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Volume 47, Issue 3 (2018)

Hypogene Karstification

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Spar caves as fossil hydrothermal systems: Timing and origin of ore deposits in the Delaware Basin and Guadalupe Mountains, New Mexico and Texas, USA
David D. Decker, Victor J. Polyak, and Yemane Asmerom

  • Spar caves and cave spar form at a spar horizon
  • The depth and temperature of the spar horizon is 500 ± 250 m and 40 to 80°C
  • This temperature overlaps hydrothermal ore deposition and oil maturation temperature
  • Evidence for geothermal systems erodes away, spar caves provide evidence of existence
  • Spar caves may help to locate hydrothermal ore deposits

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New insights on secondary minerals from Italian sulfuric acid caves
Ilenia M. D'Angeli, Cristina Carbone, Maria Nagostinis, Mario Parise, Marco Vattano, Giuliana Madonia, and Jo De Waele

  • Detailed description of fifteen sulfuric acid cave systems of Italy from mineralogical point of view
  • XRD and SEM investigation of yellowish and whitish deposits abundantly present in those SAS underground environments
  • Finding of 59 minerals strictly related to sulfuric acid speleogenesis
  • Interesting association of alunite-jarosite deposits with Ti-rich minerals and phosphates
  • Identification of hydrothemal hypogene origin through the study of geochemical signatures

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Unconfined hypogene evaporite karst: West Texas and southeastern New Mexico, USA
Kevin W. Stafford, Jon T. Ehrhart, Adam F. Majzoub, Jessica M. Shields, and Wesley A. Brown

  • Hypergene and hypogene processes have created a complex speleogenetic history for the Delaware Basin
  • Unconfined hypogene evaporite karst occurs as artesian-like discharge features and venting structures within the Delaware Basin
  • Electrical resistivity analyses coupled with field excavations confirm speleogenetic models based on surficial manifestations
  • Diverse evaporite karst manifestations create complex geohazards within the Delaware Basin

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Old and recent processes in a warm and humid desert hypogene cave: ‘A’rak Na‘asane, Israel
Amos Frumkin, Shlomi Aharon, Uri Davidovich, Boaz Langford, Yoav Negev, Micka Ullman, Anton Vaks, Shemesh Ya‘aran, and Boaz Zissu

  • A desert relict hypogene cave can support high humidity
  • Intensive condensation corrosion by air convection
  • The humid, warm environment supports specific ecosystem
  • The humid, warm environment unfavors human use

Siliciclastic Karst

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Evidence for subsurface origin of boulder caves, roofed slots and boulder-filled canyons (Broumov Highland, Czechia)
Filip Duszyński, Kacper Jancewicz, and Piotr Migoń

  • Extensive boulder fills of canyon floors interpreted as residual materials
  • Subsidence into voids the likely process of origin of boulder fills, not rock fall
  • Boulders caves in canyons are not talus caves
  • Roofed slots provide analogy to explain larger landforms
  • Geomorphometry assists in characterizing geomorphic diversity of canyons

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On biospeleothems from a Venezuelan tepui cave: U-Th dating, growth rates, and morphology
Joyce Lundberg, Charles Brewer-Carías, and Donald A. McFarlane

  • Seven silica biospeleothems have been U-Th dated
  • Growth rates are generally extremely slow
  • Growth rates are higher closer to water level
  • Detrital bands correlate with cooler, drier times of the Late Quaternary
  • Secondary alteration may compromise dates