Primary mineralogy of ODP Leg 115 basalts
Basement rocks were recovered at four sites on Leg 115 along the Reunion hotspot track in the western Indian Ocean. Plate tectonic reconstructions indicate that the drilled structures formed in three different volcanic environments. Sites 706 and 713 from the eastern side of the Saya de Malha Bank a...
Main Authors: | , |
---|---|
Format: | Dataset |
Language: | English |
Published: |
PANGAEA
1990
|
Subjects: | |
Online Access: | https://doi.pangaea.de/10.1594/PANGAEA.755762 https://doi.org/10.1594/PANGAEA.755762 |
id |
ftpangaea:oai:pangaea.de:doi:10.1594/PANGAEA.755762 |
---|---|
record_format |
openpolar |
spelling |
ftpangaea:oai:pangaea.de:doi:10.1594/PANGAEA.755762 2023-05-15T16:52:59+02:00 Primary mineralogy of ODP Leg 115 basalts Fisk, Martin R Howard, Katherine J MEDIAN LATITUDE: -5.052964 * MEDIAN LONGITUDE: 67.480065 * SOUTH-BOUND LATITUDE: -13.114000 * WEST-BOUND LONGITUDE: 59.016800 * NORTH-BOUND LATITUDE: 5.081500 * EAST-BOUND LONGITUDE: 73.831300 * DATE/TIME START: 1987-05-22T23:15:00 * DATE/TIME END: 1987-06-28T07:45:00 1990-01-14 application/zip, 15 datasets https://doi.pangaea.de/10.1594/PANGAEA.755762 https://doi.org/10.1594/PANGAEA.755762 en eng PANGAEA https://doi.pangaea.de/10.1594/PANGAEA.755762 https://doi.org/10.1594/PANGAEA.755762 CC-BY-3.0: Creative Commons Attribution 3.0 Unported Access constraints: unrestricted info:eu-repo/semantics/openAccess CC-BY Supplement to: Fisk, Martin R; Howard, Katherine J (1990): Primary mineralogy of Leg 115 basalts. In: Duncan, RA; Backmann, J; Peterson, LC; et al. (eds.), Proceedings of the Ocean Drilling Program, Scientific Results, College Station, TX (Ocean Drilling Program), 115, 23-42, https://doi.org/10.2973/odp.proc.sr.115.122.1990 115-706A 115-706B 115-706C 115-707C 115-713A 115-715A DRILL Drilling/drill rig Indian Ocean Joides Resolution Lakshadweep Sea Leg115 Ocean Drilling Program ODP South Indian Ridge South Indian Ocean Dataset 1990 ftpangaea https://doi.org/10.1594/PANGAEA.755762 https://doi.org/10.2973/odp.proc.sr.115.122.1990 2023-01-20T07:32:01Z Basement rocks were recovered at four sites on Leg 115 along the Reunion hotspot track in the western Indian Ocean. Plate tectonic reconstructions indicate that the drilled structures formed in three different volcanic environments. Sites 706 and 713 from the eastern side of the Saya de Malha Bank and the northern end of the Chagos Bank, respectively, are on a large volcanic platform analogous to Iceland on the Mid-Atlantic Ridge. Lavas at Site 707 on the northwestern side of the Saya de Malha Bank erupted during the early stages of rifting of the Seychelles from India. Basalts from Site 715 were erupted onto an isolated oceanic island that was distant from ocean ridges and continents much as Reunion Island is today. Many of the rocks were examined in thin section and found to be primarily augite-plagioclase basalts with minor olivine and rare opaque oxides. Site 715 is unusual in that it contains a variety of basalts including olivine-rich and aphyric Fe-Ti basalts. At each of the four sites the rocks were grouped into chemical types (units) on the basis of ship- board bulk-rock analyses and at least one thin section from each chemical unit was analyzed by electron microprobe. The plagioclase and augite chemistry reflects the bulk-rock chemistry and, in general, these minerals were in equilibrium with their host magmas at the time the basalts were quenched. Olivine was rarely preserved, but where it is still present it also appears to have crystallized in equilibrium with the host magma. At three of the drill sites plagioclase phenocrysts or megacrysts that crystallized from a primitive magma are also present. The one site (715) that does not contain these primitive plagioclase phenocrysts is also the site that appears to have been influenced the least by ocean- ridge or Deccan-type magmas. Site 715, furthermore, has a mineralogy that is dominated by olivine as compared with the plagioclase-rich lavas of the other sites. Dataset Iceland PANGAEA - Data Publisher for Earth & Environmental Science Indian Mid-Atlantic Ridge ENVELOPE(59.016800,73.831300,5.081500,-13.114000) |
institution |
Open Polar |
collection |
PANGAEA - Data Publisher for Earth & Environmental Science |
op_collection_id |
ftpangaea |
language |
English |
topic |
