Home – Home – Jornals – Russian Geology and Geophysics 2002 number 6

Data on the stratigraphy of siliceous-basalt deposits of Ordovician age from Central Kazakhstan have been summarized. The age, succession, and correlation between these deposits are refined. Geological dating and correlation are based chiefly on conodonts and, to a lesser extent, graptolites. It is established that the age of these formations in the west and east of Central Kazakhstan is constrained by the Early to Middle Ordovician and in the interior structures (Zhungaria-Balkhash zone) it spans the entire Ordovician and, possibly, early Silurian. The siliceous and siliceous-terrigene deposits of Ordovician age are the water-deepest hemipelagic and pelagic sediments, and their accumulation corresponds to the maximum of Arenigian-to-Llanvirnian transgression. The reported paleo-geographic and paleotectonic data are in agreement with the existing paleotectonic reconstructions according to which Central Kazakhstan was a marginal basin of the West Pacific type during the Ordovician.