  
Author(s):  
Wolf Dummann ◽  
Sebastian Steinig ◽  
Peter Hofmann ◽  
Matthias Lenz ◽  
Stephanie Kusch ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Black Shale ◽  
South Atlantic ◽  
African Continent ◽  
Short Term ◽  
Driving Mechanisms ◽  
Carbon Burial ◽  
Organic Carbon Burial ◽  
Cape Basin ◽  
Dsdp Site

Abstract. Extensive black shale deposits formed in the Early Cretaceous South Atlantic, supporting the notion that this emerging ocean basin was a globally important site of organic carbon burial. The magnitude of organic carbon burial in marine basins is known to be controlled by various tectonic, oceanographic, hydrological, and climatic processes acting on different temporal and spatial scales, the nature and relative importance of which are poorly understood for the young South Atlantic. Here we present new bulk and molecular geochemical data from an Aptian–Albian sediment record recovered from the deep Cape Basin at Deep Sea Drilling Project (DSDP) Site 361, which we combine with general circulation model results to identify driving mechanisms of organic carbon burial. A multi-million year decrease (i.e. Early Aptian–Albian) in organic carbon burial, reflected in a lithological succession of black shale, gray shale, and red beds, was caused by increasing bottom water oxygenation due to abating tectonic restriction via South Atlantic-Southern Ocean gateways. These results emphasize basin evolution and ocean gateway development as a decisive primary control on enhanced organic carbon preservation in the Cape Basin at geological time scales (> 1 Myr). The Early Aptian black shale sequence comprises alternations of shales with high (> 5 %) and relatively low (∼ 3 %) organic carbon content of marine sources, the former being deposited during the global Oceanic Anoxic Event (OAE) 1a, as well as during repetitive events before and after OAE 1a. In all cases, these short-term events of enhanced organic carbon burial coincided with strong influxes of sediments derived from the proximal African continent, indicating closely coupled climate–land–ocean interactions. Supported by our model results, we propose that fluctuations in weathering-derived nutrient input from the southern African continent, linked to fluctuations in pCO2 and/or orbitally driven humidity/aridity, were the underlying drivers of short-term organic carbon burial in the deep Cape Basin. These results suggest that deep marine environments of emerging ocean basins responded sensitively and directly to short-term fluctuations in riverine nutrient fluxes. We explain this relationship by the lack of wide and mature continental shelf seas that could have acted as a barrier or filter for nutrient transfer from the continent into the deep ocean.

scholarly journals Warm plankton soup and red herrings: calcareous nannoplankton cellular communities and the Palaeocene–Eocene Thermal Maximum

2018 ◽  
Vol 376 (2130) ◽  
pp. 20170075 ◽  
Author(s):  
Samantha J. Gibbs ◽  
Rosie M. Sheward ◽  
Paul R. Bown ◽  
Alex J. Poulton ◽  
Sarah A. Alvarez
Keyword(s):  
Global Warming ◽  
Organic Carbon ◽  
Inorganic Carbon ◽  
Climate Feedback ◽  
Short Term ◽  
Cell Size Distribution ◽  
Carbon Burial ◽  
Thermal Maximum ◽  
Carbon Transfer ◽  
Organic Carbon Burial

Past global warming events such as the Palaeocene–Eocene Thermal Maximum (PETM—56 Ma) are attributed to the release of vast amounts of carbon into the ocean, atmosphere and biosphere with recovery ascribed to a combination of silicate weathering and organic carbon burial. The phytoplanktonic nannoplankton are major contributors of organic and inorganic carbon but their role in this recovery process remains poorly understood and complicated by their contribution to marine calcification. Biocalcification is implicated not only in long-term carbon burial but also both short-term positive and negative climatic feedbacks associated with seawater buffering and responses to ocean acidification. Here, we use exceptional records of preserved fossil coccospheres to reconstruct cell size distribution, biomass production (particulate organic carbon, POC) and (particulate) inorganic carbon (PIC) yields of three contrasting nannoplankton communities (Bass River—outer shelf, Maud Rise—uppermost bathyal, Shatsky Rise—open ocean) through the PETM onset and recovery. Each of the sites shows contrasting community responses across the PETM as a function of their taxic composition and total community biomass. Our results indicate that nannoplankton PIC:POC had no role in short-term climate feedback and, as such, their importance as a source of CO 2 to the environment is a red herring. It is nevertheless likely that shifts to greater numbers of smaller cells at the shelf site in particular led to greater carbon transfer efficiency, and that nannoplankton productivity and export across the shelves had a significant modulating effect on carbon sequestration during the PETM recovery. This article is part of a discussion meeting issue ‘Hyperthermals: rapid and extreme global warming in our geological past’.

scholarly journals Black shale deposition on the northwest African Shelf during the Cenomanian/Turonian oceanic anoxic event: Climate coupling and global organic carbon burial

