Results 71 to 80 of about 62,830 (237)

A Classification of Protective Structures in Fossil Bryozoans

open access: yesУчёные записки Казанского университета: Серия Естественные науки
The protective structures of bryozoans representing four orders—Trepostomata, Cryptostomata, Fenestrata, and Cheilostomata—were analyzed and classified for the first time based on functional criteria.
Z. A. Tolokonnikova   +2 more
doaj   +1 more source

Determining impact angle from the spatial distribution of shock metamorphism: A case study of the Gosses Bluff (Tnorala) impact structure, Australia

open access: yesMeteoritics &Planetary Science, EarlyView.
Abstract The majority of planetary impacts occur at oblique angles. Impact structures on Earth are commonly eroded or buried, rendering the identification of the direction and angle of impact—using methods such as asymmetries in ejecta distribution, surface topographic expression, central uplift structure, and geophysical anomalies—challenging. In this
Eloise E. Matthews   +5 more
wiley   +1 more source

Conellae, enigmatic structures on cephalopod shells—shapes, distribution, and formation [PDF]

open access: yes, 2019
Conellae, enigmatic cone-shaped structures which can be found on the surface of internal moulds of cephalopod shells (predominantly of ammonoids), are regarded herein as the product of remote (biologically induced) biomineralization formed in closed-off ...
Hoffmann, René   +2 more
core   +1 more source

Formation Conditions and Hydrocarbons Generation Potential of Oil Source Rocks of South Tatar Arch and Surrounding Areas

open access: yesGeoresursy
The work studied the lithological and geochemical characteristics of oil and gas source rocks of the central part of the Volga-Ural oil and gas bearing province.
A. S. Khayuzkin   +6 more
doaj   +1 more source

Fascinating single‐cell red algae: models for evolution and adaptation

open access: yesNew Phytologist, EarlyView.
Summary The unicellular red algae, Cyanidiophyceae, that diverged early during Archaeplastida (algal and plant) evolution, occupy a variety of extreme habitats that are inhospitable for most other eukaryotes. With the use of modern genomics and genetics methods, Cyanidiophyceae show a remarkable taxonomic diversity, share haplodiplophasic life cycles ...
Frédéric Berger   +13 more
wiley   +1 more source

First U–Pb LA-ICP-MS Radioisotopic Ages of the Devonian–Carboniferous Boundary Black Shales (Domanik Facies) in the Kama–Kinel Trough System, Volga–Ural Petroleum Province, East European Platform

open access: yesGeoresursy
For the first time, zircons from thin volcanic ash layers contained within organic-rich black shales (Domanik facies) at the Devonian–Carboniferous boundary have been dated using the U–Pb LA-ICP-MS method.
V. V. Silantiev   +7 more
doaj   +1 more source

The making of pure quartzose sand in continental interiors: Paraná River (Brazil and Argentina)

open access: yesSedimentology, EarlyView.
ABSTRACT As part of a comprehensive project on sedimentary processes in South America, this study focuses on sediment generation in the intracratonic Paraná Basin and monitors the evolution of sand composition along the Paraná River from central Brazil to the Río de la Plata estuary in Argentina.
Eduardo Garzanti   +5 more
wiley   +1 more source

Late Devonian-Carboniferous tectonic evolution within the Firth of Forth, Midland Valley : as revealed from 2D seisimic reflection data [PDF]

open access: yes, 2003
Results of integrated seismic mapping, within the Firth of Forth in the offshore Midland Valley of Scotland, are presented and illustrate aspects of the subsurface structure and tectonic evolution of the Upper Devonian to Carboniferous succession ...
Browne, M.A.E.   +3 more
core  

The Mesozoic along-strike tectono-metamorphic segmentation of Longmen Shan (eastern Tibetan plateau) [PDF]

open access: yes, 2018
The Longmen Shan belt (eastern border of the Tibetan plateau) constitutes a tectonically active region as demonstrated by the occurrence of the unexpected 2008 Mw 7.9 Wenchuan and 2013 Mw 6.6 Lushan earthquakes in the central and southern parts of the ...
A. Robert   +80 more
core   +3 more sources

Convergent allometric trajectories in Devonian Carboniferous unornamented Polygnathus conodonts [PDF]

open access: yesActa Palaeontologica Polonica
The shape of feeding structures is reputed to be under functional constraints related to the processing of food particles. Their morphological variation through evolution and ontogeny may thus provide an insight into changes in occlu sal dynamics and ...
FÉLIX NESME   +3 more
doaj   +1 more source

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