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By Dan Sharp for the Tribune

It has taken more than one-half billion years for the Williston Basin to accrue its energy wealth.

Aside from the discovery of oil in 1951, two widely separate events stand out among many in the history of western North Dakota’s Williston Basin. The most recent, of course, is Lewis & Clark’s traverse of the area 200 years ago. When the troop returned to Missouri in 1806, the public went wild with excitement about how the party had reached the Pacific. Their stories made all the papers.

The first event, though, did not get any press at all. It happened 200 million years ago at a location just 15 miles southwest of what is now Watford City. That is when a meteorite hit the earth

and created the 5.6-mile-wide Red Wing Creek Crater that would eventually prove to be one of the Williston Basin’s most productive oil fields. Some scientists believe the impact was due to one of several meteorites that struck that very day, in present-day Canada, France and Ukraine, from a disintegrating asteroid. It is just a single event in the Williston Basin’s fascinating geologic history.

Three miles thick Geologists will tell you that the Williston Basin is a textbook example of a sedimentary and structural basin. It began forming some two billion years

ago during the Precambrian Era of geologic history. At the time, the earth’s surface was devoid of plant life. Microscopic organisms were just beginning to take hold in its seas. The rock record shows us the Precambrian climate was much warmer than today’s due to the atmosphere’s high carbon dioxide content, which produced a much stronger greenhouse effect. Eventually, the atmospheric carbon dioxide would become the hard parts of future primitive sea creatures and later a raw material for some common Williston Basin rock units.

As the millennia passed, crustal instability within the Precambrian rocks gradually caused a weak zone to develop, and sometime about a half billion years ago the zone that was to become the Williston Basin began to fill in with sediments that were eroding from North America’s core region to the northeast. The equator was situated almost directly over the young basin, the eastern edge of which would roughly divide present-day North Dakota in half. As more and more sediments accumulated, the basin

deepened – literally a self-fulfilling process that led to more sediment buildup.

In everyday terms, the Williston Basin seems a bit of a misnomer because North Dakota’s highest elevations lie as cap rocks directly above it – how could that be a basin? To the casual observer, the basin is nearly completely undetectable. The structure declines or “dips” just a degree or two to reach a maximum depth of about 16,000 feet in the Williston area. That is about a three-mile thickness of sediments. The basin underlies about 300,000 square miles – a little larger than Texas. Keep in mind, North Dakota shares the Williston Basin with Montana, South Dakota and Canada – each of which reaps resources from the basin’s rock units.

Eighteen North Dakota counties produce oil and/or natural gas from Williston Basin rock units. When plotted on a map, dozens of producing fields and thousands of well locations look like a well used dart board with holes concentrated in some high-score spots.

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