Document Type : Original Research Paper

Authors

1 M. Sc., Department of Geology, Faculty of Sciences, University of Birjand, Birjand, Iran

2 Professor, Department of Geology, Faculty of Sciences, University of Birjand, Birjand, Iran

3 Assistant Professor, Department of Mining Engineering, Birjand University of Technology, Birjand, Iran

Abstract

In the Boshgaz area in 50 kilometers northwest of Sarbisheh and eastern margin of Lut block, Tertiary
volcanic rocks with basaltic andesite, andesite and dacite composition are cropped out. The main texture
of these rocks are porphyry with microlithic-glass groundmass, glomeroporphyritic and vesicular. The main
minerals in andesite lavas are plagioclase, pyroxene, amphibole and biotite and in dacites are
plagioclase, quartz, amphibole and biotite. Geochemical investigations show that these rocks have
medium to high-K calk alkaline nature. Enrichment of  Sr, Zr, Cs, Th, K, depletion of Nb, Ti, P, Ba and
enrichment of LREE relative to HREE in the studied rocks show that these rocks are related to a subduction zone and active continental
margin setting. On the basis of trace elements diagrams, volcanic rocks of the
Boshgaz area are formed in an immature arc or early stage of subdution.
 Mg# values in volcanic rocks of the Boshgaz area are ~48 indicating the
role of mantle constituents in their formation. Low ratio of Sm/Yb(<2.5)
in the studied lavas show absence of garnet in the source. Low ratio of Zr/Ba
(average 0.34) and high ratio of La/Nb (2.22-3.19) for the studied lavas are
characteristics of lithospheric mantle source. MREE/HREE diagrams show
that lavas of the Boshgaz area originated from spinel-phlogopite lherzolite.
Low ratio of Ba/Rb (<20) and high ratio of Rb/Sr (>0.1), support
 the existence of phlogopite in the source. The uniform pattern of
REEs and medium values of La
N
/Lu
N
(8-14)inintermediate and
acidic rocks of Boshgaz indicate genetic relationbetween them.
 

