Whole rock and Cr-rich spinel geochemistry of ODP Legs 152 and 163 and DSDP Hole 38-338 samples
Coring during Ocean Drilling Program and Deep Sea Drilling Project Legs 163, 152, 104, 81, and 38 recovered sequences of altered basalt from North Atlantic seaward-dipping reflector sequences (SDRS) erupted during the initial rifting of Greenland from northern Europe and likely associated with exces...
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ftpangaea:oai:pangaea.de:doi:10.1594/PANGAEA.804790 2023-05-15T16:27:46+02:00 Whole rock and Cr-rich spinel geochemistry of ODP Legs 152 and 163 and DSDP Hole 38-338 samples Allan, James F Forsythe, Lance Natland, James H MEDIAN LATITUDE: 65.616695 * MEDIAN LONGITUDE: -17.620247 * SOUTH-BOUND LATITUDE: 63.472800 * WEST-BOUND LONGITUDE: -39.827800 * NORTH-BOUND LATITUDE: 67.785200 * EAST-BOUND LONGITUDE: 5.387700 * DATE/TIME START: 1974-08-14T00:00:00 * DATE/TIME END: 1995-10-01T13:00:00 1999-01-07 application/zip, 5 datasets https://doi.pangaea.de/10.1594/PANGAEA.804790 https://doi.org/10.1594/PANGAEA.804790 en eng PANGAEA https://doi.pangaea.de/10.1594/PANGAEA.804790 https://doi.org/10.1594/PANGAEA.804790 CC-BY-3.0: Creative Commons Attribution 3.0 Unported Access constraints: unrestricted info:eu-repo/semantics/openAccess CC-BY Supplement to: Allan, James F; Forsythe, Lance; Natland, James H (1999): Determination of primitive melt composition in the North Atlantic seaward-dipping reflector sequences from Cr-rich spinel compositions. In: Larsen, HC; Duncan, RA; Allan, JF; Brooks, K (eds.) Proceedings of the Ocean Drilling Program, Scientific Results, College Station, TX (Ocean Drilling Program), 163, 1-16, https://doi.org/10.2973/odp.proc.sr.163.121.1999 Ocean Drilling Program ODP Dataset 1999 ftpangaea https://doi.org/10.1594/PANGAEA.804790 https://doi.org/10.2973/odp.proc.sr.163.121.1999 2023-01-20T07:32:50Z Coring during Ocean Drilling Program and Deep Sea Drilling Project Legs 163, 152, 104, 81, and 38 recovered sequences of altered basalt from North Atlantic seaward-dipping reflector sequences (SDRS) erupted during the initial rifting of Greenland from northern Europe and likely associated with excessive mantle temperatures caused by an impacting mantle plume head. Cr-rich spinel is found abundantly as inclusions and groundmass crystals within the olivine-rich lavas of Hole 917A (Leg 152) cored into the Southeast Greenland SDRS, but only rarely as inclusions within plagioclase in the lavas of the Vøring Plateau SDRS, and it is absent from other cored SDRS lavas from the Rockall Plateau and Southeast Greenland. Eruptive melt compositions determined from inferred, thermodynamically-defined, spinel-melt exchange equilibria indicate that the most primitive melts represented by Hole 917A basalts have Mg/(Mg + Fe2+) at least as high as 0.70 and approach near-primary mantle melt compositions. In contrast, Cr-rich spinels from Hole 338 (Leg 38) lavas on the Vøring Plateau SDRS give evidence for melt with Mg/(Mg + Fe2+) only as high as 0.64. This study underlines that primitive melts similar to those from Hole 917A comprise only a small fraction of the eruptive North Atlantic SDRS melts, and that most SDRS basalts were, in fact, too evolved to have precipitated Cr-rich spinel, with true melt Mg/(Mg + Fe2+) likely below 0.60. The evolved nature of the SDRS basalts implies large amounts of fractionation at the base of the crust or deep within it, consistent with seismic results that indicate an abnormally thick Layer 3 underlying the SDRS. Dataset Greenland North Atlantic PANGAEA - Data Publisher for Earth & Environmental Science Greenland Vøring Plateau ENVELOPE(4.000,4.000,67.000,67.000) Rockall Plateau ENVELOPE(-18.833,-18.833,56.333,56.333) ENVELOPE(-39.827800,5.387700,67.785200,63.472800) |
institution |
Open Polar |
collection |
PANGAEA - Data Publisher for Earth & Environmental Science |
op_collection_id |
ftpangaea |
language |
English |
topic |
Ocean Drilling Program ODP |
spellingShingle |
