Analysis of Upper Paleozoic trace element characteristics and paleoenvironmental significance in the Gubei area of Jiyang depression

Abstract

The Upper Paleozoic in Gubei area of Jiyang Depression has a good combination of source, reservoir and cap, and has a good exploration prospect. The basic research on sedimentology and geochemistry of Upper Paleozoic restricts the oil and gas exploration of target strata. Moreover, the application of element characteristics is rarely applied, and there is almost no research on the longitudinal sedimentary environment evolution characteristics, and the research on paleo-environment and paleoclimate is not systematic enough. The core of the Upper Paleoozoic core bank in Gubei area was taken as the sample. The NITONXL 2·GOLDD handheld X-ray ore element analyzer of Thermo Scientific was used to test the element content of the sample, and the longitudinal variation rule of trace elements was analyzed. The enrichment degree and ratio of trace elements corresponding to different lithologies indicate the characteristics of paleoenvironment and paleoclimatology. Combined with the analysis of the geochemical characteristics of trace elements and rare earth elements, the core of three Wells (Gubeigu 1, Gubeigu 2 and Yi 136) was systematically measured and the content and ratio of elements were studied. The paleo-salinity, paleo-climate, paleo-water depth and REDOX degree of Upper Paleozoic sedimentary period in Gubei area are systematically discussed, which provides reliable evidence for the recovery of sedimentary environment evolution in this area. Among them, Gubei Gu1 well, Gubei Gu2 well and Yi 136 well are all fresh water deposits of continental facies, indicating arid climate, oxidation environment and shallow water depth. Keywords: Gubei area; Upper Paleozoic; trace element; paleoclimate; paleoenvironment