Newporte
Key facts
- Country
- United States
- Diameter
- 3.2 km
- Age
- less than about 500 million years
- Location
- 48.97° N, 101.97° W
Nothing: the structure lies about 3 km underground, beneath the prairie of Renville County, North Dakota, close to the Canadian border.
Newporte is a buried impact structure about 3.2 km across in Renville County, North Dakota, in the United States, close to the border with Canada.
Discovery. The structure was found by oil exploration. In the 1970s an oil field was discovered here, and further drilling and seismic surveys showed that the oil was held in a round structure of disturbed rock, with a raised rim and a depressed centre. In the 1990s, study of cores from the wells found shocked quartz, confirming that it was an impact crater.
What it hit. The impactor struck the edge of a sedimentary basin, where thin Cambrian sandstones lay directly on Precambrian granite and gneiss. The crater was soon buried by younger sediments of the Williston Basin, and today it lies about 3 km underground.
Age. The youngest rocks affected are Cambrian or Ordovician, so the impact happened in the early Palaeozoic, roughly 500 million years ago or a little later. Its exact age is unknown.
Oil. Oil has been produced from broken rock in the crater rim, which acts as a reservoir.
Why it matters. Newporte is one of several impact structures in the Williston Basin that have produced oil, showing how impacts can create traps for hydrocarbons. The impactor is unknown.
Did you know?
Newporte was found because oil wells were drilled into it.
It lies about 3 km underground.
Oil has been produced from broken rock in the crater rim.