Dike swarms on Seward Peninsula, Alaska, and their implications for the kinematics of Cretaceous extension in the
Abstract: Late Cretaceous dike swarms on Seward Peninsula, northwestern Alaska, represent the youngest local manifestation of a 115–75 Ma magmatic event in the Bering Strait region. Magmatism accompanied and followed high-grade metamorphism and ductile deformation. A Late Cretaceous extensional tect...
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ftciteseerx:oai:CiteSeerX.psu:10.1.1.534.7419 2023-05-15T15:44:15+02:00 Dike swarms on Seward Peninsula, Alaska, and their implications for the kinematics of Cretaceous extension in the Bering Strait Region Jeffrey M. Amato Elizabeth L. Miller James E. Wright William C. Mcintosh The Pennsylvania State University CiteSeerX Archives application/pdf http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.534.7419 http://deptweb-p.nmsu.edu/~geology/amato/SPDikes.pdf en eng http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.534.7419 http://deptweb-p.nmsu.edu/~geology/amato/SPDikes.pdf Metadata may be used without restrictions as long as the oai identifier remains attached to it. http://deptweb-p.nmsu.edu/~geology/amato/SPDikes.pdf text ftciteseerx 2016-01-08T10:46:06Z Abstract: Late Cretaceous dike swarms on Seward Peninsula, northwestern Alaska, represent the youngest local manifestation of a 115–75 Ma magmatic event in the Bering Strait region. Magmatism accompanied and followed high-grade metamorphism and ductile deformation. A Late Cretaceous extensional tectonic setting for the region is suggested by the thickness and seismic-reflection characteristics of the crust, regional basin development, formation of high-strain tectonites with subhorizontal foliations, bimodal magmatism, and dike swarms. The orientation of the dike swarms is used to address the kinematics of extension. A diabase dike swarm in the Kigluaik Mountains consists of dikes that strike northeast (040°) and dip steeply. Phenocrysts include plagioclase, clinopyroxene, orthopyroxene, and hornblende. Geochemical data indicate that SiO2 ranges from 48 % to 56%, and K2O from 1.2 % to 4.0%. The dikes are geochemically similar to the mafic to intermediate root of the 90 Ma Kigluaik pluton. Sr- and Nd-isotope data show that initial 87Sr/86Sr ranges from 0.7070 to 0.7077 and initial εNd ranges from –0.85 to –2.90. Field relations and 40Ar/39Ar geochronology bracket the dike ages between 90 and 84 Ma. Diabase dikes in the York Mountains are associated with normal faults that strike east–west to east-northeast. Dikes in the Bendeleben Mountains are both mafic and felsic, but their orientations are unknown. Alkalic dikes in the Darby Mountains strike 030°–050°, similar to those in the Kigluaik Mountains. Regional relationships including the orientation of dikes, normal faults, mineral stretching lineations, and other shear-sense indicators suggest that between 110 and 90 Ma extension on Seward Peninsula was Text Bering Strait Seward Peninsula Alaska Unknown Bering Strait Darby ENVELOPE(162.217,162.217,-77.667,-77.667) |
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ftciteseerx |
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English |
description |
Abstract: Late Cretaceous dike swarms on Seward Peninsula, northwestern Alaska, represent the youngest local manifestation of a 115–75 Ma magmatic event in the Bering Strait region. Magmatism accompanied and followed high-grade metamorphism and ductile deformation. A Late Cretaceous extensional tectonic setting for the region is suggested by the thickness and seismic-reflection characteristics of the crust, regional basin development, formation of high-strain tectonites with subhorizontal foliations, bimodal magmatism, and dike swarms. The orientation of the dike swarms is used to address the kinematics of extension. A diabase dike swarm in the Kigluaik Mountains consists of dikes that strike northeast (040°) and dip steeply. Phenocrysts include plagioclase, clinopyroxene, orthopyroxene, and hornblende. Geochemical data indicate that SiO2 ranges from 48 % to 56%, and K2O from 1.2 % to 4.0%. The dikes are geochemically similar to the mafic to intermediate root of the 90 Ma Kigluaik pluton. Sr- and Nd-isotope data show that initial 87Sr/86Sr ranges from 0.7070 to 0.7077 and initial εNd ranges from –0.85 to –2.90. Field relations and 40Ar/39Ar geochronology bracket the dike ages between 90 and 84 Ma. Diabase dikes in the York Mountains are associated with normal faults that strike east–west to east-northeast. Dikes in the Bendeleben Mountains are both mafic and felsic, but their orientations are unknown. Alkalic dikes in the Darby Mountains strike 030°–050°, similar to those in the Kigluaik Mountains. Regional relationships including the orientation of dikes, normal faults, mineral stretching lineations, and other shear-sense indicators suggest that between 110 and 90 Ma extension on Seward Peninsula was |
author2 |
The Pennsylvania State University CiteSeerX Archives |
format |
Text |
author |
Bering Strait Region Jeffrey M. Amato Elizabeth L. Miller James E. Wright William C. Mcintosh |
spellingShingle |
Bering Strait Region Jeffrey M. Amato Elizabeth L. Miller James E. Wright William C. Mcintosh Dike swarms on Seward Peninsula, Alaska, and their implications for the kinematics of Cretaceous extension in the |
author_facet |
Bering Strait Region Jeffrey M. Amato Elizabeth L. Miller James E. Wright William C. Mcintosh |
author_sort |
Bering Strait Region |
title |
Dike swarms on Seward Peninsula, Alaska, and their implications for the kinematics of Cretaceous extension in the |
title_short |
Dike swarms on Seward Peninsula, Alaska, and their implications for the kinematics of Cretaceous extension in the |
title_full |
Dike swarms on Seward Peninsula, Alaska, and their implications for the kinematics of Cretaceous extension in the |
title_fullStr |
Dike swarms on Seward Peninsula, Alaska, and their implications for the kinematics of Cretaceous extension in the |
title_full_unstemmed |
Dike swarms on Seward Peninsula, Alaska, and their implications for the kinematics of Cretaceous extension in the |
title_sort |
dike swarms on seward peninsula, alaska, and their implications for the kinematics of cretaceous extension in the |
url |
http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.534.7419 http://deptweb-p.nmsu.edu/~geology/amato/SPDikes.pdf |
long_lat |
ENVELOPE(162.217,162.217,-77.667,-77.667) |
geographic |
Bering Strait Darby |
geographic_facet |
Bering Strait Darby |
genre |
Bering Strait Seward Peninsula Alaska |
genre_facet |
Bering Strait Seward Peninsula Alaska |
op_source |
http://deptweb-p.nmsu.edu/~geology/amato/SPDikes.pdf |
op_relation |
http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.534.7419 http://deptweb-p.nmsu.edu/~geology/amato/SPDikes.pdf |
op_rights |
Metadata may be used without restrictions as long as the oai identifier remains attached to it. |
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1766378555366703104 |