Report On Geological Survey Of Bangladesh Mfk 172v6f

Report on Geological Survey of Bangladesh Experiment name: Study visit to GSB Objectives:    

To learn about the organization works To learn how the organization works To learn about the surveys they do To learn about the equipment & methods they apply

Introduction: Geological Survey of Bangladesh or GSB is an autonomous national organization working in Geo-scientific activities in Bangladesh and is located in Shegunbagicha, Dhaka, Bangladesh. We went there on a visit to learn how the organization works and what type of field work they do and the equipments used. The Geological Survey of Bangladesh was founded in 1971 immediately after the Independence of Bangladesh. The organization was formed out of the remnants of Geological Survey of Pakistan in East Pakistan. The Geological Survey of Pakistan traces its origins to the Geological Survey of India which was founded in 1836. The agency is run by the Ministry of Mineral Resources. It has discovered a number of mines in Bangladesh. GSB is combination of 17 branches. Of which we were able to view 9 branches related to our studies. We visited and were lectured by: 1. 2. 3. 4. 5. 6. 7. 8. 9.

Geological Mapping and Quaternary Geology Petrology and Mineralogy Remote Sensing and GIS Geochemistry and Water Resources Analytical Chemistry Economic Geology and Resource Assessment Gravity and Magnetic Survey Seismic and Electrical Survey Stratigraphy and Biostratigraphy

We attended a 4 day lecture from 10am to 5pm. The information we acquired during these will help us not only increase interest in our subject but also broaden our perspective. Description of the Sessional class:

The 9 branch’s respective officers gave lectures on how they operate and their methodology. In brief, all of them are discussed below: 1) Geological Mapping and Quaternary Geology: The Geological Mapping can be designated as the pioneer worker of all geological activities. Geological Mapping and Quaternary Geology Branch provides the baseline geoscientific expertise through field investigations, acquired field data and information, geological reports, geological and derivative maps. The report and maps are very important to evaluate the geological condition, mineral potential, present and future hazards etc of the area. Now a day, it is very important to acquire geological knowledge of an area to carry out sustainable development activities and any type of mineral exploration activities. It is also useful for the future development planning and sustainable infrastructure construction, combating hazards of an area especially for industrial growth and development, heavy construction, urban planning, roads and highway construction and all types of mineral exploration. Planners, developers, government, semi-government and nongovernment organizations and researchers are the main s of the geological reports and maps for the sustainable developments of an area. Responsibilities 1. 2. 3.

To prepare geological maps of the country at a usual scale of 1:50,000, To prepare geological report of an area or a structure, To carry out exploration works for surficial and near to surface economic mineral deposits, 4. To develop a modern mapping technique suitable for the country, 5. To establish the Quaternary Stratigraphy of the country, 6. To carry out research works on the Quaternary events and episodes, 7. To carry out investigation for fixing the base of the Quaternary Era, 8. To carry out investigations on the geological hazards like river erosion, river course shifting, water stagnancy, river bed siltation etc, 9. To investigate the noetectonic activities, 10. To investigate primarily the arsenic contamination of an area, 11. To extend geological s to other government organizations, universities, NGOs, local government bodies etc, 12. To share knowledge with the persons and organizations locally and internationally working in this field. Activities Present Activities Geological survey of Bangladesh is presently implementing the project - “Geological exploration for the identification of mineral resources and the areas vulnerable to natural hazards in the coastal parts of Bangladesh”. Geological Mapping and Quaternary Geology Branch is engaged

with the project. The geoscientists of this branch are fulltime engaged in the coastal geological mapping to achieve the project objectives. The achievements till today are as followsA. Field Investigation - The entire coastal belt of Bangladesh, covering an area of 33 290 sq km, has been investigated regionally. During investigation, all the possible Geo-information as below as 100 meters have been tried to collect. Samples were collected systematically to perform various types of laboratory analyses. On the basis of the acquired data from regional investigation, few areas are selected for intensive study and sampling. 1. Geological Mapping: During field investigation, the prepared base maps consisting of geological map units, geomorphic features, land-water boundary, different types of infrastructures etc are corrected in the field. 2. Boring & Logging: About 550 lithological logs have been prepared through shallow boring up to 80 meters, mechanical boring up to 100 meters, auger boring and pitting throughout the coastal belt. Moreover, about 50 Geophysical logging have been conducted in selected boreholes. 3. Sample Collection: More than 4000 sediment samples from different depths (up to 100 meters) below the surface have been collected for multi-dimensional laboratory analyses to unveil the hidden secrets of the coastal evolution. Besides regular sampling by the Mapping parties, intact samples, >1000 samples from 35 boreholes, up to a depth of 100 meters have been collected from different parts of the coastal belt of Bangladesh. 4. Fresh-water Aquifer Investigation: During the geological mapping in the coastal belt, the field parties noticed that the people of few areas, especially southwestern coastal part, are suffering intensively from drinking water. Both the surface and known sub-surface water sources are saline in this area. With the view to solve the problem, Geological Mapping Branch has undertaken a program to investigate the fresh water aquifer in the southwestern part of the coastal belt of Bangladesh to resolve the acute scarcity of Potable water. In the first phase the area under Koira, Paikgacha and Dacop upazilas of greater Khulna district has been investigated. Two potential fresh-water aquifers below 300 meters have been identified. 5. Economic Minerals Identification: During field survey, possible mineral deposits of economic importance have so far been identified in the coastal belt of Bangladesh.

