رخداد معدنی مس- نقره± طلا همراه با اکسید آهن ساق، جنوب‌شرقی تربت حیدریه: شواهدی از زمین‌شناسی، کانه‌زایی، زمین‌شیمی و سیالات درگیر

رخداد معدنی ساق در جنوب شرقی تربت‌ حیدریه، استان خراسان رضوی و در بخش شرقی کمربند ماگمایی خواف- کاشمر– بردسکن (kkbmb) واقع شده است. واحدهای سنگی منطقه به دو دسته کلی توده‌های نفوذی (مونزونیت، مونزودیوریت، دیوریت و سینیت) در نیمه‌جنوبی و واحد کنگلومرا در نیمه‌شمالی تقسیم می‌شود. کانی‌سازی در یک زون پیوسته به وسعت حدود یک کیلومتر مربع به شکل استوک ورک دیده می‌شود ولی در برخی نقاط روند خطی داشته و در توده‌های نفوذی تشکیل شده است. کانی‌های اولیه شامل اسپیکیولاریت، کالکوپیریت، پیریت، گالن و سولفوسالت بوده و کانی‌های ثانویه شامل مالاکیت، گوتیت، هماتیت، کالکوزیت، کوولیت و آنگلزیت است. بافت کانه‌زایی به صورت رگه- رگچه، پراکنده، جانشینی ثانویه و کلوفرم عمدتا همراه با آلتراسیون کلریتی- سیلیسی شدید دیده می‌شود. میانگین مقدار مس 0.8 با بیشینه بیش از 3 درصد، میانگین مقدار نقره 24.4 با بیشینه بیش از 113 گرم درتن، میانگین مقدار طلا 44 با بیشینه 250 میلی گرم در تن، میانگین مقدار سرب 761 گرم در تن با بیشینه 0.4 درصد و میانگین مقدار روی 430 گرم در تن با بیشینه 0.1 درصد است. دمای تشکیل سیال کانه‌ساز بین 159 تا 328 درجه سانتیگراد و شوری بین 7.2 تا 16.7 درصد وزنی است. مخلوط‌شدگی سیال‌ ماگمایی با آب‌های جوی با دما و شوری پایین مهمترین مکانیزم تشکیل کانی‌سازی بوده است. برپایه شواهد موقعیت تکتونیکی، سنگ‌شناسی، نوع آلتراسیون، شکل و حالت کانی‌سازی، وجود اسپیکیولاریت فراوان همراه با آنومالی مس، نقره و طلا، احتمالا منطقه ساق از نوع مس-نقره ± طلا همراه با اکسید آهن (iron oxide copper-gold) است.

sagh iron oxide cu-ag±au mineral occurrence, se of torbat-e-heydarieh: evidence of geology, mineralization, geochemistry and fluid inclusion

sagh mineral occurrence is located southeast of torbat-e-heydarieh, khorasan razavi province, and in the eastern part of the khaf-kashmar-bardeskan magmatic belt. the rock units of area are divided into two categories: intrusions (monzonite, monzodiorite, diorite, and syenite) in the southern half, and conglomerate in the northern half. one square kilometer of continuous mineralization may be observed as stockwork, while there are other locations where it has a linear trend and is supported by intrusive rocks. primary minerals include specularite, chalcopyrite, pyrite, galena, and sulfosalt, and secondary minerals include malachite, goethite, hematite, chalcosite, caveolite, and anglesite. the mineralization textures are vein-veinlet, disseminated, replacement, and cloform, mainly with a strong chloritic-silicified alteration. the average amount of copper is 0.8 with a maximum of more than 3%, the average amount of silver is 24.4 with a maximum of more than 113 ppm, and the average amount of gold is 44 with a maximum of 250 ppb. the average amount of lead is 761 ppm with a maximum of 0.4% and the average amount of zinc is 430 ppm with a maximum of 0.1%. the formation temperature of ore-forming fluid is between 159 and 328 °c and the salinity is between 7.2 and 16.7 wt.% equiv. nacl. the mixing of magmatic fluids with meteoric waters with low temperatures and salinity was the most important mechanism of mineral formation. based on the evidence of tectonic setting, lithology, type of alteration, shape, and state of mineralization, and the presence of abundant specularity with copper, silver, and gold anomalies, probably the sagh area is iron oxide cu-ag±au type. introductionthe geological settings, hydrothermal alteration, and mineralizing fluid compositions vary among the deposits of “iocg-type” (hitzman et al., 1992; sillitoe, 2003). however, they belong to a family of cu ±au deposits that include substantial hydrothermal alkali (na/ca/k) alteration and a lot of low-ti iron oxide (magnetite and/or hematite). according to williams et al. (2005), these deposits likewise exhibit strong structural constraints and a temporal but not a tight geographical relationship with igneous rocks. they formed in rift or subduction settings (hitzman, 2002) from the late archean to the pliocene (groves et al., 2010).sagh mineral occurrence is located the southeast of torbat-e-heydarieh, khorasan razavi province, and in the eastern part of the khaf-kashmar-bardeskan magmatic belt (fig.1). this belt has a high potential for iron oxide copper-gold type deposits and sometimes skarn and porphyry copper (karimpour, 2004).the purpose of this research is geological studies and determine the relationship of intrusions with mineralization, examine the total paragenesis sequence, geochemistry, fluid inclusions studies and finally determine the mineralization model, and the formation of mineral occurrences in the sagh area, for the first time is done. materials and methodsto investigate the lithology, alteration, and mineralization of the sagh area, 61 samples were taken mainly from the intrusions. 32 samples for the thin section and 10 samples for the polished thin section and polished block were selected, prepared, and studied. then, the geological and alteration-mineralization map with a scale of 1:5000 was prepared in arc gis software. furthermore, for geochemical studies of mineralization zones and veins, 24 samples were taken and sent to the zarazma laboratory for analysis. analysis was done by the icp-oes method. furthermore, 11 samples were selected for gold analysis with fire assay, and sent to zarazma laboratory. using a cooling and heating system made by linkam company, model thm 600, microthermometric tests and salinity determination were performed on 2 wafers of quartz minerals and 31 fluid inclusions at ferdowsi university of mashhad. resultthe rock units of the area are divided into two categories: subvolcanic and plutonic intrusions in the southern half and conglomerate units in the northern half. intrusive rocks are composed of monzonite, monzodiorite, diorite and syenite. mineralization can be seen in the form of stockwork in a wide and continuous zone with an area of about one square kilometer, but in some places, it has a linear trend (ne-sw and nw-se trend) which is hosted by intrusive rocks. primary minerals include specularite, chalcopyrite, pyrite, galena, and sulfosalt, and secondary minerals include malachite, goethite, hematite, chalcosite, covellite, and anglesite. vein-veinlet, disseminated, replacement, and cloform mineralization textures are seen, with a dominant chloritic-silicified alteration. the average concentration of copper is 0.8%, with a maximum concentration of more than 3%, silver is 24.4 ppm, with a maximum