scholarly journals CRETACEOUS OCEANIC ANOXIC EVENTS IN WESTERN CONTINENTAL GREECE

2018 ◽  
Vol 36 (2) ◽  
pp. 846 ◽  
Author(s):  
V. Karakitsios ◽  
H. Tsikos ◽  
Y. Van Breugel ◽  
I. Bakopoulos ◽  
L. Koletti
Keyword(s):  
Black Shale ◽  
Oceanic Anoxic Event ◽  
Anoxic Event ◽  
Anoxic Events ◽  
Organic Sediments ◽  
Preliminary Study ◽  
Western Greece

Integrated chemostratigraphy and biostratigraphy in Cretaceous pelagic carbonate successions and associated organic sediments of the Ionian basin (western Greece) show the first documentation of the Cenomanian Turonian (OAE)2 and Lower Albian (OAE)1b Oceanic Anoxic Events from western Greece. Preliminary study of the Pindos basin (western Greece) has also identified a black shale horizon which may corresponds to the Lower Albian (OAE)1b Oceanic Anoxic Event.

scholarly journals THE USE OF CARBON AND OXYGEN STABLE ISOTOPES IN THE STUDY OF GLOBAL PALAEOCEANOGRAPHIC CHANGES: EXAMPLES FROM THE CRETACEOUS SEDIMENT ROCKS OF WESTERN GREECE

2006 ◽  
Vol 39 (1) ◽  
pp. 64 ◽  
Author(s):  
V. Karakitsios ◽  
H. Tsikos ◽  
K. Agiadi - Katsiaouni ◽  
S. Dermitzoglou ◽  
E. Chatziharalambous
Keyword(s):  
Stable Isotopes ◽  
Oceanic Anoxic Event ◽  
Palaeoenvironmental Change ◽  
Oxygen Stable Isotopes ◽  
Anoxic Event ◽  
Data Record ◽  
Anoxic Events ◽  
First Time ◽  
Western Greece ◽  
Cretaceous Sediment

In the present paper we examine the use of carbon and oxygen stable isotopes in the study of global palaeoceanographic changes, with special reference to the oceanic anoxic events (OAEs). The analysis of stable isotopes was applied to the examination of Cretaceous sediments from the Ionian and Pindos zones of Western Greece. In the Ionian zone the carbon and oxygen stable isotopes, combined with biostratigraphic data, record the palaeoenvironmental change corresponding to the anoxic events Bonarelli (Cenomanian/Turonian, OAE2) and Paquier (Lower Albian, OAE1b). In the Pindos zone, within the Cretaceous sediments, we observed two organic-carbon-rich levels. According to the biostratigraphic and isotopie analysis, the first level corresponds to an OAE of Santonian age. This local oceanic anoxic event is described for the first time. The second level, Aptian - Albian age, possibly correlates to either the Paquier event (OAE 1b) or the Selli event (OAE 1a), which in Greece were until now known only in the Ionian zone.

scholarly journals Black shale deposition, atmospheric CO2drawdown, and cooling during the Cenomanian-Turonian Oceanic Anoxic Event

2011 ◽  
Vol 26 (3) ◽  
pp. n/a-n/a ◽  
Author(s):  
Ian Jarvis ◽  
John S. Lignum ◽  
Darren R. Gröcke ◽  
Hugh C. Jenkyns ◽  
Martin A. Pearce
Keyword(s):  
Black Shale ◽  
Oceanic Anoxic Event ◽  
Anoxic Event

Arctic black shale formation during Cretaceous Oceanic Anoxic Event 2

Geology ◽  
2014 ◽  
Vol 42 (9) ◽  
pp. 799-802 ◽  
Author(s):  
Marc Lenniger ◽  
Henrik Nøhr-Hansen ◽  
Len V. Hills ◽  
Christian J. Bjerrum
Keyword(s):  
Black Shale ◽  
Oceanic Anoxic Event ◽  
Oceanic Anoxic Event 2 ◽  
Anoxic Event ◽  
Shale Formation

scholarly journals The importance of diazotrophic cyanobacteria as primary producers during Cretaceous Oceanic Anoxic Event 2