Sl. Type of deposits No. 1 Heavy minerals (Radio-active Minerals) 2 Glass sand 3

White clay

4 5

Tiles clay Peat

Locality In the beach deposits of Teknaf, Cox’sbazar sadar, Sonadia island, Materbari, Kutubdia island, Nijhumdwip, Bhola island, Kuakata and Kawar char. In the valleys of Moheshkhali island, Pekua, Banskhali, Anowara and Chakaria In small lenses of the hilly terrains of Ramu, Ukhia, Moheshkhali, Pekua, Banshkhali, Anowara and Chakaria In different areas of the Coastal Plain of Satkhira district In the depressions of Gopalganj, Khulna, Bagerhat and Cox’sbazar districts (Pekua upazila) and Kutubdia island

6 7 8

Teknaf, Cox’sbazar sadar, Moheshkhali, Pekua, Banshkhali, Anowara, Chakaria, Chittagong, Feni, Bhola and Barishal Gravel and Teknaf, Cox’bazar Sadar, Ukhia, Moheshkhali, Banshkhali, Construction Sands Brick clay In different areas of the Tidal floodplains of coastal area. Construction sand

6. Identification of Hazards : The coastal belt of Bangladesh, due to its geographical position and geologic condition,experiences different types of hazards every year. Few of the potential hazards have been identified in the field which are listed below with locality-

Sl. Type of deposits Locality No. 1 Coastal and River Teknaf, Cox’bazar sadar, Kutubdia, Sandwip, Hatia, erosion Lakhmipur, Chadpur, Sariatpur, Bhola, Kuakata, Pathorghata, Hizla, Muladi, Mehendiganj, Dacope etc. 2 Water logging Noakhali, Chittagong, Patuakhali, Gopalganj, Madaripur, Bhagerhat, Khulna and Satkhira 3 Salinity (Ground and Different parts of Khulna, Bhagerhat, Satkhira, Bhola, surface water) Patuakhali, Hatia, Begumganj, Banshkhali, Moheskhali etc, 4 Land slides Hilly region of Chittagong and Cox’sbazar district. 5 Earthquake Chittagong-Teknaf hilly region 6 Cyclone and Tidal Teknaf, Cox’sbazar sadar, Kutubdia, Sandwip, Hatia, surges Lakhmipur, Sariatpur, Bhola, Kuakata, Pathorghata, Hizla, Muladi, Mehendiganj, Dacope, Pirozpur, Jalokhati and Barguna etc. along with the islands under Noakhali, Bhola, Patuakhali, Barisal districts 7 Land subsidence Satkhira, Jessore, Mdaripur, Gopalganj, Sariatpur, Barghuna and Patuakhali. 7. Grey scale mapping interpretation: Using the satellite image, it is made into black & white. With the intensity of color one can understand what is there with the help of legend. But the coloring depends on the band of the satellite. Some satellite images show river as black while others show white. B. Preparation of Geological and Derivative Maps – Preliminary Geological map of investigated areas have already been prepared in regional scale (1:250,000 scale) on the basis of extensive field survey and other primary data. The refinement of the Geological map and preparation of other derivative maps in suitable scale (1:50,000) are going on. C. Laboratory Analyses – Different types of available laboratory analyses of selected samples, up to the depth of 100 meters, have been conducting to unveil the geological secrets and assess the economic potentiality of the coastal parts of Bangladesh. Besides regular Mineralogical,

Grain-size and Chemical analyses, few specialized analyses have been continuing such as XRay Diffractogram for clay mineralogy, Palynological study for past vegetation history and Microfossil study for depositional environment. D. Preparation of Geological Data Base- All the Geological and relevant data (Augur hole, Borehole, Pit section data and other information) from the field are being processed and recorded in different formats as Geological database of the Coastal belt. GIS, ROCKWORKS, SURFER etc software are used for data processing. They mentioned various deposits: Over bank deposit: In the banks of the river, the sediment that is deposited is called over bank deposit. They are compared with other sediment to see similarities in lithological & genetically. Active channel deposit: With the flow of river comes sediment. The bank which is easily broken down contains a lot of sediment and is carried to another bank which is still intact. And it is deposited under water. Piedmont deposit: In the plateaus or in the foot of them, sediments that are stored are called piedmont deposit. Fan deposit: An alluvial fan is a fan- or cone-shaped deposit of sediment crossed and built up by streams. If a fan is built up by debris flows it is properly called a debris cone or colluvial fan. Hill deposit: When a hill is created through a deposit. Equipment:    

Large Map Scanner: To scan various maps Large Map printer: To print various maps & can print upto a width of 42inch. GPR: Has a 250mHZ which can sense upto 10meter & 10mHZ which can sense upto 30meters. In water area, it goes blind. Resistivity meter: It is used for lateral profiling. It gives out a 400 Volt into the soil and gives a quantative data.

