Skip to Main Content
Book Chapter

Deformational history and thermochronology of Wrangel Island, East Siberian Shelf and coastal Chukotka, Arctic Russia

By
Elizabeth L. Miller
Elizabeth L. Miller
1
Department of Geological Sciences, Stanford University, Stanford, CA 94305, USA
Search for other works by this author on:
V. V. Akinin
V. V. Akinin
2
North-East Interdisciplinary Scientific Research Institute, Magadan, Russia
Search for other works by this author on:
T. A. Dumitru
T. A. Dumitru
1
Department of Geological Sciences, Stanford University, Stanford, CA 94305, USA
Search for other works by this author on:
E. S. Gottlieb
E. S. Gottlieb
1
Department of Geological Sciences, Stanford University, Stanford, CA 94305, USA
Search for other works by this author on:
M. Grove
M. Grove
1
Department of Geological Sciences, Stanford University, Stanford, CA 94305, USA
Search for other works by this author on:
K. Meisling
K. Meisling
1
Department of Geological Sciences, Stanford University, Stanford, CA 94305, USA
Search for other works by this author on:
G. Seward
G. Seward
3
Department of Geological Sciences, U.C. Santa Barbara, Santa Barbara, CA 93106, USA
Search for other works by this author on:
Published:
January 01, 2018

Abstract

In Arctic Russia, south of Wrangel Island, Jura–Cretaceous fold belt structures are cut by c. 108–100 Ma plutonic rocks and a c. 103 Ma migmatitic complex (U–Pb, zircon) that cooled by c. 96 Ma (40Ar/39Ar biotite); the structures are unconformably overlain by c. 88 Ma and younger (U–Pb, zircon) volcanic rocks. Wrangel Island, with a similar stratigraphy and added exposure of Neoproterozoic basement rocks, was thought to represent the westwards continuation of the Jura–Cretaceous Brookian thrust belt of Alaska. A penetrative, high-strain, S-dipping foliation formed during north–south stretching in Triassic and older rocks, with stretched pebble aspect ratios of c. 2:1:0.5 to 10:1:0.1. Deformation was at greenschist facies (chlorite+white mica; biotite at depth; temperature c. 300–450°C). Microstructures suggest deformation mostly by pure shear and north–south stretching; the quartz textures and lattice preferred orientations suggest temperatures of c. 300–450°C. 40Ar/39Ar K-feldspar spectra (n = 1) and muscovite (n = 3) (total gas ages c. 611–514 Ma) in Neoproterozoic basement rocks are consistent with a short thermal pulse during deformation at 105–100 Ma. Apatite fission track ages (n = 7) indicate cooling to near-surface conditions at c. 95 Ma. The shared thermal histories of Wrangel Island and Chukotka suggest that Wrangel deformation is related to post-shortening, north–south extension, not to fold–thrust belt deformation. Seismic data (line AR-5) indicate a sharp Moho and strong sub-horizontal reflectivity in the lower and middle crust beneath the region. Wrangel Island probably represents a crustal-scale extensional boudin between the North Chukchi and Longa basins.

Supplementary material: Sample localities, details of the analytical methods, data tables and the full discussion of the results of electron back-scatter diffraction studies of quartz lattice preferred orientations are available at https://doi.org/10.6084/m9.figshare.c.3741272

You do not currently have access to this article.
Close Modal
This Feature Is Available To Subscribers Only

Sign In or Create an Account

Close Modal
Close Modal