Strain geometry and structural analysis of the Oshnavieh ophiolite (NW Iran): A new segment of the Neo-Tethys puzzle

Iranian Journal of Earth Sciences

مقاله 3، دوره 13، شماره 4، دی 2021، صفحه 266-278   

نوع مقاله: Original Research Paper

شناسه دیجیتال (DOI): 10.30495/ijes.2021.685394

نویسندگان

Majid Niromand؛ Mahdi Behyari^* ؛ Yousef Rahimsouri

Geology Department, Science Faculty, Urmia university, Urmia, Iran

چکیده

The closure of the Neo-Tethys ocean associated with the ophiolite obduction and the Oshnavieh ophiolite is the unknown part of the Neo-Tethys suture zone. Three well-known band ratio combinations applied to ASTER satellite image the result shows the ((2+4) /3, (5+7) /6, (7+9) /8) band ratio is the proper combination for the reorganization of rock units in the ophiolite regions. Principal component analysis of the (PC2, PC4 and PC 5) is well discriminated against to the rock unit contacts. The general trend of thrust faults is the NW-SE and dip direction is toward the NE. The rake of slickenline on the fault plane is 80°-90° and the mechanism of movement is the pure thrust. The shear sense indicator such as Z-type parasitic folds or mica-fish and S-C fabrics confirm right-lateral shearing sense in the shear zone. Strain geometry on the obducted slab evaluated by the shape of the mineral grains. In the shear zone strain ellipsoid shape is the prolate type and formed under constrictional regime, the Flinn K-value of these samples changes between 2.71 to 11.67 and lode ratio between -0.42 to -0.63. Most of the samples taken from the thrust fault zone located in the flattening zone and strain ellipsoid are pancake-shaped and formed under contractional regime the k-value varied between 0.44 to 0.80 and Lode ratio range is 0.32 to 0.5. The displacement in the thrust zone and shearing by the shear zone disrupted the ophiolite sequence and created an ophiolite mélange.

