BH250-70
Title
BH250-70
Subject
Sandstone
Description
Major Mineral: quartz
Minor Minerals: calcite, plagioclase
Mineralogy Comments: calcite cement, traces of plagioclase
The Little Elk Creek Trail in South Dakota is located in the Black Hills region, just west of Rapid City. This area is geologically significant, exposing a diverse suite of rock units that range from the Precambrian basement to younger Paleozoic sedimentary rocks. The trail provides an excellent outdoor classroom for geology students.
We use the outcrops along this trail to teach students how to measure strike and dip, and how systematic changes in these measurements reveal the presence of a monocline. While doing so, we also examine and discuss several key rock units exposed along the trail.
These include:
The Precambrian basement rocks (core of the Black Hills), represented by sample BH250-202
The Deadwood Sandstone BH250-69 (Cambrian–Ordovician)
The Minnelusa Sandstone BH250-70 (Pennsylvanian–Permian), represented by sample BH250-70
The Minnelusa Sandstone at this location is calcite-cemented and composed of angular to sub-rounded quartz grains, indicating a different depositional environment compared to the more mature and well-rounded quartz grains of the Deadwood Formation.
For more information see, BH250 – Sandstone Overview with Petrographic Notes
Minor Minerals: calcite, plagioclase
Mineralogy Comments: calcite cement, traces of plagioclase
The Little Elk Creek Trail in South Dakota is located in the Black Hills region, just west of Rapid City. This area is geologically significant, exposing a diverse suite of rock units that range from the Precambrian basement to younger Paleozoic sedimentary rocks. The trail provides an excellent outdoor classroom for geology students.
We use the outcrops along this trail to teach students how to measure strike and dip, and how systematic changes in these measurements reveal the presence of a monocline. While doing so, we also examine and discuss several key rock units exposed along the trail.
These include:
The Precambrian basement rocks (core of the Black Hills), represented by sample BH250-202
The Deadwood Sandstone BH250-69 (Cambrian–Ordovician)
The Minnelusa Sandstone BH250-70 (Pennsylvanian–Permian), represented by sample BH250-70
The Minnelusa Sandstone at this location is calcite-cemented and composed of angular to sub-rounded quartz grains, indicating a different depositional environment compared to the more mature and well-rounded quartz grains of the Deadwood Formation.
For more information see, BH250 – Sandstone Overview with Petrographic Notes
Coverage
Location: Upper Black Hills, South Dakota, USA
GPS Coordinates: 44°14'19.87"N, 103°26'20.54"W
GPS Coordinates: 44°14'19.87"N, 103°26'20.54"W
Creator
Bereket Haileab
Source
From the rock collection of Bereket Haileab. Sample 70. Housed at Carleton College in Minnesota.
Type
Thin section and hand sample
Relation
Collection
Citation
Bereket Haileab, “BH250-70,” BH250 Mineralogy Teaching Collection, accessed April 25, 2026, https://bereket-haileab.geology.sites.carleton.edu/items/show/80.