scholarly journals Bio-chemostratigraphy of the Barremian–Aptian shallow-water carbonates of the southern Apennines (Italy): pinpointing the OAE1a in a Tethyan carbonate platform

2011 ◽  
Vol 3 (2) ◽  
pp. 789-838 ◽  
Author(s):  
M. Di Lucia ◽  
M. Mutti ◽  
M. Parente
Keyword(s):  
Southern Italy ◽  
Carbonate Platform ◽  
Black Shales ◽  
Carbonate Platforms ◽  
Southern Apennines ◽  
Main Obstacle ◽  
Oceanic Anoxic Event ◽  
Anoxic Event ◽  
Anoxic Events ◽  
Isotope Stratigraphy

Abstract. Low resolution and lack of chronostratigraphic calibration of carbonate platform biostratigraphy hinder precise correlation with coeval deep-water successions. This is the main obstacle when studying the record of Mesozoic oceanic anoxic events in carbonate platforms. In this paper we use carbon isotope stratigraphy to produce the first chronostratigraphic calibration of the Barremian–Aptian biostratigraphy of the Apenninic carbonate platform of southern Italy. According to our calibration, the "Selli level" black shales of epicontinental and oceanic basins corresponds in the southern Apenninic carbonate platform to the interval between the "Orbitolina level", characterized by the association of Mesorbitolina parva and Mesorbitolina texana, and the second acme of Salpingoporella dinarica. The biocalcification crisis of nannoconids corresponds to the interval going from the first acme of S. dinarica to just above the top of the "Orbitolina level". Since these bioevents have been widely recognized beyond the Apenninic platform, our calibration can be used to pinpoint the interval corresponding to the Early Aptian oceanic anoxic event in other carbonate platforms of central and southern Tethys.

scholarly journals Bio-chemostratigraphy of the Barremian-Aptian shallow-water carbonates of the southern Apennines (Italy): pinpointing the OAE1a in a Tethyan carbonate platform

Solid Earth ◽  
2012 ◽  
Vol 3 (1) ◽  
pp. 1-28 ◽  
Author(s):  
M. Di Lucia ◽  
A. Trecalli ◽  
M. Mutti ◽  
M. Parente
Keyword(s):  
Carbon Isotope ◽  
Deep Water ◽  
Carbonate Platform ◽  
Carbonate Platforms ◽  
Δ13c Values ◽  
Oceanic Anoxic Event ◽  
Strontium Isotope Stratigraphy ◽  
Anoxic Event ◽  
Anoxic Events ◽  
Isotope Stratigraphy

Abstract. Low biostratigraphic resolution and lack of chronostratigraphic calibration hinder precise correlations between platform carbonates and coeval deep-water successions. These are the main obstacle when studying the record of Mesozoic oceanic anoxic events in carbonate platforms. In this paper carbon and strontium isotope stratigraphy are used to produce the first chronostratigraphic calibration of the Barremian-Aptian biostratigraphy of the Apenninic carbonate platform of southern Italy. According to this calibration, the segment of decreasing δ13C values, leading to the negative peak that is generally taken as the onset of the Selli event, starts a few metres above the last occurrence of Palorbitolina lenticularis and Voloshinoides murgensis. The following rise of δ13C values, corresponding to the interval of enhanced accumulation of organic matter in deep-water sections, ends just below the first acme of Salpingoporella dinarica, which roughly corresponds to the segment of peak δ13C values. The whole carbon isotope excursion associated with the oceanic anoxic event 1a is bracketed in the Apenninic carbonate platform between the last occurrence of Voloshinoides murgensis and the "Orbitolina level", characterized by the association of Mesorbitolina parva and Mesorbitolina texana. Since these bioevents have been widely recognized beyond the Apenninic platform, the calibration presented in this paper can be used to pinpoint the interval corresponding to the Early Aptian oceanic anoxic event in other carbonate platforms of central and southern Tethys. This calibration will be particularly useful to interpret the record of the Selli event in carbonate platform sections for which a reliable carbon isotope stratigraphy is not available.

scholarly journals New drilling of the early Aptian OAE1a: the Cau core (Prebetic Zone, south-eastern Spain)

2016 ◽  
Vol 21 ◽  
pp. 41-46 ◽  
Author(s):  
Pedro Alejandro Ruiz-Ortiz ◽  
José Manuel Castro ◽  
Ginés Alfonso de Gea ◽  
Ian Jarvis ◽  
José Miguel Molina ◽  
...  
Keyword(s):  
Carbonate Platforms ◽  
Oceanic Anoxic Event ◽  
Lower Aptian ◽  
Abrupt Changes ◽  
Anoxic Event ◽  
Anoxic Events ◽  
Isotope Stratigraphy ◽  
Detailed Record ◽  
Global Carbon ◽  
Shed Light