An important piece of data : We are situated in Bengal basin. To the west of us is Surma basin. As Indian Basin is similar to us, we follow the indian stratigraphy. When Bangladesh was under Pakistan, GSP followed the British stratigraphy that followed surma stratigraphy. 2) Petrology and Mineralogy: Responsibilities The prime objective of this branch is to ensure scientific and technological assistance for different research works and analysis of rocks & minerals for carrying Geological activity. For the

achievement of this objective, the Petrology and Mineralogy Branch performed the following responsibilities. 1.

Collection, storing and supply of necessary field & scientific equipment as per requirement of the geo-scientist of the organization. 2. Preparation of report in respect of petrology and mineralogy after completion of analytical and research activities. 3. Providing necessary internal and external assistance to the office and other public & private organizations as well. Achievements 1. 2.

Identification of important minerals and provide guide line of its utilization. Analysis of different rock specimen (igneous, sedimentary and metamorphic), preparation of thin section and grain slide for microscopic and XRD analysis, characteristics of the specimen, determine the properties and identification of the minerals. 3. Nomenclature of the rock specimen and its property through mineral percentage. 4. Separation of heavy and light minerals through bromoform and its identification with the help of polarizing microscope and XRD analysis. Equipment: They use X-RF,X-RD & sieve analysis. i) X-RF: X-ray fluorescence (XRF) is the emission of characteristic "secondary" (or fluorescent) X-rays from a material that has been excited by bombarding with high-energy X-rays or gamma rays. It counts the emitted photon numbers and tells what element it is. It uses to soft wares.  

Quant Express: It identifies gross elements & can identify upto 27 elements. Geo Quant: To identify rare elements & can do upto 17 rare earth elements.

Limitations:   

Can’t detect ISOTOPES Can’t detect IONIZED form Can only measure upto 27 atoms

ii) X-RD: X-ray powder diffraction (XRD) is a rapid analytical technique primarily used for phase identification of a crystalline material and can provide information on unit cell dimensions. The analyzed material is finely ground, homogenized, and average bulk composition is determined. It has 2 types of methodology.  

Consolidated Unconsolidated

We use unconsolidated method(vermiculite clay). But it creates a lot of noise. It is used to find the clay mineral distributions in coastal pasts of Bangladesh. Setup: Airtight, has a copper tube, uses 40V and 30mAmp. The sample is saturated in ethyl glycol. Then run in XRD. It is run in a 350degree centigrade setup, then a 580 degree. Then it will draw a graph in the desktop. From that with help of Brag’s law we can know what mineral that sample it is. iii) Sieve Analysis: A sieve analysis (or gradation test) is a practice or procedure used (commonly used in civil engineering) to assess the particle size distribution (also called gradation) of a granular material. The size distribution is often of critical importance to the way the material performs in use. A sieve analysis can be performed on any type of non-organic or organic granular materials including sands, crushed rock, clays, granite, feldspars, coal, soil, a wide range of manufactured powders, grain and seeds, down to a minimum size depending on the exact method. Being such a simple technique of particle sizing, it is probably the most common.

3) Remote Sensing and GIS: Remote sensing is the science of obtaining information about objects or areas from a distance, typically from aircraft or satellites. Remote sensors collect data by detecting the energy that is reflected from Earth. These sensors can be on satellites or mounted on aircraft. Remote sensors can be either ive or active. ive sensors respond to external stimuli. They record natural energy that is reflected or emitted from the Earth's surface. The most common source of radiation detected by ive sensors is reflected sunlight. In contrast, active sensors use internal stimuli to collect data about Earth. For example, a laser-beam remote sensing system projects a laser onto the surface of Earth and measures the time that it takes for the laser to reflect back to its sensor. A geographic information system (GIS) is a computer system for capturing, storing, checking, and displaying data related to positions on Earth’s surface. By relating seemingly unrelated data, GIS can help individuals and organizations better understand spatial patterns and relationships. GIS can use any information that includes location. The location can be expressed in many different ways, such as latitude and longitude, address, or ZIP code. Responsibilities Remote Sensing and GIS method plays a vital role in all sorts of geoscientific works. Using aerial photographs, satellite images (SPOT, TM, MSS, RADAR etc.), vast area can be easily observed and analyzed in short time. This branch mainly does● Year interval geomorphological and geological change detection, ● Geo-environmental degradation detection. ● Physiography, drainage and lineament study. ● River course shifting, Bank erosion, new land mass accretion and depletion detection. ● Land use planning. ●Report preparation on the basis of geoscientific information of national policy makers and national & international geoscientists.

