LITHOSPHERIC ARCHITECTURE AND TECTONIC EVOLUTION OF THE SOUTHWESTERN U.S. CORDILLERA: CONSTRAINTS FROM ZIRCON HF AND O ISOTOPIC DATA

2018 ◽  
Author(s):  
James B. Chapman ◽  
◽  
Michelle Nikolay Dafov ◽  
George E. Gehrels ◽  
Mihai N. Ducea ◽  
...  
Keyword(s):  
Tectonic Evolution ◽  
Isotopic Data

Ordo-Silurian assemblage in the Indochina interior: Geochronological, elemental, and Sr-Nd-Pb-Hf-O isotopic constraints of early Paleozoic granitoids in South Laos

2020 ◽  
Vol 133 (1-2) ◽  
pp. 325-346 ◽  
Author(s):  
Yuejun Wang ◽  
Yuzhi Zhang ◽  
Xin Qian ◽  
Vongpaseuth Senebouttalath ◽  
Yang Wang ◽  
...  
Keyword(s):  
Tectonic Evolution ◽  
High Field ◽  
Igneous Rocks ◽  
Early Paleozoic ◽  
Isotopic Data ◽  
High Field Strength ◽  
Tectonic Zone ◽  
Type Granite ◽  
Juvenile Crust ◽  
South Tibet

Abstract In order to verify the early Paleozoic accretionary assemblage in the Indochina interior and constrain the Prototethyan tectonic evolution in Southeast Asia, this study presents a set of new U-Pb geochronological, elemental, and Sr-Nd-Pb-Hf-O isotopic data for the fifty-two representative granitoids in South Laos. The granitoids from the Kontum terrane, Tam Ky-Phuoc Son tectonic zone, and southern Truong Son igneous zone in South Laos yield the crystallization ages of 464–485 Ma, 455–471 Ma, and 427–446 Ma, respectively, with a northerly younging trend within the Indochina interior. They are mainly monzogranite with A/CNK = 0.96–1.99 and K2O > Na2O, which are marked by enrichment in large-ion lithophile elements and depletion in high field strength elements with remarkable Nb-Ta, Sr-P, and Ti negative anomalies. Their initial 87Sr/86Sr ratios range from 0.70510 to 0.71559, εNd(t) from −9.5 to −3.0, (206Pb/204Pb)i from 18.65 to 19.72, (207Pb/204Pb)i from 15.66 to 15.80, and (208Pb/ 204Pb)i from 38.84 to 39.79. The corresponding zircon ɛHf(t) and δ18O values are in the range of −10.6 to +1.0 and 6.88‰ to 8.94‰, respectively. In addition, their Sr-Nd-Pb and Hf-O isotopic compositions are generally similar with those of time-equivalent granitoids in South Tibet and SW Yunnan, China, and synchronous mafic-intermediate igneous rocks in South Laos, but distinctive from those of the supracrustal sedimentary-derived South China Paleozoic granite and Lincang-Sukhothai S-type granite. The early Paleozoic granitoids in South Laos might have originated from a mixed source of the wedge-derived juvenile crust coupled with supracrustal materials. All these data synthetically suggest the southward subduction of the Tam Ky-Phuoc Son Ocean and the northerly on-growing Ordo-Silurian accretionary orogenesis within the previously defined “single-ancient” Indochina block. The assemblage of the Indochina block might initiate at ca. 430 Ma in the Silurian and terminate in the Early-Middle Devonian.

Supplemental Material: Metamorphism of the Sierra de Maz and implications for the tectonic evolution of the MARA terrane

2021 ◽  
Author(s):  
A. Tholt ◽  
S.R. Mulcahy ◽  
et al.
Keyword(s):  
Analytical Methods ◽  
Tectonic Evolution ◽  
Mineral Chemistry ◽  
Isotopic Data ◽  
Back Scatter Electron

<div>Analytical methods, garnet compositional maps, a comparison of thermobarometry methods, monazite back-scatter electron images, mineral chemistry, and garnet and monazite isotopic data.<br></div><div><br></div><div><br></div><div><br></div><div><br></div><div><br></div>

Lithospheric architecture and tectonic evolution of the southwestern U.S. Cordillera: Constraints from zircon Hf and O isotopic data

2018 ◽  
Vol 130 (11-12) ◽  
pp. 2031-2046 ◽  
Author(s):  
J.B. Chapman ◽  
M.N. Dafov ◽  
G. Gehrels ◽  
M.N. Ducea ◽  
J.W. Valley ◽  
...  
Keyword(s):  
Tectonic Evolution ◽  
Isotopic Data

scholarly journals Supplemental Material: Metamorphism and geochronology of high-pressure mafic granulites (retrograded eclogites?) in East Cathaysia terrane of South China: Implications for Mesozoic tectonic evolution

