Unbekannt
PANGAEA
In:
Supplement to: Krissek, Lawrence A; Morley, Joseph J; Lofland, Darlene K (1985): The occurrence, abundance, and composition of ice-rafted debris in sediments from Deep Sea Drilling Project Sites 579 and 580, Northwest Pacific. In: Heath GR; Burckle LH; et al. (eds.), Initial Reports of the Deep Sea Drilling Project, Washington (U.S. Govt. Printing Office), 86, 647-655, https://doi.org/10.2973/dsdp.proc.86.128.1985
Publikationsdatum:
2023-06-27
Beschreibung:
The abundance and composition of the coarse-sand fraction (250 µm-2 mm) of samples from Deep Sea Drilling Project Sites 579 and 580 were investigated to determine the chronology of ice rafting at these locations.
The ice-rafting signal at these sites is reduced relative to the generalized ice-rafting chronology of the North Pacific (Kent et al., 1971) because of increased distance to the ice-rafting source areas. These data, however, do record the general increase in ice-rafting importance as sediment age decreases, especially between 0 and 1.0 m.y. ago. In addition, peaks in ice-rafting importance since 1.0 m.y. ago at Sites 579 and 580 are generally synchronous with periods of major ice-rafting influence throughout the North Pacific. The first occurrence of ice-rafted debris at the Matuyama/Gauss magnetic boundary supports a proposed age of approximately 2.47 m.y. for the onset of major Northern Hemisphere glaciation.
The coarse-sand fraction at Sites 579 and 580 contains a significant component of non-ice-rafted material, particularly biogenic particles and volcanic pumice. Under these conditions, the standard assumption that the weight percent of the coarse-sand fraction reflects variations in ice-rafting importance may not be valid. For samples taken at some distance from the source of ice-rafted debris, both the abundance and the composition of the coarse-sand fraction must be considered to obtain a valid measure of the influence of sediment transport via ice rafting.
Schlagwort(e):
86-579; 86-579A; 86-580; AGE; Biogenic particles; Counting 250-2000 µm fraction; Deep Sea Drilling Project; DEPTH, sediment/rock; DRILL; Drilling/drill rig; DSDP; DSDP/ODP/IODP sample designation; Event label; Glomar Challenger; Ice rafted debris; Leg86; North Pacific; Sample code/label; Size fraction 2.000-0.250 mm; Volcanic components; Wet sieving
Materialart:
Dataset
Format:
text/tab-separated-values, 1227 data points
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