This paper first introduces procedures leading to the establishment of Late Permian-Middle Triassic sea level change curve of Yangtze platform. Bathymetric curves extracted from curve of habitat types are first transf...This paper first introduces procedures leading to the establishment of Late Permian-Middle Triassic sea level change curve of Yangtze platform. Bathymetric curves extracted from curve of habitat types are first transformed to sea level curves stage by stage. Comparison between curves of Yangtze and the world reveals that because the Late Permian marine sequences are lacking in most parts of the world, the Late Permian to Griesbachian curve of Yangtze may serve as an important reference for further revision of the world curve. The Early-Middle Triassic short-term changes of Yangtze are briefly concordant with those of Haq’s world curve, whereas their long-term changes are discordant. The latter, however, is representative of the East Asian regions affected by the Indosinian orogeny. Basically the third cycles of Yangtze and the world are only pertly concordant, and even in concordant cases their concrete boundaries are not coincident. This indicater that sea level changes are not strictly synchronous over the world. It seems that the 1st and 2nd cycles (supercycles and megacycles) may be world-wide, but not the 3rd cycles.展开更多
文摘This paper first introduces procedures leading to the establishment of Late Permian-Middle Triassic sea level change curve of Yangtze platform. Bathymetric curves extracted from curve of habitat types are first transformed to sea level curves stage by stage. Comparison between curves of Yangtze and the world reveals that because the Late Permian marine sequences are lacking in most parts of the world, the Late Permian to Griesbachian curve of Yangtze may serve as an important reference for further revision of the world curve. The Early-Middle Triassic short-term changes of Yangtze are briefly concordant with those of Haq’s world curve, whereas their long-term changes are discordant. The latter, however, is representative of the East Asian regions affected by the Indosinian orogeny. Basically the third cycles of Yangtze and the world are only pertly concordant, and even in concordant cases their concrete boundaries are not coincident. This indicater that sea level changes are not strictly synchronous over the world. It seems that the 1st and 2nd cycles (supercycles and megacycles) may be world-wide, but not the 3rd cycles.
