بررسی‌های زمین‌شناسی، دگرسانی، کانی‌شناسی، بافت و زمین‌شیمی در منطقه پی‌جویی طلای قوچی، شرق بجستان، قطعه لوت

نوع مقاله : مقاله پژوهشی

نویسندگان

دانشگاه فردوسی مشهد

چکیده

منطقه قوچی بخشی از پهنه آتشفشانی-نفوذی در قطعه لوت بوده و در شرق­ شهر بجستان در استان خراسان رضوی واقع  است. زمین­شناسی منطقه شامل واحدهای سنگی دگرگونی (اسلیت و ماسه­سنگ دگرگون شده) به سن ژوراسیک، سنگ­های رسوبی کرتاسه پیشین (آهک، ماسه­سنگ و کنگلومرا) و واحد آذرین نیمه عمیق (پیروکسن دیوریت پورفیری) به سن کرتاسه پسین است. کانی­سازی در راستای گسل­هایی با روند شمال­غربی- جنوب­شرقی و شرقی­- غربی در سنگ میزبان احیایی پیروکسن دیوریت ­پورفیری (کرتاسه پسین) رخ داده ­است. کانی­های اولیه شامل پیریت، اسفالریت، گالن، پیروتیت، آرسنوپیریت، کالکوپیریت، کلسیت، کوارتز و به مقدار کمتر کلریت هستند. کانی­سازی همراه با ساخت و بافت­های رگه-رگچه، پرکننده فضای خالی، پراکنده، جانشینی و ناآمیختگی دیده می­شود. دگرسانی­های عمده شامل پروپیلیتی- سرسیتی، سرسیتی- کربنات- سیلیسی و کربنات- سیلیسی± کلریت هستند. بیشترین بی­هنجاری­های زمین شیمی برای طلا 2639 میلی­گرم در تن، آرسنیک 11065 ­گرم در تن، سرب 45400 گرم در تن، روی 19400 گرم در تن، نقره 12 گرم در تن و مس 725 گرم در تن است. بر پایه بررسی های زمین­شناسی، دگرسانی، کانی­شناسی، بافت و زمین شیمی، منطقه قوچی را می­توان به احتمال بسیار در رده کانسارهای طلای وابسته به توده­های نفوذی احیایی (RIRGS) در نظر گرفت.     

کلیدواژه‌ها


عنوان مقاله [English]

Geology, alteration, mineralogy, texture and geochemistry studies in Ghoochi gold prospect, eastern Bajestan, Lut Block

نویسندگان [English]

  • Akbari
  • Malekzadeh Shafaroudi
  • Karimpour
چکیده [English]

The Ghoochi area is a part of volcanic-plutonic zone of the Lut block and is located in eastern Bajestan city in the Razavi Khorasan Province. The geology of the area includes Jurassic metamorphic (slate and metasandstone), Early Cretaceous sedimentary (limstone, conglomerate and sandstone) and Late Cretaceous subvolcanic (pyroxene diorite porphyry) rocks. Mineralization is formed along faults with northwest-southeast and east-west trends in the reduced pyroxene diorite porphyry host rock (Late Cretaceous). Hypogene minerals are pyrite, sphalerite, galena, pyrrhotite, arsenopyrite, chalcopyrite, calcite and quartz with lesser amounts of chlorite. Mineralization is seen along with the structures and textures of vein-veinlet, open space filling, disseminated, replacement and exsolution. Main alterations consist of propylitic-sericitic, sericitic-carbonate-silicification and carbonate-silicification±chlorite. Maximum geochemical anomalies observed include for gold with 2639 ppb, arsenic 11065 ppm, lead 45400 ppm, zinc 19400 ppm, silver 12 ppm, and copper 725 ppm. Based on geology, alteration, mineralogy, texture and geochemistical studies, Ghoochi area can be probably classified in reduced-intrusion related gold systems (RIRGS).
 

کلیدواژه‌ها [English]

  • alteration
  • Mineralization
  • Geochemistry
  • Gold
  • Ghoochi
  • Lut block
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