Abstract. The Cretaceous was punctuated by several episodes of accelerated global change, defined as Oceanic Anoxic Events (OAEs), that reflect abrupt changes in global carbon cycling. The Aptian Oceanic Anoxic Event (OAE1a; 120 Ma) represents an excellent example, recorded in all major ocean basins, and associated with massive burial of organic matter in marine sediments. The OAE1a is concomitant with the "nannoconid crisis", which is characterized by a major biotic turnover, and a widespread demise of carbonate platforms. Many studies have been published over the last decades on OAE1a's from different sections in the world, and provide a detailed C-isotope stratigraphy for the event. Nevertheless, new high-resolution studies across the event are essential to shed light on the precise timing and rates of the multiple environmental and biotic changes that occurred during this critical period of Earth history. Here we present a new drill core recovering an Aptian section spanning the OAE1a in southern Spain. The so-called Cau section was drilled in the last quarter of 2015. The Cau section is located in the easternmost part of the Prebetic Zone (Betic Cordillera), which represents platform deposits of the southern Iberian palaeomargin. The lower Aptian deposits of the Cau section belong to a hemipelagic unit (Almadich Formation), deposited in a highly subsident sector of the distal parts of the Prebetic Platform. Previous work on the early Aptian of the Cau succession has focused on stratigraphy, bioevents, C-isotope stratigraphy, and organic and elemental geochemistry. A more recent study based on biomarkers has presented a detailed record of the pCO2 evolution across the OAE1a (Naafs et al., 2016). All these studies reveal that the Cau section represents an excellent site to further investigate the OAE1a, based on its unusually high sedimentation rate and stratigraphic continuity, the quality and preservation of fossils, and the well-expressed geochemical signatures.

Cenomanian–Turonian drowning of the Arabian Carbonate Platform, the İnişdere section, Adıyaman, SE Turkey

2019 ◽  
Vol 498 (1) ◽  
pp. 189-210 ◽  
Author(s):  
O. Mulayim ◽  
O. I. Yilmaz ◽  
B. Sarı ◽  
K. Tasli ◽  
M. Wagreich
Keyword(s):  
Sea Level ◽  
Carbonate Platform ◽  
Accumulation Rates ◽  
Sea Level Changes ◽  
Carbonate Production ◽  
Oceanic Anoxic Event ◽  
Anoxic Event ◽  
Anoxic Events ◽  
Se Turkey ◽  
Arabian Platform

AbstractThe Cenomanian–Turonian carbonate ramp in the Adıyaman Region of SE Turkey (Northern Arabian Platform) records an abrupt shift from benthic carbonate deposits to pelagic deposits near the Cenomanian–Turonian boundary event (CTBE) in the İnişdere stratigraphic section and surrounding borehole sections. A positive δ13C excursion of up to 2.15% is recorded in carbonate and organic carbon deposited around the CTBE and provides evidence of a direct link between the CTBE and oceanic anoxic events and the demise of the shallow carbonate production in the Derdere Formation. The microfacies analyses, biostratigraphic dating and palaeoenvironmental interpretations suggest that the platform was drowned near the CTBE as a result of changing environmental conditions. The microfacies indicating significant deepening show a contemporaneity to equivalent surfaces globally and thus strongly support an isochronous formation of Cenomanian–Turonian facies by eustatic sea-level changes. Anoxia spreading over the platform drastically reduced the carbonate production as observed in the studied sections and, therefore, resulted in a reduction in carbonate accumulation rates. Regional/local subsidence and a coeval sea-level rise during the late Cenomanian to early Turonian interval were the cause of the drowning of the platform, including regional anoxia at the northern Arabian platform linked to the Cenomanian–Turonian oceanic anoxic event (OAE2).

Molecular and petrographical evidence for lacustrine environmental and biotic change in the palaeo-Sichuan mega-lake (China) during the Toarcian Oceanic Anoxic Event

2021 ◽  
pp. SP514-2021-2
Author(s):  
Weimu Xu ◽  
Johan W. H. Weijers ◽  
Micha Ruhl ◽  
Erdem F. Idiz ◽  
Hugh C. Jenkyns ◽  
...  
Keyword(s):  
Organic Matter ◽  
Sichuan Basin ◽  
Large Scale ◽  
Algal Growth ◽  
Black Shales ◽  
Content Type ◽  
Oceanic Anoxic Event ◽  
Anoxic Event ◽  
Supplementary Material ◽  
The Sichuan Basin

AbstractThe organic-rich upper Lower Jurassic Da'anzhai Member (Ziliujing Formation) of the Sichuan Basin, China is the first stratigraphically well-constrained lacustrine succession associated with the Toarcian Oceanic Anoxic Event (T-OAE; ∼183 Ma). The formation and/or expansion of the Sichuan mega-lake, likely one of the most extensive fresh-water systems to have existed on the planet, is marked by large-scale lacustrine organic productivity and carbon burial during the T-OAE, possibly due to intensified hydrological cycling and nutrient supply. New molecular biomarker and organic petrographical analyses, combined with bulk organic and inorganic geochemical and palynological data, are presented here, providing insight into aquatic productivity, land-plant biodiversity, and terrestrial ecosystem evolution in continental interiors during the T-OAE. We show that lacustrine algal growth during the T-OAE accounted for a significant organic-matter flux to the lakebed in the palaeo-Sichuan mega-lake. Lacustrine water-column stratification during the T-OAE facilitated the formation of dysoxic-anoxic conditions at the lake bottom, favouring organic-matter preservation and carbon sequestration into organic-rich black shales in the Sichuan Basin. We attribute the palaeo-Sichuan mega-lake expansion to enhanced hydrological cycling in a more vigorous monsoonal climate in the hinterland during the T-OAE greenhouse.Supplementary material at https://doi.org/10.6084/m9.figshare.c.5433544

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