Fry spacing of deformed and undeformed modeled and natural salt domes

Journal Article · Sun May 01 04:00:00 EDT 1988 · Geology; (United States)

DOI:https://doi.org/10.1130/0091-7613(1988)016<0465:FSODAU>2.3.CO;2· OSTI ID:6935753

Roennlund, P; Koyi, H

Fry's center-point spacing strain analysis is applied to experiments of gravity-driven overturn of horizontal fluid layers on scales of centimeters or decimeters, and to natural salt diapirs on scales of kilometers to tens of kilometers. Laboratory experiments in which about 100 diapirs formed from initially plane horizontal layers resulted in laterally isotropic spacing and yielded an open circle on a Fry plot with a radius equal to the wavelength (W). Lateral deformation and initial departures from horizontal layers with uniform properties may influence W. Sample experiments of diapirism with and without lateral deformation are compared to natural equivalents. The spacing of post-Late Triassic diapirs in the Zechstein salt of Germany and of post-Jurassic diapirs in the Hormuz salt of Arabia yields circles on Fry plots which indicate that these gravity structures developed without additional lateral forces. Fry plots of the spacing of salt diapirs in the Zagros Mountains define a strain ellipse with the long axis (=W in Arabia) parallel and the short axis perpendicular to post-Miocene regional fold axes. The ratio of the Zagros strain ellipse is about 1.7, which suggests a northeast-southwest shortening of 41%, rather than 10%-21% as estimated from folding alone. This mismatch may be a result of unquantified shortening due to thrusts and/or layer-parallel shortening. Center-point spacing of post-Late Triassic domes of Zechstein salt in the central North Sea also gives an ellipse. Here, the long axis coincides with the direction of Middle Jurassic to Cretaceous extension. The axial ratio of the North Sea strain ellipse is about 2.8, compared to estimates of about 1.5-2.0 by Sclater and Christie, and 1.8 by Wood and Barton.

• Research Organization: Uppsala Univ. (Sweden)
• OSTI ID: 6935753
• Journal Information: Geology; (United States), Journal Name: Geology; (United States) Vol. 16:5; ISSN GLGYB
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580100* -- Geology &amp; Hydrology-- (-1989)
ASIA
ATLANTIC OCEAN
BENCH-SCALE EXPERIMENTS
CALCULATION METHODS
CAVITIES
DEFORMATION
EUROPE
FEDERAL REPUBLIC OF GERMANY
FLUIDS
GEOLOGIC DEPOSITS
GEOLOGIC HISTORY
GRAVITATION
LAYERS
NORTH SEA
RESERVOIR FLUIDS
SALT CAVERNS
SALT DEPOSITS
SAUDI ARABIA
SEAS
STRESS ANALYSIS
SURFACE WATERS
WESTERN EUROPE