Compilation of geology, mineralization, geochemistry and geophysical study of IP/RS & ground magnetic survey at Roudgaz area, southeast of Gonabad, Khorasan Razavi province

Document Type : Research Article

Authors

• Hossein Hajimirzajan
• Mohammad Hassan Karimpour
• Azadeh Malekzadeh Shafaroudi
• Mohammad Reza Haidarian Shahri
• Seyed Javad Hamooni

Ferdowsi University of Mashhad

10.22067/econg.v5i1.22916

Abstract

Roudgaz prospect area is a Cu, Sn, Pb, Zn, and Au polymetal vein system located to the southeast of Gonabad and in the northeast of Lut block. Oxidan subvolcanic Tertiary rocks with monzonite to monzodiorite porphyry composition intruded the metamorphic rocks of middle Jurassic. The majority of intrusive bodies are affected by carbonation, argillic, sericitic, and silicification-tourmaline alteration. Mineralization in the area is controlled by fault and is present as vein with domination of NW-SE direction and 85-90º dip. Primary minerals are quartz, tourmaline, chalcopyrite, pyrite, and secondary minerals are malachite, azurite, and goethite. Geochemical sampling using chip composite method indicated high anomalies of Cu, Sn, Pb, and As (up to 10000 ppm), Zn (up to 5527 ppm), and Au (up to 325 ppb). Broad gossan zone is present in the area and is related to the oxidation of sulfide minerals. IP/RS survey was performed over the geochemical anomalies for identification of the location and extension of sulfide mineralization at depth. Generally, chargeability increases in gossan zones, veins, old workings and geochemical anomalies. Resistivity over the quartzite unit and also in locations where mineralized vein is associated with quartz has a high anomaly of up to 425 ohm-m. Due to high geochemical anomaly of Sn and its relation with reduced subvolcanic intrusives, ground magnetic survey was performed to identify the location of magnetite (oxidant) and ilmenite (reduced) series at depth. Variation of Total Magnetic Intensity (TMI) is 335.1 Gamma in the TMI map. The highest magnetic anomalies in the RTP map are located to the north of the survey area which is related to magnetite series (hornblende biotite monzodiorite porphyry) and extend to the south at depth. The lowest magnetic anomaly is located to the center of the survey area and particularly to the east of the Roudgaz village correlating the highest chargeability and geochemical anomaly. Based on coincidence of geochemical and chargeability anomalies, two holes were drilled in the area and 24 samples were collected from the core drills for geochemical analyses. The highest anomalies are accompanied by silicification and chlorite alteration and locations of extension of secondary Fe oxides.

Keywords

• Roudgaz
• Lut block
• Vein mineralization
• Chargeability
• Resistivity
• Gground magnetic
• Well-logging

20.1001.1.20087306.1392.5.1.9.7

---

References

[1] Berberian M., "Active faulting and tectonics of iran, in Gupta", H K., and Delany F.M., editors, "Zagrous- Hinda kush- Himalaya geodynamic evolution", American Geophysical Union Geodynamic Series 3 (1981) 33-69.

[2] Jackson J., Mckenzie D., "Active tectonics of the Alpine- Himalaya belt between western Turkey and Pakistan", Geophysical Journal of the Royal Astronomical Society 77 (1984) 185-264.

[3] Lindenberg H.G., Groler K., Jacobshagen V., Ibbeken H., "post-paleozoic stratigraphy, structure and orogenetic evolution of the southern Sabzevar zone and the Taknar block", Neues jahrbach for Geologie und palaontologie, Abhhandlungen 168 (1984) 287-326.

[4] Haghipour A., Aghanabati A., " Geological map of iran (2nd edition), Tehran", Geological Survey of Iran, scale 1:2500000 (1989).

[5] Alavi.M., " Tectonic map of the Middle East, Tehran", Geological Survey of Iran, scale 1:5000000 (1991a).

[6] Ramezani J., Tucker R.D., "The Saghand region, centeral Iran, U-Pb geochronology, petrogenesis and implications for Gondwana tectonics", American journal of science 303 (2003) 622-665.

