USA, Colorado:

Drilling for Electricity, Part Five - A Personal Perspective on the Pagosa Springs Geothermal Project (Pagosa Daily Post)

According to Wikipedia, Dakota Formation rocks “lie unconformably atop Paleozoic and Precambrian rocks, and are the oldest Cretaceous rocks in the northern Great Plains, including Kansas, Nebraska, Iowa, Minnesota, and Wisconsin. It consists of sandy, shallow-marine deposits with intermittent mud flat sediments, and occasional stream deposits. The Dakota Formation is an important aquifer in some areas of the Great Plains.”

I was intrigued by a comment made by Colorado Geological Survey geologist (and GRC Member) Paul Morgan during our visit to the Pagosa Verde drilling site. He mentioned the “nonconformity” of the geology underlying much of the Rocky Mountains. As I understand the geology (from Mr. Morgan’s brief summary) the Pagosa Verde core samples are likely going to include Entrada Sandstone (dated at maybe 180 million years ago) and then are going to skip a billion years of geologic history and start drilling into Precambrian rock — which the geologists date at maybe 1,400 million years old. That’s jump of a billion years.

Which might raise the question, where did a billion years worth of solid rock disappear to?

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Part One......       Part Two.....             Part Three......                Part Four......