jalna district disaster management information database & disaster ...

2.4 Geology & Geomorphology
Section III : Risk Assessment Analysis
• The entire district is occupied by basaltic lava flows of the Deccan traps of Upper
Cretaceous to Eocene age. The Deccan trap is overlain by alluvial deposits along
the major river. The alluvium forms a very fertile land.
• The geological sequence of the area is given below.
FORMATION AGE LITHOLOGY
Alluvium Recent Fine, clay, silt and sand
Deccan Upper Vesicular, amygdaloidal, zeolitic
Traps Cretaceous basalt and the hard and compact
to Eocene massive basalt with red bole beds
Alluvium
• The alluvial deposits in the district are overlying on the Deccan traps and occur along
the major river flowing through the district viz. Godavari and Purna. The alluvium
consists of clay, silt and sand. The thickness of alluvium ranges between 15 to 20 Mts.
The extent of alluvium across the river is very limited and ranges between 0.25 to
0.5 Kms.
Deccan Traps
• The major part of the district is covered by the Deccan Trap lava flows. There are a
number of flows in the district, The individual flow generally consists of two units.
The upper unit of vesicular and amygdaloidal zeolitic basalt and the lower unit,
consisting of massive basalt with joints and fractures. The two flows are often
separated by thick clay deposit called as red bole. The thickness of individual flow
ranges between 15-20 Mts.
Lineaments and Fractures
• With the use of satellite imagery number of lineaments have been identified. In this
district lineaments are oriented in NW-SE,NE-SE direction. In this district lineaments
being the weaker zone can act as potential zone for groundwater developments.
Jalna District Disaster Management Information Database Vol I - 7