scholarly journals PRELIMINARY DATA FROM THE FIRST RECORD OF THE EARLY TOARCIAN OCEANIC ANOXIC EVENT IN THE SEDIMENTS OF THE PINDOS ZONE (GREECE)

2017 ◽  
Vol 43 (2) ◽  
pp. 627 ◽  
Author(s):  
Kafousia N. Kafousia N. ◽  
V. Karakitsios ◽  
H.C. Jenkyns
Keyword(s):  
Organic Carbon ◽  
Carbon Isotope ◽  
First Record ◽  
Passive Margin ◽  
Oceanic Anoxic Event ◽  
Carbonate Carbon ◽  
Carbon Burial ◽  
Organic Carbon Burial ◽  
Anoxic Event ◽  
Regional Character

The Early Toarcian Oceanic Anoxic Event (ca 183 Ma) coincides with high palaeotemperatures, regional anoxia to euxinia, marine transgression, mass extinction and high rates of organic-carbon burial in a global context. Most of the detailed studies of this event have investigated deposits formed in the epicontinental seas of northern Europe, although coeval organic-rich shales are known locally in the Tethyan region. However, the global or regional character of this event is still under debate. In this study we present, for the first time, a high-resolution geochemical record of the Early Toarcian Oceanic Anoxic event in pelagic sediments (Kastelli Pelites) formed in a long-lived Mesozoic deep-sea basin, corresponding to the western passive margin of the Pindos Ocean of western Greece. Our data record both the positive excursion in total organic carbon (TOC) and the characteristic negative excursion in δ13Ccarb. The δ13Ccarb values are very stable in the bottom of the section (~2‰), whereas higher in the section the values drop down to ~ -5‰. Following this negative excursion, the carbonate carbon-isotope ratios return to background values. The TOC excursion is modest, rising from a background of 0.05% to ~ 2% and then returning to a background of 0.04%. Because both relative enrichment in TOC and the negative carbon-isotope excursion that characterize the Toarcian OAE are recorded in some of the deepest marine sediments of the Tethyan region, the global significance of the event is reinforced.

scholarly journals Enhanced terrestrial runoff during Oceanic Anoxic Event 2 on the North Carolina Coastal Plain, USA

2021 ◽  
Vol 17 (3) ◽  
pp. 1227-1242
Author(s):  
Christopher M. Lowery ◽  
Jean M. Self-Trail ◽  
Craig D. Barrie
Keyword(s):  
North Carolina ◽  
Organic Carbon ◽  
Carbon Isotope ◽  
Coastal Plain ◽  
Hydrologic Cycle ◽  
Oceanic Anoxic Event ◽  
Carbon Burial ◽  
Organic Carbon Burial ◽  
Oceanic Anoxic Event 2 ◽  
Anoxic Event

Abstract. A global increase in the strength of the hydrologic cycle drove an increase in the flux of terrigenous sediments into the ocean during the Cenomanian–Turonian Oceanic Anoxic Event 2 (OAE2) and was an important mechanism driving nutrient enrichment and thus organic carbon burial. This global change is primarily known from isotopic records, but global average data do not tell us anything about changes at any particular location. Reconstructions of local terrigenous flux can help us understand the role of regional shifts in precipitation in driving these global trends. The proto-North Atlantic basin was one of the epicenters of enhanced organic carbon burial during OAE2, so constraining terrigenous flux is particularly important in this region; however, few local records exist. Here, we present two new OAE2 records from the Atlantic Coastal Plain of North Carolina, USA, recognized with calcareous nannoplankton biostratigraphy and organic carbon isotopes. We use carbon / nitrogen ratios to constrain the relative contribution of marine and terrestrial organic matter; in both cores we find an elevated contribution from vascular plants beginning just before OAE2 and continuing through the event, indicating a locally strengthened hydrologic cycle. Terrigenous flux decreased during the brief change in carbon isotope values known as the Plenus carbon isotope excursion; it then increased and remained elevated through the latter part of OAE2. Total organic carbon (TOC) values reveal relatively low organic carbon burial in the inner shelf, in contrast to black shales known from the open ocean. Organic carbon content on the shelf appears to increase in the offshore direction, highlighting the need for cores from the middle and outer shelf.

