Fracture evolution in a fold-and-thrust belt and the adjacent foreland basin: an example from the Northeastern Brooks Range, Alaska

• Main Author: Loveland, Andrea M.
• Format: Thesis
• Language: English
• Published: 2010
• Subjects: Orogenic belts; Brooks Range; Geological folds; Geological faults; Geological basins; Master of Science in Geophysics; Arctic; Fairbanks; Alaska
• Online Access: http://hdl.handle.net/11122/12741

Thesis (M.S.) University of Alaska Fairbanks, 2010 "Fracture networks can enhance permeability in a reservoir, creating pathways for fluid migration. This study uses detailed surface and subsurface mapping, new and existing thermal and geochronologic data as well as observations of fractures in outcrop provide a framework for fracture development in the range front region along a surface to subsurface transect in the western part of the northeastern Brooks Range. Set 1 fractures formed prior to 45 Ma at>6 km depth, ahead of the Brooks Range mountain front in response to elevated pore fluid pressure and low differential stress. Set 2 fractures developed during the early stages of folding at a depth of ~7 km. Both Sets 1 and 2 developed synchronously with hydrocarbon generation and may have been early migration pathways, but were likely destroyed during advancement of the thrust belt. Late fracture Sets 3 and 4 formed at shallow depths in the absence of fluids and are probably related to the onset of uplift at ~25 Ma. These late sets postdate regional generation and migration, but may enhance reservoir permeability"--Leaf iii American Association of Petroleum Geologists, Arctic Energy Technology Development Laboratory, Air Logistics, Anadarko, EnCana, ConocoPhillips, Alaska Division of Geological & Geophysical Surveys, Alaska Division of Oil & Gas, U.S. Geological Survey, Andrea Krumhardt of the University of Alaska Fairbanks, Apatite to Zircon Inc., and Petro-Fluids, Inc. 1. Introduction -- 2. Geologic setting -- 2.1. Regional structural geology -- 2.2. Brooks Range cooling events -- 2.3. Regional stratigraphy and structural style of the northeastern Brooks Range -- 2.4. Hydrocarbon systems in the northeastern Brooks Range -- 2.5. Previous fracture studies in the northeastern Brooks Range -- 3. Fault-related folds and fractures -- 3.1. Types of fractures -- 3.2. Fracture initiation -- 3.3. Fractures in flat-lying rocks -- 3.4. Fold-related fractures -- 3.5. Neotectonic joints -- 3.6. ...