Compositional and thermal state of the upper mantle beneath the Bering Sea basalt province: evidence from the Chukchi Peninsula of Russia
Nephelinites and basanites of the Enmelen volcanic field, Chukchi Peninsula, Russia, contain upper mantle xenoliths of relatively calcium- and magnesium-rich spinel lherzolites, pyroxenites, and megacrysts. The phase assemblages of the lherzolites require equilibration near 1.5 GPa, and calculated e...
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crcansciencepubl:10.1139/e17-065 2023-12-17T10:28:07+01:00 Compositional and thermal state of the upper mantle beneath the Bering Sea basalt province: evidence from the Chukchi Peninsula of Russia Akinin, Vyacheslav V. Apt, Julia Roden, Michael F. Francis, Don Moll-Stalcup, Elizabeth 1997 http://dx.doi.org/10.1139/e17-065 http://www.nrcresearchpress.com/doi/pdf/10.1139/e17-065 en eng Canadian Science Publishing http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining Canadian Journal of Earth Sciences volume 34, issue 6, page 789-800 ISSN 0008-4077 1480-3313 General Earth and Planetary Sciences journal-article 1997 crcansciencepubl https://doi.org/10.1139/e17-065 2023-11-19T13:38:38Z Nephelinites and basanites of the Enmelen volcanic field, Chukchi Peninsula, Russia, contain upper mantle xenoliths of relatively calcium- and magnesium-rich spinel lherzolites, pyroxenites, and megacrysts. The phase assemblages of the lherzolites require equilibration near 1.5 GPa, and calculated equilibration temperatures for most inclusions are in the range 850–1030 °C. These temperatures are similar to those calculated for lherzolite inclusions from other Bering Sea localities (Nunivak Island and Seward Peninsula) and are higher than temperatures expected for likely conductive geotherms beneath these volcanic fields. The relatively high temperatures may be the result of magma intrusion into the mantle lithosphere and consequent perturbation of the geotherm shortly before entrainment of the xenoliths in basalt. Two Enmelen lherzolites equilibrated at higher temperatures (1230–1240 °C) and provide further evidence for heating due to intrusive magmas. Some spinel lherzolite inclusions have flat rare earth element patterns and major and trace element abundances close to that of the bulk silicate earth. Based on the occurrence of similar fertile peridotites at Nunivak Island and Seward Peninsula, near-primitive mantle compositions appear to be common in the upper mantle beneath the Bering Sea. These peridotites may represent recent additions to the mantle lithosphere from mantle plumes related to the volcanism. Other Enmelen inclusions are relatively light rare earth element-enriched group I lherzolites metasomatized by a silicate melt, group II pyroxenites precipitated from a variety of melts, and augite megacrysts with convex-upward rare earth element patterns consistent with precipitation from the host basalts at high pressures. Article in Journal/Newspaper Bering Sea Chukchi Chukchi Peninsula Nunivak Nunivak Island Seward Peninsula Canadian Science Publishing (via Crossref) Bering Sea Enmelen ENVELOPE(-175.844,-175.844,65.012,65.012) Canadian Journal of Earth Sciences 34 6 789 800 |
institution |
Open Polar |
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Canadian Science Publishing (via Crossref) |
op_collection_id |
crcansciencepubl |
language |
English |
topic |
General Earth and Planetary Sciences |
spellingShingle |
General Earth and Planetary Sciences Akinin, Vyacheslav V. Apt, Julia Roden, Michael F. Francis, Don Moll-Stalcup, Elizabeth Compositional and thermal state of the upper mantle beneath the Bering Sea basalt province: evidence from the Chukchi Peninsula of Russia |
topic_facet |
General Earth and Planetary Sciences |
description |
Nephelinites and basanites of the Enmelen volcanic field, Chukchi Peninsula, Russia, contain upper mantle xenoliths of relatively calcium- and magnesium-rich spinel lherzolites, pyroxenites, and megacrysts. The phase assemblages of the lherzolites require equilibration near 1.5 GPa, and calculated equilibration temperatures for most inclusions are in the range 850–1030 °C. These temperatures are similar to those calculated for lherzolite inclusions from other Bering Sea localities (Nunivak Island and Seward Peninsula) and are higher than temperatures expected for likely conductive geotherms beneath these volcanic fields. The relatively high temperatures may be the result of magma intrusion into the mantle lithosphere and consequent perturbation of the geotherm shortly before entrainment of the xenoliths in basalt. Two Enmelen lherzolites equilibrated at higher temperatures (1230–1240 °C) and provide further evidence for heating due to intrusive magmas. Some spinel lherzolite inclusions have flat rare earth element patterns and major and trace element abundances close to that of the bulk silicate earth. Based on the occurrence of similar fertile peridotites at Nunivak Island and Seward Peninsula, near-primitive mantle compositions appear to be common in the upper mantle beneath the Bering Sea. These peridotites may represent recent additions to the mantle lithosphere from mantle plumes related to the volcanism. Other Enmelen inclusions are relatively light rare earth element-enriched group I lherzolites metasomatized by a silicate melt, group II pyroxenites precipitated from a variety of melts, and augite megacrysts with convex-upward rare earth element patterns consistent with precipitation from the host basalts at high pressures. |
format |
Article in Journal/Newspaper |
author |
Akinin, Vyacheslav V. Apt, Julia Roden, Michael F. Francis, Don Moll-Stalcup, Elizabeth |
author_facet |
Akinin, Vyacheslav V. Apt, Julia Roden, Michael F. Francis, Don Moll-Stalcup, Elizabeth |
author_sort |
Akinin, Vyacheslav V. |
title |
Compositional and thermal state of the upper mantle beneath the Bering Sea basalt province: evidence from the Chukchi Peninsula of Russia |
title_short |
Compositional and thermal state of the upper mantle beneath the Bering Sea basalt province: evidence from the Chukchi Peninsula of Russia |
title_full |
Compositional and thermal state of the upper mantle beneath the Bering Sea basalt province: evidence from the Chukchi Peninsula of Russia |
title_fullStr |
Compositional and thermal state of the upper mantle beneath the Bering Sea basalt province: evidence from the Chukchi Peninsula of Russia |
title_full_unstemmed |
Compositional and thermal state of the upper mantle beneath the Bering Sea basalt province: evidence from the Chukchi Peninsula of Russia |
title_sort |
compositional and thermal state of the upper mantle beneath the bering sea basalt province: evidence from the chukchi peninsula of russia |
publisher |
Canadian Science Publishing |
publishDate |
1997 |
url |
http://dx.doi.org/10.1139/e17-065 http://www.nrcresearchpress.com/doi/pdf/10.1139/e17-065 |
long_lat |
ENVELOPE(-175.844,-175.844,65.012,65.012) |
geographic |
Bering Sea Enmelen |
geographic_facet |
Bering Sea Enmelen |
genre |
Bering Sea Chukchi Chukchi Peninsula Nunivak Nunivak Island Seward Peninsula |
genre_facet |
Bering Sea Chukchi Chukchi Peninsula Nunivak Nunivak Island Seward Peninsula |
op_source |
Canadian Journal of Earth Sciences volume 34, issue 6, page 789-800 ISSN 0008-4077 1480-3313 |
op_rights |
http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining |
op_doi |
https://doi.org/10.1139/e17-065 |
container_title |
Canadian Journal of Earth Sciences |
container_volume |
34 |
container_issue |
6 |
container_start_page |
789 |
op_container_end_page |
800 |
_version_ |
1785580148272136192 |