Geology and Man, Page 1 : 無料・フリー素材/写真
Geology and Man, Page 1 / darthjenni
| ライセンス | クリエイティブ・コモンズ 表示 2.1 |
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| 説明 | This is your guide through some of the most fascinating landscape in Joshua Tree National Monument.The Numbers appearing the left margin correspond with numbered markers along the tour route.Mileage starts at the intersection of the Geology Tour Road and the main Monument road. The 16 Stops along the 18-mile tour will require approximately two hours and will return you to this point.Please help us protect and maintain this natural environment so that others may benefit from it as you have.GEOLOGY AND THE MONUMENT. The face of the earth is not fixed or unchanging, but represents only a fleeting phase of a very long history. Significant changes are now going on all around us and we are able to understand present-day aspects of the earth only by a knowledge of the changes in the past.The science which deals with these changes is called geology. More precisely, geology may be defined as the study of the history of the earth as revealed in the rocks and sediments.This tour will aid you in understanding the desert landscape and forces which have created it, thereby strengthening your appreciation of the natural environment.The area encompassed by Joshua Tree National Monument has been restless for than 800 million years. Geologic maps of California indicate that perhaps as many as ten different times the Monument area sank below sea level and was covered by marine water. Things as they stand today are the result of erratic uplifting of the surface rock; its subsequent erosion now exposes much of the younger rock which had pushed its way up into the older rock types. We therefore have the opportunity to see very old rocks, intruded by younger ones. All of these have been subsequently fractured and jointed by regional crustal disturbances resulting in the earthquakes so often felt in southern California.1) 0.4 Mi. WHY A VALLEY. Mountain-rimmed Queen Valley (elevation 4,450 feet) is one of two types of valleys to be found along the tour. This and Lost Horse Valley (to the west) are formed by a difference the the rate of erosion between the rock underlying the valley itself and the rock composing the surrounding mountains.The rock making up those areas which are now valleys itself is generally less resistant to erosion than the rock forming the surrounding mountain and disintegrates sooner to form a low-lying plain (or "valley").Pleasant Valley, seen later on the tour, is the result of faulting and consequent uplift and subsidence. |
| 撮影日 | 2013-07-10 11:52:11 |
| 撮影者 | darthjenni |
| タグ | |
| 撮影地 | California, United States 地図 |
| カメラ | Artisan 730 , SEIKO EPSON CORP. |