To reveal compaction processes and mechanisms, we have studied microtextures and magnetic fabrics of unlithified sediments collected from Hole 1074A, on the eastern flank of the Mid-Atlantic Ridge, during Leg 174B. Samples consisted of nannofossil ooze with varying amounts of foraminifers, clay, radiolarians and sand. Scanning electron microscope observation shows that nannofossils and planktonic foraminifers in the sediments are well preserved, that void space in the unlithified sediments is formed by an assemblage of microfossils consisting of a stairstep structure of nannofossils and an aggregation of foraminifers, and that the number of spine-shaped nannofossil fragments tends to increase with depth, suggesting weak deformation probably due to compaction occurring during burial. Anisotropy of magnetic susceptibility results, however, provide little obvious information about deformation of the sediments. These results are consistent with those of the onboard multisensor track measurements.

Supplement to: Hirano, Satoshi; Ogawa, Yujiro; Kawamura, Kiichiro (2001): Deformation of unlithified sediments in an early stage of the compaction process deduced from microtextures and magnetic fabrics: ODP Leg 174B, Hole 1074A. In: Becker, K; Malone, MJ (eds.) Proceedings of the Ocean Drilling Program, Scientific Results, College Station, TX (Ocean Drilling Program), 174B, 1-13