scholarly journals Chemostratigraphy of the Toarcian oceanic anoxic event from the Ionian Zone, Greece

2017 ◽  
Vol 47 (2) ◽  
pp. 825
Author(s):  
N. Kafousia ◽  
V. Karakitsios ◽  
E. Mattioli ◽  
H.C. Jenkyns
Keyword(s):  
Carbon Isotope ◽  
Relative Increase ◽  
Geochemical Data ◽  
Oceanic Anoxic Event ◽  
Carbonate Carbon ◽  
Carbon Burial ◽  
Organic Carbon Burial ◽  
Anoxic Event ◽  
The Difference ◽  
The Impact

A global perturbation in the carbon cycle has been recorded in the Early Toarcian (~ 183 Ma) and is marked by enhanced organic-carbon burial and mass extinction. It is also associated with high palaeotemperatures, both positive and negative excursions in carbon-isotope ratios, and the development of anoxic to euxinic conditions in marine environments: together these phenomena have been designated as constituting an Oceanic Anoxic Event. Here we provide a high-resolution, multiproxy biostratigraphic and chemostratigraphic study from a section that belongs to the central Ionian Zone in Greece. Calcareous nannofossil distribution, as well as the TOC, δ13Ccarb and δ13Corg, have all been determined. The nannofossil zones NJT 5b, NJT 6 and NJT 7 have been recognized in the section. In the NJT 5b zone a small positive excursion in TOC and negative excursion in δ13Ccarb is recorded, tentatively assigned to the Pliensbachian/Toarcian boundary. In the NJT 6 zone, the main negative carbon-isotope excursion characteristic of this interval is developed, associated with a relative increase in TOC. The difference in this section, compared with sections from the Pindos Zone but in common with sections elsewhere, is the record of a positive excursion in the NJT 7 zone in both organic and carbonate carbon isotopes. This study offers new biostratigraphic and geochemical data for the Ionian Zone, and further illustrates the impact of Toarcian Oceanic Anoxic Event in the Tethyan region.

scholarly journals A global event with a regional character: the Early Toarcian Oceanic Anoxic Event in the Pindos Ocean (northern Peloponnese, Greece)

2011 ◽  
Vol 148 (4) ◽  
pp. 619-631 ◽  
Author(s):  
N. KAFOUSIA ◽  
V. KARAKITSIOS ◽  
H. C. JENKYNS ◽  
E. MATTIOLI
Keyword(s):  
Carbon Isotope ◽  
Passive Margin ◽  
Oceanic Anoxic Event ◽  
Northern European ◽  
Carbon Isotope Excursion ◽  
Anoxic Event ◽  
Considerable Controversy ◽  
Regional Character ◽  
Globally Distributed ◽  
Ammonite Zones

AbstractThe Early Toarcian (Early Jurassic, c. 183 Ma) was characterized by an Oceanic Anoxic Event (T-OAE), primarily identified by the presence of globally distributed approximately coeval black organic-rich shales. This event corresponded with relatively high marine temperatures, mass extinction, and both positive and negative carbon-isotope excursions. Because most studies of the T-OAE have taken place in northern European and Tethyan palaeogeographic domains, there is considerable controversy as to the regional or global character of this event. Here, we present the first high-resolution integrated chemostratigraphic (carbonate, organic carbon, δ13Ccarb, δ13Corg) and biostratigraphic (calcareous nannofossil) records from the Kastelli Pelites cropping out in the Pindos Zone, western Greece. During the Mesozoic, the Pindos Zone was a deep-sea ocean-margin basin, which formed in mid-Triassic times along the northeast passive margin of Apulia. In two sections through the Kastelli Pelites, the chemostratigraphic and biostratigraphic (nannofossil) signatures of the most organic-rich facies are identified as correlative with the Lower Toarcian, tenuicostatum/polymorphum–falciferum/serpentinum/levisoni ammonite zones, indicating that these sediments record the T-OAE. Both sections also display the characteristic negative carbon-isotope excursion in organic matter and carbonate. This occurrence reinforces the global significance of the Early Toarcian Oceanic Anoxic Event.

