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Island-arc geochemical signatures of Cenozoic alkali-rich intrusive rocks from western Yunnan and their implication.
- Source :
-
Chinese Journal of Geochemistry . 2005, Vol. 24 Issue 4, p361-369. 9p. 1 Chart, 8 Graphs, 1 Map. - Publication Year :
- 2005
-
Abstract
- Alkali-rich intrusive rocks in western Yunnan were derived from an enriched lithospheric mantle (EM II) source. The data available indicated they are alkali-rich (K2O + Na2O > 8wt%) and shoshonitic. Although formed in a within-plate environment they exhibit signatures of arc magmatic rocks, such as high amounts of LILE and LREE relative to the HFSE and HREE, and thus high Ba/Nb, Ba/Zr, Sr/Y, La/Yb ratios as well as mimic chondrite-normalized REE and primitive mantle-normalized trace element patterns of subducted sediments, and they fall in the collision- or arc-related tectonic setting field on all discrimination diagrams. This might suggest the enrichment be related to the substantial extent of sediment contamination by the Mesozoic Tethyan subduction processes. [ABSTRACT FROM AUTHOR]
- Subjects :
- *ROCKS
*IGNEOUS intrusions
*TRACE elements
*SEDIMENTS
*GEOCHEMISTRY
Subjects
Details
- Language :
- English
- ISSN :
- 10009426
- Volume :
- 24
- Issue :
- 4
- Database :
- Academic Search Index
- Journal :
- Chinese Journal of Geochemistry
- Publication Type :
- Academic Journal
- Accession number :
- 19537139
- Full Text :
- https://doi.org/10.1007/BF02873799