Results 111 to 120 of about 82,926 (239)

U-Pb Ages of Lunar Apatites [PDF]

open access: yes, 2006
Apatite is one of the minerals that is rarely utilized in U-Pb geochronology, compared to some other U-rich accessory phases. Relatively low U concentration, commonly high proportion of common Pb and low closure temperature of U-Pb system of apatite ...
Meyer, Charles   +3 more
core   +1 more source

Shoshonitic enclaves in the high Sr/Y Nyemo pluton, southern Tibet: Implications for Oligocene magma mixing and the onset of extension of the southern Lhasa terrane [PDF]

open access: yes, 2020
Post-collisional potassic and high Sr/Y magmatism in the Lhasa terrane provides critical constraints on the timing and mechanism of subduction of Indian lithosphere and its role in the uplift of the Tibetan Plateau.
Asimow, Paul D.   +8 more
core  

Geologic history of Martian regolith breccia Northwest Africa 7034: Evidence for hydrothermal activity and lithologic diversity in the Martian crust [PDF]

open access: yes, 2016
The timing and mode of deposition for Martian regolith breccia Northwest Africa (NWA) 7034 were determined by combining petrography, shape analysis, and thermochronology.
Adcock   +151 more
core   +3 more sources

Exploring the Gravimetric and Geochronological Links in Ancient Terranes of the São Francisco Craton and Borborema Province, NE‐Brazil

open access: yesTerra Nova, EarlyView.
ABSTRACT Deep crustal fragments and structural lineaments identified through satellite gravity data provide evidence for the extension of the reworked ancient basement of the Central African Block into the northern São Francisco Craton and southern Borborema Province.
Douglas Teixeira Martins   +3 more
wiley   +1 more source

Detrital zircon U-Pb geochronology and Hf isotope geochemistry of Paleozoic and Triassic passive margin strata of western North America

open access: yes, 2014
U-Pb geochronologic and Hf isotopic analyses have been conducted on detrital zircons extracted from 36 samples of Neoproterozoic through Triassic passive margin strata from western North America.
G. Gehrels, M. Pecha
semanticscholar   +1 more source

Tectonic overview of the West Gondwana margin [PDF]

open access: yes, 2008
The oceanic southern margin of Gondwana, from southern South America through South Africa, West Antarctica, New Zealand (in its pre break-up position), and Victoria Land to Eastern Australia is one of the longest and longest-lived active continental ...
Pankhurst, Robert J., Vaughan, Alan P.M.
core   +1 more source

Cryogenian Glacial Erosion and Tectonics as Agents of Crustal Recycling

open access: yesTerra Nova, EarlyView.
ABSTRACT Zircon preserves evidence of recycling processes that link surface environments to the mantle. Combined δ18O‐εHf in zircon fingerprints magmatic sources and tracks how crustal material is reworked over time. We apply statistical analyses to a global compilation that apparently resolves shifts in zircon U–Pb, δ18O, and Lu‐Hf data spanning the ...
M. Seraine   +9 more
wiley   +1 more source

Topographic Development History of the Alaska Range [PDF]

open access: yes, 2014
The overall goal of this project is to use variations in sediment source through time as a proxy for deciphering the uplift history of the Alaska Range (Fig. 1).
Davis, Kailyn N.
core  

High-precision U-Pb ages in the early Tithonian to early Berriasian and implications for the numerical age of the Jurassic-Cretaceous boundary [PDF]

open access: yes, 2019
The numerical age of the Jurassic-Cretaceous boundary has been controversial and difficult to determine. In this study, we present high-precision U-Pb geochronological data around the Jurassic-Cretaceous boundary in two distinct sections from different ...
Aguirre-Urreta, Maria Beatriz   +10 more
core   +1 more source

Near‐Synchronous Cambrian Evolution of the Transbrasiliano‐Kandi‐4°50′ Shear Zone in South America and Africa

open access: yesTerra Nova, EarlyView.
ABSTRACT The Transbrasiliano‐Kandi‐4°50′ (TK4) shear zone in western Gondwana crosscuts South America and NW Africa for at least 6000 km. Despite its impressive size, the timing of the main episode of dextral ductile shearing is uncertain. We present detailed in situ multi‐mineral geochronology of mylonites from both Brazil and Algeria supporting that ...
F. A. Caxito   +4 more
wiley   +1 more source

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