Zircon U-Pb ages of the basement rocks beneath the Songliao Basin, NE China

Zircon SHRIMP U-Pb dating of meta-diorite from the basement of the Songliao Basin and its geological significance

“…According to geochemical data of ref. [2], the two granites both show significant HREE depletion indicating a residual phase of garnet in their source regions, resemble to typical adakitic rocks [18,19] . The granite with the age of 305±2 Ma is coeval with the Late-Paleozoic accretion of arc complexes in the North Orogenic Belt [20] , whereas the 165Ma granite is generally coeval with the Mesozoic granites formed in an extension regime in eastern China [21,22] .…”

“…This suggests that the Precambrian basement do exist beneath the south Songliao Basin. Wu et al [1,2] dated by using conventional zircon U-Pb method on two gneissic granites from western and eastern sides of the Changyuan uplift beneath the central-north Songliao Basin, and obtained 206 Pb/ 238 U ages of 305±2 Ma (sample DuI-4) and 165 Ma (sample Ershen-1), respectively. The authors interpreted these ages as the emplacement ages of the two granites.…”

“…However, previous studies on the basement of the basin are relatively poor, and it has long been controversial regarding the nature and formation age of the basin. For example, some researchers suggested, mainly based on conventional zircon U-Pb ages, that there was no Precambrian basement beneath the basin, but a late paleozoic to early Mesozoic composite basement generated by accretion of several micro-plates [1,2]1) , other authors proposed that the basin had Precambrian basement, chiefly according to gravity and magnetic characteristics, which were consistent with those of Precambrian terranes [3][4][5][6] , but the latter is lack of reliable isotopic dating evidence. In this paper, we report reliable isotopic dating data, obtained by using the sensitive high resolution ion microprobe (SHRIMP), of a meta-diorite sample collected from the Si-5 drilling core in southern portion of the Songliao Basin.…”

Zircon SHRIMP U-Pb ages of the “Xinghuadukou Group” in Hanjiayuanzi and Xinlin areas and the “Zhalantun Group” in Inner Mongolia, Da Hinggan Mountains

“…Some authors proposed that there were three continental blocks in the region, from north to south, namely Ergun, Hinggan, and Songnen blocks [4,5,18,19] , and that the later two were collided along the Hegenshan-Zhalaite-Nenjiang suture during the Late Paleozoic period [20,21] . However, few data are available to constrain the position and timing of the suturing of the first two blocks.…”

LA-ICP-MS zircon U-Pb dating from granitoids in southern basement of Songliao basin: Constraints on ages of the basin basement

“…The statistical results of ages suggest that the middle Jurassic granitoids constitute the main part of basement granitoids, and that the Hercynian and Indo-Sino magmatisms also occur in the basin basement. It is implied that the Songliao basin should be a rift one formed in the intracontinent or active continental margin settings in the late Mesozoic after the Middle Jurassic orogeny took place.Songliao basin, basement, granitoid, zircon, LA-ICP-MS U-Pb datingThe Songliao basin, as the most important nonmarine oil-gas-bearing basin in eastern China, has been an issue for geologists to research its formation, evolution, and origin [1][2][3] . Compared with the study on its formation and evolution, filling sequence, and sequency stratigraphy [4] , the research on the basement, especially its chronology, is scare [2,[5][6][7] .…”