A terrigenous silt and clay facies has been shown to be the first sediment to accumulate on basement (both oceanic and continental) at many sites drilled during Leg 29, and at many DSDP sites in the Indian Ocean and Tasman Sea drilled during earlier legs. It is divided into two subfacies: a burrow-mottled subfacies which predominates and a bedded subfacies which is rare. The burrow mottled subfacies is dark olive-gray to dark brown, burrow mottled, organic-rich, pyrite, glauconite, and micronodul-bearing. It is a poorly sorted, clayey silt to clay, composed of land-derived detritus, and is characterized by a very restricted flora and fauna, the latter being dominated by siliceous, and agglutinating benthonic foraminifera. The upper third of the subfacies is silicified wherever the overlying sediments are rich in siliceous microfossils. It is inferred that the subfacies accumulated where bottom waters were oxygenated, but circulation was sluggish. It is further inferred that the subfacies accumulated during the early sea-floor-spreading phase in the evolution of the respective ocean basins. The bedded subfacies forms units that alternate with the burrow mottled subfacies at one site. It consists of slightly graded beds clayey silt. The microfossils are shallow-water benthonic foraminifera and neritic nannofossils. Graded beds are interpreted as turbidites.

West: 143.0000 East: 177.0000 North: -30.0000 South: -57.0000

West: NaN East: NaN North: NaN South: NaN

Expedition: 29

Provider: SEDIS Publication Catalogue

Data set link: http://sedis.iodp.org/pub-catalogue/index.php?id=10.2973/dsdp.proc.29.131.1975 (c.f. for more detailed metadata)

Data download: application/pdf

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