Studies on the fracture systems in the volcanic rocks, Changle-Linqu region, Shandong

The Changle-Linqu region is situated in the middle Shandong Province, and a t the Western block of the Yishu fault belt of Tanlu Fault. There are more than 200 volcanic hills, mainly occurring in the Miocene, Pliocene and Plei stocene in the region. The geological settings, occurrences, facies and the developing characteristics of the fractures and pores of volcanic rocks ar e systematically investigated in this paper. Four main pore systems are rec ognized: (1) the volcanic channel facies pore system, characterized by the well developed macro-fracture, semi-fill and pillar-plane joints; (2) the v olcanic lava facies net pore system composed of various kind, scale, occurr ence, evolution of joints, fractures and pores; (3) volcanic eruption facie s pore system, and (4) eruption-deposition facies pore system. The quantita tive models of the pore systems are also primarily established.