Microscopic fabric of sedimentary rocks based on rock magnetic properties of borehole samples: a case study for Wakkanai Formation distributed around Horonobe area in Hokkaido, Japan

Abstract

Groundwater flow is controlled by fracture network in upper crust, of which density and azimuth have been investigated in situ observations of subsurface samples. We executed rock magnetic analysis on oriented core samples of siliceous mudstone of the Wakkanai Formation obtained at Horonobe, north Hokkaido, Japan. Directions of its remanent magnetization imply tectonic rotation, and anisotropy of magnetic susceptibility delineates microscopic fabric governed by tectonic / sedimentary processes.