scholarly journals Small-sized <i>Trochammina</i> assemblages in deep-water Eocene flysch deposits (Outer Carpathians, Poland) and their palaeoecological implications

2015 ◽  
Vol 34 (1) ◽  
pp. 1-19 ◽  
Author(s):  
Anna Waśkowska
Keyword(s):  
Deep Water ◽  
Global Climate ◽  
Early Eocene ◽  
Northern Margin ◽  
Western Tethys ◽  
Thermal Maximum ◽  
Energy Environment ◽  
Outer Carpathians ◽  
Tethys Ocean ◽  
C 50

Abstract. The global climate change in the early Eocene contributed significantly to the turnover of benthic foraminifera. A major extinction within agglutinated and calcareous forms and the occurrence of opportunistic assemblages resulted. The Trochammina material described here belongs to these post-crisis assemblages. Foraminiferal assemblages with numerous Trochammina species are identified within deep-water Eocene deposits of the Polish part of the Outer Carpathians. Trochammina reach up to 80% of the assemblages, the remainder consists of cosmopolitan agglutinated foraminifera, mainly Bathysiphon, Recurvoides, Paratrochamminoides and Trochamminoides. The low biodiversity (average number of species 24, of genera 15) and the presence of dwarf forms are the main characteristics of the assemblages. These assemblages occur predominantly in shales with numerous organic traces (lower Hieroglyphic beds), deposited in the Silesian Basin (Outer Carpathians) which was on the northern margin of the western Tethys Ocean during the early Eocene (Ypresian, c. 50 Ma). The Trochammina biofacies developed in the Silesian Basin after the Paleocene–Eocene Thermal Maximum crisis, and is dominated by opportunistic forms, mainly represented by mobile epifauna and shallow-water infauna, interpreted as a recolonizing assemblage in a low energy environment.

scholarly journals Palaeocene–Eocene deep water agglutinated foraminifera from the Numidian Flysch (Rif, Northern Morocco): their significance for the palaeoceanography of the Gibraltar gateway

1996 ◽  
Vol 15 (1) ◽  
pp. 1-19 ◽  
Author(s):  
Michael A. Kaminski ◽  
Wolfgang Kuhnt ◽  
Jon D. Radley
Keyword(s):  
North Atlantic ◽  
Deep Water ◽  
Early Eocene ◽  
Long Distance ◽  
Western Tethys ◽  
The North ◽  
The North Atlantic ◽  
Stratigraphic Ranges ◽  
Tethys Ocean ◽  
Agglutinated Foraminifera

Abstract. A lower bathyal to abyssal agglutinated foraminiferal fauna (over 78 taxa belonging to 31 genera) is documented from Palaeocene–Eocene deep-water sediments of the Numidian Flysch (Talaa Lakrah Unit) in Northern Morocco. The sample locality is adjacent to the Strait of Gibraltar, which comprised an oceanic ‘gateway’ between the Tethys Ocean and the North Atlantic during the Palaeogene. The chronostratigraphy of the section is based upon long-distance comparisons with the stratigraphic ranges of identified species in the North Atlantic region and the Polish Carpathians. Although no major evolutionary turnover among deep-water agglutinated foraminifera (DWAF) is observed across the Palaeocene/Eocene boundary, a change from Palaeocene Aschemocella- and Trochamminoides-dominated assemblages to an early Eocene Glomospira assemblage is recognized. This Glomospira biofacies occurs throughout the North Atlantic and western Tethys and may indicate lowered productivity and widespread oxygenated deep-water conditions during the early Eocene greenhouse conditions. A change to an overlying Reticulophragmium amplectens biofacies in green claystones reflects renewed higher productivity. Taxonomic affinities and the succession of benthic foraminiferal assemblages from the Gibraltar gateway display greater affinities to Tethyan assemblages than North Atlantic assemblages. This is interpreted as faunal evidence for a late Palaeocene to early Eocene equivalent of ‘Mediterranean outflow water’, flowing from the western Tethys into the Atlantic.

The Smithian–Spathian boundary in North Greenland: implications for extreme global climate changes

2019 ◽  
Vol 157 (10) ◽  
pp. 1547-1567 ◽  
Author(s):  
Sofie Lindström ◽  
Morten Bjerager ◽  
Peter Alsen ◽  
Hamed Sanei ◽  
Jørgen Bojesen-Koefoed
Keyword(s):  
Climate Changes ◽  
Global Climate ◽  
Climatic Conditions ◽  
Seasonal Precipitation ◽  
Northern Margin ◽  
Global Climate Changes ◽  
Thermal Maximum ◽  
Global Cooling ◽  
North Greenland ◽  
Red Bed

