Determination of the tectonic evolution from fractures, faults, and calcite twins on the southwestern margin of the Indochina Block

Abstract

In polyphase tectonic zones, integrating a study of fault and fracture with calcite twin analysis can determine the evolving paleostress magnitudes and principle stress directions that affected the area. This paper presents the results of the analyses of fractures, striated faults, and calcite twins collected within the Khao Khwang Fold-Thrust Belt in central Thailand (SE Asia). Here we attempt to reconstruct the orientation of the principal stresses that developed during the tectonic evolution of this highly deformed, polyphase orogen. Tectonic data were collected in the Permian carbonates of the Khao Khad Formation of the Saraburi Group, and five successive tectonic stages are determined that are interpreted to have developed before, during, and after, the Triassic Indosinian Orogeny. The first three stages predate the main deformation event: the first stage is interpreted as a pre-Indosinian N-S extensional stage, the second stage described a N-S strike-slip and compressional regime, largely perpendicular to the fold axes of the main structures, while the third stage is associated with an E-W compressional strike-slip phase. A further two stages took place after, or during, the main folding event and correspond to N-S compression and to an E-W composite strike-slip/contractional stage, the latter which is interpreted to represent Cenozoic deformation related to the India-Asia collision.

Combining geophysical data and calcite twin stress inversion to refine the tectonic history of subsurface and offshore provinces: A case study on the Cooper-Eromanga Basin, Australia

“…To better constrain the stress orientation and regime through time, calcite twins (from oriented core samples), natural fractures (from borehole image log interpretation and core analysis), and seismic scale faults (from 3‐D seismic data) are measured and analyzed. Analysis of paleostress tensors measured from, or the combination of, fault slip, fracture, and calcite deformation data has been applied to many regions of the world [e.g., Ramsay , ; Angelier and Mechler , ; Etchecopar et al ., ; Etchecopar , ; Tourneret and Laurent , ; Lacombe , ; Amrouch et al ., ; Arboit et al ., , ]. However, the combination of geophysical data (faults and fractures) and calcite twin data is presented here for the first time.…”

“…Analysis of twin data has been proven to efficiently and accurately constrain five of the six parameters required to define the complete stress tensor of individual paleotectonic events [ Lacombe , , ; Amrouch et al ., ; Amrouch , ]. This inversion technique is also capable of obtaining polyphase paleostress orientations and stress magnitudes [ Lacombe et al ., ; Rocher et al ., ; Amrouch et al ., ; Arboit et al ., , ]. Analysis of measured e planes assumes that their development was under a homogenous stress field and that they were not rotated after formation [ Lacombe , ].…”

“…Ideally, fractures that require unfolding to horizontal bedding, in order to be consistent with the Andersonian system, developed prior to bedding tilting. Fracture planes that are consistent with being developed under the Andersonian system (±10°) with inclined bedding planes are treated as being developed after the bedding plane tilting event [e.g., Hancock , ; Bellahsen et al ., ; Amrouch et al ., , ; Arboit et al ., ]. This distinction can help with defining the relative chronology of natural fracture development.…”

“…In such regions, it is vital to integrate stress inversion techniques that are proven to generate meaningful results. The chronology, geometry, and deformation associated with calcite twinning [ Tourneret and Laurent , ; Lacombe and Laurent , ; Lacombe , ; Lacombe et al ., ], natural fractures [ Silliphant et al ., ; Bergbauer and Pollard , ; Bellahsen et al ., ], and faults [ Michael , ; Gephart , ; Nemcok and Lisle , ; Tavani et al ., ], as well as any combination of the three [ Friedman and Stearns , ; Amrouch et al ., , , ; Beaudoin et al ., , ; Arboit et al ., , ], have provided valuable insights into the development of paleostress inversion techniques and in constraining the tectonic evolution of complex provinces. However, these data are typically obtained from sampled outcrop with only a small number of researchers attempting to use core [ Lacombe et al ., ; Rocher et al ., ], which has prevented paleostress analysis in regions entirely overlain by loose sediment or provinces located offshore.…”

“…The use of calcite twins to determine paleostress [ Etchecopar , ] and strain [ Groshong , , ; Friedman et al ., ] has been successfully performed in areas such as the Zagros belt (Iran) [ Lacombe et al ., ], Rocky Mountains (Wyoming) [ Craddock and Van Der Pluijm , ; Amrouch et al ., , , ; Beaudoin et al ., ], Causses Basin (France) [ Constantin et al ., ], Iberian Chain (Spain) [ González‐Casado and Garcı́a‐Cuevas , ], Cuddapah Basin (India) [ Tripathy and Saha , ], Indochina Block (Thailand) [ Arboit et al ., , ], Pyrenees‐Provence Domain [ Lacombe et al ., ; Rocher et al ., ], Taiwan [ Rocher et al ., ; Lacombe , ], Albanides [ Lacombe et al ., ], and the Apennine Mountains (Italy) [ Beaudoin et al ., ]. The purpose of the following research is to provide better constraints on the principal stress orientation and stress regime of tectonic events through the analysis of microscale calcite twins, mesoscale natural fractures, and macroscale faults.…”