Billefjorden fault zone, Spitsbergen: Is it part of a major Late Devonian transform?

Abstract

Research Article| September 01, 1986 Billefjorden fault zone, Spitsbergen: Is it part of a major Late Devonian transform? D. L. LAMAR; D. L. LAMAR 1Lamar-Merifield Geologists, Inc., Santa Monica, California 90401 Search for other works by this author on: GSW Google Scholar W. E. REED; W. E. REED 2University of California, Los Angeles, California 90024 Search for other works by this author on: GSW Google Scholar D. N. DOUGLASS D. N. DOUGLASS 3Dartmouth College, Hanover, New Hampshire 03755 Search for other works by this author on: GSW Google Scholar Author and Article Information D. L. LAMAR 1Lamar-Merifield Geologists, Inc., Santa Monica, California 90401 W. E. REED 2University of California, Los Angeles, California 90024 D. N. DOUGLASS 3Dartmouth College, Hanover, New Hampshire 03755 Publisher: Geological Society of America First Online: 01 Jun 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Geological Society of America GSA Bulletin (1986) 97 (9): 1083–1088. https://doi.org/10.1130/0016-7606(1986)97<1083:BFZSII>2.0.CO;2 Article history First Online: 01 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation D. L. LAMAR, W. E. REED, D. N. DOUGLASS; Billefjorden fault zone, Spitsbergen: Is it part of a major Late Devonian transform?. GSA Bulletin 1986;; 97 (9): 1083–1088. doi: https://doi.org/10.1130/0016-7606(1986)97<1083:BFZSII>2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract The Billefjorden fault is a 2.0- to 4.0-km-wide zone of parallel and branching faults trending N4°W. Individual fault strands dip 39° to 68°. The Balliolbreen fault, the principal strand, is an east-dipping reverse fault which displaces Hecla Hoek metamorphic rocks on the east against Devonian Old Red Sandstone on the west. Large-scale mapping shows the Devonian rocks to be complexly folded and faulted and unconformably overlain by Carboniferous strata. The pre-Carboniferous folds are tight and overturned adjacent to the fault zone but become open and upright westward. Fold axes and thrusts, with separations not exceeding a few hundred metres, have sinuous patterns and trends ranging from N60°E to N45°W and do not intersect the fault zone with the consistent trend characteristic of strike-slip faulting. The gentle dip of individual fault strands as well as the pattern of folds and thrusts, suggests east-west crustal shortening. The Old Red Sandstone thins rapidly eastward in the area of the Billefjorden fault zone; thus large displacement is not required to explain the absence of Old Red Sandstone on Ny Friesland east of the fault. The over-all straight trace of the fault zone could be explained by reverse faulting along a pre–Old Red Sandstone strike-slip fault in Hecla Hoek rocks. These results suggest that the Billefjorden fault zone had post–Old Red Sandstone reverse-slip rather than strike-slip, and no support is found for earlier suggestions of 200 to 1,000 km of Late Devonian left-slip on the Billefjorden fault zone. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.