Subsidence beneath a playa basin on the Southern High Plains, U. S. A. Evidence from shallow seismic data

Journal Article · Tue Feb 01 04:00:00 EST 1994 · Geological Society of America, Bulletin; (United States)

DOI:https://doi.org/10.1130/0016-7606(1994)106<0233:SBAPBO>2.3.CO;2· OSTI ID:5173746

Paine, J G ^[1]

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1. Univ. of Texas, Austin, TX (United States)

Shallow seismic data from Sevenmile Basin, a large ephemeral lake (playa) basin in the Texas Panhandle, reveal that subsidence has been an important agent in basin formation. Sevenmile Basin is 5.5 x 3.6 km across and 14 m deep and contains 20 m of lacustrine and eolian sediments that interfinger with the Quaternary Blackwater Draw Formation. Seismic reflection and refraction data were collected from the unlithified and variably saturated clastic sequence beneath Seven-mile Basin to investigate the geological history and hydrogeological framework of playa basins, which recharge the regionally important Ogallala aquifer. Three-layer velocity models provide good solutions for reversed refraction data. Near-surface p-wave velocities (layer 1) range from 349 to 505 m/s, layer 2 velocities range from 806 to 851 m/s, and layer 3 velocities range from 2,037 to 2,161 m/s. Shallow test holes and drillers' logs suggest that layer 1 is composed of playa and upper Blackwater Draw Formation deposits, layer 2 consists of lower Blackwater Draw Formation and upper Ogallala Formation deposits, and layer 3 represents a competent and partly saturated zone near the top of the Ogallala aquifer. Reflection sections show a middle Ogallala reflector, a reflector at the top of Permian or Triassic bedrock, and internal bedrock reflectors that indicate a structural low beneath Sevenmile Basin. Increasing relief with age, from 14 m at the surface to 70 m on the middle Ogallala reflector to 110 m at the base of the Ogallala, is interpreted as evidence of subsidence of underlying Permian evaporite-bearing strata before or during Ogallala deposition. 29 refs., 12 figs., 2 tabs.

• OSTI ID: 5173746
• Journal Information: Geological Society of America, Bulletin; (United States), Journal Name: Geological Society of America, Bulletin; (United States) Vol. 106:2; ISSN 0016-7606; ISSN BUGMAF
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
422000 -- Engineering-- Mining &amp; Underground Engineering-- (1980-)
58 GEOSCIENCES
580000* -- Geosciences
AQUIFERS
COMPILED DATA
DATA
DEVELOPED COUNTRIES
EVAPORITES
GEOLOGIC STRATA
GEOLOGIC STRUCTURES
GEOPHYSICAL SURVEYS
GROUND SUBSIDENCE
INFORMATION
NORTH AMERICA
NUMERICAL DATA
ROCKS
SEDIMENTARY ROCKS
SEDIMENTS
SEISMIC SURVEYS
SURVEYS
TEXAS
USA