AbstractSmithian–lower Anisian strata in Peary Land, North Greenland, were deposited at ∼45° N on the northern margin of Pangaea in offshore to upper shoreface settings. The well-constrained succession (palynology and ammonite biostratigraphy) documents a remarkable shift from lycophyte spore-dominated assemblages in the upper Smithian to gymnosperm pollen-dominated ones in the lower Spathian in concert with a marked shift of +6 ‰ in δ13Corg. Correlation with other Smithian–Spathian boundary sections that record terrestrial floral changes indicates that the recovery of gymnosperms began earlier in the mid-latitudes of the Southern Hemisphere than in the Northern Hemisphere. The lycophyte-dominated Late Smithian Thermal Maximum is here interpreted as reflecting dry and hot climatic conditions with only brief seasonal precipitation unable to sustain large areas of gymnosperm trees, but able to revive dehydrated lycophytes. This suggests that the Late Smithian Thermal Maximum was a time of widespread aridity, which is also supported by red bed deposition in many areas globally, even as far south as Antarctica. The shift to gymnosperm-dominated vegetation during the cooling across the Smithian–Spathian boundary reflects a change to seasonally more humid climatic conditions favouring gymnosperm recovery, and could have been initiated by increased albedo over land due to the widespread aridity during the Late Smithian Thermal Maximum. The recovery of gymnosperm vegetation would have helped to draw down CO2 from the atmosphere and exacerbate global cooling.

Oceanic Anoxic Event 1d (late Albian) in deep-water sediments of the Outer Carpathians, Poland; Carbon isotope and agglutinated foraminiferal records

2021 ◽  
Author(s):  
Krzysztof Bąk ◽  
Górny Zbigniew ◽  
Marta Bąk
Keyword(s):  
Carbon Isotope ◽  
Deep Water ◽  
Environmental Parameters ◽  
Taxonomic Composition ◽  
Black Shales ◽  
Feeding Strategies ◽  
Western Tethys ◽  
Oceanic Anoxic Event ◽  
Lithostratigraphic Units ◽  
Outer Carpathians

&lt;p&gt;The Albian&amp;#8211;Cenomanian transition is stratigraphically still poorly constrained in deep-water environments below the CCD. For this reason, the recognition of the OAE1d in such sedimentary records is extremely rare. Our high-resolution carbon-isotope (&amp;#948;&lt;sup&gt;13&lt;/sup&gt;C&lt;sub&gt;org&lt;/sub&gt;) stratigraphy of the Upper Albian and Lower Cenomanian turbidite/hemipelagic succession, accumulated in the marginal Silesian Basin of the Western Tethys, made it possible to identify the interval corresponding to the OAE1d. It has been recognized within two lithostratigraphic units of the Silesian Nappe of the Outer Carpathians (the Lower and Middle Lgota Beds), which are composed mostly of turbidite sediments containing a large amount of bioclastic material occurring in the silty and sandy fraction (locally over 70%). Bioclasts were redeposited from marginal shelf of the European Platform. The hemipelagic non-calcareous claystones which separate the turbidite sequences contain deep-water agglutinated foraminiferal (DWAF) assemblages, and are devoid of calcareous benthic foraminifers.&lt;/p&gt;&lt;p&gt;Using the analysis of the DWAF morphogroups, as well as changes in the benthos abundance and its taxonomic composition in relation to the characteristics (colour and TOC content) of hemipelagic sediments, we indicated changes in the environmental conditions that took place during the OAE1d at the bottom of the Silesian Basin. The most abundant horizons of organic-rich shales are characteristic of the lower part of the OAE1d succession corresponding to the Pialli Level from the Umbria-Marche Basin, although thin intercalations of black shales are also present along the upper part of this succession, where the hemipelagic sediments are dominated by green-coloured shales. The variability of organic matter in the studied sediments only slightly correlates with the abundance of the DWAFs and with their taxonomic composition. The more visible features in the latest Albian agglutinated benthos concern relative proportions of foraminiferal morphogroups which correspond to life-style and feeding strategies, and in this way reflect changes in selected environmental parameters. It seems that fluctuations in the morphogroup distribution along the OAE1d succession reflects the influence of two groups of factors: (i) oxygen concentration in bottom waters (low in the older part of the OAE1d, with fluctuations in the younger part of this isotope event), and (ii) the organic carbon flux that was linked to the onset of a massive redeposition of biogenic material from the European shelf. The last factor is related to the sea level fall during the 3-rd order regressive cycle.&lt;/p&gt;

scholarly journals Paleocene-Eocene volcanic segmentation of the Norwegian-Greenland seaway reorganized high-latitude ocean circulation

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Jussi Hovikoski ◽  
Michael B. W. Fyhn ◽  
Henrik Nøhr-Hansen ◽  
John R. Hopper ◽  
Steven Andrews ◽  
...  
Keyword(s):  
Ocean Circulation ◽  
High Latitude ◽  
Seismic Reflection ◽  
Arctic Region ◽  
Climatic Conditions ◽  
The Arctic ◽  
Early Eocene ◽  
Subaerial Exposure ◽  
Thermal Maximum ◽  
Volcanic Facies

AbstractThe paleoenvironmental and paleogeographic development of the Norwegian–Greenland seaway remains poorly understood, despite its importance for the oceanographic and climatic conditions of the Paleocene–Eocene greenhouse world. Here we present analyses of the sedimentological and paleontological characteristics of Paleocene–Eocene deposits (between 63 and 47 million years old) in northeast Greenland, and investigate key unconformities and volcanic facies observed through seismic reflection imaging in offshore basins. We identify Paleocene–Eocene uplift that culminated in widespread regression, volcanism, and subaerial exposure during the Ypresian. We reconstruct the paleogeography of the northeast Atlantic–Arctic region and propose that this uplift led to fragmentation of the Norwegian–Greenland seaway during this period. We suggest that the seaway became severely restricted between about 56 and 53 million years ago, effectively isolating the Arctic from the Atlantic ocean during the Paleocene–Eocene thermal maximum and the early Eocene.