کلیدواژه‌ها

Ophiolite؛ ASTER image processing؛ PCA؛ Strain geometry؛ Flinn diagram؛ NW Iran

مراجع

1. Abdeen MM, Thurmond AK, Abdelsalam MG, Stern RJ (2001) Application of ASTER band-ratio images for geological mapping in arid regions: the neoproterozoic Allaqi Suture, Egypt. In: Abstract with Program Geological Society of America 3(3): 289.
2. Abrams M, Rothery D, Pontual A (1988) Mapping in the Oman ophiolite using enhanced Landsat Thematic Mapper images, Tectonophysics 151:387-401.
3. Agard P, Omrani J, Jolivet L, Mouthereau F (2005) Convergence history across Zagros (Iran): constraints from collisional and earlier deformation., International Journal of Earth Sciences 94:401-419.
4. Agard P, Omrani J, Jolivet L, Whitechurch H, Vrielynck B, Spakman W, Monié P, Meyer B, Wortel R (2011) Zagros orogeny: a subduction-dominated process, Geological Magazine 148:692-725.
5. Alavi M (1991) Sedimentary and structural characteristics of the Paleo-Tethys remnants in northeastern Iran, The Geological Society of America Bulletin 103:983-992.
6. Alavi M (1994) Tectonics of the Zagros orogenic belt of Iran: new data and interpretations, Tectonophysics 229:211-238.
7. Ali SA, Buckman S, Aswad KJ, Jones BG, Ismail SA, Nutman A (2013) The tectonic evolution of a N eo‐T ethyan (E ocene–O ligocene) island‐arc (W alash and N aopurdan groups) in the K urdistan region of the N ortheast Iraqi Zagros Suture Zone, Island Arc 22(1):104-125.
8. Amer R, Kusky T, Ghulam A (2010) New methods of processing ASTER data for lithological mapping: examples from Fawakhir, Central Eastern Desert of Egypt, Journal of African Earth Sciences 56:75-82.
9. Aswad KJ, Aziz NR, Koyi HAJGm (2011) Cr-spinel compositions in serpentinites and their implications for the petrotectonic history of the Zagros Suture Zone, Kurdistan Region, Iraq, Geological magazine  148:802-818.
10. Axen GJ, Lam PS, Grove M, Stockli DF, Hassanzadeh J (2001) Exhumation of the west-central Alborz Mountains, Iran, Caspian subsidence, and collision-related tectonics, Geology 29:559-562.
11. Babaie HA, Babaei A, Ghazi AM, Arvin M (2006) Geochemical, 40Ar/39Ar age, and isotopic data for crustal rocks of the Neyriz ophiolite, Iran, Canadian Journal of Earth Sciences 43:57-70.
12. Ballato P, Uba CE, Landgraf A, Strecker MR, Sudo M, Stockli DF, Friedrich A, Tabatabaei SH (2010) Arabia-Eurasia continental collision: Insights from late Tertiary foreland-basin evolution in the Alborz Mountains, northern Iran, Geological Society of America Bulletin 123:106-131.
13. Behyari M, Kanabi A (2019) Constraining of strain ellipsoid shape from sectional data in the au bearing shear zone west of Iran, Acta Geodynamica et Geromaterialia 16:131-143.
14. Behyari M, Mohajjel M, Sobel ER, Rezaeian M, Moayyed M, Schmidt A (2017) Analysis of exhumation history in Misho Mountains, NW Iran: Insights from structural and apatite fission track data, Neues Jahrbuch für Geologie und Paläontologie-Abhandlungen 283:291-308.
15. Behyari M, Nouraliee J, Ebrahimi DJAGSEE (2018) Structural Control on the Salmas Geothermal Region, Northwest Iran, from Fractal Analysis and Paleostress Data, . Acta Geologica Sinica‐English Editio 92:1728-1738.
16. Behyari M, Shahbazi M (2019) Strain and vorticity analysis in the Zagros suture zone (W Iran): Implications for Neo-Tethys post-collision events, Journal of Structural Geology 126:198-209.
17. Berberian M, King G (1981) Towards a paleogeography and tectonic evolution of Iran, Canadian journal of earth sciences 5:101-117.
18. Bhattacharyya P, Hudleston P (2001) Strain in ductile shear zones in the Caledonides of northern Sweden: a three-dimensional puzzle, Journal of Structural Geology 23:1549-1565.
19. Cloutis EA, Sunshine J, Morris R (2004) Spectral reflectance‐compositional properties of spinels and chromites: Implications for planetary remote sensing and geothermometry, Meteoritics & Planetary Science 39:545-565.
20. Flinn D (1962) On folding during three-dimensional progressive deformation, Quarterly Journal of the Geological Society 118:385-428.
21. Fossen H, Cavalcante G (2017) Shear zones–A review, Earth-Science Reviews 171:434-455.
22. François T, Agard P, Bernet B, Meyer B, Chung S-L, Zarrinkoub MH, Burov E, Monié P (2014) Cenozoic exhumation of the internal Zagros: first constraints from low-temperature thermochronology and implications for the build-up of the Iranian plateau, Lithos 206-207:100-112.
23. Hassanipak A, Ghazi A (2000) Petrology, geochemistry and tectonic setting of the Khoy ophiolite, northwest Iran: implications for Tethyan tectonics,  Journal of Asian Earth Sciences 18:109-121.
24. Hunt GR, Salisbury JW, Lenhoff CJ (1974) Visible and near infrared spectra of minerals and rocks: IX. Basic and ultrabasic igneous rocks, Modern Geology 5:15-22.
25. Keshavarz S, Faghih A (2020) Heterogeneous sub-simple deformation in the Gol-e-Gohar shear zone (Zagros, SW Iran): insights from microstructural and crystal fabric analyses,  International Journal of Earth Sciences 109:421-438.
26. Khalatbari-Jafari M, Juteau T, Bellon H, Emami H (2003) Discovery of two ophiolite complexes of different ages in the Khoy area (NW Iran), Comptes Rendus Geoscience 335:917-929.
