Title: Petrogenesis of Kalatongke mafic rock intrusions, Xinjiang.
Abstract: Kalatongke mafic rock intrusions, which are consisted of 13 small rocks, located at the northern margin of Junggar block. They are mainly comprised of harzburgites, olivine norites, gabbronorites, gabbros, leucogabbros and gabbro-diorites. Chrysolite, augite, hypersthenes, plagioclase and lots of brown common hornblende and biotite are the main petrogenic minerals. The main elements belong to calc-alkaline series, island-arc tholeitiitic series and tholeitiitic series affine with MORB. Most samples have high LREE/HREE ratios, enrich in LILES, relatively deplete in HFSE ( Nb, Ta, Ti). The e_(Nd)(t) value varies from 6.2 to 8.2, e_(Sr)(t) value varies from - 0.6 to - 36.3 except one is + 36.5 , Pb isotopic are characterized by (~(206) Pb/~(204) Pb), = 17.784~18.008, (~(207)Pb/~(204)Pb)_i =15.400 -15.555, (~(208)Pb/~(204)Pb)_i =36.973~37.560. Element geochemistry and Nb, Sr, Pb, Os, O, S isotope characters indicate that the magma only experienced contamination to some extent. The MgO of primary magma constrained is 11. 6%. The main dark-colored minerals are clinopyxene in the processes of the fractional crystallization and the condense of plagioclase, which lead to the dominant of leucogabbros and serious lack of ultramafic rocks. The magma source is composed of wedge matasomasised by subducting slab and aesethenosphere components, as a result, it is enriched in incompatible elements and water. The interval between the matasomatism and magma generation is short, so the depletion of radiogenic isotope is well kept. Kalatongke rock bodies are the result of the lithospherie delamination at the root and the upwelling of asthenosphere components.
Publication Year: 2009
Publication Date: 2009-01-01
Language: en
Type: article
Access and Citation
Cited By Count: 18
AI Researcher Chatbot
Get quick answers to your questions about the article from our AI researcher chatbot