scholarly journals Highly siderophile element and Os isotope results from the structurally atypical Batin dunite in the Wadi Tayin massif of the Oman ophiolite

Author(s):  
Delphine KLAESSENS ◽  
Laurie REISBERG ◽  
David JOUSSELIN ◽  
Keyword(s):  
Geology ◽  
2000 ◽  
Vol 28 (6) ◽  
pp. 555-558
Author(s):  
Ryan Mathur ◽  
Joaquin Ruiz ◽  
Francisco Munizaga

Geology ◽  
2000 ◽  
Vol 28 (6) ◽  
pp. 563-566 ◽  
Author(s):  
Bruce F. Schaefer ◽  
Simon P. Turner ◽  
Nick W. Rogers ◽  
Chris J. Hawkesworth ◽  
Helen M. Williams ◽  
...  

2016 ◽  
Author(s):  
Joshua M. Garber ◽  
◽  
Matthew Rioux ◽  
Matthew Rioux ◽  
Andrew R.C. Kylander-Clark ◽  
...  

2017 ◽  
Author(s):  
Kosuke T. Goto ◽  
◽  
Aya Sakaguchi ◽  
Maria Luisa G. Tejada ◽  
Johannes Lachner ◽  
...  

Author(s):  
Clark M. Johnson ◽  
Steven B. Shirey ◽  
Karin M. Barovich

ABSTRACT:The Lu-Hf and Re-Os isotope systems have been applied sparsely to elucidate the origin of granites, intracrustal processes and the evolution of the continental crust. The presence or absence of garnet as a residual phase during partial melting will strongly influence Lu/Hf partitioning, making the Lu–Hf isotope system exceptionally sensitive to evaluating the role of garnet during intracrustal differentiation processes. Mid-Proterozoic (1·1–1·5Ga ) ‘anorogenic’ granites from the western U.S.A. appear to have anomalously high εHf values, relative to their εNd values, compared with Precambrian orogenic granites from several continents. The Hf-Nd isotope variations for Precambrian orogenic granites are well explained by melting processes that are ultimately tied to garnet-bearing sources in the mantle or crust. Residual, garnet-bearing lower and middle crust will evolve to anomalously high εHf values over time and may be the most likely source for later ‘anorogenic’ magmas. When crustal and mantle rocks are viewed together in terms of Hf and Nd isotope compositions, a remarkable mass balance is apparent for at least the outer silicate earth where Precambrian orogenic continental crust is the balance to the high-εHf depleted mantle, and enriched lithospheric mantle is the balance to the low-εHf depleted mantle.Although the continental crust has been envisioned to have exceptionally high Re/Os ratios and very radiogenic Os isotope compositions, new data obtained on magnetite mineral separates suggest that some parts of the Precambrian continental crust are relatively Os-rich and non-radiogenic. It remains unclear how continental crust may obtain non-radiogenic Os isotope ratios, and these results have important implications for Re-Os isotope evolution models. In contrast, Phanerozoic batholiths and volcanic arcs that are built on young mafic lower crust may have exceptionally radiogenic Os isotope ratios. These results highlight the unique ability of Os isotopes to identify young mafic crustal components in orogenic magmas that are essentially undetectable using other isotope systems such as O, Sr, Nd and Pb.


Geology ◽  
2005 ◽  
Vol 33 (12) ◽  
pp. 957 ◽  
Author(s):  
Scott T. Dreher ◽  
Colin G. Macpherson ◽  
D. Graham Pearson ◽  
Jon P. Davidson
Keyword(s):  

Minerals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 480
Author(s):  
Shengbin Li ◽  
Yonghua Cao ◽  
Zeyou Song ◽  
Dan Xiao

The Shuikoushan deposit is an economic ‘skarn-type’ polymetallic Pb-Zn deposit in South China. The deposit is located at the southern margin of the Hengyang basin in the northern part of the Nanling Range. Recently, economic Fe-Cu mineralization that occurs spatially connected to skarns along the contact zone between the granodiorite and limestones was discovered in the lower part of this deposit. Detailed zircon U-Pb geochronological data indicate that the granodiorite was emplaced at 153.7 ± 0.58 Ma (Mean Square of Weighted Deviates (MSWD) = 2.4). However, the pyrite Re-Os isochron age reveals that Fe-Cu mineralization formed at 140 ± 11 Ma (MSWD) = 8.1), which post-dates the emplacement of the granodiorite, as well as the previously determined timing of Pb-Zn mineralization (157.8 ± 1.4 Ma) in this deposit. Considering that Fe-Cu mineralization was connected with the contact zone and also faults, and that sulfide minerals commonly occur together with quartz and calcite veins that crosscut skarns, we interpret this mineralization type as being related to injection of post-magmatic hydrothermal fluids. The timing of Fe-Cu mineralization (140 ± 11 Ma) is inconsistent with a long-held viewpoint that the time interval of 145 to 130 Ma (e.g., Early Cretaceous) in the Nanling Range is a period of magmatic quiescence with insignificant mineralization, the age of 140 Ma may represent a new mineralization event in the Nanling Range.


Lithos ◽  
2013 ◽  
Vol 156-159 ◽  
pp. 120-138 ◽  
Author(s):  
Nobutaka Tsuchiya ◽  
Tomoyuki Shibata ◽  
Masako Yoshikawa ◽  
Yoshiko Adachi ◽  
Sumio Miyashita ◽  
...  

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