27. Khalatbari-Jafari M, Juteau T, Bellon H, Whitechurch H, Cotten J, Emami H (2004) New geological, geochronological and geochemical investigations on the Khoy ophiolites and related formations, NW Iran,  Journal of Asian Earth Sciences 23:507-535.
28. Lisle RJ (2010) Strain analysis from point fabric patterns: An objective variant of the Fry method, Journal of Structural Geology 32:975-981.
29. Mahdavi M, Dabiri R, Hosseini ES (2015) Magmatic evolution and compositional characteristics of tertiary volcanic rocks associated with the Venarch manganese mineralization, SW Qom, central Iran. Earth Sciences Research Journal 19(2):141-5.
30. Moghadam HS, Stern RJ. (2015) Ophiolites of Iran: Keys to understanding the tectonic evolution of SW Asia:(II) Mesozoic ophiolites, Journal of Asian Earth Sciences 100:31-59.
31. Mohajjel M, Fergusson C, Sahandi M (2003) Cretaceous–Tertiary convergence and continental collision, Sanandaj–Sirjan zone, western Iran, Journal of Asian Earth Sciences 21:397-412.
32. Mohajjel M, Fergusson CL (2000) Dextral transpression in Late Cretaceous continental collision, Sanandaj–Sirjan zone, western Iran, Journal of structural geology 22:1125-1139.
33. Monsef I, Rahgoshay M, Mohajjel M, Moghadam HS. (2010) Peridotites from the Khoy Ophiolitic Complex, NW Iran: Evidence of mantle dynamics in a supra-subduction-zone context, Journal of Asian Earth Sciences 38:105-120.
34. Mookerjee M, Fortescue FQ (2016) Quantifying thinning and extrusion associated with an oblique subduction zone: An example from the Rosy Finch Shear Zone, Tectonophysics 693:290-303.
35. Mookerjee M, Nickleach S (2011) Three-dimensional strain analysis using Mathematica, Journal of Structural Geology 33:1467-1476.
36. Passchier CW, Trouw RA (1996) Microtectonics vol 2. Springer.
37. Rajendran S, Al-Khirbash S, Pracejus B, Nasir S, Al-Abri AH, Kusky TM, Ghulam A (2012) ASTER detection of chromite bearing mineralized zones in Semail Ophiolite Massifs of the northern Oman Mountains: Exploration strategy, Ore geology reviews 44:121-135.
38. Ramsay J, Graham R (1970) Strain variation in shear belts, Canadian Journal of Earth Sciences 7:786-813.
39. Ring U, Bernet M, Tulloch A (2015) Kinematic, finite strain and vorticity analysis of the Sisters shear zone, Stewart Island, New Zealand, Journal of Structural Geology 73:114-129.
40. Rowan LC, Hook SJ, Abrams MJ, Mars JC (2003) Mapping hydrothermally altered rocks at Cuprite, Nevada, using the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), a new satellite-imaging system, Economic Geology 98:1019-1027.
41. Saccani E, Allahyari K, Beccaluva L, Bianchini G. (2013) Geochemistry and petrology of the Kermanshah ophiolites (Iran): Implication for the interaction between passive rifting, oceanic accretion, and OIB-type components in the Southern Neo-Tethys Ocean,  Gondwana Research 24:392-411.
42. Saccani E, Allahyari K, Rahimzadeh B (2014) Petrology and geochemistry of mafic magmatic rocks from the Sarve-Abad ophiolites (Kurdistan region, Iran): Evidence for interaction between MORB-type asthenosphere and OIB-type components in the southern Neo-Tethys Ocean,  Tectonophysics 621:132-147.
43. Sarem MN, Abedini MV, Dabiri R, Ansari MR (2021) Geochemistry and petrogenesis of basic Paleogene volcanic rocks in Alamut region, Alborz mountain, north of Iran. Earth Sciences Research Journal 25(2):237-45.
44. Sarkarinejad K (2007) Quantitative finite strain and kinematic flow analyses along the Zagros transpression zone, Iran, Tectonophysics 442:49-65.
45. Sarkarinejad K, Faghih A, Grasemann B (2008) Transpressional deformations within the Sanandaj–Sirjan metamorphic belt (Zagros Mountains, Iran), Journal of Structural Geology 30:818-826.
46. Sarkarinejad K, Godin L, Faghih A (2009) Kinematic vorticity flow analysis and 40Ar/39Ar geochronology related to inclined extrusion of the HP–LT metamorphic rocks along the Zagros accretionary prism, Iran, Journal of Structural Geology 31:691-706.
47. Shafaii Moghadam H, Stern RJ (2011) Geodynamic evolution of Upper Cretaceous Zagros ophiolites: formation of oceanic lithosphere above a nascent subduction zone, Geological Magazine 148:762-801.
48. Shahabpour J (2005) Tectonic evolution of the orogenic belt in the region located between Kerman and Neyriz, Journal of Asian Earth Sciences 24:405-417.
49. Stallard A, Shelley D (1995) Quartz c-axes parallel to stretching directions in very low-grade metamorphic rocks, Tectonophysics 249:31-40.
50. Tangestani MH, Jaffari L, Vincent RK, Sridhar BM (2011) Spectral characterization and ASTER-based lithological mapping of an ophiolite complex: A case study from Neyriz ophiolite, SW Iran, Remote Sensing of Environment 115:2243-2254.
51. Vitale S, Mazzoli S (2010) Strain analysis of heterogeneous ductile shear zones based on the attitudes of planar markers, Journal of Structural Geology 32:321-329.
52. Watts M, Williams G (1983) Strain geometry, microstructure and mineral chemistry in metagabbro shear zones: a study of softening mechanisms during progressive mylonitization, Journal of Structural Geology 5:507-517.
53. Yazdi A, Ashja Ardalan A, Emami MH, Dabiri R, Foudazi M (2019) Magmatic interactions as recorded in plagioclase phenocrysts of quaternary volcanics in SE Bam (SE Iran). Iranian Journal of Earth Sciences 11(3):215-25.