San Gabriel Mountains to become National MonumentNorth of downtown Los Angeles, there are a few smal

San Gabriel Mountains to become National MonumentNorth of downtown Los Angeles, there are a few small ranges of hills and mountains, including the Hollywood Hills and the Verdugo Hills, pushed up by faults that sit beneath the city. Then, there is another valley; the San Fernando/San Gabriel Valley depending on the location, and then a much larger mountain range, captured here in the winter with snow-covered peaks; the San Gabriel Mountains.The San Gabriels are a fascinating area geologically. The southern edge of the San Gabes is bounded by the San Gabriel Fault, a nearly extinct strike-slip fault that accommodated hundreds of kilometers of motion. The San Gabriel Fault in fact once was the plate boundary between North America and the Pacific Plate. When the San Gabriel fault slowed down, that motion jumped to the fault that sits on the North Side of these mountains; the San Andreas fault.The San Gabriel Mountains are a large pile of sedimentary and metamorphic rocks that once sat farther south along the Pacific Coastline. The work of these two strike-slip faults brought it north to where the mountains sit today, and the orientation of them (along the big bend in the San Andreas) is causing the mountains to shoot upwards at an incredible rate.There are marine sediments in the San Gabriels only a couple million years old. These mountains were literally beneath the ocean a couple million years ago; today they tower over the Los Angeles Basin. The highest peak in the range, Mount San Antonio, is over 3000 meters (over 10,000 feet) above sea level. Its most famous peak may be Mount Wilson, home to the Mount Wilson Observatory where Edwin Hubble was able to determine that strange fuzzy features in the night sky like Andromeda were actually other galaxies separate from the Milky Way.This mountain range serves as the backdrop and as a recreation area for the city of Los Angeles. Hiking, skiing, camping, and even a home for many of the LA Basin’s communications towers can be found within the San Gabriels.Prior to today, some portions of the San Gabriels had limited protection as National Forest or as local recreation areas, but today that will change. Using the power of the Antiquities Act, President Obama is going to set aside 346,000 acres of the this territory as the San Gabriel Mountains National Monument, a much stronger designation and one only really superseded by a full national park.15 million people live within an hour or two of this area, making it one of the most accessible National Monuments in the country. It is home to a variety of animals, including bighorn sheep, mountain lions, bears, and the spotted owl. This designation follows an ~10 year study period on the impacts of declaring a national monument in the area on the property rights and other resources in the area. Designations like this are always controversial for some people, but in most cases, the long-term benefits, both economically and culturally, are huge, and I applaud this step as it happens today.-JBBImage credit: US Forest Servicehttps://www.flickr.com/photos/usfsregion5/3699427354Read more:http://www.washingtonpost.com/politics/obama-to-designate-san-gabriel-mountains-as-a-national-monument/2014/10/08/d1abdb74-4e2b-11e4-babe-e91da079cb8a_story.html -- source link

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