Abstract
| Original language | English |
|---|---|
| Pages (from-to) | 176-191 |
| Number of pages | 16 |
| Journal | Journal of Structural Geology |
| Volume | 96 |
| Early online date | 27 Jan 2017 |
| DOIs | |
| Publication status | Published - 1 Mar 2017 |
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Keywords
- mass transport deposit
- kinematic indicators
- imbricate thrust-faults
- layer-normal shearing
- fold deformation
- sandstone blocks
Cite this
Sub-seismic scale folding and thrusting within an exposed mass transport deposit : A case study from NW Argentina. / Sobiesiak, Matheus S.; Alsop, G. Ian; Kneller, Benjamin Charles; Milana, Juan Pablo.
In: Journal of Structural Geology, Vol. 96, 01.03.2017, p. 176-191.Research output: Contribution to journal › Article
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TY - JOUR
T1 - Sub-seismic scale folding and thrusting within an exposed mass transport deposit
T2 - A case study from NW Argentina
AU - Sobiesiak, Matheus S.
AU - Alsop, G. Ian
AU - Kneller, Benjamin Charles
AU - Milana, Juan Pablo
N1 - This work was carried out with support from CNPq (Conselho Nacional de Desenvolvimento Científico e Tecnológico) - Brazil, BG - Brazil and the University of Aberdeen. We would like to thank the following geologists for their support, camaraderie and countless hours of fieldwork: Arthur Giovannini, Claus Fallgatter, Victoria Valdez, Qun Liu, Carla Puigdomenech, Guilherme Bozetti and Roberto Noll Filho. We thank Christopher Jackson and an anonymous reviewer, whose constructive comments and criticism helped to improve the manuscript.
PY - 2017/3/1
Y1 - 2017/3/1
N2 - While imaging of mass transport deposits (MTDs) by seismic reflection techniques commonly reveals thrusts and large blocks that affect entire deposits, associated systems of folds are generally less apparent as they are typically below the limits of seismic resolution. However, such sub-seismic scale structures are important as they permit the direction of emplacement, gross kinematics and internal strain within MTDs to be determined. Here we present a rigorous description of two outcrop-scale MTDs exposed in La Peña gorge, northwestern Argentina. These Carboniferous MTDs enable us to illustrate structural changes from a compressional domain, marked by sets of imbricated sandstone layers, into an extensional domain, characterized by sheared blocks of sandstone embedded in a finer matrix. Folds may be progressively modified during slump translation, resulting in asymmetric folds, which undergo subsequent deformation leading to sheared fold limbs together with detached and rotated fold hinges. In order to constrain transport directions within the MTDs, we measured fold hinges, mud clast alignment, and thrust planes as kinematic indicators. We propose emplacement models for both MTDs based on the overall deformational behaviour of sandstone beds during translation. The first model is based on the internal geometries and structures of a fault-dominated MTD, and the second model is based on layer-normal shearing in a fold-dominated MTD.
AB - While imaging of mass transport deposits (MTDs) by seismic reflection techniques commonly reveals thrusts and large blocks that affect entire deposits, associated systems of folds are generally less apparent as they are typically below the limits of seismic resolution. However, such sub-seismic scale structures are important as they permit the direction of emplacement, gross kinematics and internal strain within MTDs to be determined. Here we present a rigorous description of two outcrop-scale MTDs exposed in La Peña gorge, northwestern Argentina. These Carboniferous MTDs enable us to illustrate structural changes from a compressional domain, marked by sets of imbricated sandstone layers, into an extensional domain, characterized by sheared blocks of sandstone embedded in a finer matrix. Folds may be progressively modified during slump translation, resulting in asymmetric folds, which undergo subsequent deformation leading to sheared fold limbs together with detached and rotated fold hinges. In order to constrain transport directions within the MTDs, we measured fold hinges, mud clast alignment, and thrust planes as kinematic indicators. We propose emplacement models for both MTDs based on the overall deformational behaviour of sandstone beds during translation. The first model is based on the internal geometries and structures of a fault-dominated MTD, and the second model is based on layer-normal shearing in a fold-dominated MTD.
KW - mass transport deposit
KW - kinematic indicators
KW - imbricate thrust-faults
KW - layer-normal shearing
KW - fold deformation
KW - sandstone blocks
U2 - 10.1016/j.jsg.2017.01.006
DO - 10.1016/j.jsg.2017.01.006
M3 - Article
VL - 96
SP - 176
EP - 191
JO - Journal of Structural Geology
JF - Journal of Structural Geology
SN - 0191-8141
ER -