Style, controls, and timing of fold-and-thrust deformation of the Jago stock, northeastern Brooks Range, Alaska

Involvement of the Devonian Jago stock in Cenozoic fold-and-thrust deformation of the northeastern Brooks Range illustrates the influence of a relatively small, isolated crystalline body on the mechanical stratigraphy and subsequent deformational behavior of an otherwise layered sedimentary package....

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Published in:Canadian Journal of Earth Sciences
Main Authors: Peapples, Paige R., Wallace, Wesley K., Hanks, Catherine L., Layer, Paul W., O'Sullivan, Paul B.
Format: Article in Journal/Newspaper
Language:English
Published: Canadian Science Publishing 1997
Subjects:
Online Access:http://dx.doi.org/10.1139/e17-082
http://www.nrcresearchpress.com/doi/pdf/10.1139/e17-082
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spelling crcansciencepubl:10.1139/e17-082 2024-09-15T18:00:28+00:00 Style, controls, and timing of fold-and-thrust deformation of the Jago stock, northeastern Brooks Range, Alaska Peapples, Paige R. Wallace, Wesley K. Hanks, Catherine L. Layer, Paul W. O'Sullivan, Paul B. 1997 http://dx.doi.org/10.1139/e17-082 http://www.nrcresearchpress.com/doi/pdf/10.1139/e17-082 en eng Canadian Science Publishing http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining Canadian Journal of Earth Sciences volume 34, issue 7, page 992-1007 ISSN 0008-4077 1480-3313 journal-article 1997 crcansciencepubl https://doi.org/10.1139/e17-082 2024-08-01T04:10:01Z Involvement of the Devonian Jago stock in Cenozoic fold-and-thrust deformation of the northeastern Brooks Range illustrates the influence of a relatively small, isolated crystalline body on the mechanical stratigraphy and subsequent deformational behavior of an otherwise layered sedimentary package. The small size of the stock allowed it and the structurally coupled overlying Mississippian Kekiktuk Conglomerate to deform nonpenetratively as a horse in a regional duplex, in contrast to the semiductile behavior of the nearby but much larger Okpilak batholith. Shear was localized in the upper part of the stock and the conglomerate due to partial detachment of the overlying Carboniferous Lisburne Group. North-vergent thrust-related folds formed in the mechanically layered Lisburne Group carbonates instead of the symmetrical, unfaulted detachment folds more typical of the region because an underlying regional detachment horizon in the Mississippian Kayak Shale is depositionally absent over the stock. Unusually competent contact-metamorphosed pre-Mississippian metasedimentary rocks were thrust over the stock and its cover because a ramp formed at the edge of the stock and cut upsection through the Lisburne Group due to the absence of Kayak Shale. A 40 Ar/ 39 Ar age of foliated white mica indicates thrusting of the stock by 61 Ma; fission-track ages indicate cooling at ~44 and ~28 Ma. These ages indicate a cooling history that implies ~11 km of unroofing since ~61 Ma, only ~1.5 km of which can be explained by the inferred duplex structure. The remaining ~9.5 km of unroofing is most likely due to subduplex structural thickening above a deep regional detachment. Article in Journal/Newspaper Brooks Range Alaska Canadian Science Publishing Canadian Journal of Earth Sciences 34 7 992 1007
institution Open Polar
collection Canadian Science Publishing
op_collection_id crcansciencepubl
language English
description Involvement of the Devonian Jago stock in Cenozoic fold-and-thrust deformation of the northeastern Brooks Range illustrates the influence of a relatively small, isolated crystalline body on the mechanical stratigraphy and subsequent deformational behavior of an otherwise layered sedimentary package. The small size of the stock allowed it and the structurally coupled overlying Mississippian Kekiktuk Conglomerate to deform nonpenetratively as a horse in a regional duplex, in contrast to the semiductile behavior of the nearby but much larger Okpilak batholith. Shear was localized in the upper part of the stock and the conglomerate due to partial detachment of the overlying Carboniferous Lisburne Group. North-vergent thrust-related folds formed in the mechanically layered Lisburne Group carbonates instead of the symmetrical, unfaulted detachment folds more typical of the region because an underlying regional detachment horizon in the Mississippian Kayak Shale is depositionally absent over the stock. Unusually competent contact-metamorphosed pre-Mississippian metasedimentary rocks were thrust over the stock and its cover because a ramp formed at the edge of the stock and cut upsection through the Lisburne Group due to the absence of Kayak Shale. A 40 Ar/ 39 Ar age of foliated white mica indicates thrusting of the stock by 61 Ma; fission-track ages indicate cooling at ~44 and ~28 Ma. These ages indicate a cooling history that implies ~11 km of unroofing since ~61 Ma, only ~1.5 km of which can be explained by the inferred duplex structure. The remaining ~9.5 km of unroofing is most likely due to subduplex structural thickening above a deep regional detachment.
format Article in Journal/Newspaper
author Peapples, Paige R.
Wallace, Wesley K.
Hanks, Catherine L.
Layer, Paul W.
O'Sullivan, Paul B.
spellingShingle Peapples, Paige R.
Wallace, Wesley K.
Hanks, Catherine L.
Layer, Paul W.
O'Sullivan, Paul B.
Style, controls, and timing of fold-and-thrust deformation of the Jago stock, northeastern Brooks Range, Alaska
author_facet Peapples, Paige R.
Wallace, Wesley K.
Hanks, Catherine L.
Layer, Paul W.
O'Sullivan, Paul B.
author_sort Peapples, Paige R.
title Style, controls, and timing of fold-and-thrust deformation of the Jago stock, northeastern Brooks Range, Alaska
title_short Style, controls, and timing of fold-and-thrust deformation of the Jago stock, northeastern Brooks Range, Alaska
title_full Style, controls, and timing of fold-and-thrust deformation of the Jago stock, northeastern Brooks Range, Alaska
title_fullStr Style, controls, and timing of fold-and-thrust deformation of the Jago stock, northeastern Brooks Range, Alaska
title_full_unstemmed Style, controls, and timing of fold-and-thrust deformation of the Jago stock, northeastern Brooks Range, Alaska
title_sort style, controls, and timing of fold-and-thrust deformation of the jago stock, northeastern brooks range, alaska
publisher Canadian Science Publishing
publishDate 1997
url http://dx.doi.org/10.1139/e17-082
http://www.nrcresearchpress.com/doi/pdf/10.1139/e17-082
genre Brooks Range
Alaska
genre_facet Brooks Range
Alaska
op_source Canadian Journal of Earth Sciences
volume 34, issue 7, page 992-1007
ISSN 0008-4077 1480-3313
op_rights http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining
op_doi https://doi.org/10.1139/e17-082
container_title Canadian Journal of Earth Sciences
container_volume 34
container_issue 7
container_start_page 992
op_container_end_page 1007
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