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Identification and Potential of Newly Emerging Geoheritage Karst Areas South of Hanzhong, Central China

Publication at Faculty of Science |
2022

Abstract

Four new promising karst areas were identified south of Hanzhong City, Shaanxi Province, via a detailed study of satellite and UAV images followed by field reconnaissance and documentation. The areas were named after the counties in which they occur: Ningqiang, Nanzheng, Xixiang and Zhenba.

Now, the whole region is known under the collective name Hanzhong Tiankeng Group. The Nanzheng karst area was documented in more detail, including water and solid-phase characteristics using water tracing, inductively coupled plasma emission spectrometry, X-ray diffraction analyses and micro-Raman spectroscopy, respectively.

Based on the synthesis of data from Nanzheng and findings from other areas, the following most important discoveries/knowledge was collected: Over 50 collapse dolines were discovered, a number which meets the definition for tiankengs. The Quanziya Tiankeng (520 m long, 310 m wide and up to 320 m deep) is the largest in central and northern China as yet discovered.

More than 20 caves were discovered, some with large underground spaces and the potential for tens of kilometres in length. The as yet longest cave is the Tianxingyan Cave, 12.9 km long.

This cave consists of a huge corridor with several big halls (two of them exceed 200 m in length, 100 m in width and 70 m in height) and several side passages of different ages and characters. Water analyses and tracing tests helped with the orientation among the disseminated karst features and point to the existence of several large underground drainage systems.

Solid phase identification revealed an interesting Sr-rich mineral association in the caves. Together with preliminary findings in other scientific fields, the Hanzhong Tiankeng Group offers a great potential for karstological, palaeontological and archaeological studies, and also has a great touristic potential.