This branch is also responsible to look after the Photogrammetry & Map Library and the Survey department. The Photogrammetry & Map Library are responsible for: ● Collection of hard copies of year interval Topographical maps, aerial photographs, Satellite images, Bathymetric Chart, Bench mark/Spot height and different types of Stereoscopes. ● Issues above year interval maps, images and different instruments to the geoscientists of all branches of Geological Survey of Bangladesh for research and field works according to their demands. The Survey department is responsible for: ● Land Survey such as Plain Table Survey, Theodolite Survey, Topographic Survey and Leveling. ● Demarcation of the Land according to the geoscientists in field works. ● Preparation of contour map by applying Contour Survey defining rise-fall of the land (R.LReduced Level). ● Operating Engineering Survey for embankment construction. Remote Sensing techniques: In the lecture, respected lecturers mentioned LIDAR,RADAR & SAR. Which are all part of remote sensing techniques. LIDAR: LIDAR, which stands for Light Detection and Ranging, is a remote sensing method that uses light in the form of a pulsed laser to measure ranges (variable distances) to the Earth. These light pulses—combined with other data recorded by the airborne system— generate precise, threedimensional information about the shape of the Earth and its surface characteristics.

RADAR: Radar is an object-detection system that uses radio waves to determine the range, angle, or velocity of objects. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, weather formations, and terrain. A radar system consists of a transmitter producing

electromagnetic waves in the radio or microwaves domain, a transmitting antenna, a receiving antenna (often the same antenna is used for transmitting and receiving) and a receiver and processor to determine properties of the object(s). Radio waves (pulsed or continuous) from the transmitter reflect off the object and return to the receiver, giving information about the object's location and speed.In radar, GSB uses X,L,C band. SAR: Synthetic-aperture radar (SAR) is a form of radar that is used to create two- or three-dimensional images of objects, such as landscapes. SAR uses the motion of the radar antenna over a target region to provide finer spatial resolution than conventional beam-scanning radars. SAR is typically mounted on a moving platform, such as an aircraft or spacecraft, and has its origins in an advanced form of side looking airborne radar (SLAR). The distance the SAR device travels over a target in the time taken for the radar pulses to return to the antenna creates the large synthetic antenna aperture (the size of the antenna). Typically, the larger the aperture, the higher the image resolution will be, regardless of whether the aperture is physical (a large antenna) or synthetic (a moving antenna) – this allows SAR to create high-resolution images with comparatively small physical antennas. There are different kinds of SAR techniques: 



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InSAR: Interferometric synthetic aperture radar, abbreviated InSAR (or deprecated IfSAR), is a radar technique used in geodesy and remote sensing. This geodetic method uses two or more synthetic aperture radar (SAR) images to generate maps of surface deformation or digital elevation, using differences in the phase of the waves returning to the satellite or aircraft. The technique can potentially measure millimetre-scale changes in deformation over spans of days to years. It has applications for geophysical monitoring of natural hazards, for example earthquakes, volcanoes and landslides, and in structural engineering, in particular monitoring of subsidence and structural stability. DinSAR: The SAR interferometry differential (DInSAR) technique relies on the processing of two SAR images of the same portion of the Earth’s surface. In the repeat interferometry method, the detection and the quantification of the ground displacement that occurred between the two acquisitions can be achieved by Differential InSAR (DInSAR). PSinSAR: Permenant Scatterer Interferometry (PSI) is a powerful remote sensing technique able to measure and monitor displacements of the Earth’s surface over time. Specifically, PSI is a radar-based technique that belongs to the group of differential interferometric Synthetic Aperture Radar (SAR). With these one can judges if all the buildings are in same elevation. These is mainly done over permanent structure.

