By means of various data and measurements such as rock cores, well logging, mud logging, cast thin-sections and scanning electron microscope, this paper investigates the characteristics and origins of mixed sediments and their relation with petroleum-gas resources from Cretaceous-Paleocene in Batken region of Fergana basin in the central Asia. It is considered that mixed sediments from Cretaceous-Paleocene in the research area developed with two forms:mixed rocks and mixed layer series. The mixed rocks are dominantly terrigenous clastic bearing-carbonate rock and terrigenous clastithic-carbonate rock. And the mixed layer series are mainly carbonate rockmixed rock layer series and terrigenous clastic rock-mixed rock layer series. The mixed sediments in the research area are widely distributed in various environments, including restricted platform, evaporated platform, barrier coast and neritic shelf. Furthermore, the main origin of the mixed sediments is facies mixing, followed by in situ mixing and punctuated mixing. In addition, the mixed sediments in the research area made some contribution to source-reservoir-cap rocks. To be more specific, the marlite of Paleocene is one of the main source rocks as well as regional cap rocks for the research area. Besides, the limestone reservoirs of Paleogene and Cretaceous are not pure carbonate rocks. Instead, most of them are mixed rocks or part of the mixed layer series.

mixed sediments  /  mixed rocks  /  mixed layer series  /  Batken region of Fergana basin  /  Cretaceous-Paleogene