2006 ◽  
Vol 3 (4) ◽  
pp. 467-478 ◽  
Author(s):  
N. Ohkouchi ◽  
Y. Kashiyama ◽  
J. Kuroda ◽  
N O. Ogawa ◽  
H. Kitazato
Keyword(s):  
Black Shale ◽  
Primary Producers ◽  
Oceanic Anoxic Event ◽  
Isotopic Compositions ◽  
Oceanic Anoxic Event 2 ◽  
Nitrogen Isotopic Composition ◽  
Anoxic Event ◽  
Dominant Process ◽  
Diazotrophic Cyanobacteria ◽  
The Mean

Abstract. In Livello Bonarelli black shale deposited during Cretaceous Oceanic Anoxic Event 2 (OAE-2, ca. 94 Ma), nitrogen isotopic compositions of bulk sediments are mostly in a narrow range from –2.7 to –0.7‰. We also determined molecular distribution and nitrogen isotopic compositions of geoporphyrins extracted from the black shale. The nitrogen isotopic compositions of C32 Ni deoxophylloerythroetioporphyrin (DPEP) and total Ni porphyrins are –3.5 and –3.3‰, respectively, leading us to the estimation that the mean nitrogen isotopic composition of photoautotrophic cells were around +1‰ during the formation of Bonarelli black shale. This value is suggestive of N2-fixation, a dominant process for these photoautotrophs when assimilating nitrogen. Furthermore, Ni-chelated C32 DPEP, derived mainly from chlorophyll a had the highest concentration. Based on this evidence, we conclude that diazotrophic cyanobacteria were major primary producers during that time. Cyanobacteria may be key photoautotrophs during the formation of black shale type sediments intermittently observed throughout the later half of the Earth's history, and hence may have played a crucial role in the evolution of geochemical cycles even in the later half of the Earth's history.

scholarly journals Coring the sedimentary expression of the early Toarcian Oceanic Anoxic Event: new stratigraphic records from the Tethys Ocean

2019 ◽  
Vol 26 ◽  
pp. 17-27
Author(s):  
Elisabetta Erba ◽  
Gabriele Gambacorta ◽  
Stefano Visentin ◽  
Liyenne Cavalheiro ◽  
Dario Reolon ◽  
...  
Keyword(s):  
Black Shale ◽  
Northern Italy ◽  
Global Changes ◽  
Future Scenarios ◽  
Western Tethys ◽  
Oceanic Anoxic Event ◽  
Reference Sections ◽  
Anoxic Event ◽  
Tethys Ocean ◽  
Integrated Stratigraphy

Abstract. The Toarcian Oceanic Anoxic Event (T-OAE) interval was cored at Colle di Sogno and Gajum in the Lombardy Basin (Southern Alps, northern Italy). The Sogno and Gajum cores recovered 26.83 and 31.18 stratigraphic metres, respectively, of pelagic sediments consisting of marly limestones, marlstone, marly claystone, and black shale. Drilling at both sites resulted in 100 % recovery of unweathered material. The pelagic succession comprises a relatively expanded black shale interval of 4.98 m in the Sogno core and 15.35 m in the Gajum core, with lower and upper boundaries without evidence of hiatuses. The Sogno and Gajum cores can be considered reference sections for the pelagic lower Toarcian interval of the western Tethys and will provide high-resolution micropaleontological, inorganic and organic geochemical, isotopic multiproxy data. Integrated stratigraphy and cyclostratigraphy are predicted to result in estimates of durations and rates to model the ecosystem resilience to the extreme perturbations of the T-OAE and gain a better understanding of current global changes and help provide better projections of future scenarios.

Late Jurassic – earliest Cretaceous prolonged shelf dysoxic–anoxic event and its possible causes

2020 ◽  
Vol 157 (10) ◽  
pp. 1622-1642
Author(s):  
MA Rogov ◽  
EV Shchepetova ◽  
VA Zakharov
Keyword(s):  
Organic Carbon ◽  
Black Shale ◽  
High Latitude ◽  
Late Jurassic ◽  
Black Shales ◽  
Time Interval ◽  
Oceanic Circulation ◽  
Anoxic Event ◽  
Anoxic Events

