白垩质
3.The little narrow, crooked town of Dover hid itself away from the beach, and ran its head into the chalk cliffs, like a marine ostrich.
4.Re-search results indicate that the geothermal field of Jurassic was different from that of Cretaceous. Palaeogeothermal gradient inLate Jurassic was higher than that in Cretaceous. Palaeogeothermal gradient in Early Cretaceous was between 4. 80℃ /100m to5. 50℃/100m.
5.The tectonites in this zone include tectonic gneiss and mylonite. The biotite from the granitic mylonite gives a 40Ar/39Ar age of 105.2±1.7 Ma,implying that the ductile shear zone may be traced back to the Early Cretaceous.
6.The Coqen Basin in Xizang lies between the Bangong-Nujiang suture zone and Yarlung Zangbo suture zone, and once extended northwards and southwards, respectively centred by the Qiekan-Goicang-Asog rift zone as the center of deposition and subsidence during the Middle Jurassic to the Early Creatceous. (1) During the Middle-Late Jurassic, the rift zone was occupied by deep-water turbidites, radiolarian siliceous rocks, shallow-water carbonate rocks, clastic rocks and basic-ultrabasic rocks, while both sides of it by littoral and shallow marine elastic rocks and carbonate rocks.
7.The palaeogeographic research indicate that the palaeogeographic outline of the study area recorded the evolution from a sedimentary basin in which the shallow-water carbonate platform sediments and deep-water terrigenous clastic submarine fan developed from southeast to northwest and northeast during the Late Triassic through a submarine sheet-like model composed of deep-water sandy turbidite and fine-grained turbidite during the Early Jurassic to a terrigenous clastic barrier coast during the Middle and Late Jurassic and finally to the coal-bearing delta sediments during the Late Cretaceous.
