Carboniferous and Permian integrative stratigraphy and timescale of North China Block

Abstract

The Carboniferous-Permian strata in the North China Block (NCB) contain abundant fossils, coals and natural gases. Establishing a high-resolution timescale for the Carboniferous and Permian in the NCB is essential to understand the geologic events and explore the spatial and temporal distributions of the natural resources. The upper Carboniferous and the basal part of Permian are relatively well correlated because they yield marine conodont and fusuline fossils. However, the Permian terrestrial strata mostly rely on poorly constrained palynostratigraphy and phytostratigraphy and are short of the precise geochronologic constraints on the correlation with the marine strata. This study provides a critical review on the state-of-the-art of the latest Carboniferous and Permian chronostratigraphic and biostratigraphic frameworks and stratigraphic correlation in the NCB. The Penchi Formation ranges from lower Bashkirian to lower Gzhelian; the Taiyuan Formation is assigned to the upper Gzhelian to lower Asselian; the Shansi and Lower Shihhotse formations are from middle Asselian to lower Sakmarian; the Upper Shihhotse Formation is assigned to upper Artinskian to lower Kungurian, and the Sunjiagou Formation was assigned to Lopingian, respectively. A long hiatus up to ~20 Myr between the Upper Shihhotse and Sunjiagou formations, mainly marked by a large-scale erosional surface at the base of a coarse conglomeratic sandstone unit and/or multiple paleosol layers as well as significant differences of floras between these two lithostratigraphic units, is present probably due to tectonic uplift in association with the closure of the Paleo Asian Ocean (PAO) during the Cisuralian and Guadalupian. The possible amplitude of sea-level changes from Carboniferous to Permian on the NCB is estimated from 0 to 40 m. The floral succession, depositional records and organic carbon isotope profiles suggest that the latest Carboniferous and earliest Permian was a favorable period for coal accumulation under an ever-wet and warm climate, followed by a prominent shift to dry climate from early-middle Cisuralian. This climatic shift during the Permian was mainly resulted from northward migration of the Pangea and the closure of the PAO, which is comparable with the Carboniferous and Permian trends in central Europe.

Geochemical Constraints and Astronomical Forcing on Organic Matter Accumulation of Marine–Continental Transitional Shale Deposits in the Qinshui Basin during the Carboniferous–Permian Transition

“…The TY, deposited in a tidal-flat to lagoon facies, primarily comprises limestone, sandstone, shale, and coal, with a total thickness of 125.65 m, dating from the late Gzhelian to early Asselian periods. 34 The SX, deposited in fluvial deltaic facies, mainly consisted of sandstone, shale, and coal, with a total thickness of 81.2 m, corresponding to the middle Asselian period. 34 During the sampling process, efforts were made to avoid coal beds, resulting in a collection of 20 coal-bearing shale samples, including 11 TY samples and 9 SX samples (Figure 1c).…”

“…During the C−P period, high plants were widely colonized on the land of the NCB, and coal beds were widely developed in the Qinshui Basin, resulting in substantial coal-derived natural gas resources. 31 Previous studies have determined that the TY of the 34 and associated global geological events during the C−P transition, including changes in glacial activity, 35 global atmospheric pCO 2 levels, 36 large igneous provinces (LIPs), 37,38 floral turnover, 6 global sea-level changes, 39 organic carbon isotopic compositions (δ 13 C org ; ‰, PDB), 40 and paleoclimatic fluctuations between warming and cooling. 32 Qinshui Basin was deposited in the late Carboniferous to early Permian epochs.…”

“…34 The SX, deposited in fluvial deltaic facies, mainly consisted of sandstone, shale, and coal, with a total thickness of 81.2 m, corresponding to the middle Asselian period. 34 During the sampling process, efforts were made to avoid coal beds, resulting in a collection of 20 coal-bearing shale samples, including 11 TY samples and 9 SX samples (Figure 1c). All samples were ground to a 200 mesh size using an agate grinder, with ∼10 g of powdered samples divided into two aliquots.…”

Lower Permian (Late Kungurian) conodonts from the Sibumasu Terrane, Malaysia: paleoecological, paleobiogeographical and tectonic implications

“…After Henderson (2018). Stage boundary high-precision U-Pb isotopic ages are from Shen et al (2022). …”

Geochemistry of the Permian–Triassic boundary strata in the southwest margin of the North China Craton: Provenance and tectonic implications

“…The Liujiagou Formation contains multilayer conglomerate and thickly‐bedded siltstone in its lower part, great thickly‐bedded medium‐grained sandstone in its middle part, and thickly‐bedded medium‐grained sandstone with thinly‐bedded argillaceous siltstone in its upper part (Figures 2 and 3). Systematic U–Pb dating studies have not been undertaken in the study area, but previous biostratigraphic and magnetostratigraphic studies suggest that the Sunjiagou Formation was formed in the Late Permian and the Liujiagou Formation in the Early Triassic (Guo et al, 2022; Shen et al, 2022; Tu et al, 2016; Xing et al, 2021; Yu et al, 2022).…”