scholarly journals Orbital forcing of organic carbon burial in the proto-North Atlantic during oceanic anoxic event 2

2004 ◽  
Vol 228 (3-4) ◽  
pp. 465-482 ◽  
Author(s):  
Marcel M.M. Kuypers ◽  
Lucas J. Lourens ◽  
W. Irene C. Rijpstra ◽  
Richard D. Pancost ◽  
Ivar A. Nijenhuis ◽  
...  
Keyword(s):  
Organic Carbon ◽  
North Atlantic ◽  
Orbital Forcing ◽  
Oceanic Anoxic Event ◽  
Carbon Burial ◽  
Organic Carbon Burial ◽  
Oceanic Anoxic Event 2 ◽  
Anoxic Event

scholarly journals Supplemental Material: Quantifying volcanism and organic carbon burial across Oceanic Anoxic Event 2

2022 ◽  
Author(s):  
Nina Papadomanolaki ◽  
et al.
Keyword(s):  
Organic Carbon ◽  
Oceanic Anoxic Event ◽  
Carbon Burial ◽  
Organic Carbon Burial ◽  
Oceanic Anoxic Event 2 ◽  
Anoxic Event

Supplemental information and methods, Figures S1–S4, and Tables S1 and S2.<br>

scholarly journals Supplemental Material: Quantifying volcanism and organic carbon burial across Oceanic Anoxic Event 2

2022 ◽  
Author(s):  
Nina Papadomanolaki ◽  
et al.
Keyword(s):  
Organic Carbon ◽  
Oceanic Anoxic Event ◽  
Carbon Burial ◽  
Organic Carbon Burial ◽  
Oceanic Anoxic Event 2 ◽  
Anoxic Event

Supplemental information and methods, Figures S1–S4, and Tables S1 and S2.<br>

scholarly journals "OAE 3" – regional Atlantic organic carbon burial during the Coniacian–Santonian

2012 ◽  
Vol 8 (5) ◽  
pp. 1447-1455 ◽  
Author(s):  
M. Wagreich
Keyword(s):  
Organic Carbon ◽  
Temporal Distribution ◽  
Black Shales ◽  
Time Interval ◽  
Temporal And Spatial Distribution ◽  
Oceanic Anoxic Event ◽  
The North ◽  
Carbon Burial ◽  
Organic Carbon Burial ◽  
Anoxic Event

Abstract. The Coniacian–Santonian time interval is the inferred time of oceanic anoxic event 3 (OAE 3), the last of the Cretaceous OAEs. A detailed look on the temporal and spatial distribution of organic-rich deposits attributed to OAE 3 suggests that black shale occurrences are restricted to the equatorial to mid-latitudinal Atlantic and adjacent basins, shelves and epicontinental seas like parts of the Caribbean, the Maracaibo Basin and the Western Interior Basin, and are largely absent in the Tethys, the North Atlantic, the southern South Atlantic, and the Pacific. Here, oxic bottom waters prevailed as indicated by the widespread occurrence of red deep-marine CORBs (Cretaceous Oceanic Red Beds). Widespread CORB sedimentation started during the Turonian after Oceanic Anoxic Event 2 (OAE 2) except in the Atlantic realm where organic-rich strata continue up to the Santonian. The temporal distribution of black shales attributed to OAE 3 indicates that organic-rich strata do not define a single and distinct short-time event, but are distributed over a longer time span and occur in different basins during different times. This suggests intermittent and regional anoxic conditions from the Coniacian to the Santonian. A comparison of time-correlated high-resolution δ13C curves for this interval indicates several minor positive excursions of up to 0.5‰, probably as a result of massive organic carbon burial cycles in the Atlantic. Regional wind-induced upwelling and restricted deep basins may have contributed to the development of anoxia during a time interval of widespread oxic conditions, thus highlighting the regional character of inferred OAE 3 as regional Atlantic event(s).

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