Abstract
Some geological problems on the upheaval of the northern part of the Hidaka Belt, cased on the studies of the Miocene strata, Kitami-Takinoue region, are described. The Miocene strata can be divided into the following two units in ascending order; i. e., the Kamishiyubetsu Formation (early middle Miocene) and the Oshiraneppu-gawa Formation (middle Miocene). The coarse clastic materials in the lower part of the Kamishiyubetsu Formation have been derived from the Hidaka Supergroup, during early middle Miocene. After the deposition of the muddy facies in the upper part of the Kamishiyubetsu Formation, coarse clastic materials among the Oshirneppu-gawa Formation, i. e., sandstone, slate, phyllite, hornfels, granite, and other rocks, are supplied from N-S trending Uenshiri Horst Zone (NAKAMURA et al. 1980). The Uenshiri Horst Zone, at the Central part of the Hidaka Belt, became the mountain range during the early middle Miocene. This zone provides a large amount of coarse clastic materials to the sorrounding strongly subsiding the Ishikari-Teshio Belt and Okoppe-Shikaribetsu Belt area.
