upper cretaceous
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2022 ◽  
Vol 12 (1) ◽  
Author(s):  
Márton Szabó ◽  
Robin Kundrata ◽  
Johana Hoffmannova ◽  
Tamás Németh ◽  
Emese Bodor ◽  
...  

AbstractFossil bioinclusions in amber are invaluable source of information on the past evolution and diversity of various organisms, as well as on the paleoecosystems in general. The click-beetles, Elateridae, which originated and greatly diversified during the Mesozoic, are mostly known from the adpression-like fossils, and their diversity in the Cretaceous ambers is only poorly documented. In this study, we describe a new click-beetle based on an incomplete inclusion in ajkaite, an Upper Cretaceous (Santonian) amber from the Ajka Coal Formation from Hungary. We used X-ray micro-computed tomography scanning to reconstruct its morphology because it is deposited in an opaque piece of amber. Our results suggest that the newly described Ajkaelater merkli gen. et sp. nov. belongs to subfamily Elaterinae. It represents the first Mesozoic beetle reported from Hungary, and the first Mesozoic Elateridae formally described from mainland Europe. Our discovery supports an Eurasian distribution and diversification of Elaterinae already in the Cretaceous. The paleoenvironment of the Ajka Coal Formation agrees well with the presumed habitat preference of the new fossil taxon. The discovery of a presumably saproxylic click-beetle shed further light on the yet poorly known paleoecosystem of the Santonian present-day western Hungary.


Geosciences ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 22
Author(s):  
Danuta Peryt ◽  
Zofia Dubicka ◽  
Weronika Wierny

Planktonic foraminifera are one of the most stratigraphically important groups of organisms for the Cretaceous system. However, standard foraminiferal zonations based mostly on species from the Tethyan bioprovince are hardly applicable in temperate regions where warm-water taxa are scarce or lacking. We propose a foraminiferal zonation based on foraminiferal events recognized in the northern Foraminiferal Transitional Bioprovince, which likely has a high correlation potential at least at a regional scale. Fifteen planktonic foraminiferal zones are distinguished from the upper Albian up to the uppermost Maastrichtian strata in extra-Carpathian Poland and western Ukraine. From the bottom to the top, Thalmanninella appenninica, Th. globotruncanoides, Th. reicheli, Rotalipora cushmani, Whiteinella archaeocretacea, Helvetoglobotruncana helvetica, Marginotruncana coronata, M. sinuosa, Pseudotextularia nuttalli, Globotruncana linneiana, G. arca, Contusotruncana plummerae, Rugoglobigerina pennyi, Globotruncanella petaloidea and Guembelitria cretacea. These zones are calibrated by macrofaunal zonations.


Author(s):  
Walaa A. Hassan ◽  
Ezzat A. Ahmed ◽  
Rashad Sawires ◽  
Mohamed A. Moneim ◽  
Mostafa R. Abukhadra

2022 ◽  
Vol 129 ◽  
pp. 104998
Author(s):  
Rodrigo V. Pêgas ◽  
Borja Holgado ◽  
Leonardo D. Ortiz David ◽  
Mattia A. Baiano ◽  
Fabiana R. Costa

2022 ◽  
pp. 105139
Author(s):  
Shiori Kanno ◽  
Sayaka Tokumaru ◽  
Shuhei Nakagaki ◽  
Yasuhisa Nakajima ◽  
Akihiro Misaki ◽  
...  
Keyword(s):  

2021 ◽  
Vol 54 (2F) ◽  
pp. 162-177
Author(s):  
Varoujan Sissakian ◽  
Ala Ghafur ◽  
Hawkar Abdulhaq ◽  
Hassan Omer

The Shakrook anticline has very a complicated structural form, this is attributed to three thrust faults, and the presence of four anticlinal axes with the main anticlinal body. The most northwest existing anticline is called in the current study the Sisawa anticline, the main two anticlines are called the Shakrook East and Shakrook West, whereas the fourth one is called the Biluk anticline it is developed along the southwestern limb of the Shakrook East anticline. The exposed rocks in the Shakrook anticline range from Upper Jurassic to the Paleogene age. The bulk of the main Shakrook anticline is formed by the Bekhme Formation (Upper Cretaceous age), whereas the bulk of the Sisawa anticline is formed of the Shiranish Formation (Upper Cretaceous age) with Paleogene and Neogene aged rocks. Geological maps and high-quality satellite images were used to elucidate the complex structural form of the Shakrook anticline. The updated geological map is quite different from those existing geological maps. A field investigation was carried out to check the interpreted data and to implement photography to the interested structural and geomorphological forms. Different geomorphological forms also were interpreted; they all refer to the lateral growth of the Shakrook anticline.


2021 ◽  
Vol 17 (43) ◽  
pp. 194
Author(s):  
Adekeye Olabisi Adeleye ◽  
Ogundipe Olumide ◽  
Adeoye James Adejimi ◽  
Adeyilola Adedoyin ◽  
Samuel Olukayode ◽  
...  

Upper Cretaceous shales partially exposed in the northern fringes of the Dahomey Basin are well developed in the subsurface in Southwestern part of the basin where Agbau-1 well is sited. These shales were evaluated in respect to their paleoenvironments and potentials for hydrocarbon using foraminiferal assemblages, biomarkers and Rock Eval pyrolysis studies. The dominance of benthonic foraminifera species suggests a shallow marine environment and high percentage of calcareous to arenaceous benthic www.eujournal.org 195foraminifera indicate high water salinity and hypersline environment. Dysoxic oxygen condition is also prevalent probably because most of the benthic foraminifera recovered are epifauna that live in a reduced oxygen condition. 1.90 wt%, 244 mgHC/gTOC and 429℃ average values of total organic carbon, hydrogen index and Tmax reveal that the Upper Cretaceous shales have relatively fair to good organic matter, predominantly Type II-III kerogen and currently immature. Though three is a trend of an increase in maturity down the hole. All the steranes have uniform distributions (C27>C28>C29), suggesting a relatively higher input from the marine red algae and a low level of land plant contribution to the source organic matter. Pristane/phytane ratios and C29/C27 steranes confirmed the organic matter type to be a Type II/III and anoxic source rock depositional condition as well as a reducing diagenetic system in the sediment water column. The Upper Cretaceous shales in Dahomey Basin can be targeted for exploration as an unconventional petroleum resource.


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