| Abstract: | High-resolution aeromagnetic data were acquired over the town of Poncha Springs and areas to the northwest to image faults, especially where they are concealed. Because this area has known hot springs, faults or fault intersections at depth can provide pathways for upward migration of geothermal fluids or concentrate fracturing that enhances permeability. Thus, mapping concealed faults provides a focus for follow-up geothermal studies. Fault interpretation was accomplished by synthesizing interpretative maps derived from several different analytical methods, along with preliminary depth estimates. Faults were interpreted along linear aeromagnetic anomalies and breaks in anomaly patterns. Many linear features correspond to topographic features, such as drainages. A few of these are inferred to be fault-related. The interpreted faults show an overall pattern of criss-crossing fault zones, some of which appear to step over where they cross. Faults mapped by geologists suggest similar crossing patterns in exposed rocks along the mountain front. In low-lying areas, interpreted faults show zones of west-northwest-, north-, and northwest-striking faults that cross ~3 km (~2 mi) west-northwest of the town of Poncha Springs. More easterly striking faults extend east from this juncture. The associated aeromagnetic anomalies are likely caused by magnetic contrasts associated with faulted sediments that are concealed less than 200 m (656 ft) below the valley floor. The faults may involve basement rocks at greater depth as well. A relatively shallow (<300 m or <984 ft), faulted basement block is indicated under basin-fill sediments just north of the hot springs and south of the town of Poncha Springs. |
| Genre: | USGS Numbered Series |
| ProdID: | 97775 |
| Citation Author: | Grauch, V. J. S.; Drenth, Benjamin J. |
| Citation Contributing Office: | Crustal Imaging and Characterization |
| Citation Datum: | |
| Citation Day: | |
| Citation Edition: | - |
| Citation Editor: | |
| Citation End Page: | |
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| Citation Keywords: | |
| Citation Language: | ENGLISH |
| Citation Larger Work Title: | |
| Citation LatN: | 0384500 |
| Citation LatS: | 0382230 |
| Citation LonE: | -1055230 |
| Citation LonW: | -1062230 |
| Citation Month: | |
| Citation No Pagination: | N |
| Citation Number Of Pages: | |
| Citation Online Only Flag: | Y |
| Citation Phsyical Description: | Report: v, 31 p.; Downloads Directory |
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| Citation Public Comments: | Prepared in cooperation with the Colorado Governor‘s Energy Office |
| Citation Publisher: | U.S. Geological Survey |
| Citation Series: | Open-File Report |
| Citation Series Code: | OFR |
| Citation Series Number: | 2009-1156 |
| Citation Search Results Text: | High-Resolution Aeromagnetic Survey To Image Shallow Faults, Poncha Springs and Vicinity, Chaffee County, Colorado; 2009; OFR; 2009-1156; Grauch, V. J. S.; Drenth, Benjamin J. |
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| Citation Year: | 2009 |
| Type: | citation/reference |
| Text: | High-Resolution Aeromagnetic Survey To Image Shallow Faults, Poncha Springs and Vicinity, Chaffee County, Colorado; 2009; OFR; 2009-1156; Grauch, V. J. S.; Drenth, Benjamin J. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/ofr_2009_1156.jpg |
| URL (INDEX PAGE): | http://pubs.usgs.gov/of/2009/1156/ |
| Date Other: | Wed, 19 Aug 2009 00:00 -0500 |
| Publisher: | U.S. Geological Survey |
