General Description
The Mother Lode belt is an orogenic belt including a series of gold and mineral veins found around its region. The main belt extends approximately 190 km from Georgetown, CA to Mariposa CA, as demonstrated in Figure 1. In other words, the belt is found throughout mid-California. The main belt ranges between 1.0-6 km in width throughout its entirety (Mechanical 4). It is most known for its abundance in gold, and is often attributed to the “California Gold Rush”, an 1848-1855 period which attracted roughly 300,000 people to California in search of gold.
Detailed Description
The belt includes a series of smaller faults, called the gold veins. An example of on of these faults is seen in image on the left. It is important to note that this is a representation of one of the these veins, and not the map of an actual one. As is visible in the image, the faults also shows signs of some sinistral and some dextral strike-slip. However, this motion is minimal as the the fault is mainly a reverse dip-slip (Mechanical 4).
Deformation causes
It is thought that the Smartville arc was formed over a east dipping subduction zone during the Jurassic period (Dilek 503). It collided with with North American plate, forming the Mother Lode belt , which explaining the east dip of the faults observed during the Field Trip to the Southern Mother Lode (Mechanical 6). This interpretation is very plausible considering the location and geometry of the belt. When comparing the western edge of the Smartville complex in figures 3 and 4 with the belt in figures 1 and 2, it is possible to deduce from the relative towns on the maps that the two are appear very similar. The collision would have created enough heat energy to force water from to the surface. Once cooled, the water left minerals behind, including the gold that prompted the "Gold Rush".
References
Blanchard, Douglas, Menzies, Martin, and Xenophontos, Costas. "Genesis of the Smartvill Arc-Ophiolite, Sierra Nevada Foothills, California". American Journal of Science. Vol. 280-A, p. 329-344. 1980. Web.
http://earth.geology.yale.edu/~ajs/1980/ajs_280A_1.pdf/329.pdf
Cloos, Ernst. “Mother Lode and Sierra Nevada Batholith”. The Journal of Geology. Vol. 43, No. 3, p. 225-249. Web.
http://www.jstor.org/stable/30056249?seq=4#page_scan_tab_contents
Dilek, Yildirim. “Tectonic Significance of Post-Accretion Rifting of a Mesozoic Island-Arc Terrane in the Northern Sierra Nevada, California”. The Journal of Geology. July 1989. Vol. 97. P. 503-518. Web.
http://www.jstor.org/stable/30078353?Search=yes&resultItemClick=true&searchText=smartville&searchText=block&searchUri=%2Faction%2FdoBasicSearch%3FQuery%3Dsmartville%2Bblock%26amp%3Bacc%3Don%26amp%3Bwc%3Don%26amp%3Bfc%3Doff%26amp%3Bgroup%3Dnone&seq=1#page_scan_tab_contents
Knopf, Adolph. “Mother Lode System of California”. U.S. Geol. Surv. Prof. Pap. 157, 88pp. Web.
http://pubs.usgs.gov/pp/0157/report.pdf