Strain and shortening amount analysis in the Asmari anticline, Khuzestan province
Subject Areas : Geoscience Fields in relation with Petroleum Geology
Babak
Samani
1
(Faculty of Earth Sciences, Shahid Chamran University of Ahvaz)
Abbas
Charchi
2
(Faculty of Earth Sciences, Shahid Chamran University of Ahvaz)
Narges
Khatib
3
(Faculty of Earth science, Shahid Chamran University of Ahvaz)
Keywords: Dezful embayment, Asmari anticline, Strain, Shortening, fold interlimb angle ,
Abstract :
The only outcrop of Asmari formation in the Dezful embayment is visible in the Asmari anticline. In order to estimate the strain parameters and shortening values, 26 geological cross sections were prepared perpendicular to the anticline axis. Based on the, interlimb angle measurements, the interlimb angles of the northern and central parts of the anticline show smaller angles than the southern parts. Determination of strain ratio (R) values indicates the strain values between 1.12 - 1.52. The zoning map of strain ratio values shows higher strain values in the northern and central parts of the anticline. Using geological cross sections and measuring the base length of the folded layer of Asmari formation (L0) and the straight length of the layer (L1), the percentage of shortening values were calculated in each section. The results show the occurrence of 1.8% to 12% shortening in different parts of the anticline. Shortening map of the Asmari anticline shows more shortening amounts in the northern and central parts of the anticline than the southern parts.
[1] ALAVI, M., 1994, Tectonics of the Zagros orogenic belt of Iran: new data and interpretation. Tectonophysics, 229, 211–238.
[2] ALAVI, M., 2004, Regional stratigraphy of the Zagros fold-thrust belt of Iran, and its proforeland evolution. American Journal of Science 304, 1–20.
[3] ALAVI, M., 2007, Structures of the zagros fold-thrust belt in Iran. American journal of science, vol. 307, 1064-1095.
[4] AL-AZZAWI N. K. 2008, Local Shortening of Folds and Detachment Surface Depth with Examples from the Foreland Belt of Iraq. Iraqi Journal of Earth Sciences- Vol. 8. No. 1- May
[5] BERBERIAN, M., 1995, Master ‘blind’ thrust faults hidden under the Zagros folds: active basement tectonics and surface morphotectonics, Tectonophysics, 241, 193–224.
[6] BERBERIAN, M., KING, G.C.P., 1981, Towards a paleogeography and tectonic evolution of Iran. Canadian Journal of Earth Sciences 18, 210–265.
[7] BLANCE , E.J.P., ALLEN, M.B., INGER, S., HASSANI, H., 2003, Structural styles in the Zagros Simple Folded Zone, Iran. J. Geol. Soc. 160, 401–412. doi:10.1144/0016-764902-110.
[8] BROWN, D., ALVAREZ - MARRON, J., PEREZ - ESTAFIN, A., GOROZJANIN, Y., BARYSHEVA, V., PUCHKOV, V., 1997, Geometric and kinematic evolution of the foreland thrust and fold belt in the southern Urals. Tectonics, VOL. 16, NO. 3, PAGES 551-562, JUNE 1997.
[9] ESPURT, N., HIPPOLYTE, J.C., SAILLARD, M., BELLIER, O., 2012, Geometry and kinematic evolution of a long-living foreland structure inferred from field data and cross section balancing, the Sainte-Victoire System, Provence, France. Tectonics, VOL. 31, TC4021, doi:10.1029/2011TC002988.
[10] FALCON, N.L., 1969, Problems of the relationship between surface structures and deep displacements illustrated by the Zagros range. Geol. Soc. Lond. Spec. Pub. 3, 9–22.
[11] FREHNER, M.D., GRASEMANN, B., 2012, Mechanical versus kinematical shortening reconstructions of theZagros High Folded Zone (Kurdistan region of Iraq), Tectonics, 31, TC3002, doi:10.1029/2011TC003010.
[12] FRY, N., 1979, Random point distribution and strain measurements in rocks. Tectonophysics 60:89-105.
[13] FOSSEN, H., 2016, Structural Geology. Cambridge University Press.
[14] GHASSEMI, M. R., SCHMALHOLZ, S. M., GHASSEMI, A. R., 2010, Kinematics of constant arc length folding for different fold shapes. Journal of Structural Geology . 32 (2010) 755e765.
