The assessment of spatial correlation between location of deposits and faults using geostatistical methods: case study, Yazd province

زمین شناسی اقتصادی

Article 4, Volume 5, Issue 2 - Serial Number 9, January 2014, Pages 255-265   

Document Type: Research Article

DOI: 10.22067/econg.v5i2.31891

Authors

Mostafa Dehghani Ahmadabad; Seyed Hossein Mojtahedzadeh^* ; Alireza Yarahmadi Bafghi

Yazd

Abstract

Determining the promising area for ore deposits is one of the most important steps of prospecting in regional scales. There are many different methods for identifying these areas including geochemical and geophysical methods, remote sensing and sophisticated statistical methods. Based on the theory of spatial relations between the dispersion pattern of ore deposits and metallogenic provinces, mineralization belts, faults and structural factors, some new interpretative methods can be proposed in the preliminary exploration phase of the potential areas.
In this study, the geostatistical methods were used, where the spatial location of faults and known metallic deposits were considered as the primary source of data to obtain their correlation (case study of metallic deposits in Yazd province). The research was performed on 807 major and minor faults and 76 metallic deposits, mainly from hydrothermal origins. The data was arranged in ArcViewGIS software environment. The geostatistical analysis was performed by defining the regionalized variable (distance between faults and deposits) in a Mathematica subroutine. Variography operations, in order to find the spatial structure, were performed on regionalized variable using Surpac software. It was also shown that the theory of spatial correlation was valid for the defined variable. In this work, the variography operation was used to find the direction and the range of the effect of faults and deposits. Variograms indicated that the possibility of ore deposits existence in an area could depend on the direction of the faults. By drawing the directional variogram and variogram map, the best stretches for more exploratory studies is shown to be parallel along the Azimuth 130◦ and 64 km distance. By revealing the spatial structure in different directions, the area of mineralization related to the faults and the number of ore deposits associated with major faults have been marked.

Keywords

Deposit; fault; Geostatistics; Variogram; Yazd Province

References

[1] حسنی پاک ع.ا.، "زمین آمار"، انتشارات دانشگاه تهران، (1377).

[2] حسنی پاک ع.ا.، شرف الدین م.، "تحلیل داده های اکتشافی"، انتشارات دانشگاه تهران، (1380).

[3] رادفر ش.، "ریخت زمین‌ساخت گسل کوهبنان"، مجله علوم زمین، شماره 58 (1384) ص 166-183.

[4] شفیعی بافتی ا.، "بازسازی حرکت سامانه گسلی کوهبنان در باختر بهاباد از پلیوسن پایانی تا عهد حاضر (ایران مرکزی)"، ویژه‌نامه زمین‌شناسی، دانشگاه آزاد اسلامی واحد علوم تحقیقات، (1386) ص 118-127.

[5] سازمان صنایع و معادن استان یزد، آرشیو گزارشها.

[6] مشرفی فر م.ر.، "تفکیک فازهای تنش دیرین بر پایه داده‌های گسلی ناهمگن در بخش مرکزی گسل دهشیر"، مجله علوم‌زمین، شماره 69 (1387) ص 64-73.

[7] مهرشاهی د.، "مورفوتکتونیک و مناطق عمده گسلی استان یزد"، فصلنامه تحقیقاتی جغرافیایی، شماره 72 (1384) ص 7-24.

[8]مهرنهاد ح.، "تحلیل ساختاری و سایزموتکتونیکی گسل دهشیر"، فصلنامه تحقیقاتی جغرافیایی شماره 72 (1384) ص 118-127.

[9] مرادی فر ا.، مجتهدزاده س.ح.، "مطالعه مقدماتی ارتباط کانسارها و اندیسهای سرب و روی ایران مرکزی و ارائه مدل فلززایی برای تشکیل این کانسارها"، پروژه کارشناسی دانشگاه یزد، (1383).

[10] نبئی، ت.، "منطقه‌بندی کانی شناختی رویداد دگرسانی در طول گسل ساری دره منطقه جنوب بوئین زهرا"، فصلنامه علمی و پژوهشی زمین و منابع، سال اول، شماره اول (1388) ص 65-73.

[11] Cressie N., "Fiting variogram models by weighted least squares", Math Geology 17 (1993) 563 – 586.

[12] Gemcome "User Manual of SURPAC Software International", (1999).

[13] Gringarten E., Deutsch V., "Teacher’s aide variogram interpretation and modeling", Oxford, England, Oxford University Press (2001) 180 p.

[14] Isaaks E., Srivastava R., "An introduction to applied geostatistics", New York, Oxford University Press Inc (1989).

[15] Rouhani S., "Geostatistics for environmental and geotechnical applications", ASTM Committee (1996).

[16] User Reference, Mathematica (2002).

[17] Vearncombe J., Vearncombe S., "The special distribution of mineralization: Application of fry analysis", Economic Geology 94 (1999) 567-575.

[18] Verly G., "Geostatistics for natural resources characterization", North Atlantic Treaty Organization (1984).

[19] Wallace A. R., "Structural and mineralogical characteristics and distribution of carbonate-dominated fault breccias associated with uranium deposits, Front Range, Colorado", journal of Economic Geology v. 77, 8 (1982) 1945-1950.

[20]http://www.ngdir.ir/SiteLinks/Abandoned_Mines/index.asp

[21] Yaghubpur A., Hassannejad A.A., "The spatial distribution of some chromite deposits in Iran, Using Fry Analysis", Journal of Sciences, Islamic Republic of Iran 17(2) (2006) 147-152.