Data report: permeability and microfabric of mud(stone) samples from IODP Sites C0011 and C0012, NanTroSEIZE subduction inputs: Expedition 322

Abstract

This report documents the results of constant-flow permeability tests in the horizontal (cross-core) and vertical (along-core) directions, administered at an effective isotropic confining stress of 0.55 MPa (80 psi). The whole-round specimens of mud(stone) were collected from depths of ~34 to 748 meters below seafloor at Integrated Ocean Drilling Program Sites C0011 and C0012 in the Shikoku Basin. Unfortunately, only ten samples were tested successfully; five samples failed because of drilling-induced core damage or friability. Most test results show minor anisotropy effects, with horizontal permeability greater than vertical. At Site C0011, the range of hydraulic conductivity (K) is 1.76 × 10–8 to 3.70 × 10–10 cm/s. Intrinsic permeability (k) ranges from 1.75 × 10–17to 3.67 × 10–19 m2, and the average ratio of horizontal to vertical permeability (kh/kv) is 1.26. At Site C0012, values of K range from 3.80 × 10–8 to 1.69 × 10–9 cm/s. Intrinsic permeability ranges from 3.77 × 10–17 to 1.68 × 10–18, and the average ratio of kh/kv is 1.58. Environmental scanning electron microscopy shows that grain fabric is random and does not vary significantly among the specimens tested. Moreover, the correlation of microfabric statistics with kh/kv values is not statistically significant.