Skip Links

USGS - science for a changing world

Open-File Report 03-327

Association of Deformation and Fluid Events in the Central Brooks Range Fold-and-Thrust Belt, Northern Alaska

By Thomas E. Moore, Christopher J. Potter, Paul B. O’Sullivan, Kevin L. Shelton, and Michael B. Underwood

Thumbnail of and link to report PDF (31 MB)Introduction

Ocentral Brooks Range consists of two superposed north-directed contractional orogens, one formed between 140-120 Ma and the other at ~60-45 Ma. The older orogen was an arc-continent collisional zone characterized by far-traveled allochthons and relatively low structural relief. The younger orogen is a retroarc thrust belt with relatively low amounts of shortening and high structural relief. Folding and thrusting of the younger episode is superimposed on the thin-skinned deformational wedge of the earlier orogen and also produced a frontal triangle zone in a thick sequence of mid-Cretaceous foreland basin sediments to the north. Stable isotope compositions of calcite and quartz veins indicate two fluid events including: (1) an earlier, higher-temperature (~250-300° C) event that produced veins in deformed Devonian clastic rocks, and (2) a younger, lower-temperature (~150° C) event that deposited veins in deformed Mississippian through Albian strata. The fluids in the first event had variable d18O values, but nearly constant d13C values buffered by limestone lithologies. The vein-forming fluids in the second event had similarly variable d18O values, but with distinctly lower d13C values as a result of oxidation of organic matter and/or methane. Zircon fission track ages demonstrate cooling to temperatures below 200° C between 140-120 Ma for the Devonian rocks, whereas zircon and apatite fission track ages show that Mississippian to Albian rocks were never heated above 200° C and cooled below 110-90° C at ~60-45 Ma. These data are interpreted as indicating that the older, high-temperature fluid event was active during thrusting at 120-140 Ma, and the younger fluid event during deformation at ~60-45 Ma. The data and results presented in this poster will be published in early 2004 in Moore and others (in press).

First posted September 12, 2003

For additional information, contact:
Energy Program contacts
U.S. Geological Survey
12201 Sunrise Valley Drive
National Center, MS 913
Reston, VA 20192

Part or all of this report is presented in Portable Document Format (PDF). For best results viewing and printing PDF documents, it is recommended that you download the documents to your computer and open them with Adobe Reader. PDF documents opened from your browser may not display or print as intended. Download the latest version of Adobe Reader, free of charge.


Suggested citation:

Moore, Thomas E., Potter, Christopher J., O'Sullivan, Paul B., Shelton, Kevin L., Underwood, Michael B., 2003, Association of Deformation and Fluid Events in the Central Brooks Range Fold-and-Thrust Belt, Northern Alaska: U. S. Geological Survey Open-File Report 03-327, http://pubs.usgs.gov/of/2003/0327/.


Accessibility FOIA Privacy Policies and Notices

Take Pride in America logo USA.gov logo U.S. Department of the Interior | U.S. Geological Survey
URL: http://pubsdata.usgs.gov/pubs/of/2003/0327/index.html
Page Contact Information: GS Pubs Web Contact
Page Last Modified: Monday, 07-Apr-2014 12:27:30 EDT