Download Exposures of Himalayan Frontal Thrust (HFT)

Geological Survey of India
Exposures of Himalayan Frontal Thrust (HFT) found in Panchkula
District, Haryana
The Himalayan Frontal Thrust (HFT) also known as Himalayan Frontal Fault (HFF) is a
regional, southern most and youngest major structural discontinuity, parallel to the
Himalayan ranges that separates the outermost Siwalik sub-Himalayas from the IndoGangetic plains. HFT is believed to be a blind fault as it has few surface exposures and
therefore usually shown as “trace of HFT” in geological maps defining the southern
topographic break of Himalayan ranges. This fault has been active during the
Quaternary period and caused several modifications in the younger geological,
geomorphological and drainage features. Many of the recent moderate earthquakes in
Himalayas have originated in the zone between the HFT and Main Central Thrust (MCT).
While carrying out lithostratigraphic mapping of Siwalik rocks in Haryana
(Item:STM/NR/PHH/2010/008) the team comprising Sh. Rajinder Kumar and Hemant
Kumar, Senior Geologists led by Dr H.S Saini, Director found good exposures of HFT at
two locations in ‘nalla’ sections in the Panchkula district of Haryana where Siwalik rocks
are overriding the younger sediment layers.
In the exposures, HFT is a northerly dipping, WNW-ESE trending fault which has brought
Tatrot Foramtion of Upper Siwalik over the Late Quaternary gravels (Fig 1). The hanging
wall consisting of friable coarse grained, grey micaceous sandstone, mudstones shows
deformation in the form of folding, faulting and crushing in about 500m thick zone. The
deformation is also visible in the loose gravel of footwall in which pebble layers show
warping and dragging. North of the fault, minor faults are traceable for over a km
length. These exposure sites may be potentially appropriate for GPS measurements for
slip rate, strain built up etc.
Northern Region
1
Geological Survey of India
Fig 1. Himalayan Frontal Thrust (HFT) showing Tatrot Formation of Upper Siwalik over
the Late Quaternary gravels.
Northern Region
2