California's Gold Rush hardly seems a fitting history to tell unless we start from the beginning, when the gold itself rushed in to California. The term rushed is used rather loosely here to describe a time frame of some 400 million years. A number that plays a wonderful juxtaposition to the frantic pace of Marshall finding gold in 1848 to the Sawyer court decision ending hydraulic mining tailings (legally) in 1884.
Beginning roughly 400 million years ago and for over 200 million years much of California was being formed. Plate tectonics were slowly spreading the ocean floor until it subducted (sank) below the continent of North America. During this process parts of the ocean floor, some carrying gold placed by underwater volcanism, accreted (accumulated) onto the North American landmass. Around 160 million years ago the docking of Smartville, a gold rich island arc, created much of what is today know as California's Mother Lode.
Not long after, a mere 20 million years, an event known as the Nevadan Orogeny (a term for mountain building) over a span of 40 million years created and pushed up the Sierra Nevada Batholith (a giant complex of granite), and with it veins of quartz and gold. Then the mountains began to erode, and for up to 80 million years the gold was slowly concentrated and deposited downstream in gravel beds along the Sierra foothills. These ancient gravel beds richly laced with gold, were then cut into by modern rivers such as the American and Feather exposing the gold for the North American settlers to discover.
It is this unique geologic history that made the Gold Rush possible. Most of our planet does not contain the quantity of highly consolidated gold that made California the hot spot it became. These gold rich gravel beds are responsible not only for the influx of people to the California coastline but also for a host of breakthroughs in technology engineered for the specific needs of extracting the gold from the often hard to reach places. Check back again for more on the people and technological advances of the California Gold Rush.