Mineralization and alteration in the Roshtkhar Iron deposit and related host rocks

Abstract

Roshtkhar Iron deposit is located in southeast of Khorasan Razavi Province about 48 Km east of Roshtkhar. This deposit is geologically located in the northeast of the Lut block in the Khaf-Bardaskan volcanic- plutonic belt. Intermediate igneous rocks such as stock, dyke, lava and pyroclastic deposits are host rock. Igneous rocks are dioritic porphyry, monzosyenitic porphyry, andesite, basalt and lithic tuff that are granular, porphyry, microlitic porphyry and hyalomicrolitic in texture and consist of plagioclase, K-feldspar, amphibole and pyroxene. The sedimentary units are sandstone, shale and conglomerate. The Fe mineralization in this deposit occurs as east-west veins in the intrusive rocks. These veins are varied in thickness (from a few centimeters to two meters) and length (up to 20 meters?) that are mainly layered and brecciated. The main Iron mineralizations are spicularite and magnetite, whereas primary copper mineral is chalcopyrite that was altered to Cu carbonates (malachite and azurite) and iron hydroxide (goethite and limonite) by supergene processes. The main gangue minerals are calcite and quartz. Propylitic, sericitic-propylitic, silicic and argillic are major alterations, due to alteration of some minerals such as plagioclase, K- feldspar and amphibole to sericite, chlorite and clay mineral.

Keywords


1 کریم‌پور م. ح.، ملک‌زاده شفارودی آ.، "ژئوشیمی وکانی‌شناسی زون‌های اسکارنی و سنگ‌شناسی سنگ منشأ کانسار آهن سنگان خراسان رضوی"، علوم زمین سال 17، شماره 65 (1386) ص 108-124.

2 یوسفی سورانی ل.، "پتانسیل یابی ورقه 100000/1 دولت آباد با استفاده از داده‌های ژئوشیمی رسوبات رودخانه‌ای، ژئوفیزیکی و پردازش و تفسیر تصاویر ماهواره‌ای"، پایان نامه کارشناسی ارشد، دانشگاه فردوسی مشهد (1385).

[3] Hitzman M. M., Orekes N., and Einaudi M. T., Geological characteristics and tectonic setting of proterozoic iron oxide (Cu-U-LREE) deposits. Precambrian research 58, (1992) 241-287.

[4] Ancelin J., Danesfaleh M., Sajedi T., "Geological map of Iran 1:100000 series sheet 7959-Roshtekhar", Geological and mineral survey of Iran (1983).

[5] Danesfaleh M., and Sajedi T.,"Geological map of Iran 1:250000 series Gonabad ", Ministry of mines and metals geological survey of Iran, (1983).

[6] Streckeisen A., "Classification and nomenclature of plutonic rocks", Geology Rdsch. 63 (1974) 773-786.

[7] Streckeisen A., "Classification and nomenclature of volcanic rocks, Lamprophyres carbontites and melilitic rocks", Recommendations and suggestions of the IUGS Subcommission on the systematics of igneous rocks: Geology 7 (1979) 331-335.

[8] Guilburt J. M., and Park C. F.,"The Geology of ore deposits", W.H. Freeman in NewYork (1986) 985P.

[9] Mucke A. and Cabral A. R., "Redox and non-redox reactions of magnetite and hematite in rocks", Chemie der Erde Geochemistry 65 (2005) 271-278.

[10] Ohmoto H., "Non-redox transformations of magnetite-hematite in hydrothermal system", Economic Geology 98 (2003) 157-161.

[11] Otake T., Wesolowski D. J., Anovitz L. M., Allard L. F.,and Ohmoto H., "Mechanisms of Iron oxide transformations in hydrothermal systems", Geochmica et Cosmochimica Acta 74 (2010) 6141-6156.

[12] Craig J.R. and Vokes F.M., "The metamorphism of pyrite and pyritic ores", an overview, Mineralogical Magazine, V.57 (1993) 3-183.