Natural fracturing in carbonate rocks as a function of lithology and structural position in a detachment fold: examples from the northeastern Brooks Range, Alaska

• Main Author: Brinton, Joseph S.
• Format: Thesis
• Language: English
• Published: 2002
• Subjects: Fairbanks; Brooks Range; Alaska
• Online Access: http://hdl.handle.net/11122/6277

Thesis (M.S.) University of Alaska Fairbanks, 2002 Fractures in detachment folded Mississippian-Pennsylvania Lisburne Group carbonates provide insight into the distribution and character of natural fractures as a function of folding and lithology. Data from five detachment folds suggest that hinges show a higher fracture density than limbs. This study also suggests that the amount of shortening does not play a significant role in determining fracture density or uniformity of fracture orientation. A mechanical classification based on lithologic homogeneity reflects natural fracture distribution as a function of lithology more accurately than conventional lithologic classifications. Two main fracture sets were observed, a N-S set, perpendicular to fold axes, and an E-W set, parallel to fold axes. Statistical analyses suggest that E-W fracturing occurred before and during folding and that N-S fracturing occurred both before and after folding.