No abstract

Abstract:The study area is the Hakaluki Haor which is the second largest wet land of Bangladesh. It spans over the districts of Moulvibazar and Sylhet in southeast Bangladesh. The study was focused in the exploration of peat reserve, reconstruction of the paleo-environment as well as the utilization of the peat resources. Peat is found randomly from 0.5 m to 7 m below the surface and 1 m to 11 m thickness at over 40 beels as well as small plain lands of 90 km2 area of Hakaluki Haor. The total reserve of peat is 282 million ton in wet condition and 112 million ton in dry condition. Peat bearing Hakaluki Haor is a lowlying wet land which geological term is synclinal depression. It may be a syncline between two anticlines which was filled with sediments as well as various plant materials derived from the hilly region (anticline) on both sides (west and east) of the Haor. On the other hand vegetation occurred in this depression as aquatic plants which might have been destroyed by large natural disasters or any tectonic reason. As environment dictates the characteristics and the source of sediments, various aspects of the sediment are indicators of condition of peat deposition. Peat has mainly industrial importance as a fuel for power production, traditionally used for cooking, domestic heating and in brick fields, also used as insulator in many industries, agricultural purposes, retaining moisture in soil, raw material in horticulture and colour industries etc. Power plants of about 100 MW capacities may be established in this region based on peat of Hakaluki Haor which may be continued more than one hundred years.

A detail geological investigation was carried out in order to explore white clay deposite at 10 square kilometer areas of Madhabpur and 0.5 square kilometer areas of Bahubal Upazilas in Habiganj District of Bangladesh using hand auger and shallow drilling method. The whole surveyed area was identified for white clay deposits from qualitative as well as quantitative aspect. These deposits were marked at depths from 0.2 meter to 8.0 meter below the surface. Average thickness of white clay at Madhabpur and Bahubol area are 4.0 meter and 5.0 meter, respectively. The estimated reserve of white clay at Madhabpur area is about 68 million tons and that at Bahubal area is 2.8 million tons. Geological investigation suggests that the source rock near Tripura ranges was weathered, transported and deposited as feldspathic sandstone surrounding the present deposition of white clay. Later the sandstone was exposed and much of its feldspar content were weathered to the clay mineral (Kaolinite). Along with white clay peat, peaty clay, sticky clay and silica sand were also observed at depths ranging from 1.5 to 8 meter. Collected white clay samples are yellowish grey to light grey in color and highly compact in dry condition but pasty in wet condition. The dry white clay is soapy to feel, slakes in water, moderately sticky and plastic in nature. Al2O3 content ranged from 25.51 to 27.61% while average SiO2, and Fe2O3 content were found 54.58 and 3.872% respectively. Considering the physical and chemical properties the white clay of the studied area can be considered as moderate to good in quality. This white clay can use in ceramics and other industries. Therefore, this deposit of white clay may help to meet the current national demand and consequently to increase the economic growth.

No abstract