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- Kaufmann, G., Romanov, D., and Nielbock, R.
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Cave detection using multi-geophysical methods:
- The Unicorn Cave, Harz Mountains, Germany
- Geophysics, 76(3), B71-B77, 2011.
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65. |
Cave
detection using multi-geophysical methods: The Unicorn Cave, Harz
Mountains, Germany |
Georg
Kaufmann1, Douchko Romanov1 Ralf
Nielbock2 |
1Institute
of Geological Sciences, Free University Berlin, 12249 Berlin,
Germany
2Gesellschaft Unicornu fossile eV, Im Strange 12, 37520
Osterode am Harz, Germany |
Geophysics,
76(3), B71-B77, 2011. |
Unicorn cave in the
southern Harz Mountains of Germany is a show cave in dolomitic rocks
of the Zechstein Formation. The cave¿s trunk passage is interrupted
by larger rooms. The overburden is only around 15 m. The passages
are filled with sediments that can be up to 50 m thick. We used
gravimetry and electrical resistivity imaging over the cave area to
identify the subsurface voids and the extent of the sediment infill
of the cave passages. Our choice of methods was based on several
conditions unique to the cave: (1) well surveyed, (2) shallow
overburden, (3) large air-filled passages, and (4) thick sediment
cover, concealing true passage size. Using the cave survey as an
initial model for the subsurface structure, we successfully
identified the air-filled cave with both methods. We then inferred
the thickness of the sediment infill by forward modeling and
identified a possible southward continuation beyond the currently
explored passages.
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