Geochemistry of the volcanic rock association from Lianghe area in Mianluesuture zone, southern Qinling and its tectonic significance.

Citation
Sc. Lai et al., Geochemistry of the volcanic rock association from Lianghe area in Mianluesuture zone, southern Qinling and its tectonic significance., ACTA PETR S, 16(3), 2000, pp. 317-326
Citations number
17
Language
CHINESE
art.tipo
Article
Categorie Soggetti
Earth Sciences
Journal title
ACTA PETROLOGICA SINICA
ISSN journal
1000-0569 → ACNP
Volume
16
Issue
3
Year of publication
2000
Pages
317 - 326
Database
ISI
SICI code
1000-0569(200008)16:3<317:GOTVRA>2.0.ZU;2-A
Abstract
The volcanic rock slab in Lianghe area is located in the boundary tectonic zone: Bashan arcuate tectonic melange between Qinling microplate and Yangtz e plate. The rocks consisted of subalkaline tholeiitic basalt and calc-alka line dacitic rhyolite. Both of the basalt and dacitic rhyolite exhibit the typical geochemical features of high content of element Bar low content of elements Th and U. remarkable depletion of element Nb, Ta and Ti. Especiall y, the Th/Yb-Ta/Yb and Ti/Zr-Ti/Y features of the basalt indicate that the volcanic rock association in the studied area developed in a special tecton ic setting which belongs to a rift valley within an island-arc. The volcani c rock association in the studied area was the result of magmatism that due to the ancient oceanic crust subduction and rift valley development within the island-arc during the evolutionary process of Mianlue ancient ocean ba sin at Middle Paleozoic-Early Mesozoic era. This volcanic rock block should be an important evidence which indicates that the Mianxian-Lueyang suture zone had extended to the Bashan arcuate area.