[7] هامونی س.ج.، کریم‌پور م.ح.، ملک‌زاده شفارودی آ.، " زمین‌شناسی، آلتراسیون و کانی سازی منطقه اکتشافی رودگز، جنوب شرق گناباد"، سومین همایش زمین‌شناسی اقتصادی ایران، دانشگاه شهید چمران اهواز، (1390).

[8] Karen P., Barry B., " The geophysical response of the tusker gold deposite, Lake Victoria gold fields, Tanzania" ( 2005).

[9] Esdale D.J., Pridmore D. F., Coggen J. H., Muir P.M., Williams P. K., Fritz F.P., " Olympic Dam deposite- Geophysical case history", 5th ASEG Conference, (1987) 47-49.

[10] Rajagopalan S., Haydon S.J., " The Benambra volcanic hosted massive sulphide deposits", Geological Survey of Victorya report 119, Australian Society of Exploration geophysicists special publication 11 (1999).

[11] Guo W., Dentith M., Zhao Y., " Geophysical exploration in the Xi-Cheng lead-zinc orefield, Gansu Province, China", Exploration Geophysics 31 (2000) 243-247.

[12] Dentith M., Stuart R., " Sediment-hosted stratiform copper deposits in the Adelaide Geosyncline, South Australia", Geophysical responses of mineralisation and themineralised environment, Geophysical Signatures of South Australian Mineral Deposits (2002) 169-195.

[13] Busuttil S., Law S., " The geophysics of the Kalkaroo prospect, Olary Domain, South Australia", Geophysical Signatures of South Australian Mineral Deposits (2001) 121-126.

[14] White R.M.S., Collins S., Denne R., Hee R. Brown P., " A new survey design for 3D IP modelling at Copper hill", Exploration Geophysics 32 (2001) 152-155.

[15] آقانباتی ع.، " زمین‌شناسی ایران" ، سازمان زمین‌شناسی و اکتشافات معدنی کشور (1383) ٦٠٦ ص.

[16] قائمی ف.، " نقشه زمین‌شناسی 1:100000 گناباد"، سازمان زمین‌شناسی و اکتشافات معدنی کشور (1384).

[17] مرادی م.، کریم پور م.ح.، فارمر ل.، و استرن چ.، " ژئوشیمی ایزوتوپهای Rb-Sr و Sm-Nd سن سنجی زیرکن U-Pb و پتروژنز باتولیت گرانودیوریتی- گرانیت نجم آباد، گناباد"، مجله زمین شناسی اقتصادی، شماره 3 (1390) ص127-145.

[18] Ishihara S.," The granitoid series and mineralization", Economic Geology 75th Anniv (1981) 458-484.

[19] http://wdc.kugi.kyoto-u.ac.jp/igrf/point/

[20]http://www.ngdc.noaa.gov/geomagmodels/IGRFWMM.jsp

[21] Gunn P.J., " Workshop Interpretation of aeromagnetic data", AGSO Journal of Australian Geology & Geophysics 17(2) (1996) 105-113.

[22] Urquhart W.E.S., "Airborne magnetic data compilation and interpretation", Geophysical Airborne Survey Compilation and Interpretation (2007) 1-13.

[23] Clark D.A., "Magnetic pethrophisics and magnetic petrology:aids to geological interpretation of magnetic surveys", AGSO Journal of Australian Geology & Geophysics 17 (2) (1997) 83-103.

[24] Nakatsuka T., Okuma S., " Reduction of magnetic anomaly observations from helicopter surveys at varying elevations", Exploration Geophysics 37 (2006) 121-128.

[25] Ford K., Kating P., Thomas M.D., " Overview of Geophysical Signatures Assosiated with Canadian Ore deposite, CSC" (2006).

[26] Cooper G.R.J., Cowan D.R., "Filtering using variable order vertical derivatives", Computers & Geosciences 30 (2004) 455-459.

[27] Gunn P.J., Madment D., Milligan P.R., "Interpreting aeromagnetic data in areas of limited outcrop", AGSO Journal of Australia Geology & Geophysics 17(2) (1997) 175-185.

[28] Tarlowski C., Gunn P.J, Mackey T., " Enhancements of the magnetic map of Australia", AGSO Journal of Australia Geology & Geophysics 17(2) (1997) 77-82.