Batman Universitesi Yasam Bilimleri Dergisi
Cilt 1, Sayı 2 Ocak-Haziran 2012 (ISSN: 2147-4877, E-ISSN: 2459-0614)
Yaşar Eren, M. Tahir Nalbantçılar, Turgay Beyaz, Salih Dinç, Murat Ünal, ŞükrüArslan,Süleyman Polat
||Formation Mechanism of Esentepe (Gültepe-Batman) Sinkhole
A sinkhole has been discovered in the alluvial rocks at the South part of
Esentepe Hill at 6 October 2011. In the area, pebbly-sandy mudstone with calische
pods and gypsium crystals, sandstone and conglomerate forms the basement.
These units are unconformably overlied by the unconsolidated alluvial fan rocks.
The Esentepe sinkhole is located at theboundary of the two units. Two other small
depressions also determined in the area. All of the three depressions trend paralel to
the N-40-50W direction. The Esentepe sinkhole is one meter in length and 0,75 m in
width at the surface. From the surface to 5 m depth, it has elipsoidic shape with 4x2
dimensions. Between 5 to 17 m in depth, it has rectangular shape with the 6x3 m in
dimension. Beyond this depth to the 30 m, the hole is contracting. After the this point,
the sinkhole is invisible from the surface.
The field observations have shown that the sinkhole is controlled by a fault zone
which is located between the boundary of the two units. The fault at the northwall
of the sinkhole is burried under the 5 meter thick recently deposited sediments. Thes
lickenlines indicates that thefault is strike-slip fault. There are a lot of small scaled
strike slip and normal faults around the sinkhole. Besides these, liquefaction and
neptunian dike structures can be observed in the area. Investigations indicate that
the sinkhole is formed due to solution of carbonate pods and gypsum crystalls by the
groundwater in the crushed and sheared rocks of the fault zone.