Results 121 to 130 of about 138,394 (310)

Polymict melt‐bearing breccia dikes in the Morokweng impact structure formed by slip‐induced mechanical mixing of pseudotachylite and cataclasite along large‐displacement impact faults

Meteoritics &Planetary Science, EarlyView.
Abstract A core drilled through shocked and faulted Archean granitoid gneisses and dolerites in the eroded peak ring of the 70–80 km diameter Morokweng impact structure intersects multiple centimeter‐ to meter‐wide clastic‐matrix breccias containing a polymict clast population of lithic and mineral clasts and altered, millimeter‐ to centimeter ‐size ...
Roger L. Gibson, S'lindile S. Wela, Leonidas C. Vonopartis, Marco A. G. Andreoli   +3 more
wiley   +1 more source

Temporal relations between mineral deposits and global tectonic cycles [PDF]

, 2013
Natural Environment Research Council (grant NE/J021822/1) supported this research.Mineral deposits are heterogeneously distributed in both space and time, with variations reflecting tectonic setting, evolving environmental conditions, as in the ...
Cawood, Peter Anthony, Hawkesworth, Chris   +1 more
core   +2 more sources

Confirming the impact origin of the São Miguel do Tapuio structure, northeastern Brazil

Meteoritics &Planetary Science, EarlyView.
Abstract The São Miguel do Tapuio structure (SMT) is a remarkable, nearcircular feature of about 21 km diameter, centered at 5°37.6′ S, 41°23.3′ W in Piauí state, northeastern Brazil. The structure is located within the sedimentary strata of the Paleozoic–Mesozoic Parnaíba Basin and predominantly comprises sandstones of the Devonian Pimenteiras and ...
Alvaro Penteado Crósta, Neivaldo Araújo de Castro, Marcos Alberto Rodrigues Vasconcelos, Airton Natanael Coelho Dias, Ludovic Ferrière, Wolf Uwe Reimold, Ana Maria Góes, Jackson Alves Martins, Liliana Sayuri Osako, Raimundo Mariano Gomes Castelo Branco   +9 more
wiley   +1 more source

Testing the fidelity of zircon as a provenance indicator in fluvial‐fan successions: An example from the Palaeogene Colton Formation, Central Utah, USA

The Depositional Record
The stratigraphic, spatial and temporal variability of detrital zircon age populations in continental sedimentary successions is a critical tool in understanding palaeodrainage networks and how these systems distributed detritus within sedimentary basins.
Davide Carraro, Sean P. Gaynor, Dario Ventra, Alexey Ulyanov, Andrea Moscariello   +4 more
doaj   +1 more source

Natural Resources and Political Patronage in Africa: An Ethnicity Level Analysis

Review of Development Economics, EarlyView.
ABSTRACT We investigate the effect of resource discoveries on ethnicity‐level political patronage in Africa using a large geospatial dataset of 254 ethnic groups in 15 countries over the period 1960–2004. We find that the first (or single first) resource discovery in a virgin ethnic homeland increases the share of cabinet posts of that ethnicity.
Sambit Bhattacharyya, Nemera Mamo
wiley   +1 more source

Thermo‐Tectonic History of Archean Basement Rocks in the Aktash Tagh, Southeastern Tarim Craton: Constraints From Zircon U‐Pb, Zircon and Apatite Fission‐Track Dating

Geochemistry, Geophysics, Geosystems
Stable craton lithosphere can undergo complex tectonic events at its margins due to peripheral tectonic activity. In this study, we conducted a comprehensive analysis of zircon U‐Pb dating, apatite and zircon fission‐track thermochronology on the Aktash ...
Xiao Hu, Zhiyuan He, Ganqing Xu, Johan DeGrave, Rongfeng Ge, Guangwei Li, Wenbin Zhu   +6 more
doaj   +1 more source

Zircon ages in granulite facies rocks: decoupling from geochemistry above 850 °C?

Contributions to Mineralogy and Petrology, 2018
Granulite facies rocks frequently show a large spread in their zircon ages, the interpretation of which raises questions: Has the isotopic system been disturbed? By what process(es) and conditions did the alteration occur?
B. Kunz, D. Regis, M. Engi
semanticscholar   +1 more source

Microbially generated ferruginous crusts: A potential biosignature of continental input in coastal settings

Sedimentology, EarlyView.
ABSTRACT Thin ferruginous sandy crusts are common on top of sandstone beds in the Early Permian post‐glacial deposits of the Paraná Basin in southern Brazil. These crusts usually preserve wrinkle structures, suggesting that they might be a product of microbial mediation.
Patrícia Weschenfelder, Renata Guimarães Netto, Alisson Klayton Martins   +2 more
wiley   +1 more source

LATE DEVONIAN VERKHNEURALSK VOLCANIC-PLUTONIC ASSOCIATION (EAST MAGNITOGORSK PALEOISLAND ARC, SOUTH URALS): AGE, PETROLOGY, GEOCHEMISTRY, ORE POTENTIAL AND GEODYNAMIC SETTING [PDF]

Минералогия
The geology and petrogeochemical features of the Verkhneuralsk volcanic-plutonic association in the South Urals are characterized. The relevance of the work is determined by necessary analysis of magmatic evolution of the region to clarify ideas on ...
T. N. Surin
doaj   +1 more source

Disentangling palaeoecological and outcrop controls on MISS occurrence in c. 1 Ga fluvio‐lacustrine facies of the Diabaig Formation, Scotland

Sedimentology, EarlyView.
ABSTRACT The c. 1 Ga Diabaig Formation of north‐west Scotland preserves diverse lacustrine and fluvial facies and abundant microbial and non‐microbial surficial sedimentary features. 172.6 m of section was logged across seven localities to assess the distribution of microbially induced sedimentary structures (MISS) relative to lithofacies, substrate ...
Seán T. Herron, Neil S. Davies, William J. McMahon   +2 more
wiley   +1 more source