2005 ◽  
Vol 20 (1) ◽  
pp. n/a-n/a ◽  
Author(s):  
Sadat Kolonic ◽  
Thomas Wagner ◽  
Astrid Forster ◽  
Jaap S. Sinninghe Damsté ◽  
Ben Walsworth-Bell ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Black Shale ◽  
Oceanic Anoxic Event ◽  
Carbon Burial ◽  
Organic Carbon Burial ◽  
Anoxic Event

scholarly journals Past climate variations recorded in needle-like aragonites correlate with organic carbon burial efficiency as revealed by lake sediments in Croatia

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ivan Razum ◽  
Petra Bajo ◽  
Dea Brunović ◽  
Nikolina Ilijanić ◽  
Ozren Hasan ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Stable Carbon Isotope ◽  
Climate Variations ◽  
Before Present ◽  
Stable Carbon ◽  
Climate Trends ◽  
Geochemical Proxies ◽  
Carbon Burial ◽  
Organic Carbon Burial ◽  
Burial Efficiency

AbstractThe drivers of organic carbon (OC) burial efficiency are still poorly understood despite their key role in reliable projections of future climate trends. Here, we provide insights on this issue by presenting a paleoclimate time series of sediments, including the OC contents, from Lake Veliko jezero, Croatia. The Sr/Ca ratios of the bulk sediment are mainly derived from the strontium (Sr) and calcium (Ca) concentrations of needle-like aragonite in Core M1-A and used as paleotemperature and paleohydrology indicators. Four major and six minor cold and dry events were detected in the interval from 8.3 to 2.6 calibrated kilo anno before present (cal ka BP). The combined assessment of Sr/Ca ratios, OC content, carbon/nitrogen (C/N) ratios, stable carbon isotope (δ13C) ratios, and modeled geochemical proxies for paleoredox conditions and aeolian input revealed that cold and dry climate states promoted anoxic conditions in the lake, thereby enhancing organic matter preservation and increasing the OC burial efficiency. Our study shows that the projected future increase in temperature might play an important role in the OC burial efficiency of meromictic lakes.

scholarly journals Climate influence on organic carbon burial efficiency as revealed from a multi-proxy lake sediment record in Croatia

2020 ◽  
Author(s):  
Ivan Razum ◽  
Petra Bajo ◽  
Dea Brunović ◽  
Nikolina Ilijanić ◽  
Ozren Hasan ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Lake Sediment ◽  
Sediment Record ◽  
Carbon Burial ◽  
Organic Carbon Burial ◽  
Burial Efficiency

Long-term Aptian marine osmium isotopic record of Ontong Java Nui activity

Geology ◽  
2021 ◽  
Author(s):  
Hironao Matsumoto ◽  
Rodolfo Coccioni ◽  
Fabrizio Frontalini ◽  
Kotaro Shirai ◽  
Luigi Jovane ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Volcanic Eruptions ◽  
Hydrothermal Activity ◽  
Published Data ◽  
Isotopic Data ◽  
Oceanic Plateaus ◽  
Carbon Burial ◽  
Organic Carbon Burial ◽  
Isotopic Records

The early to mid-Aptian was punctuated by episodic phases of organic-carbon burial in various oceanographic settings, which are possibly related to massive volcanism associated with the emplacement of the Ontong Java, Manihiki, and Hikurangi oceanic plateaus in the southwestern Pacific Ocean, inferred to have formed a single plateau called Ontong Java Nui. Sedimentary osmium (Os) isotopic compositions are one of the best proxies for determining the timing of voluminous submarine volcanic episodes. However, available Os isotopic records during the age are limited to a narrow interval in the earliest Aptian, which is insufficient for the reconstruction of long-term hydrothermal activity. We document the early to mid-Aptian Os isotopic record using pelagic Tethyan sediments deposited in the Poggio le Guaine (Umbria-Marche Basin, Italy) to precisely constrain the timing of massive volcanic episodes and to assess their impact on the marine environment. Our new Os isotopic data reveal three shifts to unradiogenic values, two of which correspond to black shale horizons in the lower to mid-Aptian, namely the Wezel (herein named) and Fallot Levels. These Os isotopic excursions are ascribed to massive inputs of unradiogenic Os to the ocean through hydrothermal activity. Combining the new Os isotopic record with published data from the lowermost Aptian organic-rich interval in the Gorgo a Cerbara section of the Umbria-Marche Basin, it can be inferred that Ontong Java Nui volcanic eruptions persisted for ~5 m.y. during the early to mid-Aptian.

Organic Carbon Burial in Lakes and Reservoirs of the Conterminous United States

2015 ◽  
Vol 49 (13) ◽  
pp. 7614-7622 ◽  
Author(s):  
David W. Clow ◽  
Sarah M. Stackpoole ◽  
Kristine L. Verdin ◽  
David E. Butman ◽  
Zhiliang Zhu ◽  
...  
Keyword(s):  
United States ◽  
Organic Carbon ◽  
Carbon Burial ◽  
Organic Carbon Burial ◽  
Lakes And Reservoirs
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