Ocean Drilling Program ODP Allan, James F Forsythe, Lance Natland, James H Whole rock and Cr-rich spinel geochemistry of ODP Legs 152 and 163 and DSDP Hole 38-338 samples |
topic_facet |
Ocean Drilling Program ODP |
description |
Coring during Ocean Drilling Program and Deep Sea Drilling Project Legs 163, 152, 104, 81, and 38 recovered sequences of altered basalt from North Atlantic seaward-dipping reflector sequences (SDRS) erupted during the initial rifting of Greenland from northern Europe and likely associated with excessive mantle temperatures caused by an impacting mantle plume head. Cr-rich spinel is found abundantly as inclusions and groundmass crystals within the olivine-rich lavas of Hole 917A (Leg 152) cored into the Southeast Greenland SDRS, but only rarely as inclusions within plagioclase in the lavas of the Vøring Plateau SDRS, and it is absent from other cored SDRS lavas from the Rockall Plateau and Southeast Greenland. Eruptive melt compositions determined from inferred, thermodynamically-defined, spinel-melt exchange equilibria indicate that the most primitive melts represented by Hole 917A basalts have Mg/(Mg + Fe2+) at least as high as 0.70 and approach near-primary mantle melt compositions. In contrast, Cr-rich spinels from Hole 338 (Leg 38) lavas on the Vøring Plateau SDRS give evidence for melt with Mg/(Mg + Fe2+) only as high as 0.64. This study underlines that primitive melts similar to those from Hole 917A comprise only a small fraction of the eruptive North Atlantic SDRS melts, and that most SDRS basalts were, in fact, too evolved to have precipitated Cr-rich spinel, with true melt Mg/(Mg + Fe2+) likely below 0.60. The evolved nature of the SDRS basalts implies large amounts of fractionation at the base of the crust or deep within it, consistent with seismic results that indicate an abnormally thick Layer 3 underlying the SDRS. |
format |
Dataset |
author |
Allan, James F Forsythe, Lance Natland, James H |
author_facet |
Allan, James F Forsythe, Lance Natland, James H |
author_sort |
Allan, James F |
title |
Whole rock and Cr-rich spinel geochemistry of ODP Legs 152 and 163 and DSDP Hole 38-338 samples |
title_short |
Whole rock and Cr-rich spinel geochemistry of ODP Legs 152 and 163 and DSDP Hole 38-338 samples |
title_full |
Whole rock and Cr-rich spinel geochemistry of ODP Legs 152 and 163 and DSDP Hole 38-338 samples |
title_fullStr |
Whole rock and Cr-rich spinel geochemistry of ODP Legs 152 and 163 and DSDP Hole 38-338 samples |
title_full_unstemmed |
Whole rock and Cr-rich spinel geochemistry of ODP Legs 152 and 163 and DSDP Hole 38-338 samples |
title_sort |
whole rock and cr-rich spinel geochemistry of odp legs 152 and 163 and dsdp hole 38-338 samples |
publisher |
PANGAEA |
publishDate |
1999 |
url |
https://doi.pangaea.de/10.1594/PANGAEA.804790 https://doi.org/10.1594/PANGAEA.804790 |
op_coverage |
MEDIAN LATITUDE: 65.616695 * MEDIAN LONGITUDE: -17.620247 * SOUTH-BOUND LATITUDE: 63.472800 * WEST-BOUND LONGITUDE: -39.827800 * NORTH-BOUND LATITUDE: 67.785200 * EAST-BOUND LONGITUDE: 5.387700 * DATE/TIME START: 1974-08-14T00:00:00 * DATE/TIME END: 1995-10-01T13:00:00 |
long_lat |
ENVELOPE(4.000,4.000,67.000,67.000) ENVELOPE(-18.833,-18.833,56.333,56.333) ENVELOPE(-39.827800,5.387700,67.785200,63.472800) |
geographic |
Greenland Vøring Plateau Rockall Plateau |
geographic_facet |
Greenland Vøring Plateau Rockall Plateau |
genre |
Greenland North Atlantic |
genre_facet |
Greenland North Atlantic |
op_source |
Supplement to: Allan, James F; Forsythe, Lance; Natland, James H (1999): Determination of primitive melt composition in the North Atlantic seaward-dipping reflector sequences from Cr-rich spinel compositions. In: Larsen, HC; Duncan, RA; Allan, JF; Brooks, K (eds.) Proceedings of the Ocean Drilling Program, Scientific Results, College Station, TX (Ocean Drilling Program), 163, 1-16, https://doi.org/10.2973/odp.proc.sr.163.121.1999 |
op_relation |
https://doi.pangaea.de/10.1594/PANGAEA.804790 https://doi.org/10.1594/PANGAEA.804790 |
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.804790 https://doi.org/10.2973/odp.proc.sr.163.121.1999 |
_version_ |
1766017279515951104 |