Formation

Dolines are widespread, and have a variety of names, including swallow-hole, swallet and sinkhole (Goudie, 1990). The term doline is derived from the Slavic word dolina, is largely used by European geomorphologists (Gutierrez et al., 2014). Sinkhole is most frequently used by North American geomorphologists and in the international literature dealing with engineering and environmental issues (Gutierrez et al., 2014).  For these articles we shall be referring to them as dolines. There shapes are conelike karst hollow forms with diameters ranging from a few metres to 100 metres wide, up to 10 metres deep or even greater  (Bonacci, 1987). There formation is frequently within karst landscapes. Karst landscapes are landscapes that show irregularities in surface rock form by rock dissolution (Freeze & Cherry, 1979).  Pueyo-Anchuela et al. (2010) describes the development of dolines through the dissolution of underlying evaporites. The distribution of dolines is that they are often in groups situated along lines of faults (Bonacci, 1987). Gutierrez et al., (2014) discusses that dolines display a wide range of morphologies (cylindrical, conical, bowl- or pan-shaped) and vary in size. Evolution of dolines depend on the velocity of the solution process, related to the minerals involved such as gypsum (Salvany, 2009) & the mechanical behaviour of the alluvial Quaternary cover (Pueyo-Anchuela et al., 2010).

Dolines occur in different forms such as subsidence doline and collapsed dolines (Goudie, 1990). Below is a diagram of three types of dolines. Please note collapsed dolines are sometimes more reported within the media. These images are from the USGS (2014).

Dissolution dolines:

The figure also gives a description on how they occur.

Figure 1: A dissolution doline (USGS, 2014)

Cover-subsidence sinkholes are the ones that most frequently take longer to be located. The USGS (2014) stated they tend to develop gradually where the covering sediments are permeable and contain sand. These cover materials may be thicker and tend to take longer to detect. Below in figure 2 it can be seen these processes and how they progress through the stages.

Figure 2:Cover-Subsidence Sinkhole (USGS,2014)

Cover-collapse sinkholes may develop abruptly and can cause large amounts of damage (USGS, 2014). Occur where covering sediments have large amounts of clay and overtime when it collapses creates a bowl-shaped depression (USGS, 2014). Figure 3 demonstrates the development of a cover-collapse sinkhole.

Figure 3: Cover-Collapse Sink Hole (USGS,2014)

Whilst in figure 4 it can show you a cover-collapse sinkhole within an urban environment such as the Guatemala sinkhole within 2010.

Figure  4: Sinkhole Guatamala (Kval,2014)

The video below represents a doline in the collapse phase within the natural environment.

The image below is of the video above it is adapted to potentially suggest the type of doling that occurs at this location.

The doline discussed above is potentially a solution doline which is connected to an underlying cave with the formation of a freshwater lake above. This doline created many hazards to the surrounding area due to previous land uses around the surrounding area. This is something to consider when reviewing doline formation in the sense what other factors could contribute or exacerbate the effects of these doline.

Dolines can also be modelled to try predicting the effects of dolines in specific areas (Kaufmann, 2014). This modelling can also be formed from looking at evidence from Holocene evidence that investigates dolines (Evelpdou et al., 2011). In comparison to modelling, some studies have attempted to assess the distribution of doline detection with cluster analysis (Shim et al., 2010). This modelling is largely very successful for the distributed detection.