Results 1 to 10 of about 1,054 (150)

Bashkirian meganticlinorium: Late Riphean-Vendian hiatuses and possible transformations of basin provenances

open access: yesЛитосфера, 2020
The object of research. At the top of the Upper Riphean-Vendian sedimentary sequence of the Bashkirian meganticlinorium (western and central parts of the named structure, corresponding to the stratotypical locality of Riphean) there is a series of fairly
А. V. Maslov
doaj   +3 more sources

Proterozoic and early Cambrian protists: evidence for accelerating evolutionary tempo. [PDF]

open access: yesProc Natl Acad Sci U S A, 1994
In rocks of late Paleoproterozoic and Mesoproterozoic age (ca. 1700-1000 million years ago), probable eukaryotic microfossils are widespread and well preserved, but assemblage and global diversities are low and turnover is slow.
Knoll AH.
europepmc   +3 more sources

First Results of the Intraformational Conglomerate Test of the Late Riphean Katav Formation (Southern Urals)

open access: yesУчёные записки Казанского университета: Серия Естественные науки
Detailed petrographic, electron-microscopic, and paleomagnetic studies were conducted on flatbedded synsedimentary carbonate breccias from three blocks of rocks (one block from Minyar, two blocks from Katav-Ivanovsk) to verify the ideas about the time of
N. P. Parfiriev   +3 more
doaj   +2 more sources

Early eukaryotic microfossils of the late Palaeoproterozoic Limbunya Group, Birrindudu Basin, northern Australia

open access: yesPapers in Palaeontology, Volume 9, Issue 6, November/December 2023., 2023
Abstract Fine‐grained, siliciclastic units of the >1642 ± 3.9 Ma late Palaeoproterozoic Limbunya Group, Birrindudu Basin host rich, well‐preserved organic‐walled microfossil assemblages that include members of total‐group eukaryotes. These assemblages include taxa characteristic of this interval such as Tappania plana and Satka favosa, as well as less ...
Leigh Anne Riedman   +4 more
wiley   +1 more source

The role of siliciclastics in carbonate fabric diversity and preservation: A case study from the Neoproterozoic carbonate − siliciclastic Horse Thief Springs Formation, Death Valley

open access: yesSedimentology, Volume 69, Issue 5, Page 2284-2318, August 2022., 2022
Abstract The sedimentary record of the Pahrump Group in Death Valley comprises well‐exposed successions of mixed carbonate and siliciclastic deposits. Despite the abundance of studies focussing on the depositional dynamics of mixed carbonate – siliciclastic deposition in the Phanerozoic, the record of similar Proterozoic examples is comparatively ...
Daniel Smrzka   +7 more
wiley   +1 more source

Constraints on the origins of iron silicide spherules in ultrahigh‐temperature distal impact ejecta

open access: yesMeteoritics &Planetary Science, Volume 56, Issue 7, Page 1369-1405, July 2021., 2021
Abstract Terrestrially occurring iron silicide spherules, described in the geological literature for 160 years as cosmogenic and approved as “extraterrestrial” minerals by IMA CNMMN in 1984, so far have escaped any serious examination by meteoriticists.
Sergei Batovrin   +5 more
wiley   +1 more source

New data on oil and gas potential of the Vychegda Trough

open access: yesGeoresursy, 2020
This article is devoted to the problem of studying the petroleum potential of the underexplored territories of the European part of Russia, in particular, the Vychegda trough.
Tatyana V. Karaseva   +3 more
doaj   +1 more source

TIME CONSTRAINTS ON THE FORMATION OF THE KANDALAKSHA AND KERETSK GRABENS OF THE WHITE SEA PALEO-RIFT SYSTEM FROM NEW ISOTOPIC GEOCHRONOLOGICAL DATA

open access: yesГеодинамика и тектонофизика, 2021
Initially, the age and stratigraphic position of the Tersk formation were determined with respect to the fact that this formation overlaps the Early Proterozoic granitoids.
N. B. Kuznetsov   +10 more
doaj   +1 more source

A Cryptic Alternative for the Evolution of Hyphae

open access: yesBioEssays, Volume 42, Issue 6, June 2020., 2020
The current view that hyphae evolved about 400 million years ago when plants and fungi colonized land is challenged. Recent recognition of a deep biosphere fossil record provides an alternative view on hyphae: one where the fundamental functions of hyphae developed in ancient cryptic habitats and already where adapted for a terrestrial life‐style when ...
Magnus Ivarsson   +3 more
wiley   +1 more source

Chemostratigraphy of Neoproterozoic carbonates: implications for 'blind dating' [PDF]

open access: yes, 2001
The delta C-13(carb) and Sr-87/Sr-86 secular variations in Neoproteozoic seawater have been used for the purpose of 'isotope stratigraphy' but there are a number of problems that can preclude its routine use.
Aharon P.   +55 more
core   +1 more source

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