نتایج جستجو برای: late neoproterozoic

تعداد نتایج: 196368  

2005
David Pollard James F. Kasting

[1] The late Neoproterozoic era, 600–800 Myr ago, was marked by at least two intervals of widespread cold that left glacial deposits at low paleolatitudes. Both ‘‘Snowball’’ solutions with global ice cover and ‘‘Slushball’’ solutions with ice-free tropical oceans have been proposed to explain the paleomagnetic data. The Snowball model is best able to explain the auxiliary geological evidence, p...

2015
Qiming Mei Volodymyr Dvornyk Nicholas S Foulkes

BACKGROUND Photolyases and cryptochromes are evolutionarily related flavoproteins, which however perform distinct physiological functions. Photolyases (PHR) are evolutionarily ancient enzymes. They are activated by light and repair DNA damage caused by UV radiation. Although cryptochromes share structural similarity with DNA photolyases, they lack DNA repair activity. Cryptochrome (CRY) is one ...

Journal: :زمین شناسی اقتصادی 0
مرتضی چشمه سری علی عابدینی اکرم علیزاده سید محمد موسوی

the dalir phosphate horizon is located ~57 km southwest of chalous, mazandaran province. the horizon developed as stratiform within upper shale of soltanieh formation (late neoproterozoic - early cambrian). according to mineralogical data, the major minerals of the phosphate horizon are calcite, fluorapatite, dolomite, quartz, pyrite, muscovite, and illite. microscopic evidence such as existenc...

Journal: :Science Advances 2021

Early Paleozoic bottom waters were mainly ferruginous, like the Neoproterozoic, with a shift to increased euxinia in Devonian.

2012
NICHOLAS L. SWANSON-HYSELL ADAM C. MALOOF JOSEPH L. KIRSCHVINK DAVID A. D. EVANS GALEN P. HALVERSON MATTHEW T. HURTGEN

The supercontinent Rodinia is hypothesized to have been assembled and positioned in tropical latitudes by the early Neoproterozoic Era. Paleomagnetic data from limestones of Svalbard and basaltic dikes of South China have been interpreted to record rapid changes in paleogeography driven by true polar wander that may have rotated the supercontinent in association with the 800 Ma Bitter Springs c...

2003
Frank A. Corsetti Alan J. Kaufman

An unusual richness of biogeochemical events is recorded in Neoproterozoic– Cambrian strata of the Death Valley region, California, United States. Eight negative carbon isotope (d13C) excursions are found in carbonate units between 1.08 Ga and the Precambrian/Cambrian boundary; four of these excursions occur in carbonates that contain textural features similar to those found globally in postgla...

2017
Andrew H. Knoll Martin A. Nowak

The integration of fossils, phylogeny, and geochronology has resulted in an increasingly well-resolved timetable of evolution. Life appears to have taken root before the earliest known minimally metamorphosed sedimentary rocks were deposited, but for a billion years or more, evolution played out beneath an essentially anoxic atmosphere. Oxygen concentrations in the atmosphere and surface oceans...

Journal: :Minerals 2021

The Terra Nova Intrusive Complex (TNIC) in northern Victoria Land, Antarctica, results from widespread magmatism during the Early Paleozoic Ross Orogeny. According to field relationships, geochemistry, and geochronology data, part of TNIC comprises Browning Unit (BIU), which is associated with an arc crustal melting including migmatization Wilson Metamorphic Complex, later Campbell (CIU), attri...

Journal: :Proceedings of the National Academy of Sciences 2018

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