Combining Nd isotopes in monazite and Hf isotopes in zircon to understand complex open-system processes in granitic magmas

Geology ◽  
2017 ◽  
Vol 45 (3) ◽  
pp. 267-270 ◽  
Author(s):  
Christopher M. Fisher ◽  
John M. Hanchar ◽  
Calvin F. Miller ◽  
Stacy Phillips ◽  
Jeffrey D. Vervoort ◽  
...  
Keyword(s):  
Open System ◽  
Hf Isotopes ◽  
Nd Isotopes

Multiple S isotopes, zircon Hf isotopes, whole-rock Sr-Nd isotopes, and spatial variations of PGE tenors in the Jinchuan Ni-Cu-PGE deposit, NW China

2015 ◽  
Vol 51 (4) ◽  
pp. 557-574 ◽  
Author(s):  
Jun Duan ◽  
Chusi Li ◽  
Zhuangzhi Qian ◽  
Jiangang Jiao ◽  
Edward M. Ripley ◽  
...  
Keyword(s):  
Spatial Variations ◽  
Hf Isotopes ◽  
Nd Isotopes ◽  
Nw China ◽  
S Isotopes

scholarly journals Petrogenesis of the Nashwaak Granite, West-Central New Brunswick, Canada: Evidence from Trace Elements, O and Hf Isotopes of Zircon, and O Isotopes of Quartz

Minerals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 614 ◽  
Author(s):  
Wei Zhang ◽  
David R. Lentz ◽  
Kathleen G. Thorne
Keyword(s):  
Trace Elements ◽  
New Brunswick ◽  
Open System ◽  
Biotite Granite ◽  
Hf Isotopes ◽  
Magmatic Zircon ◽  
Basement Rocks ◽  
O Isotopes ◽  
Isotopic Disequilibrium

The petrogenesis of the Pridoli to Early Lochkovian granites in the Miramichi Highlands of New Brunswick, Canada, is controversial. This study focuses on the Pridoli Nashwaak Granite (biotite granite and two-mica granite). In situ trace elements and O and Hf isotopes in zircon, coupled with O isotopes in quartz, are used to reveal its magmatic sources and evolution processes. In the biotite granite, inherited zircon cores have broadly homogenous δ18OZrc ranging from +6.7‰ to 7.4‰, whereas magmatic zircon rims have δ18OZrc of +6.3‰ to 7.2‰ and εHf(t) of −0.39 to −5.10. The Hf and Yb/Gd increase with decreasing Th/U. Quartz is isotopically equilibrated with magmatic zircon rims. The biotite granite is interpreted to be solely derived by partial melting of old basement rocks of Ganderia and fractionally crystallized at the fO2 of 10−21 to 10−10 bars. The two-mica granite has heterogeneous inherited zircon cores (δ18OZrc of +5.2‰ to 9.9‰) and rims (δ18OZrc of +6.2‰ to 8.7‰), and εHf(t) of −11.7 to −1.01. The two-mica granite was derived from the same basement, but with supracrustal contamination. This open-system process is also recorded by Yb/Gd and Th/U ratios in zircon and isotopic disequilibrium between magmatic zircon rims and quartz (+10.3 ± 0.2‰).

Library as a Complex Open System

2012 ◽  
Vol 3 (2) ◽  
pp. 160-161
Author(s):  
JIGAR L DAVE ◽  
Keyword(s):  
Open System

Radiometric dating of hillslope calcrete in the Negev Desert, Israel

2008 ◽  
Vol 104 (11/12) ◽  
Author(s):  
J.C. Vogel ◽  
M.A. Geyh
Keyword(s):  
Open System ◽  
Negev Desert ◽  
Radiometric Dating ◽  
Jordan Valley ◽  
Partial Recrystallization ◽  
Uranium Series ◽  
Uranium Series Dating

The radiometric dating of calcrete is often problematical because impurities and open system conditions affect the apparent ages obtained. By applying both radiocarbon and uranium-series dating to calcrete in colluvium, it is shown that such conditions can be identified. In correlation with the stratigraphy, it is found that partial recrystallization severely decreases the radiocarbon ages of the upslope and shallower samples further down, whereas incorporation of limestone fragments from bedrock significantly increases the apparent ages of some of the uranium-series samples. It is concluded that the hillslope calcrete at the study site near Sede Beker in the Negev Desert, Israel, mainly developed shortly after 40 kyr ago, at a time when the Jordan Valley was being inundated to form the fossil Lake Lisan. Since their formation would have required higher rainfall than today, the results provide further evidence that the whole region was experiencing an increase in precipitation.

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