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Identification of the favorable salt-and potash-forming layer, we still mainly rely on logging interpretation and coring verification. However, we both know that the continuously carbonate platform is cyclical growing. It has recorded valuable information about the phase transition of carbonate rocks, which were synchronized with the relative sea-level cycles. This paper presents a fast and efficient way to preliminary judge favorable potassium-rich intervals: utilizing the natural gamma ray logging data, using numerical simulation, highfrequency sedimentary cycles could be identified effectively from the sedimentary record, then we can inverse the distribution model and stacking patterns of these cycles, restore the ancient relative sea-level trends，and finally deduce the favorable salt-and potashforming phases from the low-stand depositional system. On the basis of these principles, in this paper, a case study has been taken in Triassic of Guang'an area, in the central of Sichuan Basin. We deem that the interval form the Fifth Member of the Jialingjiang Formation to the First Member of the Leikoupo Formation is the most potential salt-and potash-forming layer (Fig. 1). The favorable potassium interval that we identified is consistent with the potassiumrich layer which is realized by other academics according to the drill core. It shows that this ZHOU Jiayun, GONG Daxing, CHEN Kegui, LI Chunmei and LI Meng, 2014. Sea-level Eustatic Cycles and Potash Formation Event: A Case Study of Triassic Sichuan Basin. Acta Geologica Sinica (English Edition), 88(supp. 1): 285-286. Fig. 1. Integrated column of sea-level change in the early and middle Triassic, in Guang'an area, Sichuan, China.

Eastern China is made of a number of large and small continental fragments throughout late Paleozoic and Mesozoic time, and is still the best natural laboratory for examining kinematic models of continent tectonics. The paleoelevation history of eastern China provides direct insight into the tectonic processes in China. Here we present basalt-vesicularity based estimates of the paleoaltimetry of the early Cretaceous basalts in northern East China, which indicate that the studied basalt units were at an elevation of more than 4 kilometers in late Mesozoic. Two vesicular basaltic rocks have been collected form bottom to top along the lava flow outcrop in eastern Inner Mongolia. After the digital precessing to the sample cross-sections, and taking advantage of the stereological conversion method to acquire the bubble size distributions, paleoelevation estimate was calculated for East China in the early Cretaceous. The results show that the elevation has been near 4700±750 m when the lava flows was cooling, implying that there were highland regions in the northern part of the East China Plateau during the early Cretaceous. Combined with other geological evidence, we conclude that there was a high plateau with elevation near 5000 m above sea level in Eastern China during the late Mesozoic. This ancient high plateau in eastern China was most likely formed by the collision of the north and south China blocks.early Cretaceous, east China Plateau, vesicular-basalt, paleoaltimetry, north and south China collision

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