A Geoscience Digital Image Library

TitleGranitic needle and two rock climbers, Black Hills, South Dakota
DescriptionThe core of the Black Hills is composed of 1.7 billion year old granite that intruded a Pre-Cambrian schist. The tough Harney Peak Granite has resisted weathering and is exposed in many places. It forms Mt. Rushmore, other (uncarved) domes and in some places has weathered into spectacular spires and needles which are partly a result of how it intruded and partly due to weathering. Some of the most accessible needles are in Custer State Park, along the Needles Highway, just east of Custer, South Dakota, where his photo was taken.
LithostratigraphyHarney Peak Granite
Geologic provinceBlack Hills
LocationUSA ▹ South Dakota ▹ Pennington. Near Rapid City. Custer State Park.
PhotographerDexter Perkins. 1969.
Key wordsgranite, Black Hills, South Dakota, stock, weathering
Tech details515 KB. Vista. Canon A1, Agfachrome 100.
GeoDIL number2394