Magmatism and extension - the thermal and mechanical effects of the Yellowstone hotspot

Journal Article · Thu Oct 01 04:00:00 EDT 1992 · Journal of Geophysical Research; (United States)

DOI:https://doi.org/10.1029/92JB01376· OSTI ID:6895492

Anders, M H; Sleep, N H ^[1]

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1. Columbia Univ., Palisades, NY (United States) Stanford Univ., CA (United States)

Currently, there is a parabolic-shaped pattern of seismicity and latest Quaternary faulting which centers on the axis of the eastern Snake River Plane (SRP) and has its apex at the Yellowstone Plateau. We present a one-dimensional, finite-difference, thermomechanical model that accounts for the observed pattern for increasing faulting followed by fault quiescence within the circum-eastern SRP. In this model, mafic magmas are intruded into a lithosphere that is already extending. This intrusions heat the surrounding rocks resulting in locally increased strain rates. As the intruded magmas solidify, the length of time required to return strain rates to their pre-intrusion level is then determined. We assume intruded rock rheology to be a Maryland diabase; mantle rheology we base on dry olivine; we represent the crust by both dry granite and dry anorthosite rheologies. Our results suggest that 2 to 3 m.y. appears to be a reasonable length of time for strain rates to return to levels present before a midcrustal mafic intrusion equivalent in magnitude to the Yellowstone intrusion. This corresponds closely to the length of time between the onset of along-axis accelerated faulting and subsequent fault quiescence, assuming a hotspot velocity of 3.5 to 4.0 cm/yr relative to the North American Plate. 84 refs.

• OSTI ID: 6895492
• Journal Information: Journal of Geophysical Research; (United States), Journal Name: Journal of Geophysical Research; (United States) Vol. 97; ISSN JGREA2; ISSN 0148-0227
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
540210* -- Environment
Terrestrial-- Basic Studies-- (1990-)
58 GEOSCIENCES
580000 -- Geosciences
CALCULATION METHODS
CENOZOIC ERA
FINITE DIFFERENCE METHOD
GEOLOGIC AGES
GEOLOGIC FAULTS
GEOLOGIC FRACTURES
GEOLOGIC STRUCTURES
ITERATIVE METHODS
MAGMA
MATHEMATICAL MODELS
NUMERICAL SOLUTION
ONE-DIMENSIONAL CALCULATIONS
PUBLIC LANDS
RHEOLOGY
STRAIN RATE
STRESSES
YELLOWSTONE NATIONAL PARK