|
|
 |
|||||||||||||||||
|
|||||||||||||||||
 |
|||||||||||||||||
| JOURNAL HOME | HELP | CONTACT PUBLISHER | SUBSCRIBE | ARCHIVE | SEARCH | TABLE OF CONTENTS |
1 Climate Change Research Center and Department of Earth Sciences, Institute for the Study of Earth, Oceans and Space, University of New Hampshire, Durham, New Hampshire 03824, USA
2 Department of Geological Science, University of Texas, Austin, Texas 78712, USA
We have developed a technique for measuring paleoelevation on the basis of the vesicularity of basaltic lava flows. We are currently applying this technique to determine the timing and extent of Cenozoic uplift of the Colorado Plateau. Because the technique measures paleoatmospheric pressure, it is not subject to uncertainties stemming from the use of proxies that depend on environmental factors other than elevation alone. Vesicular lavas preserve a record of paleopressure at the time and place of lava emplacement because the difference in internal pressure in bubbles at the base and top of a lava flow depends on atmospheric pressure and lava flow thickness. The modal size of the vesicle (bubble) population is larger at the top than at the bottom. This leads directly to paleoatmospheric pressure and thus elevation because the thickness of the flow can easily be measured in the field, and the vesicle sizes can be measured in the laboratory. On the Colorado Plateau, volcanic fields are generally found around the margins of the plateau. Basaltic lavas range in age from 0 to 23 Ma; present elevations range from 1.7 km to 3.3 km. Samples were collected from lava flows in the areas of Marysvale, Springerville, Grand Mesa, and the San Juan Mountains and analyzed to determine the timing and extent of uplift. The analysis of the samples using X-ray computed tomography imaging and our numerical techniques for determining vesicle population statistics indicate uplift of 350–2200 m, depending on age. There is a clear relationship between age and amount of uplift (original elevation subtracted from present elevation). The results indicate slow uplift of 
40 m/m.y. between 25 Ma and 5 Ma (only 800 m of uplift during that time), and rapid uplift of 220 m/m.y. since 5 Ma (1100 m during that time). These results reconcile the long-standing controversy between interpretations of ancient versus recent uplift by providing an uplift history curve for the Colorado Plateau.
Key Words: Colorado Plateau • vesicular texture • basalt flows • paleogeography
This article has been cited by other articles:
|
|
 |
|
  M. J. Kohn and T. J. Fremd Miocene tectonics and climate forcing of biodiversity, western United States Geology, October 1, 2008; 36(10): 783 - 786. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 G. P. Eaton Epeirogeny in the Southern Rocky Mountains region: Evidence and origin Geosphere, October 1, 2008; 4(5): 764 - 784. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. Moucha, A. M. Forte, D. B. Rowley, J. X. Mitrovica, N. A. Simmons, and S. P. Grand Mantle convection and the recent evolution of the Colorado Plateau and the Rio Grande Rift valley Geology, June 1, 2008; 36(6): 439 - 442. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 R.M. Flowers, B.P. Wernicke, and K.A. Farley Unroofing, incision, and uplift history of the southwestern Colorado Plateau from apatite (U-Th)/He thermochronometry Geological Society of America Bulletin, May 1, 2008; 120(5-6): 571 - 587. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. E. Spencer, G. R. Smith, and T. E. Dowling Middle to late Cenozoic geology, hydrography, and fish evolution in the American Southwest Geological Society of America Special Papers, January 1, 2008; 439(0): 279 - 299. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
K. E. Karlstrom, R. S. Crow, L. Peters, W. McIntosh, J. Raucci, L. J. Crossey, P. Umhoefer, and N. Dunbar 40Ar/39Ar and field studies of Quaternary basalts in Grand Canyon and model for carving Grand Canyon: Quantifying the interaction of river incision and normal faulting across the western edge of the Colorado Plateau Geological Society of America Bulletin, November 1, 2007; 119(11-12): 1283 - 1312. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 D. Sahagian and A. Proussevitch Paleoelevation Measurement on the Basis of Vesicular Basalts Reviews in Mineralogy and Geochemistry, October 1, 2007; 66(1): 195 - 213. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. E. McMillan, P. L. Heller, and S. L. Wing History and causes of post-Laramide relief in the Rocky Mountain orogenic plateau Geological Society of America Bulletin, March 1, 2006; 118(3-4): 393 - 405. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 P. M. Blisniuk and L. A. Stern Stable isotope paleoaltimetry: A critical review Am J Sci, December 1, 2005; 305(10): 1033 - 1074. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. C. McElwain Climate-independent paleoaltimetry using stomatal density in fossil leaves as a proxy for CO2 partial pressure Geology, December 1, 2004; 32(12): 1017 - 1020. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. C. Libarkin and C. G. Chase Timing of Colorado Plateau uplift: Initial constraints from vesicular basalt-derived paleoelevations: Comment and Reply: COMMENT Geology, February 1, 2003; 31(2): 191 - 191. [Full Text] [PDF]
|
|
|
|
|
|
D. Sahagian, A. Proussevitch, and W. Carlson Reply Geology, February 1, 2003; 31(2): 192 - 192. [Full Text] [PDF]
|
|
| JOURNAL HOME | HELP | CONTACT PUBLISHER | SUBSCRIBE | ARCHIVE | SEARCH | TABLE OF CONTENTS |
