Geology of Park City

Read about Park City's geology and then scroll down to the worksheet.

Geology of Park City

Geology: The science dealing with the structure of the earth's crust and the formation and development of its various layers: it includes the study of individual rock types and early forms of life found as fossils in rocks. Why was Park City the site of such tremendous quantities of silver, lead and other metals? The answer is in the unique geology beneath our feet. The story is a long and complex interplay of geologic events that spans 100s of millions of years. Let's start with Chapter 1.

Chapter 1: At the Beach

Let us begin the story some 300 million years ago when Park City was almost completely covered by a shallow sea. For millions of years sand, silt, and ocean organisms were collected in great layers in and around this quiet sea. Eventually, these layers were compressed into sedimentary rocks. They were called sandstones, siltstones and limestone and were the rocks that became hosts to Park City bonanza ores containing silver, lead and zinc.

Chapter 2: Throwing up Mountains

For the next 100 million years, a period of great upheaval affected all of the West. Have you heard of continental drift? The earth's crustal plates moved and collided! This caused the building of the Rocky Mountains, of which the Wasatch and Uinta Mountains are a small part. The layers of rock in Park City were uplifted, warped, fractured, and faulted. Some faults, like the Crescent Fault, were displaced over 1,000 feet. But the most significant feature was the huge highly faulted upwarp that formed at Park City. This upwarp, called the Park City anticline, seemed to control the location of the richest ore deposits. Why?

Chapter 3: In Hot Water!

Some 35 million years ago, from deep within the earth came intrusions of molten rock. They are the source of super-heat