In:
Acta Geologica Sinica - English Edition, Wiley, Vol. 87, No. 2 ( 2013-04), p. 333-345
Abstract:
The Helegangnaren feldspar granite exposed in the eastern part of East Kunlun, is characterized by high concentrations of SiO 2 and alkaline, low abundances of Fe, Mg and Ca, metaluminous‐weak peraluminous. Trace elements analysis shows that the granite is depleted extremely in Ba, Sr and Eu, and rich in some large‐ion lithophile elements and high field strength elements. Besides, the granite has high Ga contents, the values of 10 4 (Ga/Al) vary from 2.50 to 2.77, which is mainly greater than the lower limit of A‐type granites (2.6), and is higher than the I‐ and S‐type granites’ average (2.1 and 2.28, respectively). Rare earth element (REE) is characterized by relatively high fractionations of light REE (LREE) and heavy REE (HREE) (LREE/HREE=9.3–13.60, (La/Yb) N =10.92–18.02), pronounced negative Eu anomalies (δEu=0.08–0.13), and exhibits right‐dipping gull pattern. Major elements, rare elements and trace elements features show the granite is ascribed to A‐type granite and A2 subtype in tectonic genetic type. They are plotted into post‐collision or within‐plate area in a variety of tectonic discriminations. Geological and geochemical data comprehensively suggest that the granite is formed in a post‐collision extensive tectonic setting. Laser ablation inductively coupled plasma mass spectrometry (LA‐ICP‐MS) zircon U‐Pb dating yields a weighted mean age of 425 Ma, belonging to Middle Silurian, which is similar to the age of the post‐collision geological events in the region. The differences of magmatic rocks in formation age, rocks assemblage and rocks series systematically indicate that the regional tectonic stress regime in the East Kunlun orogenic belt experienced a major transformation from compress to extension in Middle Silurianin, and the Helegangnaren feldspar granite intruded in the early stage of tectonic transformation.
Type of Medium:
Online Resource
ISSN:
1000-9515
,
1755-6724
DOI:
10.1111/acgs.2013.87.issue-2
DOI:
10.1111/1755-6724.12054
Language:
English
Publisher:
Wiley
Publication Date:
2013
detail.hit.zdb_id:
2420386-5
SSG:
6,25
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