@article { author = {Bemani, Mahdi and Mojtahedzadeh, Seyed Hossein and Kouhsari, Amir Hossein}, title = {Geochemical analysis of brine samples for exploration of Borate deposits in the South of Sabzevar}, journal = {Journal of Economic Geology}, volume = {8}, number = {1}, pages = {1-20}, year = {2016}, publisher = {Ferdowsi University of Mashhad}, issn = {2008-7306}, eissn = {2423-5865}, doi = {10.22067/econg.v8i1.23165}, abstract = {Introduction Mohammad-abad Oryan is the only potential source of borate in the North-east of Iran located in 50 km South of Sabzevar. The area is located in tuff marl, tuffaceous marl, volcanic braccia and tuff braccia structures. Remote sensing techniques, geological studies and integration of this data in GIS were applied in an area of about 600 square kilometers to locate the promising areas of borate mineralization for detailed studies (Bemani, 2012). The aim of this detailed geochemical study is to confine the anomaly areas for exploratory drilling and trenching. Materials and methods Field studies were carried out in 9 geological traverses, mainly in Tonakar and Borje Kharkan area and 126 brine samples were taken from hydrothermal springs and 13 rock samples were taken from trenches. All the samples were analyzed for four elements, including B, K, Li and Mg. In order to determine the threshold quantities of the samples and isolation of anomaly, the data were analyzed using statistical methods including classical statistics, fractal geometry and EDA methods (Bemani, 2012). Result Initial data analysis showed that there were no censored data. Also, by applying statistical hypothesis testing, no significant relation was observed between the elements in the two areas (except for Li). Therefore, all the statistical analyses were carried out separately. After outlier correction, based on the amount of skewedness and histograms and probability plots of different elements, it became clear that none of the elements in the raw data distribution were normal and required to be transformed to be close to normal. In this study, logarithmic and three-parameter logarithm transformation were used in order to normalize the data . Based on the mean values, standard deviation of the normalized data, and background value and threshold, probable and possible anomalies were obtained and geochemical anomaly maps were drawn to identify the promising areas. With the exception of the fractal pattern, anomaly separation methods are based on the differences of fractal dimensions between communities of geochemical data (Hasanipak and Sharafoddin, 2005). In this study, concentration area fractal method was used to separate anomalies from the background. Using fractal geometry, threshold value corresponding to the two areas (Tonakar and Borje Kharkan) were obtained and were plotted separately on geochemical maps. Exploratory data analysis (EDA) is an approach to analyze data sets to summarize their main characteristics, often with visual methods (Filliben and Heckert, 2005). Exploratory data analysis is a useful method for analysis of geochemical exploration data. This is a statistical method known as the Robust Statistic classification (Carranza, 2009). In geochemical exploration, box plots, histograms and scatter plot are more practical. According to the box plots, the data of Tonakar and Borje Kharkan areas were classified and threshold levels were determined (Bemani, 2012). Discussion Using the results obtained from different methods, geochemical maps of each area were prepared for all the elements and thresholds were obtained for each method. Moreover, the geochemical maps of each area were plotted for each element. According to the geochemical maps of Tonakar area, boron anomaly was observed in the East and West zones and the anomaly of the latter is larger. These areas were recommended for further detailed exploration and borehole drilling. Also, geochemical maps of Borje Kharkan showed