Publication Date:
2023-06-27
Description:
This paper provides a brief, descriptive, sedimentological background for the chapters on hydraulic piston core Site 480 in this symposium, and supplements data given in the site chapter for Sites 479-480 (this volume, Pt. 1). Sediments are composed primarily of planktonic diatoms, with minor numbers of silicoflagellates, radiolarians, and varying amounts of both benthic and planktonic foraminifers, along with a large terrigenous component of olive brown, silty clay. The section contains meter-thick intervals of finely laminated facies alternating with nonlaminated zones. A few paleoenvironmental events are documented within the generally uniform sequence by sporadic occurrences of thin turbidites, phosphatic concretions, fish debris concentrations, an ash layer, and a thin layer of diagenetic dolomite. The distribution of nonlaminated and laminated zones is attributed to fluctuations of bottom-water oxygen content caused by variations in circulation, fertility, and productivity. Homogeneous sections are interpreted as coinciding with cooler climatic periods, whereas laminated sections seem to correspond to upwelling conditions during drier periods.
Keywords:
64-480; 64-481; Calcite (peak height); Chlorite (peak height); Clay minerals; Comment; Deep Sea Drilling Project; DRILL; Drilling/drill rig; DSDP; DSDP/ODP/IODP sample designation; Event label; Glomar Challenger; Height; Illite (peak height); Kalifeldspar (peak height); Leg64; North Pacific/Gulf of California/BASIN; Plagioclase (peak height); Pyrite (peak height); Quartz (peak height); Sample code/label; Silica, amorphous; Smectite (peak height); X-ray diffraction (XRD)
Type:
Dataset
Format:
text/tab-separated-values, 102 data points
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