AbstractThe Late Jurassic – earliest Cretaceous time interval was characterized by a widespread distribution of dysoxiс–anoxiс environments in temperate- and high-latitude epicontinental seas, which could be defined as a shelf dysoxic–anoxic event (SDAE). In contrast to black shales related to oceanic anoxic events, deposits generated by the SDAE were especially common in shelf sites in the Northern Hemisphere. The onset and termination of the SDAE was strongly diachronous across different regions. The SDAE was not associated with significant disturbances of the carbon cycle. Deposition of organic-carbon-rich sediment and the existence of dysoxic–anoxic conditions during the SDAE lasted up to c. 20 Ma, but this event did not cause any remarkable biotic extinction. Temperate- and high-latitude black shale occurrences across the Jurassic–Cretaceous boundary have been reviewed. Two patterns of black shale deposition during the SDAE are recognized: (1) Subboreal type, with numerous thin black shale beds, bounded by sediments with very low total organic carbon (TOC) values; and (2) Boreal type, distinguished by predominantly thick black shale successions showing high TOC values and prolonged anoxic–dysoxic conditions. These types appear to be unrelated to differences in accommodation space, and can be clearly recognized irrespective of the thickness of shale-bearing units. Black shales in high-latitude areas in the Southern Hemisphere strongly resemble Boreal types of black shale by their mode of occurrence. The causes of this SDAE are linked to long-term warming and changes in oceanic circulation. Additionally, the long-term disturbance of planktonic communities may have triggered overall increased productivity in anoxia-prone environments.

scholarly journals Black shale deposition and early diagenetic dolomite cementation during Oceanic Anoxic Event 1: The mid-Cretaceous Maracaibo Platform, northwestern South America

2016 ◽  
Vol 316 (7) ◽  
pp. 669-711 ◽  
Author(s):  
D. A. Petrash ◽  
N. Gueneli ◽  
J. J. Brocks ◽  
J. A. Mendez-Dot ◽  
G. Gonzalez-Arismendi ◽  
...  
Keyword(s):  
South America ◽  
Black Shale ◽  
Oceanic Anoxic Event ◽  
Anoxic Event

scholarly journals Global controls on phosphatization of fossils during the toarcian oceanic anoxic event

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sinjini Sinha ◽  
A. D. Muscente ◽  
James D. Schiffbauer ◽  
Matt Williams ◽  
Günter Schweigert ◽  
...  
Keyword(s):  
Lower Jurassic ◽  
X Ray ◽  
Oceanic Anoxic Event ◽  
Exceptional Preservation ◽  
Level Change ◽  
Environmental Controls ◽  
Anoxic Basins ◽  
Anoxic Event ◽  
Anoxic Events ◽  
Posidonia Shale

AbstractKonservat-Lagerstätten—deposits with exceptionally preserved fossils—vary in abundance across geographic and stratigraphic space due to paleoenvironmental heterogeneity. While oceanic anoxic events (OAEs) may have promoted preservation of marine lagerstätten, the environmental controls on their taphonomy remain unclear. Here, we provide new data on the mineralization of fossils in three Lower Jurassic Lagerstätten—Strawberry Bank (UK), Ya Ha Tinda (Canada), and Posidonia Shale (Germany) —and test the hypothesis that they were preserved under similar conditions. Biostratigraphy indicates that all three Lagerstätten were deposited during the Toarcian OAE (TOAE), and scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) show that each deposit contains a variety of taxa preserved as phosphatized skeletons and tissues. Thus, despite their geographic and paleoenvironmental differences, all of these Lagerstätten were deposited in settings conducive to phosphatization, indicating that the TOAE fostered exceptional preservation in marine settings around the world. Phosphatization may have been fueled by phosphate delivery from climatically-driven sea level change and continental weathering, with anoxic basins acting as phosphorus traps.

The Late Hauterivian Faraoni ‘Oceanic Anoxic Event’: an update

2014 ◽  
Vol 185 (6) ◽  
pp. 359-377 ◽  
Author(s):  
François Baudin ◽  
Laurent Riquier
Keyword(s):  
Middle Part ◽  
Time Interval ◽  
Oceanic Anoxic Event ◽  
Anoxic Event ◽  
Anoxic Events ◽  
The Mediterranean ◽  
Definition Of ◽  
Geochemical Studies ◽  
New Occurrences

AbstractMost oceanic anoxic events (OAEs) took place during the middle part of the Cretaceous and the Late Hauterivian probably recorded the first anoxic event within this peculiar time interval. The so-called Faraoni event (~131 Ma) was initially defined as a short-lived anoxic event restricted to the Mediterranean domain. Since its recognition, numerous geochemical studies were conducted on the Faraoni event and new occurrences of this event were suggested outside the Tethyan domain. This paper presents an update on the Late Hauterivian Faraoni event and examines if this event agrees with the definition of OAEs.

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