UPPER TRUCKEE RIVER<br />I live directly across the street from the Upper Truckee River. I simply walked across the street and found a treasure trove of geological evidence. Here is what I observed.<br />
UPPER TRUCKEE RIVER<br />The push pin represents where I did my field trip. Hwy 50 is the road running vertical.<br />
HISTORY<br />The main rocks identified within the area are granitic rocks and glacial deposits. Other rocks, that are much less extensive are pluvial and alluvial deposits, volcanic rock, and metamorphic rock. (Tahoe Regional Planning Agency and U.S. Forest Service, 1971, plate)<br />The geology of the area can be characterized by lake and glacial deposits at lower altitudes, flatlands, and low-lying hills. Also, by granitic rocks that make up the steep and high mountain slopes and peaks. The only volcanic rocks within the area are in the extreme headwaters of the Upper Truckee River. The only metamorphic rocks are two small areas above Echo Lake and two small areas in the low-lying hill between the City of South Lake Tahoe and Fallen Leaf Lake. Lake deposits are evident in a few high-mountain meadows and along the lower stream channels in the Upper Truckee River and Trout Creek. (Tahoe Regional Planning Agency and U.S. Forest Service, 1971, plate)<br />Landforms of the area were primarily shaped from tectonic and glacial processes. A combination of basin-and-range style fault-bounded blocks, as well as glacial erosion and deposition, resulted in the formation of the present-day landforms. Four periods of major glaciation shaped these landforms. (Tahoe Regional Planning Agency and U.S. Forest Service, 1971, plate)<br />The major landforms attributed to glaciation are deep basin-fill deposits, steep mountain slopes adjacent to the topmost reaches of the Upper Truckee River and Trout Creek, and large lateral moraines that divide the Trout Creek from the Upper Truckee River and the Upper Truckee River from Fallen Leaf Lake. (Tahoe Regional Planning Agency and U.S. Forest Service, 1971, plate)<br />The basin-fill deposits within the area are comprised entirely of lake, stream, and glacial deposits. Also, the underlying basement rock is assumed to be entirely granitic. Thicknesses of the basin-fill deposits in the South Lake Tahoe area near Lake Tahoe may be as great as 1,600 - 1,900 ft (Blum, 1979).<br />
Rocks<br />These igneous and sedimentary rocks are laying all together near the shoreline of the Truckee River.<br />
Rocks<br /><ul><li>This sample is smoothed from being tumbled in the river.
It is grey with bands of lighter and darker grey as well as bands of red-orange.
The entire shoreline and river is littered with this rock.</li></li></ul><li>Rocks <br /><ul><li>I believe that this is serpentine rock
It is dark green with black crack lines all the way through.
It is smooth from being tumbled in the river.</li></li></ul><li>Flora and Fauna<br />The above picture (although not very clear) is of Cliff Swallow’s nests located under the bridge that crosses over the Truckee River. I discovered that although very prevalent to the area, they aren’t as easy to snap a picture of as I thought!<br />
Sierra Lupin<br /><ul><li>Beautiful, dark purple multi flowerets with velvety silvery-green leaves.
Species Lupinus grayi (S. Watson) S. Watson – Sierra lupine</li></ul>(USDA Natural Resources Conservation)plants.usda.gov<br />
Sierra Lupin (Cont.’d)<br />The oldest unambiguous angiosperm fossil extends back at least to the early Cretaceous, conservatively around 132 million years ago (Crane et al., 2004).<br />Lupinus comprises c. 280 annual and perennial species. The majority of species occur in the New World, with two main centers of species diversity in western North America (c. 100 species) and the Andes (c. 85 species). (Ruth J. Eastwood, et al.)<br />
Cliff Swallows<br />Petrochelidonpyrrhonota<br /> <br />Cliff Swallow Range Map<br />12<br />(Cornell Lab of Orintholgy)<br />
Cliff Swallows (Cont.’d)<br />Small, long-winged stocky songbird. <br />Small bill.<br />Wings are long and pointed. (“dart”-like)<br />They have a dark throat.<br />Their tail is square.<br />Their backside is pale.<br />The nest is a covered bowl made of mud pellets, with a small entrance tunnel on one side. Typically lined with grass. Nests are placed on a vertical wall, usually just under an overhang. These birds form colonies. (Brown, C. R., and M. B. Brown. 1995. Cliff Swallow (Hirundopyrrhonota). In The Birds of North America, No. 149 (A. Poole and F. Gill, eds.). The Academy of Natural Sciences, Philadelphia, PA, and The American Ornithologists' Union, Washington, D.C.)<br />They are insectivorous and an important part of the summer ecology in Lake Tahoe.<br />Unknown as to when they first presented in Lake Tahoe, but they are a common perch-bird across the country.<br />
Cliff Swallows (Cont.’d)<br />The original nesting sites of cliff swallows were cliffs and walls of canyons. Man's structures (e.g., buildings, bridges, overpasses) and agricultural activities (e.g., irrigation, canals, reservoirs) have increased the number and distribution of suitable nesting sites and cliff swallow populations have increased accordingly. Historically, cliff swallows were presumed to be most common in the western mountains and spread eastward following man’s settling and development of eastern North America (Erksine 1979).<br /> <br />Records for living species of the Hirundinidae that are known as fossils are as follows: Petrochelidonpyvrhonota. Cliff Swallow. Late Pleistocene, McKittrick, California; Quaternary (Late Pleistocene or Early Recent), Natural Chimneys local fauna, Augusta County, Virginia. Petrochelidonjulva. Cave Swallow. Late Pleistocene cave deposits in the Dominican Republic; prehistoric cave deposits in Puerto Rico. (J. ALAN FEDUCCIA, The University of Michigan Museum of Zoology, Ann Arbor, Michigan 48104, 18 November 1966.)<br /> <br />The most striking occurrence is the presence of numerous bones of Cliff Swallow (Hirundopyrrhonotu) in the lower deposits, mainly sub-zone IIa (10 500 to 10 000 B.P.). (A 10 500-Year Sequence of Bird Remains from the Southern Boreal Forest Region of Western Canada, JONATHAN C. DRIVER’ and KEITH A. HOBSON’(Received 4 March 1991; accepted in revised form I l June 1991)<br />
Resources<br />USDA Natural Resources Conservation Service (plants.usda.gov)<br />USGS WRIR 00-4001 ---Surface- and Ground Water Characteristics in the Upper Truckee River and Trout Creek Watersheds (Tahoe Regional Planning Agency and U.S. Forest Service, 1971, plate)<br />ERSKINE, A.J. 1979. Man's influence on potential nesting sites and populations of swallows in Canada. Can. Field-Nat. 93:371-377. <br />Crane P. R. P. Herendeen E. M. Friis 2004 Fossils and plant phylogeny.American Journal of Botany 91: 1683-1699<br />Cornell Lab of Ornithology--Brown, C. R., and M. B. Brown. 1995. Cliff Swallow (Hirundopyrrhonota). In The Birds of North America, No. 149 (A. Poole and F. Gill, eds.). The Academy of Natural Sciences, Philadelphia, PA, and The American Ornithologists' Union, Washington, D.C. (www.allaboutbirds.org)<br />DIVERSITY AND EVOLUTIONARY HISTORY OF LUPINS –INSIGHTS FROM NEW PHYLOGENIES Ruth J. Eastwood, Christopher S. Drummond, Maria Teresa Schifino-Wittmann and Colin E. Hughes<br />Geology.com—used for identifying rock samples<br />Google Earth—used for map of Upper Truckee River area<br />Photos of Cliff Swallow and Range Map belong to the Cornell Lab or Ornithology<br />