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| Titel |
Estimating Uplift Rate Histories From River Profiles: Examples From the Colorado Plateau |
| VerfasserIn |
Gareth G. Roberts, Nicky White |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250051671
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| Zusammenfassung |
| It is widely agreed that a region encompassing the Colorado Plateau has been uplifted by
sub-crustal processes. Admittance calculations, tomographic studies and receiver function
analyses suggest that dynamic support is generated by a combination of large-scale
convective upwelling and lithospheric thickness changes. Notwithstanding important
advances in our understanding of the present-day setting, uplift rate histories of this region
are poorly constrained and much debated: an improved history will help to discriminate
between a variety of proposed uplift models. Here, we show that a regional uplift rate history
can be obtained by inverting longitudinal river profiles. Our approach assumes that the shape
of a river profile is controlled by uplift rate and moderated by erosion. Inverse modeling of
river profiles from the Colorado River and Rio Grande catchments shows that three
phases of regional uplift affected the Colorado Plateau. The first phase occurred
between 80 and 50 Myrs, when ~ 1 km of regional uplift was generated at a rate of
~ 0.03 mm/yr. A second phase occurred between 55 and 35 Myrs, when ~ 1.5 km of
regional uplift was generated at a faster rate of ~ 0.08 mm/yr. A third phase of
minor uplift started within the last 5 Myrs. Distinct phases of Late Cretaceous and
Oligocene uplift are corroborated by thermochronometric data, and by stratigraphic
evidence of periodic clastic efflux delivered into the Gulf of Mexico. An episodic
uplift history is consistent with the staged removal of thick lithospheric mantle
beneath a large region, which is currently centered on the Yellowstone Hotspot. |
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