Keywords

Aldanmaz, E., Pearce, J. A., Thirlwall, M. F. and Mitchell, J. G., 2000- Petrogenetic evolution of late Cenozoic, postcollision volcanism in western Anatolia, Turkey. Journal of Volcanology and Geothermal Research 102: 67– 95.
Alici, Sen P., Temel, A. and Gourgaud, A., 2004- Petrogenetic modeling of Quaternary postcollisional volcanism: a case study of central andeastern Anatolia. Geological Magazine 141: 81-98.
Almeida, M. E., Macambira, M. J. B. and Oliveira, E. C., 2007- Geochemistry and zircon geochronology of the I-type high-K calc-alkaline and S-type granitoid rocks from southeastern Roraima, Brazil: Orosirian collisional magmatism evidence (1.97-1.96 Ga) in Central portion of Guyana shield. Precambrian Research 15: 69-97.
Arjmandzadeh, R. and Santos, J. F., 2014- Sr-Nd isotope geochemistry and tectonomagmatic setting of the Dehsalm Cu-Mo porphyry mineralizing intrusives from Lut Block, eastern Iran. Int J Earth Sci (Geol Rundsch) 103: 123-140.
Arslan, M. and Aslan, Z., 2006- Mineralogy, petrography and whole-rock geochemistry of the Tertiary granitic intrusions in the Eastern Pontides, Turkey. Journal of Asian Earth Sciences 27: 177-193.
Aydınçakır, E., 2016- Subduction-related Late Cretaceous high-K volcanism in the Central Pontides orogenic belt: constraints on geodynamic implications. Geodinamica Acta 28: 1-33.
Boynton, W. V., 1984- Geochemistry of the rare earth elements: meteorite studies. Rare Earth Element Geochemistry 16: 63-114.
Brown, G. C., Thorpe, R. S. and Webb, P. C., 1984- The geochemical characteristics of granitoids in contrasting arcs and comments on magma sources. Journal of Geological Society London 141: 413-426.
Camp, V. E. and Griffis, R. J., 1982- Character, genesis and tectonic setting of igneous rocks in the Sistan suture zone, eastern Iran. Lithos 15: 221-239.
Castillo, P. R., 2006- An overview of adakite petrogenesis: Chinese Science Bulletin 51: 257-268.
Chashchin, A. A., Sorokin, A. A., Lebedev, V. A. and Blokhin, M. G., 2016- Age, Main Geochemical Characteristics, and Sources of Late Cenozoic Volcanic Rocks in the Udurchukan Volcanic Area (Amur Region), published in Tikhookeanskaya 35: 3-13.
Chen, L., Zheng, Y. F. and Zhao, Z. F., 2016- Geochemical constraints on the origin of Mesozoic andesites from the Ningwu basin in the Middle-Lower Yangtze Valley, South China. Lithos 254: 94-117.
De Angelis, S. H., Larsena, J., Dunna, A. and Haydenc, L., 2015- Amphibole reaction rims as a record of pre-eruptive magmatic heating: An experimental approach. Earth and Planetary Science Letters 426: 235-245.
Esmaeily, D., Nedelec, A., Valizadeh, M. V., Moore, F. and Cotton, J, 2005- Petrology of the Jurassic Shah-Kuh granite (eastern Iran), with reference to tin mineralization. Journal of Asian Earth Sciences 25: 961-980.
Fu, D., Bo, H., Songbai, P., Timothy, M. K., Wenxiao, Z. and Mengchun, G., 2016- Geochronology and Geochemistry of Late Carboniferous Volcanic Rocks from Northern Inner Mongolia, North China: Petrogenesis and Tectonic Implications. Gondwana Research 36: 545-560.
Furman, T. and Graham, D., 1999- Erosion of lithospheric mantle beneath the East African Rift system: geochemical evidence from the Kivu volcanic province. Developments in Geotectonics 24: 237-262.
Geng, H., Sun, M., Yuan, C., Xiao, W. J., Xian, W. S., Zhao, G. C., Zhang, L. F., Wong, K. and Wu, F. Y., 2009- Geochemical, Sr–Nd and zircon U–Pb–Hf isotopic studies of Late Carboniferous magmatism in the West Junggar, Xinjiang: implications for ridge subduction?. Chemical Geology 26: 364–389.
Gill, J. B., 1981- Orogenic Andesites and plate tectonic. Springer-Verlag, Berlin, 390
Gorton, M. P. and Schandl, E. S., 2000- From continental to island arc: A geochemical index of tectonic setting for arc - related and within plate felsic to intermediate volcanic rocks. The Canadian Mineralogist 38:1065- 1073.
Goss, A. R. and Kay, S. M., 2009- Extreme high field strength element (HFSE) depletion and nearchondritic Nb/Ta ratio in Central Andean adakite-like lavas ( 28°S, 68° W). Earth and Planetary Science Lettres 279: 97-109.
Gusev, A. I. and Korobeinikov, A. F., 2009- Mantle–crustal interaction in the generation of different types of mineralization: geophysical and petrological aspects, Izv. Tomsk. Politekhn.Unive 315(1): 18-25.
Helvaci, C., Ersoy, E. Y., Sözbilir, H., Erkül, F., Sümer, Ö. and Uzel, B., 2009- Geochemistry and 40Ar/39Ar geochronology of Miocene volcanic rocks from the Karaburun Peninsula: Implications for amphibole-bearing lithospheric mantle source, Western Anatolia. Journal of Volcanology and Geothermal Research 185: 181–202.
Karimpour, M. H., Stern, C. R., Farmer, L., Saadat, S. and Malekzadeh, A., 2011- A review of age, Rb-Sr geochemistry and petrogenesise of Jurassic to Quaternary igneous rocks in Lut block, Eastern Iran. Journal of Geopersia: 19-36. 
Karsli, O., Dokuz, A., Uysal, I., Kandemir, R. and Wijbrans, J., 2010- Generation of the Early Cenozoic adakitic volcanism by partial melting of mafic lower crust, Eastern Turkey: Implications for crustal thickening to delamination. Lithos 114: 109-120.
Kürkcüoglu, B., 2010- Geochemistry and petrogenesis of basaltic rocks from the Develida_g volcanic complex, Central Anatolia, Turkey. Journal of Asian Earth Sciences 37, 42-51.
Kuscu, G. G. and Geneli, F., 2010- Review of post-collisional volcanism in the central Anatolian volcanic province (Turkey), with special reference to the Tepekoy volcanic complex. International Journal of Earth Sciences 99: 593-621.