Photogrammetry: Photogrammetry is the science of making measurements from photographs, especially for recovering the exact positions of surface points. Photogrammetry is as old as modern photography, dating to the mid-19th century and in the simplest example, the distance between two points that lie on a plane parallel to the photographic image plane, can be determined by measuring their distance on the image, if the scale (s) of the image is known. Photogrammetric analysis may be applied to one photograph, or may use high-speed photography and remote sensing to detect, measure and record complex 2-D and 3-D motion fields by feeding measurements and imagery

analysis into computational models in an attempt to successively estimate, with increasing accuracy, the actual, 3-D relative motions. GIS Basic steps: In GSB, they were suing the software ARC-GIS to use the GIS tool. We were showed two basic steps in using GIS. Geo-referencing & Digitizing. Geo-referencing: Georeferencing means that the internal coordinate system of a map or aerial photo image can be related to a ground system of geographic coordinates. The relevant coordinate transforms are typically stored within the image file (GeoPDF and GeoTIFF are examples), though there are many possible mechanisms for implementing georeferencing. Basic steps done in georeferencing:  Uncheck auto adjust: We must first load up the geoPDF or the image file containing the map. After loading it, we undo the auto adjust.  Point Value: We must set the co-ordinate values on image map. Without geo-referencing is impossible.  Check auto adjust: Then we must again recheck the auto adjust, the software will automatically perform the required tasks.  Go view link table: We must input the data of where the map originated from  In transformation give adjust: after setting all the points, map origin, we must perform adjust.  Update geo-referencing: Then after all data has been inputted and adjusted we must update the info for the software.  Define projector: we must chose the co-ordinate system. In GSB they use WGS 1984 & UTM as they are used worldwide.

By doing all these steps one can geo-reference a map. And it is one of the most important basic steps, without it, GIS tool can’t perform further operations. Digitizing: It is the Digitization of maps. In here special features of maps are colored. For a river map, rivers are well defined with various color, while others features are less highlighted. The same river are sometime highlighted across various eras of maps to see if there has been any change in the landscape. Depending on the map, there is a resolution difference. For a landslide map, there is only a 30m resolution image.

In here we can see with the help of digitizing, one can highlight buildings, the street surrounding it & other. Some basic steps:  First one must select the map from catalogs  Then create a separate folder and input required all the necessary data there.

 Then through the feature tabs we must add features class, name, co-ordinate system. Then import on the selected co-ordinate system.  Then load the layer and paint the area under study with distinguished lines.  The painted shapes are stored as vector data. If the lining wasn’t correct, then we must edit the vector and draw it 7 then paint it.  Now, we can collect desired info from the attribute table. We can see the old data of that map.  Then we must add legend. Then grid, scale, long-latitude. Equipments: As GIS is a software, so they are done in a computer & Photogrammetry uses a mirror stereoscope. Mirror stereoscope: A stereoscope is a device for viewing a stereoscopic pair of separate images, depicting left-eye and right-eye views of the same scene, as a single three-dimensional image. A typical stereoscope provides each eye with a lens that makes the image seen through it appear larger and more distant and usually also shifts its apparent horizontal position, so that for a person with normal binocular depth perception the edges of the two images seemingly fuse into one "stereo window". In current practice, the images are prepared so that the scene appears to be beyond this virtual window, through which objects are sometimes allowed to protrude, but this was not always the custom. A divider or other view-limiting feature is usually provided to prevent each eye from being distracted by also seeing the image intended for the other eye.

Most people can, with practice and some effort, view stereoscopic image pairs in 3D without the aid of a stereoscope, but the physiological depth cues resulting from the unnatural combination of eye convergence and focus required will be unlike those experienced when actually viewing the scene in reality, making an accurate simulation of the natural viewing experience impossible and tending to cause eye strain and fatigue.

Although more recent devices such as Realist-format 3D slide viewers and the View-Master are also stereoscopes, the word is now most commonly associated with viewers designed for the standard-format stereo cards that enjoyed several waves of popularity from the 1850s to the 1930s as a home entertainment medium.

4) Geochemistry and Water Resources: It is one of the principle branches of the Geological Survey of Bangladesh. The branch deals with geo-chemical exploration work by own personnel of the branch and also in collaboration with other branches for the investigation of subsurface mineral deposits and also did research based work on environmental aspects. In laboratory detail differential geo-chemical analyses have been done both surface and subsurface drill hole samples to find out the pathway of mineral deposits, identified the mineral bearing zones or at least to determine the clues of mineral deposits in an area. The personnel of this Branch did work on arsenic investigation in different parts of the country and at the same time they did some work on geochemical behavior and contamination of water of Buriganga River. At present the personnel of this branch is working in on arsenic investigation in the costal areas of Bangladesh under the field activities of the project Titled “Investigation of mineral resources and determination of vulnerable areas in the coastal part of Bangladesh”. Field investigation has been revealed some patients of arsenic diseases. During 2002-2003, detail fieldwork was done in Kasba and Brahmanpara upazila of Brahmanbaria District. Their methodology is  

Collecting ground water samples from the area under study. Example: hand boring tube well, SPT Making a data table

  

Matching physio-chemical parameters. pH, ppm, DO, ORP, electric-conductivity EC,TDS Making a 3-D model of ground water system Ana;yze water quality & impact on human health

In geochemistry they look for Iron, Chlorine, Nitrate etc.

