1. The document describes a research study on the mineralogical and geochemical characterization of mudrocks from the Neogene succession in Bangladesh. 2. The study will analyze mudrock samples using XRD, XRF, and laser particle size analysis to determine their depositional environments, diagenetic changes, and potential as petroleum seals or source rocks. 3. The research aims to better understand the clay mineralogy, elemental composition, grain size, and diagenetic alterations of mudrocks in two anticlines in Bangladesh and infer their depositional environments.

1. Md. Yousuf Gazi
Department of Geology
University of Dhaka
Dhaka-1000
Title: Mineralogical and geochemical characterization of Mudrocks of Neogene
succession in Bangladesh in relation to depositional environment, diagenesis and
petroleum geology.
Research Methodology: X-ray diffraction pattern, x-ray florescence technique, Laser
particle size analyzer, Geospatial technique.
Study Area: Bangle Basin.

2. Introduction:
Mudrocks cover a major part of Neogene succession in Bangladesh. This is extensively
exposed in the eastern fold belt. The present research will charecterize the mudrocks of the
fold belt areas in terms of its textural, mineralogical, geochemical and petroleum aspects.It
includes shales, claystone and mudstone depending on its mineralogy. The depositional
environments of the Neogene mudrocks are generally considered as shallow marine to
deltaic environment that gradually changes to fluvial system at late Neogene. This research
will primarily relate the acquired data on mudrocks to its specific depositional environment.
The interpretation will be based on the analysis of surface samples for mineralogy and
geochemistry. The diagenetic changes from deposition to deep burial will be studied based
on x-ray diffraction and x-ray florescence. The mudrock has been a major seal in the
petroleum entrapment in Bangladesh gas pools. The study will assess the rocks for their
efficiency as petroleum seal based on its mineralogical and geochemical properties.
Problem Statement:
The main purpose of the study is to know the detail clay mineralogy, elemental abundances,
particle grain size and the background processes of clay mineral alteration in the axial
regions in Sitakund anticline. This study also concerning the bending mechanism of clay
flakes and mineralogical behavior in the onion structure (Traditionally named).Numerous
studies have been put forward to know the diagenetic changes in shales but the presence of
peeling with clay flakes just like onion peeling in shales and the mineralogical changes have
given the less attention .Here, this study want to disclose the mechanism behind this and
associated mineralogy. From the data obtained from analysis will assist to infer the
depositional environment.

3. Literature Revirew:
A comparative study of the diagenetic alteration of clayminerals in Mesozoic shales from
Papua, New Guinea, and in tertiary shales from Louisiana, U.S.A conducted by
(Moort.1969). Similar studies also delineated concerning sediment geochemistry, clay
mineralogy, and diagenesis titled as a synthesis of data, Nankai trough (Underwood et
al.1993). In the context of Bangladesh (Alam at el.2009) demonstrated the clay mineralogy
and diagenesis of dupitila shales of Bandarban anticline, Bangladesh. Based on a study ofthe
mineralogical composition of recent marine sediments, the diagenesis of clay minerals was
first analyzed by Dietz (1941). Numerous studied have documented on shale diagenesis
based on clay mineralogy (Perry and hower.1970; Howeret al.1976; Imam and Shaw.1985).
Research Objective:
1. What is the mineralogical composition of the shales sampled from the studied
area?
2. What sort of diagenetic changes related to this mineralogical traces and
weathering phenomena?
3. What is the background mechanism of forming onion structure (Traditionally
named) and mineralogical difference between this and the shales that don’t
contain the onion structure?
4. What are the detail sediment geochemistry and evidences of weathering?
5. What are the depositional environments?
6. What is the potentiality of these Mudrocks to occur as Petroleum seal and source
rocks?
Study Area:
The investigated areas are the hilly uplifted terrain of Bangladesh namely Sitakund anticline
and Bandarban anticline. In these areas many outcrops of Neogene Mudrocks are available
to study. Neogene succession of these areas include Surma group and Tipam-Bokabil rock
sequences.

4. Methodology:
Samples will be collected from the outcrops of the anticline. Important experiments are
intended to run during this investigation that is locally available. Namely, X-ray diffraction
pattern, X-ray fluorescence and the samples peak sharpness, Laser particle size analyzer.
Spatial techniques namely remote sensing and GIS can be used to process and display the
data.
Time Frame:
Including fieldwork, Sample collection, Lab Analysis and Thesis submission will belated
from June 2016 to June 2017.

5. Socioeconomic Importance:
In Bangle basin, Surma group contains the largest petroleum system. There are numerous
researches on reservoir sandstones in Bangladesh. Very few studies were conducted on
source rock characterization. In recent years, source rock is the prime interest to explore
petroleum in many developed and developing countries. This study will assess the
petroleum potentially of the Mudrocks of these areas as source rock and occurrences as seal.
Conclusion:
Neogene mudrocks characterization based on XRF, XRD and laser will reveal the detailed
mineralogy, geochemistry and Petrography. From this analysis, the research will determine
the diagenetic changes, depositional environment, source rock potentiality and occurrences
as seal of these Mudrocks. We will be able to extrapolate the result in the subsurface
succession.
References:
1. Colten-Bradley, V.A., 1987. Role of pressure in smectite dehydration effects on
geopressure and smectite-to-illite transformation. AAPG Bull., 71:1414-1427.
2. Cook, H.E., Zemmels, I., and Matti, J.C, 1975. X-ray mineralogy data, far
western Pacific, Leg 31 Deep Sea Drilling Project. In Karig, D.E., Ingle, J.C, Jr.,
et al., Init.Repts. DSDP, 31: Washington (U.S. Govt. Printing Office), 883-895.
3. Coulbourn, W.T., 1986. Sedimentological summary, Nankai Trough Sites 582
and 583, and Japan Trench Site 584. In Kagami, H., Karig, D.E., Coulbourn,
W.T., et al., Init.Repts. DSDP, 87: Washington (U.S. Govt. Printing Office),
909-926.
4. Hower, J., Eslinger, E.V., Hower, M.E., and Perry, E.A., 1976. Mechanism of
burial metamorphism of argillaceous sediment: 1. mineralogical and chemical
evidence. Geol. Soc. Am. Bull, 87:725-737
5. Perry, E., and Hower, J., 1970. Burial diagenesis in Gulf Coast pelitic sediments.
Clays Clay Miner., 18:165-177
6. Keller, "vV. D. (1957) Principles of Chemical Weathering: Lucas Bros., Pub.,
Columbia, Me., 1 llpp.