Structural geology in Amphoe Wang Nam Khiao area, Changwat Nakhon Ratchasima

Abstract

Tectonic evolution in study area all along had been effected to bring about the apparent geological structure in Amphoe Wang Nam Khiao Area, where situated between the Sibumasu terrane, the Sukhothai-Chanthaburi terrane and the Indochina terrane. The rocks stratigraphy in study area in term of age form older to younger can be recognized to be five groups, including the Permian sedimentary rocks, the Permo-Triassic volcanic rocks, the Triassic Intrusive rocks in NE part of the study area, the Triassic hornblende granite and the Mesozoic in the Khorat group. Structural geology studies by measuring the orientations of apparent structure in outcrops such as foliations, bedding which plotted in stereonet diagrams and complied with stratigraphy, suggests two groups of trend. The first group includes the Permian sedimentary rocks, the Permo-Triassic volcanic rocks, some part of the Triassic intrusive rocks and the hornblende granite illustrated trend ENE-WSW to ESE-WNW and NE-SW. The second group consists of the Triassic intrusive rocks in SW part of the study area illustrated NW-SE orientation trends. Microstructures study further show evidence of brittle and ductile deformation mechanism. The orientations analysis of structural geology obtain and stratigraphy from the study area are indicated two deformations, as a result the former deformation (D1) generated first fold (F1) in ENE-WSW to ESE- WNW and NE-SW directions. The first fold was superimposed by the later deformation (D2) generated second fold (F2) in NW-SE direction. The resulting of two deformations caused structure like dome and basin apparent in Amphoe Wang Nam Khiao Area.