[15] HAYNES, S.J., MCQUILLAN, H., 1974, Evolution of the Zagros suture zone, Southern Iran. Geol. Soc. Am. Bull. 85, 739–744.
[16] IMBER J, PERRY T, JONES R, WIGHTMAN RH 2012, Do cataclastic deformation bands form parallel to lines of no finite elongation (LNFE) or zero extension direction? J Struct Geol 45:158–172.
[17] JAHANI, S., CALLOT, J.P., FRIZON de LAMOTTE, D., LETOUZEY, J., LETURMY, P., 2007, The Salt Diapirs of the eastern Fars province (Zagros, IRAN): a Brief outline of their past and present. In: Lacombe, O., Lavé, J., Roure, F., Vergés, J. (Eds.), Thrust Belt and Foreland Basin. Springer Berlin Heidelberg, pp. 289–308.
[18] KESHAVARZ, S., FAGHIH, F., 2020, Heterogeneous sub–simple deformation in the Gol–e–Gohar shear zone (Zagros, SW Iran): insights from microstructural and crystal fabric analyses. Int. J. Earth Sci. 109, 421–438.
[19] KODABAKHSHNEZHAD, A., ARIAN, M., POURKERMANI, M., 2015, Folding mechanism in the Asmari anticline, Zagros, Iran, Open Journal of Geology, 5, 197-208.
[20] MCQUARRIE, N., 2004, Crustal scale geometry of the Zagros fold–thrust belt, Iran. Journal of Structural Geology 26, 519–535.
[21] MOLINARO, M., ZEYEN, H., LAURENCIN, X., 2005, Lithospheric structure beneath the southeastern Zagros Mountains, Iran: Recent slab break-off? Terra Nova 17, 1–6. doi:10.1111/j.1365-3121.2004.00575.x.
[22] RAMSAY, JG., 1967, Folding and fracturing of rocks. McGraw-Hill, New York.
[23] RAMSAY, JG, HUBER, MI., 1983, The techniques of modern structural geology, 1: strain analysis. Academic Press, London.
[24] SAMANI, B., 2017, Deformation flow analysis and symmetry of Goushti shear zone, Sanandaj-Sirjan metamorphic belt, Iran. Geopersia. 7, 117-130.
[25] SARKARINEJAD, K., AZIZI, A., 2008, Slip partitioning and inclined dextral transpression along the Zagros Thrust System, Iran. Journal of Structural Geology, 30: 116–136.
[26] SARKARINEJAD, K, SAMANI, B, FAGHIH, A, GRASEMANN, B, MORADIPOOR, M., 2010, Implications of strain and vorticity of flow analyses to interpret the kinematics of an oblique convergence event (Zagros Mountains, Iran). J Asian Earth Sci 38:34-43.
[27] SARKARINEJAD, K., KESHAVARZ, S., FAGHIH, A., SAMANI, B., 2017, Kinematic analysis of rock flow and deformation temperature of the Sirjan thrust sheet, Zagros Orogen, Iran. Geol. Mag. 154, 147–165.
[28] SKERKATI, S., MOLINARO, M., FRIZON DELAMOTTE, D., LETOUZEY, J., 2005, Detachment folding in the Central and Eastern Zagros fold-belt (Iran): salt mobility, multiple detachments and late basement control.J.Struct. Geol. 27,1680–1696.
[29] STOCKLIN, J., 1968, Structural history and tectonics of Iran, a review, A. A. P. G. Bull., 52(7), PP. 1229-1258.
[30] TALEBIAN, M., JACKSON, J., 2004, A reappraisal of earthquake focal mechanisms and active shortening in the Zagros mountains of Iran. Geophys. J. Int. 156, 506–526.
[31] TEYSSIRE, C., 1985, A crustal thrust system in an intracratonic tectonic environment. Journal of Structural Geology. Vol 7. No 6, pp. 689 to 700.
[32] VERNANT, P., CHERY, J., 2006, Mechanical modeling of oblique convergence in the Zagros, Iran. Geophys. J. Int. 165, 991–1002.
[33] VITALE, S, MAZZOLI, S., 2008, Heterogeneous shear zone evolution: the role of shear strain hardening/softening. J Struct Geol 30:1383–1395.