Detailed Geologic and Geomorphic Mapping and Characterization of the Lake Mary Fault Zone
| dc.contributor.author | Ben-Horin, J.Y. | |
| dc.contributor.author | Pearthree, P. A. | |
| dc.contributor.author | Holm, R.F. | |
| dc.contributor.author | Heizler, M. | |
| dc.date.accessioned | 2023-01-19T22:42:10Z | |
| dc.date.available | 2023-01-19T22:42:10Z | |
| dc.date.issued | 2021 | |
| dc.identifier.citation | Ben-Horin, J.Y., Pearthree, P.A. Holm, R.F. and Heizler, M., 2021, Detailed Geologic and Geomorphic Mapping and Characterization of the Lake Mary Fault Zone. Arizona Geological Survey Open-File Report OFR-21-02, 16 p. | en_US |
| dc.identifier.uri | http://hdl.handle.net/10150/667592 | |
| dc.description | The Lake Mary Fault System (LMFS) is located in Flagstaff, Arizona. Prior to this study, much was unknown related to its slip rate or whether the fault system was still active. The LMFS is a 30-45km long set of normal faults and multiple splays that displace Pliocene-Quaternary lava flows and sediments. Detailed mapping efforts identified offset lava flows, two of which are Quaternary in age, and resulted in the discovery of less active fault strands in the southern portion of the mapping area. In addition, detailed mapping provided the geologic constraints for locating potential paleoseismic sites. The LMFS has segments that have been active for several million years and have a complex faulting history that has resulted in dense fracturing of bedrock, reactivation of older reverse and normal faults, much of which have little vertical offset. The Lake Mary fault which is considered the active strand of the LMFS appears to be a normal fault with near vertical dip and a strike that varies from N60W to N-S. The main trace of the Lake Mary fault has up to 40m of vertical offset of a colluvial deposit with clasts from a Quaternary basaltic lava flow, dated for this study with 40Ar/39Ar at 1.17Ma old. Geochemical analyses of volcanic clasts found in the Lake Mary fault footwall corroborated the hand identification showing the clasts’ originating from the Qbwc flow. The clasts were analyzed using inductively coupled plasma-mass spectrometry (ICP-MS) for Rare Earth Elements (REEs). ICP-MS data infer 3 different rock types for the 12 samples. Slip rate estimates were calculated using 40Ar/39Ar dates obtained for this study and the vertical offset measurements of Tob (5.9Ma) and Qbwc (< 1.17Ma) for a slip rate range of 0.022mm/yr to 0.035mm/yr. | en_US |
| dc.language.iso | en | en_US |
| dc.publisher | Arizona Geological Survey (Tucson, AZ) | en_US |
| dc.relation.ispartofseries | OFR-21-02 | en_US |
| dc.relation.url | https://library.azgs.arizona.edu/ | |
| dc.rights | Arizona Geological Survey. All rights reserved. | en_US |
| dc.rights.uri | http://rightsstatements.org/vocab/InC/1.0/ | en_US |
| dc.subject | earthquake | en_US |
| dc.subject | fault | en_US |
| dc.subject | Geologic hazard | en_US |
| dc.subject | unreinforced masonry | en_US |
| dc.subject | Permian | en_US |
| dc.subject | Pleistocene | en_US |
| dc.subject | Quaternary | en_US |
| dc.subject | Coconino County | en_US |
| dc.subject | Flagstaff | en_US |
| dc.subject | Lake Mary | en_US |
| dc.subject | Mormon Lake | en_US |
| dc.title | Detailed Geologic and Geomorphic Mapping and Characterization of the Lake Mary Fault Zone | en_US |
| csdgm.bounding.west | -111.648 | en_US |
| csdgm.bounding.east | -111.387 | en_US |
| csdgm.bounding.north | 35.1271 | en_US |
| csdgm.bounding.south | 34.8684 | en_US |
| dc.description.collectioninformation | Documents in the AZGS Documents Repository collection are made available by the Arizona Geological Survey (AZGS) and the University Libraries at the University of Arizona. For more information about items in this collection, please contact azgs-info@email.arizona.edu. | en_US |
| refterms.dateFOA | 2023-01-19T22:42:12Z |
