Preliminary exploration of Laterite horizon in Heyder Abad

Author Eftekharnejad - Qeisy
Published At 13 September 1996


Mapping and studies of land of south West of Azerbaijan and northern Kurdistan was discovered and reported in 1346 for first time existence of laterite horizon with Upper Permian carbonate sediments by one of the authors of this report. (J. Eftekharnejad 1977 and 1980).


Preliminary exploration of Laterite horizon in Heyder Abad Mapping and studies of land of south West of Azerbaijan and northern Kurdistan was discovered and reported in 1346 for first time existence of laterite horizon with Upper Permian carbonate sediments by one of the authors of this report. (J. Eftekharnejad 1977 and 1980). To due to the extension of this horizon from south to north of Lake Orumieh to north of Saghez and precise evaluation throughout did not carry out. Most attention was limited to areas that the horizon of bauxite and Kaolinite had particular importance and at areas such as north of Saghez and south of Orumieh Lake which this horizon with Permian rocks influenced strongly by dynamothermic phase, related to Laramyde orogeny phase. Economic evaluation was not performed. Studies of extraordinary were limited to mineralogical studies. Surveying of the horizon in terms of possible of existence mineral deposits or in South of Orumieh Lake was initiated in 1368 by Mohammad Hossein and Mohammad Bagher Qeysi Soltanzadeh (West Azerbaijan Services Companies) with guidance of J- Eftekharnejad (GSI). The result of initial studies has characterized possibility of some rare metamorphic minerals somehow in considerable amount. These results justify the necessity of exploration operations thoroughly. Hereunder a brief description of your findings and action plan based on the detailed exploration is recommended. Brief explanation of Upper Permian Laterite in Bafgh Generally, carbonate platform of Iran undergoes Epirogenic movements and this practice resulted in complete regression of the sea and short gap in sedimentation in Central Iran, Zagros and Alborz. This regression is often accompanied with Laterization and creation of horizon with laterite lenses in Upper Permian sediments and even its extent can be followed in east of Turkey. Because regression and transgression of sea and predominance of carbonate sedimentary basin has been done gradually and so they can be observed with Laterite deposits, detrital and coastal deposits sediments like sandstone and iron-bearing shale and it might form large diameter of the horizon, detrital shallow sediments. In this section, thre is not specific classification even in  Laterite deposits and probably laterization has been taken place in near place and transported to sedimentary environment and so references of the Laterite horizon instead of lateritic lenses as more correlation to existed nature. In general this horizon is rich of iron and aluminates and silica – bearing minerals that percentage changes of these three elements may be in part of horizon resulted in special importance in terms of reservoirs of Boukite, Kaolinite – Iron inthat part of Laterite. Generally, the lower part of the Laterite horizon is composed of dolomite or dolomitic limestones of the Permian, and perhaps laterization act on dolomite resulted in on carbonate dissolution, exit of that from focus environment of aluminates, silica and iron oxide in little amounts that are in lower dolomite. Of course, volcanic activity is equivalent to laterite horizon in a part of Permian platform around of Mahabad that Volcanic rocks can be origin and the mother Lateritic horizon. The upper horizon of this horizon is formed from dark color limestone with chert- bearing crypto-crystaline that more or less common it is throughout in the region and Hyderabad area is not also exempted. In this location also as well as gray crystallized dolomite is silicified with brief massive layering with a dip of approximately 45 degrees below the Lateritic horizon and it forms lower waste on gray and dark to black recrystallized lateritic horizon of limestone with nodules or chert – bearing veins is located on the lateritic horizon and forms upper waistline horizon. Only a hard layer of Laterite horizon is in diameter of 1 to 3 m due to the mineralogic specific combination is safe from weathering and erosion and has outcrops. This is resulted in identified of Laterite horizon in ground surface easily. However the major part of the horizon is often composed of Kaolinite - ferruginous and considerable aluminates –bearing shale substantial (industrial soil) and formation of sandstone has been severely affected by erosion and is covered by soil surface. Generally with considering to positive evidences, judge in mineralogical of horizon in this stage is somehow difficult. As it was implied, main exposure from lateritic horizon is very hard and it has flinty manner and is nonpisolite.  This horizon can undergo to weathering and it can be followed easily and even in some points which horizon is completely covered but even with observation of upper dark chert – bearing limestone  . with rather severely affected by erosion have been, but the amount of aluminate as a marker bed can be characterized their existence under coverage of surface soil. Fortunately in a distance of 1.5 km in resistant and hard part of horizon has out crop against to erosion continuously and discontinuous and so it has been resulted easily in following and identification. Surface trenches is drilled in suitable locations but unfortunately erosion of main part of horizon has not been exposed for studying and gathering. In primary suryeying, sampling was carried out from hard and resistant part was gathered and mineralogical composition and chemical analyze is summarized in the table. Another sample from location of sample 5 of mentioned table and also a sample from soft weathered talus is related to upper part of laterite horizon and mineralogic result is as follow explanation.   Generally all of samples were gathered from one resistant layer in 2 meters and above results show only mineralogic changes and chemical analysis in this layer. In this stage of exploratory operation, surveying in whole of diameter of horizon can not be possible in  a thickness more than 10 meters and it is often covered and without surface exposure.