scholarly journals Paleoenvironmental changes across the Eocene-Oligocene boundary: insights from the Central-Carpathian Paleogene Basin

2010 ◽  
Vol 61 (5) ◽  
pp. 393-418 ◽  
Author(s):  
Ján Soták
Keyword(s):  
Sea Level ◽  
Carbonate Platform ◽  
Temperature Drop ◽  
Runoff Water ◽  
Paleoenvironmental Changes ◽  
Proxy Records ◽  
Early Oligocene ◽  
Water Influx ◽  
Continental Runoff ◽  
Mass Stratification

Paleoenvironmental changes across the Eocene-Oligocene boundary: insights from the Central-Carpathian Paleogene Basin The sedimentary sequence of the Central-Carpathian Paleogene Basin provides proxy records of climatic changes related to cooling events at the Eocene/Oligocene boundary (TEE). In this basin, climatic deterioration is inferred from the demise of the carbonate platform and oligotrophic benthic biota in the SBZ19 and from the last species of warm-water planktonic foraminifers in the E14 Zone. Upper Eocene formations already indicate warm-temperate to cool-temperate productivity and nutrient-enriched conditions (Bryozoan Marls, Globigerina Marls). Rapid cooling during the earliest Oligocene (Oi-1 event) led to a temperature drop (~11 °C), humidity, fresh water influx and continental runoff, water mass stratification, bottom water anoxia, eutrofication, estuarine circulation and upwelling, carbonate depletion, sapropelitic and biosiliceous deposition, H2S intoxication and mass faunal mortality, and also other characteristics of Black Sea-type basins. Tectonoeustatic events with the interference of TA 4.4 sea-level fall and the Pyrenean phase caused basin isolation at the beginning of the Paratethys. The Early Oligocene stage of Paratethyan isolation is indicated by a stagnant regime, low tide influence, endemic fauna development, widespread anoxia and precipitation of manganese deposits. The episodic rise in the sea-level, less humid conditions and renewed circulation is marked by calcareous productivity, nannoplankton blooms and the appearance of planktic pteropods and re-oxygenation. Paleogeographic differentiation of the Carpatho-Pannonian Paleogene basins resulted from plate-tectonic reorganization during the Alpine orogenesis.

Seismic evidence of the Messinian events in the Adriatic basin

2021 ◽  
Author(s):  
Alessandra Lanzoni ◽  
Anna Del Ben ◽  
Edy Forlin ◽  
Federica Donda ◽  
Massimo Zecchin
Keyword(s):  
Sea Level ◽  
Adriatic Sea ◽  
Carbonate Platform ◽  
Primary Role ◽  
Seismic Profiles ◽  
Northern Adriatic ◽  
Platform Margin ◽  
Gargano Promontory ◽  
Po Delta ◽  
Adriatic Basin

<p>The Adriatic basin represents one of several restricted basins located in the Mediterranean Area. It consists of the foreland of three different orogenic belts: the Dinarides to the East, active during the Eocene, the Southern Alps to the North, active since the Cretaceous time, and the Apennines to the West, active since the Paleogene. The Apennines had a primary role during the Messinian Salinity Crisis (MSC), conditioning the connection between the Adriatic basin, the Ionian basin, and the proto-Tyrrhenian basin. During the Messinian, the present Adriatic Sea was characterized by shallow water domains, where gypsum evaporites initially deposited and often successively incised or outcropped. </p><p>In the past 50 years, a massive dataset, composed of 2D multichannel seismic data and boreholes, was collected, covering almost the whole Adriatic basin in the Italian offshore. In this work, we interpreted the Plio-Quaternary base (PQb), based on available public datasets and on seismic profiles present in literature, which provided regional information from the northernmost Trieste Gulf (Northern Adriatic Sea) to the Otranto Channel (Southern Adriatic Sea). Here, we propose the PQb time-structural map, obtained by analyzing more than 600 seismic profiles. The PQb represents both the Messinian erosion and/or the top of the Messinian evaporites. It is characterized by a high-amplitude reflector, commonly called “horizon M” in the old literature. Principal findings concerning the Messinian event are summarized as below: </p><p>-The Northern Adriatic (Gulf of Trieste, Gulf of Venice, Po delta, Kvarner Area) reveals widespread channelized systems produced by the initial decrease of the sea level, followed by subaerial erosion, related to further sea level decrease. High-grade erosion involved the nearby Adriatic carbonate platform in the Croatian offshore, where deep valleys, filled with Last Messinian or post- Messinian sediments, cut through the limestones.</p><p>-The Central Adriatic (from the Po delta to the Gargano Promontory) displays a higher evaporites accumulation than the northern sector. Meanwhile, the Mid-Adriatic Ridge was already developing, along with the Apennine Chain, which was in a westernmost position. Erosional features in the deeper area are related to channelized systems, which followed the evaporites deposition. Meanwhile, also the Mid-Adriatic Ridge was affected by erosion.</p><p>-The Southern Adriatic (from the Gargano Promontory to the Otranto Channel) is characterized by the Mesozoic Apulia carbonate platform, covered by a thin Cenozoic sequence affected by subaerial erosion or non-deposition. The platform margin and the slope leading to the deepest South Adriatic basin, where a Messinian gypsum layer, also recorded in the Albanian and Croatian offshore, shows a lower level of upper erosion.</p><p>In general, we notice strongly variable thicknesses of the horizon M, which is related to submarine erosion (channels), subaerial erosion (discontinuous surfaces), non-deposition (possible unconformity), and tilting toward the surrounding chains (deepening horizons). In this work, we evaluate these different components from a regional point of view.  </p>

scholarly journals The biostratigraphic record of Cretaceous to Paleogene tectono-eustatic relative sea-level change in Jamaica