115-706A 115-706B 115-706C 115-707C 115-713A 115-715A DRILL Drilling/drill rig Indian Ocean Joides Resolution Lakshadweep Sea Leg115 Ocean Drilling Program ODP South Indian Ridge South Indian Ocean |
spellingShingle |
115-706A 115-706B 115-706C 115-707C 115-713A 115-715A DRILL Drilling/drill rig Indian Ocean Joides Resolution Lakshadweep Sea Leg115 Ocean Drilling Program ODP South Indian Ridge South Indian Ocean Fisk, Martin R Howard, Katherine J Primary mineralogy of ODP Leg 115 basalts |
topic_facet |
115-706A 115-706B 115-706C 115-707C 115-713A 115-715A DRILL Drilling/drill rig Indian Ocean Joides Resolution Lakshadweep Sea Leg115 Ocean Drilling Program ODP South Indian Ridge South Indian Ocean |
description |
Basement rocks were recovered at four sites on Leg 115 along the Reunion hotspot track in the western Indian Ocean. Plate tectonic reconstructions indicate that the drilled structures formed in three different volcanic environments. Sites 706 and 713 from the eastern side of the Saya de Malha Bank and the northern end of the Chagos Bank, respectively, are on a large volcanic platform analogous to Iceland on the Mid-Atlantic Ridge. Lavas at Site 707 on the northwestern side of the Saya de Malha Bank erupted during the early stages of rifting of the Seychelles from India. Basalts from Site 715 were erupted onto an isolated oceanic island that was distant from ocean ridges and continents much as Reunion Island is today. Many of the rocks were examined in thin section and found to be primarily augite-plagioclase basalts with minor olivine and rare opaque oxides. Site 715 is unusual in that it contains a variety of basalts including olivine-rich and aphyric Fe-Ti basalts. At each of the four sites the rocks were grouped into chemical types (units) on the basis of ship- board bulk-rock analyses and at least one thin section from each chemical unit was analyzed by electron microprobe. The plagioclase and augite chemistry reflects the bulk-rock chemistry and, in general, these minerals were in equilibrium with their host magmas at the time the basalts were quenched. Olivine was rarely preserved, but where it is still present it also appears to have crystallized in equilibrium with the host magma. At three of the drill sites plagioclase phenocrysts or megacrysts that crystallized from a primitive magma are also present. The one site (715) that does not contain these primitive plagioclase phenocrysts is also the site that appears to have been influenced the least by ocean- ridge or Deccan-type magmas. Site 715, furthermore, has a mineralogy that is dominated by olivine as compared with the plagioclase-rich lavas of the other sites. |
format |
Dataset |
author |
Fisk, Martin R Howard, Katherine J |
author_facet |
Fisk, Martin R Howard, Katherine J |
author_sort |
Fisk, Martin R |
title |
Primary mineralogy of ODP Leg 115 basalts |
title_short |
Primary mineralogy of ODP Leg 115 basalts |
title_full |
Primary mineralogy of ODP Leg 115 basalts |
title_fullStr |
Primary mineralogy of ODP Leg 115 basalts |
title_full_unstemmed |
Primary mineralogy of ODP Leg 115 basalts |
title_sort |
primary mineralogy of odp leg 115 basalts |
publisher |
PANGAEA |
publishDate |
1990 |
url |
https://doi.pangaea.de/10.1594/PANGAEA.755762 https://doi.org/10.1594/PANGAEA.755762 |
op_coverage |
MEDIAN LATITUDE: -5.052964 * MEDIAN LONGITUDE: 67.480065 * SOUTH-BOUND LATITUDE: -13.114000 * WEST-BOUND LONGITUDE: 59.016800 * NORTH-BOUND LATITUDE: 5.081500 * EAST-BOUND LONGITUDE: 73.831300 * DATE/TIME START: 1987-05-22T23:15:00 * DATE/TIME END: 1987-06-28T07:45:00 |
long_lat |
ENVELOPE(59.016800,73.831300,5.081500,-13.114000) |
geographic |
Indian Mid-Atlantic Ridge |
geographic_facet |
Indian Mid-Atlantic Ridge |
genre |
Iceland |
genre_facet |
Iceland |
op_source |
Supplement to: Fisk, Martin R; Howard, Katherine J (1990): Primary mineralogy of Leg 115 basalts. In: Duncan, RA; Backmann, J; Peterson, LC; et al. (eds.), Proceedings of the Ocean Drilling Program, Scientific Results, College Station, TX (Ocean Drilling Program), 115, 23-42, https://doi.org/10.2973/odp.proc.sr.115.122.1990 |
op_relation |
https://doi.pangaea.de/10.1594/PANGAEA.755762 https://doi.org/10.1594/PANGAEA.755762 |
op_rights |
CC-BY-3.0: Creative Commons Attribution 3.0 Unported Access constraints: unrestricted info:eu-repo/semantics/openAccess |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.1594/PANGAEA.755762 https://doi.org/10.2973/odp.proc.sr.115.122.1990 |
_version_ |
1766043497559752704 |