The Heterogeneous Tethyan Oceanic Lithosphere of the Alpine Ophiolites

Elements ◽  
2021 ◽  
Vol 17 (1) ◽  
pp. 23-28 ◽  
Author(s):  
Elisabetta Rampone ◽  
Alessio Sanfilippo
Keyword(s):  
Oceanic Lithosphere ◽  
Passive Margin ◽  
Crustal Material ◽  
Crustal Accretion ◽  
Mantle Dynamics ◽  
Western Tethys ◽  
Mantle Peridotites ◽  
Slow Spreading ◽  
Tethys Ocean ◽  
Basaltic Crust

The Alpine–Apennine ophiolites are lithospheric remnants of the Jurassic Alpine Tethys Ocean. They predominantly consist of exhumed mantle peridotites with lesser gabbroic and basaltic crust and are locally associated with continental crustal material, indicating formation in an environment transitional from an ultra-slow-spreading seafloor to a hyperextended passive margin. These ophiolites represent a unique window into mantle dynamics and crustal accretion in an ultra-slow-spreading extensional environment. Old, pre-Alpine, lithosphere is locally preserved within the mantle sequences: these have been largely modified by reaction with migrating asthenospheric melts. These reactions were active in both the mantle and the crust and have played a key role in creating the heterogeneous oceanic lithosphere in this branch of the Mesozoic Western Tethys.

The dire straits of Paratethys: Gateways to the anoxic giant of Eurasia

2021 ◽  
pp. SP523-2021-73
Author(s):  
D. V. Palcu ◽  
W. Krijgsman
Keyword(s):  
Carbon Sink ◽  
Global Climate ◽  
Water Masses ◽  
Source Rocks ◽  
Global Ocean ◽  
Tectonic Processes ◽  
Anoxic Environments ◽  
Geological Evolution ◽  
History Of ◽  
Tethys Ocean

AbstractA complex interplay of palaeoclimatic, eustatic and tectonic processes led to fragmentation and dissipation of the vast Tethys Ocean in Eocene-Oligocene times. The resulting Paratethys Sea occupied the northern Tethys region on Eurasia, grouping water masses of various subbasins, separated from each other and from the open ocean through narrow and shallow gateways and land bridges. Changes in marine gateway configuration and intra-basinal connectivity affected the regional hydrology, shifting most Paratethyan basins to extreme carbon-sink anoxic environments, anomalohaline evaporitic or brackish conditions or even endorheic lakes. Paratethys gateway restriction triggered the onset of a long-lasting (∼20 Myr) giant anoxic sea, characterised by stratified water masses and anoxic bottom water conditions, resulting in thick hydrocarbon source rocks. Here, we review the geological evolution of the “dire straits” of Paratethys that played a crucial role in the Eocene-Oligocene connectivity history of the Central Eurasian seas and we show that the main anoxic phases (Kuma and Maikop) correspond to restricted connectivity with the global ocean and a period of CO2 depletion in the atmosphere. Paratethys represents one of the largest carbon sinks of Earth's history and may thus have played a prominent role in global climate change.

scholarly journals Scaled biotic disruption during early Eocene global warming events

2012 ◽  
Vol 9 (11) ◽  
pp. 4679-4688 ◽  
Author(s):  
S. J. Gibbs ◽  
P. R. Bown ◽  
B. H. Murphy ◽  
A. Sluijs ◽  
K. M. Edgar ◽  
...  
Keyword(s):  
Climate Change ◽  
Carbon Cycle ◽  
Threshold Value ◽  
Early Eocene ◽  
Natural Experiments ◽  
Thermal Maximum ◽  
Carbon Release ◽  
Long Time ◽  
Extinction Events ◽  
The Relationship

Abstract. Late Paleocene and early Eocene hyperthermals are transient warming events associated with massive perturbations of the global carbon cycle, and are considered partial analogues for current anthropogenic climate change. Because the magnitude of carbon release varied between the events, they are natural experiments ideal for exploring the relationship between carbon cycle perturbations, climate change and biotic response. Here we quantify marine biotic variability through three million years of the early Eocene that include five hyperthermals, utilizing a method that allows us to integrate the records of different plankton groups through scenarios ranging from background to major extinction events. Our long time-series calcareous nannoplankton record indicates a scaling of biotic disruption to climate change associated with the amount of carbon released during the various hyperthermals. Critically, only the three largest hyperthermals, the Paleocene–Eocene Thermal Maximum (PETM), Eocene Thermal Maximum 2 (ETM2) and the I1 event, show above-background variance, suggesting that the magnitude of carbon input and associated climate change needs to surpass a threshold value to cause significant biotic disruption.

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