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

Journal Article · Tue Feb 01 00:00:00 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), Vol. 106:2; ISSN 0016-7606
• Country of Publication: United States
• Language: English

Related Subjects

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