@inproceedings{Sponholz1993,
  author    = {Sponholz, Barbara},
  title     = {Holocene fulgurite formation in the southern Central Sahara (Niger)},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-56584},
  year      = {1993},
  abstract  = {Fulgurites (= natural glasses formed by lightning strikes to the ground) are indicators of thunderstorms (e.g. Julien 1901). The distribution pattern of fulgurites in the study area (Grand Erg de Bilma and Erg de Tenere between 11.5°E and 16.5° and 18.5°N) shows decreasing fulgurite concentration from south to north. The fulgurite sites are concentrated in the area of fossil dune complexes, where they occur topographically above palaeolimnic deposits in mid-slope position of interdune depressions.},
  subject      = {Geographie},
  language  = {en}
}
@article{SponholzBaumhauerFelixHennignsen1993,
  author    = {Sponholz, Barbara and Baumhauer, Roland and Felix-Hennignsen, P.},
  title     = {Fulgurites in the southern central Sahara, Republic of Niger and their palaeoenvironmental significance},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-63337},
  year      = {1993},
  abstract  = {The mineralogical and chemical characteristics of fulgurites ( = natural glasses forrned by lightning strikes to the ground) from the southern Centrat Sahara (Niger) are presented. The fulgurites are indicators of thunderstorms. The northernmost important fulgurite formation in the study area reached up to about l8°N, with decreasing fulgurite concentration from south to north. Their distribution pattern and the relative dating of their formation in relation to Iandscape history from the Late Pleistocene onwards (e.g., palaeolakes, palaeosols), and to Neolithic settlement reveals their value as palaeoenvironmental indicators. They indicate: (1) local palaeoenvironmental conditions depending on the topographical situation in a complex dune relief; (2) climatic change during the mid-Holocene from northerly rains to southerly rains; and (3) the northernmost Iimit of important thunderstorrns and rainfall activity since this time in the southern Centrat Sahara.},
  subject      = {Sahara},
  language  = {en}
}