Results 51 to 60 of about 60,917 (227)

87Sr/86Sr chemostratigraphy of Neoproterozoic Dalradian limestones of Scotland and Ireland: constraints on depositional ages and time scales [PDF]

open access: yes, 2004
New calcite <sup>87</sup>Sr/<sup>86</sup>Sr data for 47 limestones from the metamorphosed and deformed Neoproterozoic-Cambrian Dalradian Supergroup of Scotland and Ireland are used to identify secular trends in seawater <sup>
Ellam, R.M.   +3 more
core   +1 more source

Thorncliffe Formation: A proglacial to subglacial lacustrine basin sequence, Greater Toronto Region, Canada

open access: yesBoreas, EarlyView.
Map of Lower sediment (LS) thickness is a surrogate for the distribution of Thorncliffe Formation (TF) and ~75% of TF thickness from the slope of Niagara Escarpment east to Brighton. Inset images show the LS sequence at the Don Valleys brickyards (DVBY) and undeformed TF sand and gravel (~15 m) below Newmarket Till (NT) at sites L and Co.
David R. Sharpe   +3 more
wiley   +1 more source

AGE CONSTRAINTS AND SOURCE AREAS FOR THE PRECAMBRIAN TO CAMBRIAN STRATA OF THE SOUTHERN YENISEI RIDGE (REDKOLESNAYA AND OSTROVNOY FORMATIONS)

open access: yesГеодинамика и тектонофизика, 2023
The Precambrian to Cambrian strata at the southwestern margin of the Siberian Platform are ubiquitously characterized by a gradual transition from red-colored alluvial and deltaic deposits to shallow-marine carbonates, reflecting a transgressive infill ...
V. V. Marusin   +3 more
doaj   +1 more source

Timing of Metamorphism and Deformation in the Neoarchean Quetico Metasedimentary Belt, Superior Craton, Constrained by Garnet Trace‐Element Mapping and Lu–Hf Geochronology

open access: yesJournal of Metamorphic Geology, EarlyView.
ABSTRACT The Quetico subprovince of the Superior Province is among the largest metasedimentary belts globally and provides evidence of tectonic processes at play during the final stages of Archean cratonization. Although previous studies have shown that deformation and metamorphism of the 2.7‐Ga turbiditic protolith resulted in regional subvertical ...
Adrian G. Rehm   +4 more
wiley   +1 more source

NEW CHRONOSTRATIC SCHEME OF SOUTH-EASTERN FENNOSCANDIA AND ITS USE IN THE PREPARATION OF SMALL-SCALE GEOLOGICAL MAPS OF THE PRECAMBRIAN REGIONS

open access: yesИзвестия высших учебных заведений: Геология и разведка, 2017
A new chronostratic scheme of South-East (SE) Fennoscandia has been developed, based on the International Stratigraphie Scale, taking into account some elements of the Common Stratigraphic Scale of Russia and the regional stratigraphic scheme of the ...
V. S. Kulikov   +2 more
doaj   +1 more source

Population and herbarium genomics provide a comprehensive framework for a revision of Microcoleus (Cyanobacteria)

open access: yesJournal of Phycology, EarlyView.
Abstract Microcoleus is a cosmopolitan, filamentous cyanobacterium and a key component of biological soil crusts—complex microbial communities essential for primary production in diverse terrestrial environments. Here, we performed a taxonomic revision of several species of Microcoleus based on a large population genomic dataset.
Svatopluk Skoupý   +7 more
wiley   +1 more source

Geology of the Northern Llano Uplift, Junction to Llano, Texas [PDF]

open access: yes, 2016
This year\u27s Texas Academy of Science Geology Field Trip will visit nine interesting locations in two different areas in the Texas Hill Country (Figure 1). In the first area we will look at the Cretaceous stratigraphy around Junction, Texas (Figures 1,
Barker, Chris, Nielson, R. LaRell
core   +1 more source

Structure and Depositional Environments of the Cenomanian–Coniacian Sequence in Crimea

open access: yesRussian Journal of Earth Sciences
This paper presents the results of a facies analysis of the Upper Cretaceous deposits in Southwestern and Central Crimea and a characterization of the Cenomanian–Coniacian sequence.
Shishlov Sergey Borisovich   +5 more
doaj   +1 more source

Earth's middle age [PDF]

open access: yes, 2014
This research was funded through Natural Environment Research Council (grant NE/J021822/1) and the APC was paid through the RCUK OA block grant.Earth's middle age, extending from 1.7 to 0.75 Ga, was characterized by environmental, evolutionary, and ...
Cawood, Peter Anthony   +1 more
core   +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

Home - About - Disclaimer - Privacy