Mineralogy and pore characteristics of marine gas hydrate-bearing sediments in the northern South China Sea

Properties of host sediments are critical to understanding the formation and occurrence of gas hydrates in nature. This study investigates the mineralogy and pore characteristics of marine gas hydrate-bearing sediments (GHBS) within and below two high-saturation zones cored in drilling site W01 in the Qiongdongnan Basin in the South China Sea. The study involves an original application of high-resolution SEM imaging and automated mineralogy to fields-of-view (FOVs) large enough to undertake quantitative analyses at micro- to nano-scales. The samples are mainly fine-grained (1 μm are as important as those 0.1–1 μm in size. A third sample from an underlying zone has similar mineral compositions, grain-size and pore-size distributions to those in the uppermost high-saturation hydrate bearing zone. The largest pores are due to microfossil cavities, but their contribution to total porosity is