2021 ◽  
Author(s):  
Yanfei Xia ◽  
Changqing Yin ◽  
et al.
Keyword(s):  
High Pressure ◽  
Trace Element ◽  
South China ◽  
Tectonic Evolution ◽  
Trace Element Data ◽  
Isotopic Data ◽  
Element Data ◽  
Mineral Compositions

Supplemental tables contain the whole-rock and mineral compositions, PT estimates, zircon SIMS Th-U-Pb isotopic data and trace element data.

scholarly journals Supplemental Material: The Mesozoic magmatic, metamorphic, and tectonic evolution of the eastern Gangdese magmatic arc, southern Tibet

2021 ◽  
Author(s):  
Zeming Zhang
Keyword(s):  
Trace Element ◽  
Late Cretaceous ◽  
Tectonic Evolution ◽  
Chemical Compositions ◽  
Isotopic Data ◽  
Southern Tibet ◽  
Magmatic Arc ◽  
Magmatic Rocks

Table S1: Major features of the reported Jurassic magmatic rocks of the eastern Gangdese arc; Table S2: Zircon U-Pb dating and trace element (in ppm) data of the studied Jurassic magmatic rocks of the eastern Gangdese arc; Table S3: Zircon Hf isotopic data of the studied Jurassic magmatic rocks of the eastern Gangdese arc; Table S4: Whole-rock chemical compositions of the studied Jurassic magmatic rocks of the eastern Gangdese arc; Table S5: Whole-rock chemical compositions of the Mesozoic magmatic rocks of the eastern Gangdese arc; Table S6: Whole-rock SiO2 and Cu concentrations of the Late Cretaceous magmatic rocks of the eastern Gangdese arc.

Origin and tectonic evolution of the NE basement of Oman: a window into the Neoproterozoic accretionary growth of India?

2017 ◽  
Vol 155 (5) ◽  
pp. 1150-1174 ◽  
Author(s):  
BRANDON L. ALESSIO ◽  
MORGAN L. BLADES ◽  
GEORGE MURRAY ◽  
BENJAMIN THORPE ◽  
ALAN S. COLLINS ◽  
...  
Keyword(s):  
Tectonic Evolution ◽  
Thermal Gradient ◽  
Leading Edge ◽  
Isotopic Data ◽  
Geochronological Data ◽  
Nubian Shield ◽  
The Difference ◽  
And Migration ◽  
Arabian Nubian Shield ◽  
Basement Inlier

AbstractThe Omani basement is located spatially distant from the dominantly juvenile Arabian–Nubian Shield (ANS) to its west, and its relationship to the amalgamation of those arc terranes has yet to be properly constrained. The Jebel Ja'alan (NE Oman) basement inlier provides an excellent opportunity to better understand the Neoproterozoic tectonic geography of Oman and its relationship to the ANS. To understand the origin of this basement inlier, we present new radiogenic isotopic data from igneous bodies in Jebel Ja'alan. U–Pb and 40Ar/39Ar geochronological data are used to constrain the timing of magmatism and metamorphism in the jebel. Positive εHf and εNd values indicate a juvenile origin for the igneous lithologies. Phase equilibria modelling is used to constrain the metamorphic conditions recorded by basement. Pressure–temperature (P–T) pseudosections show that basement schists followed a clockwise P–T path, reaching peak metamorphic conditions of c. 650–700°C at 4–7.5 kbar, corresponding to a thermal gradient of c. 90–160°C/kbar. From the calculated thermal gradient, in conjunction with collected trace-element data, we interpret that the Jebel Ja'alan basement formed in an arc environment. Geochronological data indicate that this juvenile arc formed during Tonian time and is older than basement further west in Oman. We argue that the difference in timing is related to westwards arc accretion and migration, which implies that the Omani basement represents its own tectonic domain separate to the ANS and may be the leading edge of the Neoproterozoic accretionary margin of India.

scholarly journals Supplemental Material: The Mesozoic magmatic, metamorphic, and tectonic evolution of the eastern Gangdese magmatic arc, southern Tibet

2021 ◽  
Author(s):  
Zeming Zhang
Keyword(s):  
Trace Element ◽  
Late Cretaceous ◽  
Tectonic Evolution ◽  
Chemical Compositions ◽  
Isotopic Data ◽  
Southern Tibet ◽  
Magmatic Arc ◽  
Magmatic Rocks

Table S1: Major features of the reported Jurassic magmatic rocks of the eastern Gangdese arc; Table S2: Zircon U-Pb dating and trace element (in ppm) data of the studied Jurassic magmatic rocks of the eastern Gangdese arc; Table S3: Zircon Hf isotopic data of the studied Jurassic magmatic rocks of the eastern Gangdese arc; Table S4: Whole-rock chemical compositions of the studied Jurassic magmatic rocks of the eastern Gangdese arc; Table S5: Whole-rock chemical compositions of the Mesozoic magmatic rocks of the eastern Gangdese arc; Table S6: Whole-rock SiO2 and Cu concentrations of the Late Cretaceous magmatic rocks of the eastern Gangdese arc.

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