Bulletin of the Mineral Research and Exploration (BMRE)
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OROGENIC GOLD PROSPECTIVITY MAPPING USING GEOSPATIAL DATA INTEGRATION, REGION OF SAQEZ, NW OF IRAN
No full textThe aim of this study is to map orogenic gold prospecting areas in the region of Saqez, NW of Iran. In order to achieve this task geological, geochemical and airborne geophysical data are analyzed and integrated using index overlay and fuzzy logic methods. Geological map of Saqez (1:100.000 scale) is used to assign lithological weights based on their favorability for hosting orogenic Au mineralization. Also a fault density map is produced and assigned based on the structural map which is included in the geological map. For preparing geochemical evidence maps, data from 535 stream sediment samples are examined using Number-Size multifractal method for Au, As, Bi and Hg. The detected thresholds are used to assign the catchment basins of the stream sediment samples. Aeromagnetic data is employed to detect the edges of magnetic anomalies based on an enhanced edge detection method. Extracted lineaments are then converted to a density map and assigned properly. Airborne radiometric data is also used to produce two evidence maps. Potassium count grid independently and K/Th ratio map are employed to distinguish locations with hydrothermal activity. Finally after integrating evidence maps, new locations with high potentials of Au mineralization are identified considering that the gold indications of the study area (Qolqoleh, Kervian and Ghabaghloujeh) are placed in the first priority of the fuzzy logic prospectivity map.
HALLOYSITE INTERCALATION OF NORTHWEST ANATOLIA
No full textIn this study, the representative samples were taken from the halloysite deposits located in Çanakkale-Balıkesir regions in the northwestern Anatolia. At first, the dehydration temperatures of the samples were determined after the sample preparation and characterization studies. It was found that halloysite samples start to loose their interlayer waters at 50°C and goes up to 70°C. The intercalation studies were carried out on the dehydrated samples by using ethylene glycol, potassium acetate, dimethyl sulfoxide and formamide. Although the negative results by ethylene glycol and potassium acetate, the satisfactory results were obtained by dimethyl sulfoxide and formamide. It is undertood that the most effective reagent in terms of intercalation is formamide
REFINEMENT OF THE REVERSE EXTRUSION TEST TO DETERMINE THE TWO CONSISTENCY LIMITS
No full textLiquid limit (LL) and plastic limit (PL) are the two most commonly used index properties of fine-grained soils. They have been used in not only classification of soils but also in correlation with certain engineering properties. Therefore, they have been subjected to numerous researches since they were first introduced by Atterberg in 1911. While their mechanisms were well defined in many codes and they have been in use for decades, criticisms often arose pertinent to the uncertainties inherent to them. Incredible amount of effort has been exerted to invent more rational testing methods in place of both the Casagrande’s cup and bead rolling methods. Part of those efforts has been on devicing a single tool to measure the two relative index properties together. Recently, the reverse extrusion test was brought into the use of geotechnical engineers. It was shown that this tool has a potential of measuring LL, PL, and even the shrinkage limit (SL). The aim of this investigation is to reassess the ability of the reverse extrusion test to determine LL and PL with further refinement. In this regard 70 finegrained soils covering a large range of plasticity were employed. Fall-cone method and rolling-device method were employed to determine LL and PL, respectively. The reverse extrusion tests were carried out at least five different water contents per soil sample. Extrusion pressures were plotted against water content and a curve fitting was applied to data pairs, from which the y-intercept (the coefficient a) and the slope (the coefficieent b) of the curve were determined. Those reverse extrusion coefficients were utilized to determine the representative extrusion pressures corresponding to LL and PL, as was done by the earlier researchers; however, the degree of success for the prediction of LL and PL using the representative extrusion pressures was not encouraging. Different from the previously proposed approaches, the reverse extrusion coefficients (i.e., a and b) were subjected to a multiple regression analysis along with the results of the conventional testing methods of fall-cone and rolling-device to determine the LL and PL as functions of the reverse extrusion parameters. It was shown that LL and PL can be predicted with a great degree of success using the reverse extrusion coefficients. While a great majority of the liquid limits found by using the fall-cone method were predicted with a ±10% error, almost all of the plastic limits found by the rolling device were predicted with a ±10% error. This refined investigation on the reverse extrusion test confirmed and proved that the reverse extrusion test is a simple, robust and inexpensive method capable of predicting both of two fundamental consistency limits using a single device
LATE CENOZOIC EXTENSIONAL TECTONICS IN WESTERN ANATOLIA: EXHUMATION OF THE MENDERES CORE COMPLEX AND FORMATION OF RELATED BASINS
