Bryan, Wilfred B; Duncan, Robert A (1983): (Table 1) K-Ar age determinations on biotite from coarse sand within DSDP Sample 72-516F-76-4,107-115 [dataset]. PANGAEA, https://doi.org/10.1594/PANGAEA.811427, Supplement to: Bryan, WB; Duncan, RA (1983): Age and provenance of clastic horizons from Hole 516F. In: Barker, PF; Carlson, RL; Johnson, DA; et al. (eds.), Initial Reports of the Deep Sea Drilling Project (U.S. Govt. Printing Office), 72, 475-477, https://doi.org/10.2973/dsdp.proc.72.118.1983
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Abstract:
Qualitative petrographic study of selected clastic horizons within the Eocene section of Hole 516F has revealed the presence of abundant fine-grained lithic fragments, probably volcanic, along with coarser fragments of quartz and feldspar apparently derived from a nearby plutonic terrain. In detail, poor sorting, presence of graded bedding, and an abundance of clay suggest these are turbidite horizons locally derived from a mixed volcanic/plutonic terrain, possibly with some direct contribution from contemporary volcanic ash falls. A progressive increase in plutonic versus volcanic components with time is, however, more consistent with an erosional origin for most of this material. Unusual euhedral dark biotite is abundant in several of the lower clastic horizons; it is most easily interpreted as microphenocrysts weathered in situ out of alkalic volcanic ash. Biotite separated from Sample 516F-76-4,107-115 cm, has been dated by the K-Ar method at about 46 Ma. Alkaline volcanoes active on the Rio Grande Rise in the middle Eocene would be the most probable source of this ash and would be consistent with other evidence for potassic, alkaline volcanism along the Rio Grande Rise and at the Tristan da Cunha hot spot.
Project(s):
Deep Sea Drilling Project (DSDP)
Coverage:
Latitude: -30.276500 * Longitude: -35.285000
Date/Time Start: 1980-03-11T00:00:00 * Date/Time End: 1980-03-11T00:00:00
Minimum Elevation: -1313.0 m * Maximum Elevation: -1313.0 m
Event(s):
72-516F * Latitude: -30.276500 * Longitude: -35.285000 * Date/Time: 1980-03-11T00:00:00 * Elevation: -1313.0 m * Penetration: 1270.6 m * Recovery: 690.1 m * Location: South Atlantic/CONT RISE * Campaign: Leg72 * Basis: Glomar Challenger * Method/Device: Drilling/drill rig (DRILL) * Comment: 127 cores; 1092.5 m cored; 9 m drilled; 63.2 % recovery
Comment:
Ages were calculated from the following decay and abundance constants: lambda-e = 0.581 x 10**-10 yr.**-1; lambda-beta = 4.962 x 10**-10 yr . - 1 ; 40K/K= 1.167 x 10**-4 mol/mol.
Parameter(s):
| # | Name | Short Name | Unit | Principal Investigator | Method/Device | Comment |
|---|---|---|---|---|---|---|
| 1 | Sample code/label | Sample label | Bryan, Wilfred B | DSDP/ODP/IODP sample designation | ||
| 2 | Identification | ID | Bryan, Wilfred B | |||
| 3 | Potassium | K | % | Bryan, Wilfred B | Atomic absorption spectrometry (AAS) | |
| 4 | Argon-40 | 40Ar | 10-7 cm3/g | Bryan, Wilfred B | Mass spectrometry | Radiogenic |
| 5 | Argon-40 | 40Ar | % | Bryan, Wilfred B | Mass spectrometry | Radiogenic |
| 6 | Age, dated | Age dated | ka | Bryan, Wilfred B | Age, 40K/40Ar Potassium-Argon | |
| 7 | Age, dated standard deviation | Age dated std dev | ± | Bryan, Wilfred B | Age, 40K/40Ar Potassium-Argon |
License:
Creative Commons Attribution 3.0 Unported (CC-BY-3.0)
Size:
14 data points