Coupling Clumped Isotope Thermometry And In-Situ U-Pb Dating To Reconstruct Thermal Evolution History Of Deeply-Buried Paleozoic Carbonate Intervals In Tarim Basin

Abstract

Thermal history research in sedimentary basins is fundamental for basin analysis and hydrocarbon system studies. The Ordovician carbonate intervals of Tarim basin are hot spots for hydrocarbon exploration and are characterized by deep burial depth (>5000m) and high burial temperature (>140℃). However, due to limited material availability and usable temperature range required by conventional thermochonometric tools (e.g. fission-track analysis, (U-Th)/He dating), thermal histories reconstruction of Paleozoic carbonate intervals is in urgent need for breakthrough. Carbonate clumped isotopes record carbonate mineral crystallization temperature and will be driven to equilibrate with ambient temperature under elevated burial temperature due to solid-state reordering of 13C-18O bonds, indicating that carbonates clumped isotope could serve as a new thermometric proxy. Coupling with existing solid-state reordering kinetic models, thermal history (or at least peak burial temperature) can be constrained by modeling possible temperature-time scenarios using measured carbonate clumped isotopes. We measured the clumped isotope of different fabrics (e.g. micrite, veins and cements) of carbonate rock in Ordovician carbonate intervals of Tarim basin, with an emphasis on Shuntuoguole area. In the meantime, In-situ U-Pb dating will be applied to these fabrics to give starting anchors for thermal history modeling using solid-state reordering models. The combination of carbonate clumped isotope thermometry and in-situ U-Pb dating has been applied to several studies in different realms. This is the first time to couple these two emerging methods with solid-state reordering models to reconstruct basin thermal history of deeply-buried carbonate intervals with high burial temperature.

AAPG Datapages/Search and Discovery Article #90351 © 2019 AAPG Foundation 2019 Grants-in-Aid Projects