The Study Of The Late Paleozoic Intrusive Rocks And The Tectonic Evolution In Emin Area, Xinjiang

The Emin area is located to north of the West Junggar, The tectonic setting is verycomplex, magmatic activity is very strong, more lager area intermediate to acidic rock anddiabase dykes swarm in late Carboniferous to early Permian distributed in Emin area, for theresearch region magma-tectonic evolution provides favorable conditions. This paper takesthe late Paleozoic intrusive rocks in Emin as the research object, combined with matchingvolcanic rocks, from the petrology, chronology, rock geochemistry and tectonic environmentaspects study of late Paleozoic tectonic evolution. Gained achievement as follows:1. Basid on materials of the predecessor and the results of team members, have carriedon a large number of petrochemistry, geochemistry and isotope research about intrusive rockin the area, for studying magmatism and tectonic environment provides an important material.Shaque sequence. From early to late for quartz diorite-quartz monzodiorite, for "I" typegranite, belong to the mantle-derived magma diagenesis; Kulumusu sequence includingmonzonitic granite、fine-grained syenogranite、medium to coarse-grained syenogranite、alkali-feldspar granite、alkali-granite porphyry from early to late, for A2type granite; Kexikesequence including monzonitic granite、syenogranite、alkali-feldspar granite from early tolate, for A2－A1type granite.2. The earth’s crust material obviously to join in diabase dykes in place and diageneticprocess, the source region is a inadequate of oceanic lithosphere mantle source. It,s likely toinfer that this source region is related with long lasting residusl oceanic basin and the relatedlithosphere since Paleozoic in West Junggar.3. LA-ICP-MS zircon U-Pb dating were305Ma and288~293Ma in Shaque sequence andKulumusu sequence, As well as293Ma and289Ma in Kexike sequence and diabase dykes.That taking stronge evdent for rebuilding tectonic framework and recovering magmaevolution in West Junggar.4. Rock geochemistry reseach indicated, Kulumusu sequence formatted in the late ofpost-collision setting, during compresse environment transform to extension environment.Shaque sequence has island-arc granite marking, formatted in the early of post-collisionsetting. Kexike sequence formatted in the transition period which post-collision setting shift to intraplate system, it is derived from partial melting of lower crust in extensionalenvironment. Diabase dykesv formatted in extension tectonicb regime at the end ofpost-collision setting.5. For studying the tectonic magmatic event of intrusive rocks and matching volcanicrocks in the area, we can draw the conclusion that：the tectonic setting has experienced fourperiods: ocean basin、volcanic arc、postorogenic、anorogenic period during Devonian to earlyPermian, tectonic stress system also experienced tension to extrusion to tension.