Deep-water fine-grained sediments; history, methodology and terminology

Abstract

To introduce this collection of papers presented at an international research workshop in Halifax, Canada (1982), we highlight briefly three aspects of deep-water fine-grained sediments that are alluded to throughout the volume but never discussed specifically. These are: (a) an historical outline of the research that has made both possible and necessary the workshop and the volume; (b) a review of the methodology currently used in the study of fine-grained sediments; and (c) an assessment of the state of terminology as applied to this class of rocks.

Can remanence anisotropy detect paleomagnetic inclination shallowing due to compaction? A case study using Cretaceous deep‐sea limestones

“…Almost all specimens can be termed limestones (more than half calcite according to Reijers and HsE [1986]). Only specimen 315A-26-2-123 can confidently be termed a claystone (dominated by siliciclastic grains, more than two thirds of which are < 4 #m in diameter according to Stow and Piper [1984] …”

Significance of Turbidites at Site 767 (Celebes Sea) and Site 768 (Sulu Sea)

“…There is a distinct change in the petrology of the material from stage 2 to stage 3: quartz is rare or absent in sand composed mainly of rock fragments (which include chert), rare feldspar and biotite mica. The siltstone layers show the characteristics of Tc-e and Td-e rhythms and the finer grained layers can be defined as T3 to P sequences (sensu Stow and Piper 1984). Stage 4, which is 81.5 m thick (Core 124-767B-35X to 124-767B-43X; 325 to 406.5 mbsf), consists of thin-to thickbedded silty clay and mud turbidites (Td-e, T4-P) which are of similar composition to those of stage 3.…”

“…In their original habitat, bolivinids would be low-oxygen markers, cassidulinids have an outer shelf and deeper occurrence, while the epiphytic discorbids would represent shallow water. In terms of Bouma (1962) sequences the beds consist of Td-e intervals and may be classified using the Stow and Piper (1984) scheme as T4-P and T6-P sequences. The base of the beds is usually sharp, but some layers show gradational contacts with underlying deposits, probably as a result of bioturbation of the thin silt layers.…”

“…For fine-grained mud and silt turbidites which contain only Bouma Td and Te intervals the Stow and Piper (1984) classification scheme has been additionally used to allow further subdivision into T1-T8 and P (pelagic or hemipelagic) intervals.…”

Biogenic Sedimentary Structures in Outer Bengal Fan Deposits Drilled during Leg 116

“…In this case the patchily distributed fauna cannot compensate for the rapid deposition (see above). Typical sedimentary structures (Stow and Piper, 1984) were used to identify muddy turbidites, and when such structures were lacking the gradation of physical properties was used (see Stow et al, this volume).…”