Graphic Correlation in Frontier Petroleum Provinces: Application to Upper Paleozoic Sections in the Tarim Basin, Western China

Abstract

When they were graphically correlated against a composite standard database, paleontologic data sets from the Carboniferous and Lower Permian of the western Tarim basin revealed a punctuated stratigraphic succession in which most of geologic time is contained within regional hiatuses (up to 15 m.y. duration). These hiatuses occur beneath rock packages of late Bashkirian-middle Moscovian, late Moscovian-early Kasimovian, late Gzhelian-early Asselian, and early Sakmarian-Artinskian ages. This interpretation differs from other views that hold that Permian-Carboniferous deposition in the Tarim basin was continuous, or nearly continuous with only minor breaks. The results suggest that late Paleozoic sedimentation in the Tarim basin was controlled primarily by local processes, not by third-order, global, sea level cycles (1-3 m.y. duration). The graphic correlation technique is capable of superior biostratigraphic resolution because it uses the ranges of all fossils within a data set, not just guide fossils or those associated with zonal definitions. Moreover, a composite standard that is linearly calibrated to geologic time makes possible inferences regarding rates of rock accumulation within stratigraphic sequences and the durations of sequence-bounding hiatuses. The resulting chronostratigraphic framework enables and constrains sequence stratigraphic and seismic stratigraphic interpretations.