State by State
- Specimen Number
Rounded boulder of rust-stained quartzite with original cross-bedding plainly visible.
- Location & Occurrence
Likely from northeast Kansas, transported here by ice sheets from the glaciated north. Identified by survey staff as Sioux Quartzite, an Early Protorozoic metamorphic sandstone. Alphabetically, this is the first state stone that is ex situ, meaning having originated from somewhere else, as opposed to in situ, meaning having been sampled in place from crustal rock. The specimen from North Dakota is also ex situ.
- Geological Age
Early Protorozoic source rock, dating between 1760 add 1630 Ma. Glacial emplacement ~600,000 years ago (ka).
Kansas is covered by young sedimentary rocks, but its streams and terraces contain ancient boulders and cobbles from the Cordillera, and it's northeastern corner was glaciated at least twice, first about 600,000 years ago.