anomaly in the central zone for all of the elements. The results showed that the highest and the lowest amounts of boron in brines samples vary between 6 ppm to 5930 ppm. Among boron and the three other elements (i.e. lithium, magnesium and potassium) a significant correlation was not observed. In terms of frequency, in most cases brines with high levels of boron (more than 1000 ppm) were concentrated in the South East of the Tonakar area. So, this area was suggested for detailed exploration (Bemani et al., 2014). Generally speaking, for considering the spatial distribution of data the fractal method could better identify the anomalies. Also, EDA is a quick and easy method to detect anomalies. Acknowledgment The authors are grateful to the Kaniran Mining Company and the south Khorasan branch of the Iranian Mining Engineering Organization for their financial support of this study. References Bemani, M., 2012. Prospecting and Exploring of Borax in the south of Sabzevar, combination of remote sensing, field surveying and geochemical studying. M.Sc. Thesis, University of Yazd, Yazd, Iran, 137 pp (in Persian with English abstract). Bemani, M., Mojtahedzadeh, S.H. and Kohsari, A.H., 2014. Investigation of geology, mineralogy and genesis of Mohammadabad-Oryan index boron (south of Sabzevar). Iranian Journal of Crystallography and Mineralogy 22(1): 173- 186 (in Persian with English abstract). Carranza, E.J.M., 2009. Geochemical Anomaly and Mineral Prospectivity Mapping in GIS. In: M. Hale (Editor), Handbook of exploration and environmental geochemistry. Elsevier, Amsterdam, pp. 51-115. Filliben, J.J. and Heckert, A., 2005. Exploratory data analysis. Engineering Statistics Handbook, Internet, National Institute of Standards and Technology, http://www.itl.nist.gov/div898/handbook/eda/section3/eda356.htm. Hasanipak, A.A. and Sharafaddin, M., 2005. Exploratory Data Analysis.Tehran University press, Tehran 996 pp (in Persian).}, keywords = {classical statistics,fractal geometry,EDA,Brine samples,index of Mohammad-abad Oryan}, title_fa = {تحلیل ژئوشیمیایی نمونه‌ های شورابه ای جهت اکتشاف کانی سازی بورات در جنوب سبزوار}, abstract_fa = {منطقه مورد پژوهش در 50 کیلومتری جنوب سبزوار واقع شده است. در این منطقه اثراتی از کانیهای بورات دیده می‌شود. اندیس بور‌محمدآباد عریان، تنها اندیس بورات شمال شرق ایران است و در واحدهای سنگی مارن کرمرنگ، مارن توفی و ولکانیک برش و توف برش قرار گرفته است. دو گسل از نوع راندگی یا معکوس، محدوده‌ کانسار را در بر می گیرند و دارای امتداد NE-SW هستند. می توان گفت: این گسلها به‌عنوان معبری برای محلولهای سازنده کانسار و همچنین ایجادکننده فضاهای لازم برای جای گزینی کانسار عمل کرده اند. بررسیهای صورت‌گرفته در ترانشه‌های حفر شده در منطقه نشان می‌دهد؛ که از سطح به عمق از شدت کانی سازی کم می شود. وسعت محدوده مورد بررسی، در ابتدا بیش از 600 کیلومتر مربع بوده است؛ که بعد از انجام بررسیهای دورسنجی، زمین‌شناسی، ساختاری و تلفیق این لایه‌های اطلاعاتی، مناطق امید‌بخش کانی سازی بورات‌ها تعیین و این منطقه محدودتر شد. برای انجام بررسیهای مفصل‌تر، بررسیها و پژوهشهای صحرایی صورت گرفت و تعداد 9 پیمایش انجام شد. در هر یک از پیمایش‌ها، واحدهای زمین‌شناسی مورد بررسی قرار گرفت و در مناطقی که چشمه‌های هیدورترمالی وجود داشت، نمونه‌های شورابه‌ای برداشت شد. سرانجام، منطقه مورد بررسی با توجه به محل برداشت نمونه‌ها به دو منطقه توناکار و برج خارکن محدود و بررسیها و تجزیه و تحلیل آماری داده‌های ژئوشیمیایی روی این دو منطقه انجام شد. مجموعه نمونه‌های برداشت شده از منطقه، بعد از آنالیز با استفاده از روشهای آماری مورد تجزیه و تحلیل قرار گرفت. در تجزیه و تحلیل آماری داده‌ها، برای تعیین مقدار حد آستانه نمونه‌ها و جداسازی میزان زمینه از آنومالی، از روشهای آماری کلاسیک، هندسه فرکتال و EDA و Median+2MAD استفاده شد. با استفاده از هر روش مناطق آنومالی برای انجام بررسیهای تفصیلی تر، تعیین شد.}, keywords_fa = {آمار کلاسیک,هندسه فرکتال,EDA,Median+2MAD,نمونه‌ های شورابه ای، اندیس بور محمدآباد عریان}, url = {https://econg.um.ac.ir/article_31118.html}, eprint = {https://econg.um.ac.ir/article_31118_cffee45908c0036e26218068ae754578.pdf} }