HU3 - Bauxite deposits of the Vértes Hills, Hungary

Leader: Andrea Mindszenty (Eötvös L. University, Budapest,

Practical information:
  • Duration: 1 day (8 AM - 5 PM)
  • Mid-conference: 24.08.2010, Budapest (HU) - Budapest (HU)
  • Length: 150 km
  • Min. number of participants: 5
  • Max. number of participants: 30
  • Field trip registration fee
    • Student/young scientist: EUR 15
    • Normal: EUR 30
  • Meals cost: included in the registration fee
  • Demands: 2-3 km easy walk on dirt roads and in the former open pit, normal field trip equipment is recommended.
  • Means of transport: bus / van
  • Accommodation: None
Full technical details in PDF format
Photo: Thin section photograph of gravelly bauxite (scale 2mm), Gánt (HU)
Thin section photograph of gravelly bauxite (scale 2mm), Gánt (HU)

Scientific focus (keywords): bauxite sedimentology; tectonics; palaeohydrology; diagenetic alteration; mining heritage

Photo: Preserved fault plane (~N-S strike) in the former Bagolyhegy open pit, Gánt (HU) Karst bauxites occurring at a major regional unconformity between late Triassic dolomites and late Middle Eocene marly limestones are exposed in several old abandoned quarries close to the village of Gánt. The most spectacular open-pit, called Bagolyhegy, was converted into a Geological Park where visitors may have an insight into the details of karst bauxite geology. Aside the open-pit there is a little museum displaying the history of bauxite mining in the area giving an overview of the techniques of open-cast and underground mining as well. The age of the bauxite is Eocene. Subaerial exposure resulting in uplift and tectonically controlled erosion of the uplifted terrain was related to Eoalpine deformation having affected the area of the Vértes Hills in Late Cretaceous to Eocene times. The bauxite is supposed to have been deposited as a muddy debris-flow on the low-level karst terrain. Major mineral phases identified in the Gánt bauxite are: boehmite, gibbsite, kaolinite, hematite, goethite and anatase. From the micromineralogical fraction staurolite, kyanite, garnet, volcanogenic zircon, ilmenite, metamorphic rock fragments and the ultrastables (routile, zorcon, tourmaline) were described. The bauxite fills the uneven karst topography of a highly brecciated Triassic dolomite and is covered by a distinct non-bauxitic paleosoil immediately overlain by the transgressive Eocene cover-sequence rich in fossils. The most spectacular phenomenon to be observed at Gánt is the relationship of bauxites and tectonics displayed by several well-exposed fault-planes including a system of relay-ramps developed in association with en-echelon strike-slip faults having affected the deposit in post-Eocene times. On the fault planes the effects of weathering and karstification on the exposed brecciated dolomite surface can also be studied in details.
Preserved fault plane (~N-S strike) in the former Bagolyhegy open pit, Gánt (HU)

Daily programme:

Budapest, Eötvös University: departure 8 AM - Gánt: Bagolyhegy Geological Park, former bauxite open pit - Budapest, Eötvös University: arrival 5 PM

On-line registration >>

Map of the field trip with the key locations (or download Kml file for Google Earth):

View HU3 Bauxite deposits of the Vértes Hills, Hungary in a larger map