MOTHER LODE 80 Western W 50 Metamorphic Belt
Excerpt from Geologic Trips, Sierra Nevada by Ted Konigsmark ISBN 0-9661316-5-7 GeoPress All rights reserved. No part ofthis book may be reproduced without written permission, except for critical articles or reviews. For other geologic trips see: www.geologictrips.com 190 - Auburn Trip 6. THE MOTHER LODE 80 Western W 50 Metamorphic Belt Placerville M Mother Lode 50 M Melones fault W W Gr Granitic rocks 49 88 Plymouth 10 Miles Jackson 4 88 Gr San Andreas 108 12 Columbia 4 Sonora Coloma Placerville 120 120 Jackson 49 Mokelumne Hill Mariposa Angels Camp r Caves ive 132 d R rce Columbia Me Table Mountain 140 Melones Fault Mariposa The Placer County Department of Museums operates six museums that cover different aspects of Placer County’s gold mining activity. For information, contact Placer County Museums, 101 Maple St., Auburn, CA 95603 (530-889-6500). - 191 Trip 6 THE MOTHER LODE The Gold Rush This trip begins in Coloma, on the bank of the South Fork of the American River, where the gold rush began. From there, the trip follows Highway 49 to Mariposa, passing through the heart of the Mother Lode. As the highway makes it way along the Mother Lode, it closely follows the Melones fault, weaving from side to side, but seldom leaving the fault for long. The Melones fault is one of the major faults within the Western Metamorphic Belt, and fluids generated in the deep parts of the Franciscan subduction zone left deposits of gold in the shattered and broken rocks along the fault. Most of the large gold mines of the Mother Lode lie within a mile or so of the fault, and Highway 49 follows the gold mines.