Authigenic Minerals of Paleozoic-Cenozoic Volcanogenic-Sedimentary Rocks in the Southern Primorye Region

Authigenic minerals of volcanogenic-sedimentary and sedimentary rocks have been studied from the Permian to the Miocene in the southern Primorye region. Corrensite, rectorite, highly ordered mixed-layer chlorite-smectite (corrensite-like) and illite-smectite (rectorite-like) varieties, mica, vermiculite-like varieties (?), chlorite, defective chlorite, kaolinite, calcite, and zeolites were found. Such a range of minerals indicates that the thickness of the deposites in the sedimentary basins studied could attain 3 to 5 km and the temperature of their formation was higher than 150 degrees C. The formation of Lower Cretaceous and Paleocene sedimentary strata are characterized by similar features and probably first occurred in the shallow sea basin on the continental margin (rift stage), sometimes under conditions close to evaporitic (presence of corrensite?), with frequent alternations of the facial situation from shallow to deep sedimentation, episodic volcanic material supply and gradual deepening of sedimentation basins. It is proposed that in the Early Cretaceous and Paleogene, sedimentation basins that formed a scattered network on the continental margin of northeastern Asia evolved under an integrated mineralogical and tectono-sedimentological regime of crustal extension. The minerals were accumulated in the sediments, which were transformed during epigenesis in the following directions: (a) smectite-rectorite-mica; (b) smectite (palygorskite, sepiolite?)-corrensite-chlorite. In the examined sedimentary complexes, three mineralogical "stages" have been distinguished: (1) chlorite-mica (mica-chlorite)-mica-chlorite (Permian-to-Cretaceous); (2) transitional-mixed-layer corrensite-like and rectorite-like minerals (Cretaceous-Paleocene-Eocene), and (3) smectite (from Oligocene up to the present).