Le Maitre, R. W., 2002- Igneous rocks: a classification and glossary of terms: recommendations of the International Union of Geological Sciences. Subcommission on the Systematics of Igneous Rocks. Cambridge University Press: 236p.
Lee, C. T. A. and Bachmann, O., 2014- How Important Is the Role of Crystal Fractionation in Making Intermediate Magmas? Insights from Zr and P Systematics. Earth and Planetary Science Letters 393: 266-274.
Litvak, V. D., Spagnuolo, M. G., Folguera, A., Poma, S., Jones, R. E. and Ramos, V. A., 2016- Late Cenozoic calc-alkaline volcanism over the Payenia shallow subduction zone, South-Central Andean back-arc (34°30’-37°S), Argentina. Journal of South American Earth Sciences 64:365-380.
McArthur, A. N., Cas, R. A. F. and Orton G. J., 1998- Distribution and significance of crystalline, perlitic and vesicular textures in theOrdovician Garth Tuff (Wales). Bulletin of Volcanology 60: 260–285.
McDonough, W. F. and Sun, S. S., 1995- Composition of the Earth. Chemical Geology 120: 223–253.
Müller, D., Rock, N. M. S. and Groves, D. I., 1992- Geochemical discrimination between shoshonitic and potassic volcanic rocks in different tectonic settings: a pilot study. Mineralogy and Petrology 46: 259–289.
Olafsson, M. and Eggler, D. H., 1983- Phase relations of amphibole, amphibole-carbonate and phlogopite-carbonate peridotite: petrologic constraints on the asthenosphere: Earth and Planetary Science Letters 64: 305-315.
Pearce, J. A., 1983- Role of the sub-continental lithosphere in magma genesis at active continental margins. In: Continental basalts and mantle xenoliths (Eds. Hawkesworth, C. J. and Norry, M. J.). Shiva, Nantwich: 230-249.
Pearce, J. A., 2008- Geochemical fingerprinting of oceanic basalts with applicationsto ophiolite classification and the search for Archean oceanic crust. Lithos 100:14–48.
Peccerillo, A. and Taylor, S. R., 1976- Geochemistry of Eocene calc-alkaline volcanic rocks from the Kastamonu area, northern Turkey. Contributions to Mineralogy and Petrology 58: 63–81.
Prouteau, G., Scaillet, B. and Pichavant, M., Maury R., 2001- Evidence for mantle metasomatism by hydrous silicic melts derived from subducted oceanic crust: Nature 410: 197-200.
Richards, J. P., Spell, T., Rameh, E., Razique, A. and Fletcher, T., 2012- High Sr/Y magmas reflect arc maturity, high magmatic water content, and porphyry Cu ± Mo ± Au potential: examples from the the Tethyan Arcs of Central and Eastern Iran and Western Pakistan. Economic Geology 107:295-332
Rollinson, H., 1993- Rising geochemical data:evaluation, presentation, interpretation. Longman John Wiley and Sons, New York, 352 p.
Sharma, M., 1997- Siberian traps. In: Large Igneous Provinces: Continental, Oceanic, and Planetary Flood Volcanism (Eds. Mahoney, J. J. and Coffin, M. F.). American Geophysical Union: 273-295.
Siddiqui, R. H., Asif Khan, M. and Qasim Jan, M., 2007- Geochemistry and petrogenesis of the Miocene alkaline and sub-alkaline volcanic rocks from the Chagai arc, Baluchistan, Pakistan: Implications for porphyry Cu-Mo-Au deposits: Himalayan Earth Sciences 40: 1-23.
Sun, S. S. and McDonough, W. F., 1989- Chemical and isotopic systematic of ocenic basalts: implications for mantel compositions and processes In: Sanders A.D. and Norry M.J. (Eds), Magmatism in Ocean basins. Geological Society London Special Publications 42: 313-345.
Terentiev, R. A., Savko, K. A. and Santosh, M., 2016- Paleoproterozoic crustal evolution in the East Sarmatian Orogen: Petrology, geochemistry, Sr-Nd isotopes and zircon U-Pb geochronology of andesites from the Voronezh massif, Western Russia. Lithos 246-247: 61-80.
Thirlwall, F. M., Upton, B. G. J. and Jenkins, C., 1994- Interaction between continentam lithosphere and Iceland plume-Sr–Nd–Pb isotope geochemistry of Tertiary basalts, NE Greenland. J. Petrol, 35: 839–879.
Tirrul, R., Bell, L. R., Griffis, R. J. and Camp, V. E., 1983- The Sistan suture zone of eastern Iran. Geological Society of America bulletin 84:134-140.
Ustunisik, G., Attila, K. and Roger, L. N., 2014- New Insights into the Processes Controlling Compositional Zoning in Plagioclase. Lithos 200: 80-93.
Vahdati Daneshmand, F. and Eftekharnezhad, J., 1991- Basement rock map of the Birjand, scale 1:250000, 1 sheet
Wilson, M., 1989- Igneous petrogenesis a global tectonic approach: Department of earth Science. University of leeds: 466.
Winter, J. D., 2001- An introduction to igneous and metamorohic petrology. Prentice Hall publication, New Jersey, 699p.
Withney, D. and Evans, B., 2010- Abbreviations for names of rock-forming minerals, American Mineralogist 95: 185–187.
Yang, W. and Li, Sh., 2008- Geochronology and geochemistry of the Mesozoic volcanic rocksin Liaoning: Implications for lithospheric thinning of the North China Craton. Lithos 102: 88-17.
Yu, Q., Ge, W.C., Zhang, J., Zhao, G. C., Zhang, Y. L. and Yang, H., 2016- Geochronology, Petrogenesis and Tectonic Implication of Late Paleozoic Volcanic Rocks from the Dashizhai Formation in Inner Mongolia, Ne China. Gondwana Research 47: 164-177.
Zhu, W. G., Zhong, H., Li, Z. X., Bai, Z. J. and Yang, Y. J., 2016- SIMS zircon U–Pb ages, geochemistry and Nd–Hf isotopes of ca. 1.0 Gamafic dykes and volcanic rocks in the Huili area, SW China: Origin and tectonic significance. Precambrian Research 237: 67-89