Welcome to visit Geoscience!

Geoscience ›› 2008, Vol. 22 ›› Issue (4): 586-591.

• Engineering Geology and Environmental Geology • Previous Articles     Next Articles

Geochemical Tracing of Fluid from Upper Cambrian-Ordovician in Well Gucheng 4,Eastern Tarim Basin

WANG Dong1,WANG Guo-zhi1,RAN Qi-gui2,LIU Shu-gen3,HU Jiu-zhen3,ZHANG Chang-jun3   

  • Received:2008-03-28 Revised:2008-06-17 Online:2008-04-20 Published:2008-04-20

Abstract:

Comparison studies for Upper Cambrian and Ordovician in well Gucheng 4 in eastern Tarim basin based on carbon,oxygen,strontium isotope geochemistry and fluid inclusions between country rocks of carbonate and fills in fissure,suggest that source of fluid in the MiddleUpper Ordovician is much different from that in Upper Cambrian.87Sr/86Sr of calcites filled in limestone fissure in Middle-Upper Ordovician is 0.708,4-0.708,8 and it is similar to that from Ordovician seawater;the fluid belongs to CH4-H2Osystem.Obvious isotopic differences of carbon and oxygen between fills in fissure and country rock indicate that the fluid is not directly  from the country rock and from Ordovician carbonate at other locations.The87Sr/86Sr of calcites filled in dolomite fissure in Upper Cambrian is 0.713,8 and it is higher than that of contemporary seawater,and the fluid belongs toCH2-H2O system.Fluid in the lower system is an introduced fluid with abundant Sr.Different fluid sources in Upper Cambrian and Ordovician imply that Upper Cambrian has a better preservation condition.

Key words: Cambrian, Ordovician, fluid, geochemistry, eastern Tarim basin, well Gucheng 4, carbon,oxygen,and strontium isotopes

CLC Number: