Results 11 to 20 of about 12,911 (237)

Large Igneous Province Record Through Time and Implications for Secular Environmental Changes and Geological Time‐Scale Boundaries

open access: yesGeophysical Monograph Series, Page 1-26., 2021

Exploring the links between Large Igneous Provinces and dramatic environmental impact

An emerging consensus suggests that Large Igneous Provinces (LIPs) and Silicic LIPs (SLIPs) are a significant driver of dramatic global environmental and biological changes, including mass extinctions.
Richard E. Ernst   +8 more
wiley  

+12 more sources

Sequence stratigraphy in Proterozoic successions

open access: yesGeology, 1988
Sedimentological logging and facies mapping have been used to identify depositional sequences bounded by subtle but regionally persistent unconformities in rocks of Proterozoic age in the western United States, South Australia, and northwestern Canada. We conclude from these studies that the sequence stratigraphic approach is of considerable importance
Christie-Blick, Nicholas   +2 more
openaire   +4 more sources

Morphometric convergence between Proterozoic and post-vegetation rivers [PDF]

open access: yesNature Communications, 2017
It has been previously assumed that deep river channels could not have developed in the Proterozoic due to lack of vegetation. Here, the authors present remote sensing and outcrop data to show that large scale and deeply channelled river networks did ...
Alessandro Ielpi   +3 more
doaj   +2 more sources

Precambrian glaciations and the evolution of the atmosphere [PDF]

open access: yesAnnales Geophysicae, 1994
Precambrian glaciations appear to be confined to two periods, one in the early Proterozoic between 2.5 and 2 Gyears BP (Before Present) and the other in the late Proterozoic between 1 and 0.57 Gyear BP. Possible reasons for these broad features of the
J. H. Carver, I. M. Vardavas
doaj   +1 more source

On the ages of some granitoid and schist complexes in northern Finland [PDF]

open access: yesBulletin of the Geological Society of Finland, 1982
Contact observations and most radiometric datings indicate that the large complex of granitoid rocks and migmatites in Central Lapland is late Svecokarelian (Proterozoic) in age. The geological setting of the complex suggests, however, that it previously
R. Lauerma
doaj   +1 more source

Earth's anomalous middle-age magmatism driven by plate slowdown

open access: yesScientific Reports, 2022
The mid-Proterozoic or "boring billion" exhibited extremely stable environmental conditions, with little change in atmospheric oxygen levels, and mildly oxygenated shallow oceans.
C. O’Neill   +3 more
doaj   +1 more source

Long-term memory of subduction processes in the lithospheric mantle: evidence from the geochemistry of basic dykes in the Gardar Province of South Greenland [PDF]

open access: yes, 2002
The rift-related magmas of the Proterozoic Gardar Igneous Province were emplaced across the contact between the South Greenland Archaean craton and the Palaeoproterozoic Ketilidian mobile belt.
R. M. Ellam   +6 more
core   +1 more source

Phase Diagrams of Carbonate Materials at High Pressures, with Implications for Melting and Carbon Cycling in the Deep Earth

open access: yesGeophysical Monograph Series, Page 137-165., 2020

This book is Open Access. A digital copy can be downloaded for free from Wiley Online Library.

Explores the behavior of carbon in minerals, melts, and fluids under extreme conditions

Carbon trapped in diamonds and carbonate-bearing rocks in subduction zones are examples of the continuing exchange of substantial carbon ...
Konstantin Litasov   +3 more
wiley  

+2 more sources

Not armour, but biomechanics, ecological opportunity and increased fecundity as keys to the origin and expansion of the mineralized benthic metazoan fauna [PDF]

open access: yes, 2005
This paper offers a new biotic interaction hypothesis for the Cambrian 'explosion' of mineralized, benthic, metazoan diversity. It proposes that organic-mineral composite structures (e.g.
Cohen, B.L.
core   +1 more source

A revision of the Proterozoic-Archean boundary of the Northern Bothnian schist belt with a discussion of the geochemistry of related basic metavolcanics [PDF]

open access: yesBulletin of the Geological Society of Finland, 1986
Geophysical analysis suggests the need for a revision of the eastern border of the early Proterozoic Northern Bothnian (or Kiiminki) schist belt. Recent geological field work has revealed places where the discordance and hiatus between Proterozoic and ...
Y. Kähkonen, E. Mattila, J. Nuutilainen
doaj   +1 more source

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