Results 71 to 80 of about 16,733 (259)

Mountain‐top spherules: Criteria to identify natural and synthetic particles

open access: yesMeteoritics &Planetary Science, EarlyView.
Abstract Natural microspherules are important tracers of geologic and environmental processes in modern and ancient deposits. However, anthropogenic contamination can dilute natural collections by releasing synthetic microspherules into the environment.
M. R. Boyd, M. J. Genge
wiley   +1 more source

SHRIMP U-Pb Geochronology of the Socorro Batholith and implications for the Neoproterozoic evolution in SE Brazil

open access: yesBrazilian Journal of Geology
: The Socorro Batholith is one of the most expressive granite manifestations associated with the Neoproterozoic evolution in SE Brazil, occupying large areas (~1,200 km 2 ) in the southern portion of the Socorro-Guaxupé Nappe.
Bárbara Bueno Toledo   +2 more
doaj   +1 more source

Mineral chemistry of late Variscan gabbros from central Spain: constraints on crystallisation processes and nature of the parental magmas [PDF]

open access: yes, 2015
© 2016. Universidad Complutense de Madrid. The commercial rights of the printed and online versions of Journal of Iberian Geology are property of the Universidad Complutense de Madrid (UCM) and the Consejo Superior de Investigaciones CientÍficas (CSIC),
Jeffries, T   +3 more
core   +3 more sources

Sedimentology of silica granules and haematite in the 3.47 Ga Antarctic Creek Member, Mount Ada Basalt, Western Australia

open access: yesSedimentology, EarlyView.
ABSTRACT The Paleoarchean Antarctic Creek Member of the Mount Ada Basalt, Eastern Pilbara Terrane, Western Australia, includes beds of jasper and white chert composed of sand‐sized silica granules that often contain or are mixed with silt‐sized particles of haematite.
Donald R. Lowe, Gary R. Byerly
wiley   +1 more source

U-Pb and 40Ar/39Ar geochronology of the coastal Sonora batholith: New insights on Laramide continental arc magmatism

open access: yesRevista Mexicana de Ciencias Geológicas, 2018
The coastal Sonora batholith comprises a series of Cretaceous granitoids that intruded a metasedimentary basement of possible Mesozoic age. They are partially covered by Tertiary volcanic flows and pyroclastic rocks.
Ernesto Ramos-Velázquez   +5 more
doaj  

Nature of the Coast Batholith, Southeastern Alaska: Are there Archean analogs [PDF]

open access: yes
The comparison of Phanerozoic Andean margins and their possible Archean analogs was made. Geochemical and isotopic data was presented for the episodic intrusion of the elongate, continental margin Coast batholith of southeastern Alaska and British ...
Arth, J. G., Barker, Fred
core   +1 more source

Ductile Extrusion Triggered by Continental Collision in NE Brazil

open access: yesTerra Nova, EarlyView.
ABSTRACT The Borborema Province in northeastern Brazil hosts one of the world's largest strike‐slip shear zone networks, active during the late Neoproterozoic assembly of West Gondwana. Whether these shear zones initiated during active continental collision or as a post‐orogenic response to far‐field stresses remains debated.
L. R. Tesser   +6 more
wiley   +1 more source

Petrographic Control on the Geomorphological Evolution of the Quixeramobim River Batholith, Northeastern Brazil

open access: yesRevista Brasileira de Geomorfologia
Petrographic control has a strong influence on the geomorphological evolution of granitic plutons in the Borborema Province (Northeast Brazil), which are made up of varied natures, shapes and dimensions.
Antonio Edvanio Anastacio Souza   +4 more
doaj   +1 more source

Fluid evolution from quartz veins in micaschists from the thermal aureole around the Acari batholith, Northeast Brazil

open access: yesGeologia USP. Série Científica, 2021
Micaschists that host the Acari batholith (Ediacaran age, 572 to 577 My) are characterized by a large number of quartz veins. The veins are more abundant in higher-temperature metamorphic zones and, together with lower metamorphic zones, form an aureole ...
Laécio Cunha de Souza   +2 more
doaj  

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.
Ellam, R.M.   +2 more
core   +2 more sources

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