No full textThe Aegean region (Western Anatolia, Aegean Sea and Greece) is one of the areas of the earth under the effect of extensional tectonics and includes the typical features of core complexes in this type of region. The Menderes Massif in Western Anatolia was exhumed initially as an asymmetric core complex in the Early Miocene due to extension beginning in the Oligocene and then the central Menderes Massif was further exhumed as a symmetric core complex. This article discusses the exhumation mechanisms of the Menderes Massif and development of surrounding sedimentary basins in light of new findings. The proposed model successfully explains, the location of the Oligocene Kale basin, different movement directions of the Lycian nappes in northern and southern parts of the Datça-Kale Main Breakaway Fault and the top-to- the NNE directed shearing dominantly observed in the whole Menderes Massi
GEOLOGICAL HERITAGE AND FRAMEWORK LIST OF THE GEOSITES IN TURKEY
No full textGeosites and the special type of geosite called geological heritage are tangible materials such as rocks, fossils, minerals, sedimentary sequences, or structures about which there are results and/or documents of significant events in the geological history. A Framework List deciphers the geological events of the past without mentioning the localities or results. Ideally, there is only one Framework List for every country. The Framework List for Turkey proposed by this study includes 85 titles (frame) in 10 categories. The Stratigraphic and Volcanic-Metamorphic-Sedimentary Petrology categories are the richest for the Frameworks; however they two already contain the majority of the geosites in the JEMIRKO inventory, which contains a total of 815 geosites
BENTHIC FORAMINIFERAL BIOSTRATIGRAPHY OF MALATYA OLIGO-MIOCENE SUCCESSION (EASTERN TAURIDS, EASTERN TURKEY)
No full textThe benthic foraminiferal biostratigraphy of Oligo-Miocene aged Muratlı and Petekkaya formations which crop out over wide regions around Akçadağ town, west of Malatya province in Eastern Taurids were revealed in this study. Systematical sampling was carried out in measured stratigraphical sections in four locations in order to perform stratigraphical and paleontological investigations. Benthic foraminifera taken from 182 hard rock samples were defined and three biozones were determined as; SBZ 21-22, belonging to Oligocene (Rupelian - Early Chattian), SBZ 23 (Late Chattian) and SBZ 25 belonging to Lower Miocene in shallow marine deposits in the region. It was stated that the assemblage of planktic foraminifer and nannoplankton which stratigraphically detected within Chattian - Burdigalian units in the succession most probably indicated Aquitanian age. Besides; Oligo-Miocene transition in the region was approved with this study based on biostratigraphical locations of benthic foraminiferal taxa
EVALUATION OF ASBESTOS EXPOSURE IN DUMANLI VILLAGE (ÇANAKKALE-TURKEY) FROM A MEDICAL GEOLOGY VIEWPOINT: AN INTER-DISCIPLINARY STUDY
No full textBiga Peninsula has many varied and interesting medical geologic problems, as well as being rich in natural geological resources. Mainly these problems are natural radioactivity, mineral dust, metal/mineral contamination in drinking water, acid rock/mine drainage, and problems related to geothermal and drinking water. With this view exposure to asbestos was surveyed and the results of this survey were evaluated by earth scientists and medical doctors. This inter-disciplinary study was done in Dumanl› village (Çanakkale-Turkey) in the Biga Peninsula, NW Turkey. Studies have been carried out in earth sciences and the health sciences simultaneously. The asbestiform minerals around Dumanl› village are contained in sheared serpentinites which occur as tectonic slices and lenses within Çaml›- ca metamorphics. These tectonic slices and lenses are bounded by strike-slip faults and probably obtained their final tectonic positions in a transpressional regime during late Cretaceous-early Eocene time. Asbestiform minerals occur within stretching-shear zones in the strike-slip system. Petrographic and mineralogic indications show that the asbestiform minerals are clinochrysotile, lizardite, antigorite and actinolite. In parallel with earth science studies; verbal autopsy, pulmonary function tests and radiological examination studies were carried out. A significant correlation between asbestos exposure and radiographic pathology was identified in the region and it was understood that the duration of exposure in these cases varies from 23-80 years
POSSIBLE INCISION TIME OF THE LARGE VALLEYS IN SOUTHERN MARMARA REGION, NW TURKEY
No full textSurface water and sediments derived from the southern Marmara region (= Susurluk Drainage basin- SDH) transport to lakes Manyas and Ulubat first and then go to the Sea of Marmara via the Kocasu River only. The present drainage system of the SDH provides a good opportunity to study erosion rate and subsequently occurrence times of large-scale valleys in the region. To achieve it, depositional characteristics and ion contents of the ancient lacustrine sediment has been investigated and re-interpreted using cores taken from Lake Ulubat. The boron content of these sediments increased upward suddenly at the 4 m level, most probably due to starting of erosion at Emet borate beds in the drainage basin. Taking into consideration equilibrium between natural erosion and sedimentation, the incision rate in the Emet valley was found 1.4 cm.yr-1. From here one can calculate a time span of 75 ky for the formation of the whole valley itself. However, it is known that working of the geological processes was not monotonous in the past; hence, this date is not absolute. Newertheless, formation of the large valleys of the southern Marmara region shouldn’t be older than 300 kyrs. An important reason on rapid erosion was likely lowered base-level as the Marmara Sea was a closed lake during the last Glacial Period. High altitudinal difference between source and depositional areas caused acceleration of the erosion