Saddle Mountains: the evolution of an anticline in the Yakima Fold Belt

Journal Article · Mon Oct 01 04:00:00 EDT 1984 · Am. J. Sci.; (United States)

DOI:https://doi.org/10.2475/ajs.284.8.942· OSTI ID:6448665

Reidel, S P

Thickness variations record paleostructural relief and thus provide a method of calculating the growth rate of the Saddle Mountains. These calculations indicate the uplift was growing at about 250 m/my during Grande Ronde time but slowed to less than 40 m/my by the end of the Miocene. Thickness variations and amount of uplift of suprabasalt sediments indicate this low average rate persisted at least until 3.5 Ma. This low average rate of uplift, projected to the present time, accounts for the present structural relief of the Saddle Mountains. Estimates of the rate of shortening are of the same order of magnitude as that of uplift. Studies of other folds in the province show a similar pattern of evolution suggesting that the age, timing, and growth rate of the Saddle Mountains provide a model for anticlinal folds of the Yakima Fold Belt. The close correlation of growth rate of the folds with rate of magma supply of the Columbia River Basalt Group suggests that the Yakima Fold Belt resulted from the same tectonic processes that produced eruption of the Columbia River basalt.

• Research Organization: Rockwell International, Richland, WA
• OSTI ID: 6448665
• Journal Information: Am. J. Sci.; (United States), Journal Name: Am. J. Sci.; (United States) Vol. 284:8; ISSN AJSCA
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580100* -- Geology & Hydrology-- (-1989)
ANTICLINES
BASALT
CENOZOIC ERA
CHEMICAL ANALYSIS
COLUMBIA RIVER
FEDERAL REGION X
GEOLOGIC AGES
GEOLOGIC FAULTS
GEOLOGIC FORMATIONS
GEOLOGIC FRACTURES
GEOLOGIC MODELS
GEOLOGIC STRUCTURES
GEOLOGIC SURVEYS
GEOLOGY
IGNEOUS ROCKS
MAGNETISM
NONDESTRUCTIVE ANALYSIS
NORTH AMERICA
OROGENESIS
PALEOMAGNETISM
RIVERS
ROCKS
SEDIMENTARY ROCKS
STRATIGRAPHY
STREAMS
SURFACE WATERS
SURVEYS
TECTONICS
TERTIARY PERIOD
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VOLCANIC ROCKS
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X-RAY EMISSION ANALYSIS
X-RAY FLUORESCENCE ANALYSIS