Equipments: Turbidity-meter: Used for finding out how much water is murky or opaque. Turbidity is caused by particles and colored material in water. It can be measured relative to water clarity, or directly with a turbidity instrument such as a turbidimeter or turbidity sensor. Arsenice testing: Bottle, strips, sample water & special regents. The bottle has the sample water and it is mixed with the regents. After shaking continuously, the strip is attached to small opening of the bottle and then on the basis of the color we will know if there is arsenic or not. Multimeter: In the multimeter, a different typed of nodes can be added. pH nodes,Do nodes, ORP nodes etc.

5) Analytical Chemistry : Analytical Chemistry Branch is one of the core disciplines like Geology, Geophysics, and Drilling. Analytical Chemistry Branch has a very fundamental role in executing overall function of GSB. The main objectives of this branch are to provide chemical and geo-chemical data of the geological investigation and exploration work. The analytical Chemistry laboratory is now equipped with most modern Atomic Absorption Spectroscopy (AAS) with Graphite furnace, (Spectra AA 55B, VARIAN), Microwave Digestion system (MAKS, CEM CORP.), and Volta metric Analyzer (797 VA Computrace, Metrohm). Besides these, UV/Visible Spectrophotometer, Flame Analyzer, Bomb Calorimeter, Muffle Furnace, Different type of Fume hood, High calibration Balance etc. are widely used in this laboratory. Different wet methods are also used in qualitative and quantitative analysis. Equipments: I-OES( Inductively coupled plasma- Optical Emission Spectrometer): I-OES is a tracelevel, elemental analysis technique that uses the emission spectra of a sample to identify, and quantify the elements present. Samples are introduced into the plasma in a process that desolates, ionises, and excites them. The constituent elements can be identified by their characteristic emission lines, and quantified by the intensity of the same lines. Bomb Calorimeter: A bomb calorimeter is a type of constant-volume calorimeter used in measuring the heat of combustion of a particular reaction. Bomb calorimeters have to withstand the large pressure within the calorimeter as the reaction is being measured. Electrical energy is used to ignite the fuel; as the fuel is burning, it will heat up the surrounding air, which expands

and escapes through a tube that leads the air out of the calorimeter. When the air is escaping through the copper tube it will also heat up the water outside the tube. The change in temperature of the water allows for calculating calorie content of the fuel. CHNSO analyzer: Rapidly determine the carbon, hydrogen, nitrogen, sulfur, or oxygen in inorganic and other types of materials. Our proven elemental analyzers handle a wide variety of sample types including solids, liquids, volatile and viscous samples. UV spectrogram: A spectrogram is a visual representation of the spectrum of frequencies of sound or other signal as they vary with time or some other variable. Spectrograms are sometimes called spectral waterfalls, voiceprints, or voicegrams. Spectrograms can be used to identify spoken words phonetically, and to analyse the various calls of animals. They are used extensively in the development of the fields of music, sonar, radar, and speech processing, seismology, and others. Atomic Absorption Spectrometer: Atomic absorption spectroscopy (AAS) is a spectroanalytical procedure for the quantitative determination of chemical elements using the absorption of optical radiation (light) by free atoms in the gaseous state. The technique makes use of absorption spectrometry to assess the concentration of an analyte in a sample. It requires standards with known analyte content to establish the relation between the measured absorbance and the analyte concentration and relies therefore on the Beer-Lambert Law. In short, the electrons of the atoms in the atomizer can be promoted to higher orbitals (excited state) for a short period of time (nanoseconds) by absorbing a defined quantity of energy (radiation of a given [wavelength]. This amount of energy, i.e., wavelength, is specific to a particular electron transition in a particular element. In general, each wavelength corresponds to only one element, and the width of an absorption line is only of the order of a few picometers (pm), which gives the technique its elemental selectivity. The radiation flux without a sample and with a sample in the atomizer is measured using a detector, and the ratio between the two values (the absorbance) is converted to analyte concentration or mass using the Beer-Lambert Law. IC ION Chromotography: is a chromatography process that separates ions and polar molecules based on their affinity to the ion exchanger. It works on almost any kind of charged molecule— including large proteins, small nucleotides, and amino acids. The two types of ion chromatography are anion-exchange and cation-exchange. It is often used in protein purification, water analysis, and quality control. DI(de-ionization) unit: is a water treatment technology that utilizes an electricity, ion exchange membranes and resin to deionize water and separate dissolved ions (impurities) from water. It differs from other water purification technologies in that it is done without the use of chemical treatments and is usually a polishing treatment to reverse osmosis (RO). Furnance: A furnace is a device used for high-temperature heating. The name derives from Greek word fornax, which means oven. The heat energy to fuel a furnace may be supplied directly by fuel combustion, by electricity such as the electric arc furnace, or through induction heating in induction furnaces. Microwave Digestion system: Microwave digestion is a common technique used by elemental scientists to dissolve heavy metals in the presence of organic molecules prior to analysis by inductively coupled plasma, atomic absorption, or atomic emission measurements. This technique

