Guadalupe Group

The Guadalupe Group (Grupo Guadalupe, K2G, Ksg) is a geological group of the Altiplano Cundiboyacense, Eastern Ranges of the Colombian Andes. The group, a sequence of shales and sandstones, is subdivided into three formations; Arenisca Dura, Plaeners and Arenisca Labor-Tierna, and dates to the Late Cretaceous period; Campanian-Maastrichtian epochs and at its type section has a thickness of 750 m.

Etymology
The group was published in 1978 by Pérez and Salazar and named after its type locality Guadalupe Hill in the Eastern Hills of Bogotá.

Lithologies
The Guadalupe Group is characterised by three formations; two sandstone sequences, Arenisca Dura and Arenisca Labor-Tierna, and an intermediate shale formation; Plaeners.

Stratigraphy and depositional environment
The Guadalupe Group overlies the Conejo Formation in the central part of the Altiplano Cundiboyacense and the Chipaque Formation in the eastern part and is overlain by the Guaduas Formation. Some authors define the Guadalupe Group as a formation and call the individual formations members. The thickness of the Guadalupe Group in its type locality Guadalupe Hill and the El Cable Hill is 750 m. The age has been estimated to be Campanian-Maastrichtian. The Guadalupe Group has been deposited in a marine environment.

Outcrops
The formations of the Guadalupe Group are apart from its type locality at Guadalupe Hill, Bogotá, found in other parts of the Eastern Hills of Bogotá, the Ocetá Páramo and many other locations, such as the Piedras del Tunjo in the Eastern Ranges.

At present, the Guadalupe Group in the anticlinals of Zipaquirá and Nemocón contains rock salt. These halite deposits are not originally deposited in the Late Cretaceous Guadalupe Group, yet are allochthonous diapirs formed when the Jurassic-Lower Cretaceous normal faults were reactivated as reverse faults during the mayor Miocene tectonic movements of the Eastern Ranges. The salt had been deposited during the Early Cretaceous (Valanginian-Barremian, approximately 135 to 125 Ma), intruding into the overlying formations of the Upper Cretaceous.