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Sedimentation
Dynamics in a Proterozoic Submarine Fan System: A Case Study
from Singhbhum Basin, Jharkhand, India
-- Rashmi and S Das
The
Proterozoic Singhbhum Basin is a distinct litho-tectonic unit
of the Singhbhum crustal province of the Eastern Indian shield.
The sedimentary cover (ca 2.3 Ga) is a deformed folded sequence
of metaclastic units in which records of depositional history
are well preserved along the eastern cratonic margin of an
unstable foreland trough formed during the early phase of
the Singhbhum Orogeny. A total continuity of sedimentation
and stratigraphic history from the basin margin towards the
north following a slope controlled channelized submarine fan
system that originates from the south and opening up towards
the north is recorded. The development of submarine fan is
related to intra- and extra-basinal factors. Proximal, medial
and distal associates of the submarine fan system are well
preserved. The proximal sequence is a product of submarine
fluidized non-cohesive granular-debris flow, triggered by
instability of the basin flank. The medial and distal components
of the fan are excellently preserved as sandstone-shale turbidite
deposited in overlapping submarine fan system. During basin
filling, instability of the basin flank and basin floor strongly
influenced the sedimentary character through various scales
of turbidity current activities, and intra-basinal contemporaneous
flows. This was followed by an ultimate stagnation and onset
of post depositional processes.
©
2007 IUP . All Rights Reserved.
Water
Recharge Problems in a Semi-arid Zone (Climatic and Anthropogenic
Impacts): The Case of the Essaouira Aquifers System (Mogador,
Morocco)
-- M Bahir and M
A Misdaq
Water
samples were collected from drillings, different sources and
wells belonging to the plioquaternary and turonian aquifers
in the study region and the piezometric map of the Essaouira
synclinal basin (Morocco) was prepared. Electric conductivity
as well as 18O, 2H and 3H
concentrations of water samples were measured. A meteoric
local line was determined and compared with the world meteoric
line. The radiocarbon ages of the studied aquifers were evaluated.
Recharge of the main aquifers in the study region was investigated.
It has been shown by this study that the recharge rate of
the deep turonian aquifer is too low, which may cause a shortage
of water supply to the Essaouira city and its surrounding
region. Based on the study, it is suggested that the Moroccan
authorities, considering the drought in the region during
the past few years, must envisage building small dams on the
Ksob river for a better management of floodwaters, which are
presently let into the Atlantic ocean.
©
2007 IUP . All Rights Reserved.
Hydrogeochemical
Framework of Quaternary Aquifer of English Bazaar Block, Malda
District, West Bengal
-- Surajit
Chakraborty, P K Sikdar and P K Paul
A
hydrogeochmical survey was carried out in English Bazar block,
Malda district, West Bengal, to assess the quality of groundwater
for drinking and irrigation purposes. Integrating GIS into
such a methodology can provide more refined spatial analyses,
and more accurate water quality reporting. 42 groundwater
samples from tube wells were collected and analyzed for pH,
EC, TDS, major cations, major anions and heavy metals. The
study area is occupied by Quaternary formations. Groundwater
occurs in an unconfined condition in the alluvial sediments.
Use of groundwater from the area covered by Recent Alluvium
and Older Alluvium may lead to high and medium salinity hazards,
respectively. According to the water quality index (WQI),
water quality is classified as: good, poor, very poor and
unsuitable for drinking. The last two types of groundwaters
contain high concentrations of heavy metals (such as Cu, Cd,
Mn, Fe, and Cr and As). Anthropogenic activities are the possible
sources of heavy metals. In general, the water quality in
the study area is found to be poor.
©
2007 IUP . All Rights Reserved.
Land
Subsidence in Salt Lake City and Adjoining Areas of Kolkata
-- A K Bhattacharya and M N Patra
Based
on the change in piezometric level from the middle of the
1950s to the end of the 20thcentury, decrease
of pore water pressure in the aquifers and corresponding increase
of the effective stresses in different soil strata of Salt
Lake City and adjoining areas of Kolkata are calculated. This
increase of effective stress results in consolidation of the
soil, which has manifested itself as land subsidence. The
city of Kolkata region forms a part of the lower deltaic plains
of the Ganga River system. However, in the Salt Lake area,
the upper layers of soil are composed of filled up materials,
(e.g., alluvium dredged from the riverbed of Hooghly). Due
to excessive groundwater withdrawal, the consolidation resulting
in subsidence is maximum in Ultadanga—Salt Lake area
of Kolkata, (10-20 mm/y); this is also becoming prominent
in cracks found in some buildings in a few blocks of Salt
Lake.
©
2007 IUP . All Rights Reserved.
Cartographic
Limitations and Possibilities on Mobile Devices
--
K Ram Mohan Rao,
Rajinder Singh Nagi ,
Milap Punia and
Corné van Elzakker
The
fields of geoinformation technology and cartography have seen
dramatic changes in the last decade. The dissemination of
digital geospatial data is no longer bound by desktop platform.
It is now monitored on mobile devices such as Palmtops, Personal
Digital Assistants (PDAs), and Smart phones. The map display
on a handheld device is a challenge to cartography due to
the limiting factors of screen size, colors, resolution, processing
power, memory and power supply. Though with technological
advancements, these limiting factors are improving at a great
pace, the small size display of devices still remains the
same. Technological developments in the field of mobile computing
are significant and more research is directed towards the
use of mobile devices in geoinformation applications. However,
new methods for location-based information, symbolization,
data formats, context-based generalization and server-based
real-time rendering are being explored for better cartographic
visualization on the small display devices. Most of the present
approaches are technology-driven, and have neglected the basic
cartographic visualization aspects. This paper aims to present
the limitations, and possibilities of map design for mobile
applications with design recommendations for improving visualization.
©
2007 IUP . All Rights Reserved.
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