is usually accomplished by exposing a sample to a strong acid in a closed vessel and raising the pressure and temperature through microwave irradiation. This increase in temperature and pressure of the low pH sample medium increases both the speed of thermal decomposition of the sample and the solubility of heavy metals in solution. Once these heavy metals are in solution, it is possible to quantify the sample through elemental techniques. Potentiometer: A potentiometer is a three-terminal resistor with a sliding or rotating that forms an adjustable voltage divider. If only two terminals are used, one end and the wiper, it acts as a variable resistor or rheostat. 6) Stratigraphy & Bio-stratigraphy: Stratigraphy & Biostratigraphy branch is one of the significant branch of GSB. Two different laboratories (Stratigraphy and Biostratigraphy) are associated with it. This branch offers different scientific research work to meet the requirements of this organization. The name of the branch is according to the subject Stratigraphy & Biostratigraphy. The subject deals with the mutual relationship and succession of rocks. It aims at the grouping of natural association of rocks, establishing their ages and correlating them with rock formation of different areas. Biostratigraphy is based on the study of fossil records of micro organisms, such as foraminifera, radiolaria, ostracodes, diatoms, pollens and spores etc. can be collected from the surface and subsurface rock samples and even from the cores of the bore holes which have wide application for the classification and correlations of the rock formations and in the exploration of petroleum and natural gas. Their main focus is palynology & paleontology. Paleontology: It includes the study of fossils to determine organisms' evolution and interactions with each other and their environments (their paleoecology). Paleontological observations have been documented as far back as the 5th century BC. Paleontology lies on the border between biology and geology, but differs from archaeology in that it excludes the study of anatomically modern humans. It now uses techniques drawn from a wide range of sciences, including biochemistry, mathematics, and engineering. Use of all these techniques has enabled paleontologists to discover much of the evolutionary history of life, almost all the way back to when Earth became capable of ing life, about 3.8 billion years ago. As knowledge has increased, paleontology has developed specialised sub-divisions, some of which focus on different types of fossil organisms while others study ecology and environmental history, such as ancient climates. Foraminifera- this micro fossil tells there was a ocean or deep ocean at the place it was found. Benthic- It shows the place it was found to be once a shallow dweller, many years ago. Why it is important? With the interpretation of fossils, one can say the depth & the saltiness of the sea, the fossil originated from. Even with these fossil, using FCL (floraminifera coloring index) we can identify the oil maturation, in turn it can tell us the quality of the oil and the age of the reservoir.

Palynology: Palynology is the "study of dust" or "particles that are strewn". A classic palynologist analyses particulate samples collected from the air, from water, or from deposits including sediments of any age. The condition and identification of those particles, organic and inorganic, give the palynologist clues to the life, environment, and energetic conditions that produced them. Chemical preparation: Chemical digestion follows a number of steps. Initially the only chemical treatment used by researchers was treatment with potassium hydroxide (KOH) to remove humic substances; defloculation was accomplished through surface treatment or ultra-sonic treatment, although sonification may cause the pollen exine to rupture. The use of hydrofluoric acid (HF) to digest silicate minerals was introduced by Assarson and Granlund in 1924, greatly reducing the amount of time required to scan slides for palynomorphs. Palynological studies using peats presented a particular challenge because of the presence of well-preserved organic material, including fine rootlets, moss leaflets and organic litter. This was the last major challenge in the chemical preparation of materials for palynological study. Acetolysis was developed by Gunnar Erdtman and his brother to remove these fine cellulose materials by dissolving them. n acetolysis the specimen is treated with acetic anhydride and sulfuric acid, dissolving cellulistic materials and thus providing better visibility for palynomorphs.

Some steps of the chemical treatments require special care for safety reasons, in particular the use of HF which diffuses very fast through the skin and, causes severe chemical burns, and can be fatal. Analysis: The sample are put under a microscope. The researcher looks for similarities in the sample with other known samples. And identifies it’s origin and other characteristics. Through this, one can say what type of land the origin place of the sample was.

7) Economic Geology and Resource Assessment: Mineral search have always been high agenda of activities of Geological Survey of Bangladesh. The Economic Geology and Resource Assessment Branch since its establishment have been making all out efforts for unveiling mineral resources (except oil and gas) disseminated throughout the country and concealed beneath the surface. The efforts of the surveys over the years through this branch have yielded rich natural resources by the way of crediting the nation with pride discoveries of coal, peat, glass sand, white clay, limestone, hard rocks etc required for diverse industries. To expedite exploration activities various projects are being implemented by its skilled manpower for locating and evaluating newer mineral resources is a routine work of this branch. Methodology:

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Auger: An auger is a drilling device, or drill bit, that usually includes a rotating helical screw blade called a "flighting" to act as a screw conveyor to remove the drilled out material. The rotation of the blade causes the material to move out of the hole being drilled. Chopping Method Rotary Drilling : Rotary drilling is characterized as a method of drilling that employs a sharp, rotational drill bit to bite its way through the earth’s crust. One of the most effective and common methods of drilling, it is used in the construction, mining, and oil industries for its ability to cut through even the most challenging and hardest formations. SPT: (Standard penetration test) For soft characteristics sediment, we use this method to get intact sample. Pit digging: 10 feet is cut to see the upper soil formation of that place.

