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Cyclic
Fine-Grained Deposits with Polymict Boulders in Olaipadi Member
of the Dalmiapuram Formation, Cauvery Basin, South India:
Plausible Causes and Sedimentation Model
-
-
Mu
Ramkumar
The
fine-grained cyclic deposits of Olaipadi member of the Dalmiapuram
Formation, Cauvery basin, contain large boulder sized lithoclasts
of gneissic basement rocks and older sedimentary rocks. Earlier
these were interpreted as glacial drop deposits and siliciclastic
coral reef complex, etc. Many sedimentary characteristics,
typical of these deposits are neither been documented nor
explained by previous studies. They are: a. occurrence of
large, genetically unrelated lithoclasts in typical basinal
sediments that show a general fining upward nature; b. occurrence
of conformable bedding planes along the margins of these large
extraformational and extrabasinal boulders; c. repetitive
occurrences of classic Bouma sequences; and d. sedimentary
structures in the bases of sandy and silty layers indicative
of fluidized flow and post-depositional dewatering, general
reduction of thicknesses of sandy layers from basal beds to
top and coeval increase in thickness of claystone layers.
Examination of new exposures helped documentation of sedimentary
textural, structural and lithofacies characteristics, contact
relationships, facies association and tectonic structures.
It is inferred that sedimentation of Olaipadi deposits was
initiated by hyperpycnal flow following faulting and upliftment
of former shelf and coastal regions that led to the gravity
flow of fractured and unstable fault scarp blocks resulting
in the turbidite deposition on the adjacent deeper regions
of sea. Maturation of depositional topography from rugged
fault controlled to gentle slope took place concomitant with
progradation of fan into deeper basinal regions along with
sea level oscillations.
©
2008 IUP . All Rights Reserved.
Geotechnical
Mapping of the Jamalpur Municipality and Surrounding Areas
of Bangladesh
- - A
S M Shafiul Azam and Sohail Kabir Jamalpur
municipality along the river Brahmaputra was established in
1869. Since then the population has been increasing at a higher
rate following urbanization. Geomorphologically, the area
is divided into nine mappable units, such as active channel,
abandoned channel, ephemeral channel, channel bar, oxbow lake,
madhupur clay, low flood plain, high flood plain and flood
basin. A geotechnical zonation map has been prepared using
a geomorphological map, subsurface lithology, geotechnical
properties of different geomorphic units and clay mineralogy.
Zone-A is the best possible zone for engineering construction.
Zone-B could be used for engineering construction with a little
modification of the site and also for waste disposal site,
whereas Zone-C and Zone-D are not suitable for any kind of
construction.
©
2008 IUP . All Rights Reserved.
Structural
Inferences from Total Magnetic Intensities in the Gadag Region:
A Case
Study
- - Veeraiah
B, Himabindu D and Ramadass G 2-D
total field intensity magnetic observations were made over
an area of approximately 2,750 sq km with maximum N-S and
E-W extents of 55 and 50 km respectively in the geologically
and tectonically interesting Gadag region with a view to obtain
a clear perception of the structural configuration of the
region. From the qualitative analysis of the total magnetic
intensity data, several tectonic featuresdeep seated faults
and magnetic linears in the region were identified. The quantitative
evaluation consisted of modeling. Eleven profiles were digitized
from the low pass filtered output of the magnetic data and
modeled for the regional magnetic interface. The computed
depths to this interface along each profile were digitized
and contoured to obtain its subsurface topography. This magnetic
interface was found to vary between depths of less than 1
to 8 km. Further, from the results of forward modeling of
the anomalous body within the schistose zone in the region,
it was found that the Banded Iron Formation (BIF) occurred
at depths ranging from 300 to 1,300 m.
©
2008 IUP . All Rights Reserved.
Hydrogeomorphological
Mapping for Groundwater Prospects Using Remote Sensing Data:
A Case Study of a Part of Bhind District, Madhya Pradesh
- - Vineesha
Singh and Khare M C Groundwater
is a valuable resource, which needs proper evaluation and
management for all developmental activities of human beings.
Remote sensing data have proved to be an indispensable tool
in the evaluation of hydrogeomorphological features and groundwater
resources. Hydrogeomorphological study was carried out in
a part of Bhind district, Madhya Pradesh. In the present study,
the different hydrogeomorphological units and associated lineaments
have been delineated, using remote sensing data IRS-1B LISS
II. The geology, geomorphology and lineament information along
with other collateral data have been analyzed and integrated
to evaluate the groundwater prospective geomorphic units.
Hydrogeomorphologically, the entire area is classified into
categories such as alluvial plain, valley fill, pediment,
pediplain, buried pediplain and structural hill. The analysis
reveals that the area covered by alluvial plain has excellent
to good, and pediplain and buried pediplain have moderate
to good groundwater conditions.
©
2008 IUP . All Rights Reserved.
Monitoring
the Coseismic Movement of Koyna Dam Using Gps
-
- Nisha
Radhakrishnan, Madhav N Kulkarni and Kamal Sakr On
June 8, 2005, the Koyna region in Western Maharashtra, India,
was rocked by a magnitude 4.2 earthquake. This earthquake
was followed by an aftershock of M 3.6. The locations of the
two earthquakes were about 20 km SE of the dam situated in
Koyna. For monitoring the deformation of the dam, a GPS receiver
was set up on the top of the dam by Indian Institute of Technology
Bombay (IITB), which was continuously operating even during
the time of occurrence of the earthquakes. The GPS group of
IITB has been working over six years in the field of deformation
measurements and analysis of Koyna Dam under a research project
funded by the Department of Science and Technology, Government
of India. A GPS network has been established for this purpose,
and observed periodically in order to investigate the potential
of GPS Technology in deformation measurement analysis. The
data collected by the GPS receiver on June 8, 2005 was used
to analyze the movement of the dam due to the earthquakes.
The analysis of the data collected just before and after the
earthquake occurrences showed a displacement in the NW direction
with a certain magnitude of deflection. After the occurrence
of the earthquakes, the dam was observed to attain its original
position by shifting in the opposite direction (SE) with the
same degree of deflection as observed during the time of the
earthquakes. These results reflect the reflex movement of
the dam body and its response to the occurrence of the main
shock and its aftershock. These results indicate the high
stability of the Koyna Dam.
©
2008 IUP . All Rights Reserved.
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