Characteristics and controlling factors of lacustrine source rocks in the Lower Cretaceous, Suhongtu depression, Yin-E basin, Northern China

Tectonic–thermal evolution since the Mesozoic in the Suhongtu Depression, Yingen–Ejina Basin: Constraints from Apatite fission track and vitrinite reflectance

“…Low-temperature thermochronology such as AFT and vitrinite reflectance (Ro) are powerful tools for studying tectonic evolution processes and characterizing the refined time of the tectonic event in the superimposed basin. AFT data record the thermal history of rocks at about 60-120 C (Ketcham et al, 2000;Qi et al, 2018), which is consistent with the hydrocarbon generation threshold temperature of source rocks. Fission track length distribution and annealing modelling are valuable methods to reconstruct the relationship between thermal history and regional tectonic evolution (Barbarand et al, 2003;Ketcham et al, 2000).…”

“…Han et al (2011Han et al ( , 2014Han et al ( , 2015 and Zhang et al (2021) discovered that the tectonic event was diachronous in the eastern and western parts of the YEB. Apatite fission track (AFT) data can provide a high-resolution timetable for the tectonic evolution, while vitrinite reflectance (Ro) can offer diagnostic evidence for the thermal history of source rocks (Ding et al, 2016;Qi et al, 2018;Ren, 1995). The combination of these methods will resolve the differences in the tectonic and hydrocarbon evolution in the YEB.…”

A Study on the Applicability of Aromatic Parameters in the Maturity Evaluation of Lacustrine Source Rocks and Oils Based on Pyrolysis Simulation Experiments

“…The basin was developed on Precambrian crystalline block or Paleozoic folded basement. − Since the Mesozoic, the basin has experienced four evolution stages: Triassic–Early Middle Jurassic transtensional fault-induced subsidence, Late Jurassic compressional uplift-induced denudation, Early Cretaceous extensional rifting, and Late Cretaceous Paleogene subsidence . The Suhongtu Depression (longitude 102°05′ to 106°00′ and latitude 40°50′ to 41°50′), located in the northern part of the Yingen-Ejinaqi Basin, is a second-order structural unit of the basin (Figure b). , The sedimentary fill in the Suhongtu Depression contains the Lower Cretaceous Bayingobi formation (K 1 b), Suhongtu formation (K 1 s), Yingen formation (K 1 y), Upper Cretaceous Wulansuhai formation (K 2 w), and Cenozoic covering succession. The Bayingobi formation can be divided into three members, namely, the first member of the Bayingobi formation (K 1 b 1 ), the second member of the Bayingobi formation (K 1 b 2 ), and the third member of the Bayingobi formation (K 1 b 3 ), from bottom to top, respectively (Figure c). ,, K 1 b 2 was deposited in deep-lake to semi-deep-lake environments, so it mainly formed fine-grained sediments.…”

“…The Suhongtu Depression (longitude 102°05′ to 106°00′ and latitude 40°50′ to 41°50′), located in the northern part of the Yingen-Ejinaqi Basin, is a second-order structural unit of the basin (Figure b). , The sedimentary fill in the Suhongtu Depression contains the Lower Cretaceous Bayingobi formation (K 1 b), Suhongtu formation (K 1 s), Yingen formation (K 1 y), Upper Cretaceous Wulansuhai formation (K 2 w), and Cenozoic covering succession. The Bayingobi formation can be divided into three members, namely, the first member of the Bayingobi formation (K 1 b 1 ), the second member of the Bayingobi formation (K 1 b 2 ), and the third member of the Bayingobi formation (K 1 b 3 ), from bottom to top, respectively (Figure c). ,, K 1 b 2 was deposited in deep-lake to semi-deep-lake environments, so it mainly formed fine-grained sediments. Moreover, the water environment at that time was brackish and weak reduction-weak oxidation, as it can be seen from Figure a that the source rocks generally have a high gammacerane content.…”

“…Lacustrine source rocks are widely distributed, especially in the Mesozoic formations of northern China. Lacustrine deposits are a field of interest for petroleum exploration and exploitation in China, with several large oil fields having been discovered in these lacustrine basinsincluding the Ordos, Songliao, and Bohaiwan, among others. − Comparing these with marine source rocks, the heterogeneity of lacustrine source rocks is stronger and their influencing factors on aromatic maturity parameters are more complex. The same is true for oils generated by lacustrine source rocks. − However, previous studies on aromatic maturity parameters have largely focused on application; the validity and mechanism have seldom been considered.…”