Driving mechanisms of organic carbon burial in the Early Cretaceous South Atlantic Cape Basin (DSDP Site 361)
<p>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, o...
| Main Authors: | , , , , , , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2021-02-01
|
| Series: | Climate of the Past |
| Online Access: | https://cp.copernicus.org/articles/17/469/2021/cp-17-469-2021.pdf |
| _version_ | 1818871317477195776 |
|---|---|
| author | W. Dummann W. Dummann S. Steinig S. Steinig P. Hofmann M. Lenz S. Kusch S. Flögel J. O. Herrle C. Hallmann C. Hallmann J. Rethemeyer H. U. Kasper T. Wagner |
| author_facet | W. Dummann W. Dummann S. Steinig S. Steinig P. Hofmann M. Lenz S. Kusch S. Flögel J. O. Herrle C. Hallmann C. Hallmann J. Rethemeyer H. U. Kasper T. Wagner |
| author_sort | W. Dummann |
| collection | DOAJ |
| description | <p>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 (<span class="inline-formula">></span> 1 Myr). The Early Aptian black shale
sequence comprises alternations of shales with high (<span class="inline-formula">></span> 6 %) and
relatively low (<span class="inline-formula">∼</span> 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.</p> |
| first_indexed | 2024-12-19T12:21:00Z |
| format | Article |
| id | doaj.art-e0eb3fc706164db1b8a22244046782c4 |
| institution | Directory Open Access Journal |
| issn | 1814-9324 1814-9332 |
| language | English |
| last_indexed | 2024-12-19T12:21:00Z |
| publishDate | 2021-02-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Climate of the Past |
| spelling | doaj.art-e0eb3fc706164db1b8a22244046782c42022-12-21T20:21:47ZengCopernicus PublicationsClimate of the Past1814-93241814-93322021-02-011746949010.5194/cp-17-469-2021Driving mechanisms of organic carbon burial in the Early Cretaceous South Atlantic Cape Basin (DSDP Site 361)W. Dummann0W. Dummann1S. Steinig2S. Steinig3P. Hofmann4M. Lenz5S. Kusch6S. Flögel7J. O. Herrle8C. Hallmann9C. Hallmann10J. Rethemeyer11H. U. Kasper12T. Wagner13Institute of Geology and Mineralogy, University of Cologne, 50674 Cologne, Germanynow at: Institute of Geosciences, Goethe University Frankfurt, 60438 Frankfurt am Main, GermanyGEOMAR Helmholtz Centre for Ocean Research Kiel, 24148 Kiel, Germanynow at: School of Geographical Sciences, University of Bristol, Bristol, BS8 1SS, UKInstitute of Geology and Mineralogy, University of Cologne, 50674 Cologne, GermanyInstitute of Geology and Mineralogy, University of Cologne, 50674 Cologne, GermanyInstitute of Geology and Mineralogy, University of Cologne, 50674 Cologne, GermanyGEOMAR Helmholtz Centre for Ocean Research Kiel, 24148 Kiel, GermanyInstitute of Geosciences, Goethe University Frankfurt, 60438 Frankfurt am Main, GermanyMax Planck Institute for Biogeochemistry, 07745 Jena, GermanyMARUM, University of Bremen, 28359 Bremen, GermanyInstitute of Geology and Mineralogy, University of Cologne, 50674 Cologne, GermanyInstitute of Geology and Mineralogy, University of Cologne, 50674 Cologne, GermanyLyell Centre, School of Energy, Geoscience, Infrastructure and Society, Heriot-Watt University, Edinburgh, EH14 4AS, UK<p>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 (<span class="inline-formula">></span> 1 Myr). The Early Aptian black shale sequence comprises alternations of shales with high (<span class="inline-formula">></span> 6 %) and relatively low (<span class="inline-formula">∼</span> 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.</p>https://cp.copernicus.org/articles/17/469/2021/cp-17-469-2021.pdf |
| spellingShingle | W. Dummann W. Dummann S. Steinig S. Steinig P. Hofmann M. Lenz S. Kusch S. Flögel J. O. Herrle C. Hallmann C. Hallmann J. Rethemeyer H. U. Kasper T. Wagner Driving mechanisms of organic carbon burial in the Early Cretaceous South Atlantic Cape Basin (DSDP Site 361) Climate of the Past |
| title | Driving mechanisms of organic carbon burial in the Early Cretaceous South Atlantic Cape Basin (DSDP Site 361) |
| title_full | Driving mechanisms of organic carbon burial in the Early Cretaceous South Atlantic Cape Basin (DSDP Site 361) |
| title_fullStr | Driving mechanisms of organic carbon burial in the Early Cretaceous South Atlantic Cape Basin (DSDP Site 361) |
| title_full_unstemmed | Driving mechanisms of organic carbon burial in the Early Cretaceous South Atlantic Cape Basin (DSDP Site 361) |
| title_short | Driving mechanisms of organic carbon burial in the Early Cretaceous South Atlantic Cape Basin (DSDP Site 361) |
| title_sort | driving mechanisms of organic carbon burial in the early cretaceous south atlantic cape basin dsdp site 361 |
| url | https://cp.copernicus.org/articles/17/469/2021/cp-17-469-2021.pdf |
| work_keys_str_mv | AT wdummann drivingmechanismsoforganiccarbonburialintheearlycretaceoussouthatlanticcapebasindsdpsite361 AT wdummann drivingmechanismsoforganiccarbonburialintheearlycretaceoussouthatlanticcapebasindsdpsite361 AT ssteinig drivingmechanismsoforganiccarbonburialintheearlycretaceoussouthatlanticcapebasindsdpsite361 AT ssteinig drivingmechanismsoforganiccarbonburialintheearlycretaceoussouthatlanticcapebasindsdpsite361 AT phofmann drivingmechanismsoforganiccarbonburialintheearlycretaceoussouthatlanticcapebasindsdpsite361 AT mlenz drivingmechanismsoforganiccarbonburialintheearlycretaceoussouthatlanticcapebasindsdpsite361 AT skusch drivingmechanismsoforganiccarbonburialintheearlycretaceoussouthatlanticcapebasindsdpsite361 AT sflogel drivingmechanismsoforganiccarbonburialintheearlycretaceoussouthatlanticcapebasindsdpsite361 AT joherrle drivingmechanismsoforganiccarbonburialintheearlycretaceoussouthatlanticcapebasindsdpsite361 AT challmann drivingmechanismsoforganiccarbonburialintheearlycretaceoussouthatlanticcapebasindsdpsite361 AT challmann drivingmechanismsoforganiccarbonburialintheearlycretaceoussouthatlanticcapebasindsdpsite361 AT jrethemeyer drivingmechanismsoforganiccarbonburialintheearlycretaceoussouthatlanticcapebasindsdpsite361 AT hukasper drivingmechanismsoforganiccarbonburialintheearlycretaceoussouthatlanticcapebasindsdpsite361 AT twagner drivingmechanismsoforganiccarbonburialintheearlycretaceoussouthatlanticcapebasindsdpsite361 |