The branch works mainly in accessing heavy minerals & coals. Coal: This branch discovered the 4 mines out of the present 5. The first coal field, Jamalgange. It hails from the parmean era, in that time there was a lot of vegetation. Due to natural hazard & tectonic activities they turned into coal. Bituminous coal originated there 250-275 million years ago. Lignite originated there around 2-2.5 corer years ago. Peat: Peat deposited around 282 million tons at Hakaluki Hawar. It was found using augering upto 30 feet. That area is divided up in western & Eastern areas. Eastern area has wet peat but 10m thick. The western peat has 3-2 meter bottom surface with 1-1.5m thick dry peat. Limestone: They found a deposit in lalghat. And another large deposit was proved in Jopurhat. White clay: These are recent deposit. They generate in a clam place by the river in an Aluminum rich kaolinite environment. Hawar Bil, Agair & Moddhopara has white clay deposits. Silica Sand: They are found at platue of Habiganj. Beneath 5-6feeet underground, silica sand can be found. Hardrock: These are found as basement rocks. Heavy Minerals: If the density of reservoir is above 2.65, that is considered as heavy minerals. Of those, Zirkon, Rotile, Garnet, Monazite, Illuminite, Biotet & Muscovite are sought out.

8) Gravity and Magnetic Survey: Gravity and magnetic surveys involve measuring the Earth's gravitational and magnetic fields using highly sensitive instruments. These Potential Field measurements can be made on the Earth surface, both on land and the sea bottom, from ships or from aircraft. The data from the surveys are processed in a number of ways but usually produce some form of anomaly value, i.e. a variation from what would normally be expected at that point. These gravity and magnetic anomalies can be attributed to variations in the Earth's crust and are a major asset in mineral and hydrocarbon exploration, as well as furthering our understanding of the deeper Earth structure and processes.

Based on gravity survey scientists have created the Potsdam Gravity Potato & Ryiand Bouge Gravity Anomaly map. Coal & basement rock can be found gravity density is high as 4.5-4.8. Magnetic survey on the other hand is cost effective. It can done by Air Bourne, Ship Bourne & Ground base. Equipments: CG-5 Autograv: A gravimeter is an instrument used in gravimetry for measuring the local gravitational field of the Earth. A gravimeter is a type of accelerometer, specialized for measuring the constant downward acceleration of gravity, which varies by about 0.5% over the surface of the Earth. Though the essential principle of design is the same as in other accelerometers, gravimeters are typically designed to be much more sensitive in order to measure very tiny fractional changes within the Earth's gravity of 1 g, caused by nearby geologic structures or the shape of the Earth and by temporal tidal variations. This sensitivity means that gravimeters are susceptible to extraneous vibrations including noise that tend to cause oscillatory accelerations. In practice this is counteracted by integral vibration isolation and signal processing. Magneto Meter: A magnetometer is an instrument that measures magnetism—either magnetization of magnetic material like a ferromagnet, or the direction, strength, or the relative change of a magnetic field at a particular location. A com is a simple example of a magnetometer, one that measures the direction of an ambient magnetic field. 9) Seismic and Electrical Survey: Seismic survey is is a method of exploration geophysics that uses the principles of seismology to estimate the properties of the Earth's subsurface from reflected seismic waves. The method requires a controlled seismic source of energy, such as dynamite/Tovex blast, a specialized air gun or a seismic vibrator, commonly known by the trademark name Vibroseis. Electrical resistance survey(also called earth resistance or resistivity survey) is one of a number of methods used in archaeological geophysics. In this type of survey electrical resistance meters are used to detect and map subsurface archaeological features and patterning. Types of electrical resistivity:   

VES- the receivers and transmitters have to be placed 2/3 times more than the depth reading we want. Electrical profiling- 2D method of depth & lateral variation. Electrical Magnetic method

Equipments: MCSEIS-X 48 : It has 48 geophones patched to it. It used the basic principle of seismic wave and creates a graph on basis of that. Resistivity Meter: It has 2 electrical 7 potentiometer attached to it. The distance between the electrical transmitter is the half length of depth of resistivity meter.

TEM: This equipment is used to identify large obstacles like hard rock. Value is recorded when the current is stopped. It has a 200x200 cm coil in the equipment.