Results 71 to 80 of about 39,183 (233)
A tale of two microbialites: Stromatolites and microbially induced sedimentary structures
Sedimentology, EarlyView.ABSTRACT Microbialites are biosedimentary structures built by microbial mats. Five microbialite groups are distinguished: stromatolites, thrombolites, dendrolites, leiloites and microbially induced sedimentary structures (MISS). This contribution discusses the two most abundant microbialite groups in marine settings, stromatolites and MISS.
Nora Noffke, Stanley M. Awramik
wiley +1 more source
Dating mylonitic overprinting of ancient rocks
Communications Earth & Environment, 2023 The timing of deformation in ancient shear zones of the Akia Terrane, Greenland, is recorded by the Proterozoic Rb-Sr age of mylonitic biotite which is determined through collision cell laser ablation and inverse thermal history modelling.
Christopher L. Kirkland +6 more
doaj +1 more source
Recycling of the Proterozoic crystalline basement in the Coastal Block (Moroccan Meseta): New insights for understanding the geodynamic evolution of the northern peri-Gondwanan realm [PDF]
, 2018 Detrital zircon age spectra from the siliciclastic rocks of the Lalla Mouchaa Calcschists and El Jadida Dolomitic formations (the Coastal Block of the Moroccan Meseta) are dominated by Paleoproterozoic and Ediacaran ages.
El Attari, Ahmed +8 more
core +1 more source
A case for biotic morphogenesis of coniform stromatolites
, 2004 Mathematical models have recently been used to cast doubt on the biotic origin of stromatolites. Here by contrast we propose a biotic model for stromatolite morphogenesis which considers the relationship between upward growth of a phototropic or ...
Arp +28 more
core +1 more source
Proterozoic basins of Canada: Early Proterozoic sequences in Labrador
, 1981 Early Proterozoic ( Aphebian) sedimentary and volcanic rocks in Labrador are described from two tectonic belts: the Churchill Province of western Labrador, and the Makkovik Subprovince of eastern Labrador. The Aphebian in the Churchill Province is represented mainly by the Labrador Trough ( Kaniapiskau Supergroup) but also in the Laporte Croup, Lake ...
R J Wardle, D G Bailey
openaire +1 more source
Paradigm shift in determining Neoproterozoic atmospheric oxygen [PDF]
, 2016 ACKNOWLEDGMENTS We thank the Geological Survey of Australia for permission to sample the Empress 1A and Lancer 1 cores, the Natural Sciences and Engineering Research Council of Canada for financial support (grant #7961–15) of U.
Benison, Kathleen +7 more
core +3 more sources
, 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
Minerals in Afghanistan : the potential for gold [PDF]
, 2006 Gold has been worked in Afghanistan for centuries from many areas including Takhar province in the north and from Ghazni, Zabul, and Kandahar provinces in the south-west of the country.
Benham, Antony John, Coats, Stan
core
Frontiers in Earth Science, 2014 The recently discovered high, plume-like 3He/4He ratios at Rungwe Volcanic Province (RVP) in southern Tanzania, similar to those at the Main Ethiopian Rift in Ethiopia, strongly suggest that magmatism associated with continental rifting along the entire ...
Paterno R Castillo +3 more
doaj +1 more source
Earth science field work: Role and status [PDF]
, 1988 This essay contends that the outstanding contributions currently being made to the earth sciences by theoretical and laboratory endeavors increase rather than decrease the need for sound field observations.
Sharp, Robert P.
core +1 more source