2018 ◽  
Author(s):  
David Patrick Gold ◽  
James P. G. Fenton ◽  
Manuel Casas-Gallego ◽  
Vibor Novak ◽  
Irene Pérez-Rodríguez ◽  
...  
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Carbonate Platform ◽  
Caribbean Region ◽  
Level Curve ◽  
Relative Sea Level ◽  
Carbonate Production ◽  
Platform Drowning ◽  
Relative Sea Level Rise ◽  
Strong Control

The island of Jamaica forms the northern extent of the Nicaraguan Rise, an elongate linear tectonic feature stretching as far as Honduras and Nicaragua to the south. Uplift and subaerial exposure of Jamaica during the Neogene has made the island rare within the Caribbean region, as it is the only area where rocks of the Nicaraguan Rise are exposed on land. Biostratigraphic dating and palaeoenvironmental interpretations using larger benthic foraminifera, supplemented by planktonic foraminifera, nannopalaeontology and palynology of outcrop, well and corehole samples has enabled the creation of a regional relative sea-level curve through identification of several depositional sequences. This study recognises ten unconformity-bounded transgressive-regressive sequences which record a complete cycle of relative sea level rise and fall. Sequences are recognised in the Early to ‘Middle’ Cretaceous (EKTR1), Coniacian-Santonian (STR1), Campanian (CTR1), Maastrichtian (MTR1-2), Paleocene-Early Eocene (PETR1), Eocene (YTR1-3) and Late Eocene-Oligocene (WTR1). These transgressive-regressive cycles represent second to fourth order sequences, although most tie with globally recognised third order sequences. Comparisons of the Jamaican relative sea-level curve with other published global mean sea-level curves show that local tectonics exerts a strong control on the deposition of sedimentary sequences in Jamaica. Large unconformities (duration >1 Ma) are related to significant regional tectonic events, with minor overprint of a global eustatic signal, while smaller unconformities (duration <1 Ma) are produced by global eustatic trends. The relatively low rates of relative sea-level rise calculated from the regional relative sea-level curve indicate that carbonate production rates were able to keep pace with the rate of relative sea-level rise accounting for the thick successions of Maastrichtian carbonates and those of the Yellow and White Limestone Groups. Carbonate platform drowning within the White Limestone Group during the Oligocene to Miocene is attributed to environmental deterioration given the low rates of relative sea-level rise.

scholarly journals Bio-Sequence Stratigraphy of Asmari Formation in the Southeast of Norabad (Zagros Basin, SW Iran)

2021 ◽  
Author(s):  
Mohammadsadegh Dehghanian
Keyword(s):  
Sea Level ◽  
Sequence Stratigraphy ◽  
Carbonate Platform ◽  
Reservoir Rock ◽  
Dispersion Pattern ◽  
Asmari Formation ◽  
Level Curve ◽  
Zagros Basin ◽  
Lithostratigraphic Units ◽  
Global Sea Level

Abstract Asmari Formation is the thick sequence of carbonate sediment in the range of Oligocene-Miocene which is deposited in the foreland basins of the Zagros and is considered as the original and most famous reservoir rock of Zagros basin. To study of lithostratigraphic units and sequence stratigraphy of this Formation, the section in the southeast of Norabad was selected. Field study indicated that Asmari Formation possessed the thickness of 401.5m and included 9 lithostratigraphic units. According to the study of microfacies, Stacking pattern and identification of main sequence level, three depositional sequences including two-second order and one-third order sequence were recognized. The sea-level curve in the studied section indicated that it was correspondence to the global sea level curve. These facies deposited in five environmental sedimentations as follow Open Sea Shelf (Fore Barrier), Bar, Lagoon, Back bar shelf, and Shoal. The environment is part of a carbonate platform that has been formed on an open shelf. In addition, according to the Study of foraminifer dispersion pattern the range of Asmari Formation in Norabad was suggested to be Oligocene (Rupelian- Chattian) to lower Miocene (Aquitanian- Burdigalian).

scholarly journals Ocean drilling constrains carbonate platform formation and Miocene sea level on the Australian margin

Eos ◽  
2001 ◽  
Vol 82 (41) ◽  
pp. 469-469 ◽  
Author(s):  
A. R. Isern ◽  
F. S. Anselmetti ◽  
P. Blum
Keyword(s):  
Sea Level ◽  
Carbonate Platform ◽  
Ocean Drilling
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