(Table 1) K-Ar age determinations on biotite from coarse sand within DSDP Sample 72-516F-76-4,107-115
Fuente:
PANGAEA
Saved in:
| Main Authors: | , |
|---|---|
| Format: | Dataset Open Access |
| Language: | en |
| Published: |
PANGAEA
1983
|
| Subjects: | |
| Online Access: | |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1867171815591247872 |
|---|---|
| author | Bryan, Wilfred B Duncan, Robert A |
| author_facet | Bryan, Wilfred B Duncan, Robert A |
| collection | Datos científicos de ciencias marinas y ambientales |
| contents | 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. |
| format | Dataset Open Access |
| id | pangaea_https___doi_org_10_1594_PANGAEA_811427 |
| institution | PANGAEA |
| language | en |
| publishDate | 1983 |
| publisher | PANGAEA |
| record_format | pangaea |
| spellingShingle | (Table 1) K-Ar age determinations on biotite from coarse sand within DSDP Sample 72-516F-76-4,107-115 Bryan, Wilfred B Duncan, Robert A 72-516F; Age, 40K/40Ar Potassium-Argon; Age, dated; Age, dated, standard deviation; Argon-40; Atomic absorption spectrometry (AAS); Deep Sea Drilling Project; DRILL; Drilling/drill rig; DSDP; DSDP/ODP/IODP sample designation; Glomar Challenger; Identification; Leg72; Mass spectrometry (MS); Potassium; Sample code/label; South Atlantic/CONT RISE 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. |
| title | (Table 1) K-Ar age determinations on biotite from coarse sand within DSDP Sample 72-516F-76-4,107-115 |
| topic | 72-516F; Age, 40K/40Ar Potassium-Argon; Age, dated; Age, dated, standard deviation; Argon-40; Atomic absorption spectrometry (AAS); Deep Sea Drilling Project; DRILL; Drilling/drill rig; DSDP; DSDP/ODP/IODP sample designation; Glomar Challenger; Identification; Leg72; Mass spectrometry (MS); Potassium; Sample code/label; South Atlantic/CONT RISE |
| url | https://doi.org/10.1594/PANGAEA.811427 |