Aspen anomaly
Aspen anomaly is a geological structure in
seismic velocity anomaly in the mantle which underpins the highest sector of the Rocky Mountains
.
Characteristics
The Aspen anomaly is a
The Aspen anomaly coincides with the highest region of the Rocky Mountains (such as the San Juan Mountains and the Sawatch Range[6]) and divergent drainages (Arkansas River, Colorado River and Gunnison River) which have cut deep gorges. This region underwent significant uplift during the Cenozoic[3] starting from 10-5 million years ago and was subsequently eroded by the Colorado River.[7] Ongoing present-day uplift of the San Juan Mountains may be linked to the Aspen anomaly.[5]
River
Lees Ferry, Arizona.[9]
pluton close to Leadville, Colorado.[11]
Context
In
Rio Grande Rift.[13] The Aspen anomaly has been compared with the Yellowstone hotspot,[3] but it lacks a volcanic caldera that Yellowstone has.[5]
Origin
The Aspen anomaly has been interpreted in several ways.
- It may be a mantle plume, but the steep tilt angle is unusual for a mantle plume.[12]
- It may be a lithospheric melt zone, but the lithosphere is not thick enough to contain such a structure.[14]
- It may be a Proterozoic structure, maybe the leftover of a subduction zone.[13] Prolonged subduction would have enriched a segment of mantle with water and thus lowered its melting point.[15]
- Shallower upwelling (such as
- Crustal weaknesses.[10]
References
- ISBN 9780813700182.
- ^ a b Dueker, Yuan & Zurek 2001, p. 6.
- ^ Bibcode:2007AGUFM.T11C0723C.
- ^ a b "CO2-RICH SPRINGS AND TRAVERTINES OF THE ROCKY MOUNTAIN REGION: MANTLE HELIUM ASSOCIATED WITH THE ASPEN ANOMALY AND GEOMICROBIOLOGY OF "CONTINENTAL SMOKERS"". gsa.confex.com. Retrieved 2018-04-08.
- ^ ISBN 9781607320852.
- ISSN 0016-7606.
- Bibcode:2009AGUFM.T51F..04K.)
{{cite journal}}: CS1 maint: multiple names: authors list (link - Bibcode:2008AGUFM.T11C1893D.
- Bibcode:2005AGUFM.T23C0580S.
- ^ Bibcode:2009AGUFM.S13B1745M.)
{{cite journal}}: CS1 maint: multiple names: authors list (link - ^ "GEO AND THERMOCHRONOLOGICAL EVICENDE FOR THE EMPLACEMENT AND EXHUMATIONAL HISTORY OF THE TWIN LAKES BATHOLITH: IMPLICATIONS FOR THE LARAMIDE OROGENY". gsa.confex.com. Retrieved 2018-04-08.
- ^ a b Dueker, Yuan & Zurek 2001, p. 7.
- ^ a b Karlstrom et al. 2005, p. 425.
- ^ Dueker, Yuan & Zurek 2001, p. 8.
- ^ Karlstrom et al. 2005, p. 429.
Sources
- Dueker, Ken; Yuan, Huaiyu; Zurek, Brian (2001). "Thick-Structured Proterozoic Lithosphere of the Rocky Mountain Region". GSA Today. 11 (12): 4. .
- Karlstrom, Karl E.; Whitmeyer, Steven J.; Dueker, Ken; Williams, Michael L.; Bowring, Samuel A.; Levander, Alan R.; Humphreys, E. D.; Keller, G. Randy; Group, CD-ROM Working (2005). "Synthesis of results from the CD-ROM Experiment: 4-D image of the lithosphere beneath the Rocky Mountains and implications for understanding the evolution of continental lithosphere". The Rocky Mountain Region: An Evolving Lithosphere Tectonics, Geochemistry, and Geophysics. Geophysical Monograph Series. Vol. 154. American Geophysical Union (AGU). pp. 421–441. ISBN 978-0-87590-419-1.