Humboldt River Chronology Part II – Pre-Twentieth Century 2,000,000 Years Ago to 10,000 Years Ago (Pleistocene Epoch) The prehistory of the Humboldt River Basin is marked by profound changes in climate and hydrology. Ancient lake shorelines have provided invaluable information into the scope of these changes. For example, shoreline altitudes of a number of pluvial lakes (e.g., ancient Lake Lahontan) in the northern and western Great Basin1 have indicated successively smaller lakes from the Early to the Late Pleistocene Epoch.2 This decrease in lake size suggests a long-term drying tend in the region’s climate over the last two million years. Calculations based on differences in lake areas suggest that the highest levels of these pluvial lakes would have required a regional effective moisture of up to three times greater than the effective moisture level estimated to have existed in the Late Pleistocene. These previously unknown peak lake elevations (highstands) reflect significant changes in climate, tectonics and/or drainage basin configurations that could have facilitated the migration of aquatic species throughout the Great Basin.3 Lake Lahontan’s Early Pleistocene surface level (4,590 feet MSL) was more recently estimated to have been over 200 feet above its Late Pleistocene shoreline (4,380 feet MSL), a surface elevation widely recognized as this lake’s highstand. At this higher elevation, the Early Pleistocene Lake Lahontan would have extended its reach further up the Humboldt River from the Late Pleistocene highstand, which had been estimated to have reached just above Red House (about five miles above Comus). This earlier lake highstand extended up the Humboldt River Valley by another 45 miles to just above Argenta, thereby submerging the Battle Mountain area beneath nearly 70 feet of water. Other evidence shows that Lake Lahontan may have extended even further up the Humboldt River, possibly by another 28 miles to the lower end of Palisade Canyon.4 75,000–10,000 Years Ago (Late Pleistocene Epoch) During the Wisconsin Age of the Late Pleistocene Epoch, and as recently as 12,500 years ago, the upper reaches of the Humboldt River Basin in the Ruby Mountains lay under heavy glaciers while much of the lower Humboldt River Basin, to include Lovelock Valley and all of the Humboldt Sink, was covered by pre-historic Lake Lahontan.5 This 8,665 square-mile Ice Age lake, along with the much larger 19,970 square-mile Lake Bonneville,6 which covered most of northwestern Utah and parts of eastern Nevada, represented the Great Basin’s major Ice Age lakes. The cooler temperatures, lower rates of evaporation and more abundant precipitation (i.e., higher “effective” moisture) that were prevalent during this period provided a more lush and hospitable environment for both flora and fauna. Now, the Great Salt Lake remains as a reminder of the prehistoric presence of Lake Bonneville, and Pyramid Lake and Walker Lake remain in western Nevada as the only major lake remnants of Nevada’s Lake Lahontan. During the Late Pleistocene, Lake Lahontan experienced several peaking enlargements at approximately 65,000, 45,000, 30,000, and as recently as 12,500 years ago, and at other times nearly dried up.7 At its peak surface Late Pleistocene elevation, which occurred approximately Nevada Water Basin Information and Chronology Series II–1 Humboldt River Chronology—Part II DIVISION OF WATER PLANNING 65,000 years ago, Lake Lahontan covered an area equal to almost eight percent of the State of Nevada’s present total surface area. This Ice Age lake was fed by the flows of the Truckee, Carson, Walker, Humboldt, Susan and Quinn rivers.8 It attained a maximum surface elevation of approximately 4,380 feet above mean sea level (MSL), and reached a maximum depth of at least 886 feet where Pyramid Lake (terminus of the Truckee River), the lowest point in the system, now remains.9 Lake Lahontan also covered the Lahontan Valley wetlands (Stillwater National Wildlife Refuge and the Carson Lake and Pasture in the lower Carson River Basin) to a depth of 500-700 feet.10 Also in the lower Carson River Basin, Lake Lahontan covered the site of the present-day Fallon townsite by almost 420 feet, and in the Walker River Basin it created a pool in Walker Lake some 520 feet deep.11 In the Humboldt River Basin, the late Pleistocene Lake Lahontan cut some 100 miles off the Humboldt River’s current 300-mile length, covering the sites of Humboldt and Toulon Lakes by approximately 490 feet. Further upriver, Lake Lahontan submerged the present-day site of Lovelock by nearly 400 feet, and also submerged the Humboldt River bed at the present-day site of the City of Winnemucca by nearly 120 feet. From Winnemucca, Lake Lahontan extended up the Little Humboldt River, past the Sand Dunes formation and up into Paradise Valley by some 26 miles. Beyond this point, Lake Lahontan extended further up the Humboldt River main stem by some 32 miles to a point about five miles above Comus to the present-day location of Red House. At this location the lake formed a bay of approximately 30 square miles and extending some six miles immediately to the south of Red House. At its peak surface elevation, the north-south extent of Lake Lahontan stretched from just below the Nevada-Oregon border in the north to just south of Walker Lake to present-day site of Hawthorne, Nevada, a point some eight miles past Walker Lake’s present southern shoreline. In the west, Lake Lahontan extended up the Carson River to a point just below the present-day community of Dayton. Also in the west, Lake Lahontan extended up the lower Truckee River canyon from Wadsworth towards, but not quite reaching, the Truckee Meadows and the present- day cities of Reno and Sparks, Nevada, to a point near the present-day location of Lockwood near Lagomarsino Canyon.12 Just to the north, Lake Lahontan also spilled westward over into eastern California filling the Honey Lake sub-basin. To the east, Lake Lahontan’s reach extended some 100 miles up the Humboldt River Valley, reaching the present-day location of Red House.13 50,000 – 40,000 Years Ago (Fauna and Flora) Animal bones found in a cave located high in a mountain range approximately 65 miles southwest of Elko, Nevada, have provided scientists with a rare glimpse of the late-middle Pleistocene Epoch ecosystem in the Great Basin before the last big Ice Age, some 18,000 years ago. The mouth of the cave is a small opening on a steep outcropping overlooking a canyon in the Sulphur Spring Range in the vicinity of Baily Pass (6,812 feet MSL). The variety of bones indicates that the cave was the home to a succession of predators. The cave’s cool, nearly constant 40-degree temperature and the bones’ encasement in the moist, clay floor, resulted in a remarkably well- preserved environment. The bones include cheetah (only the second set discovered in Nevada), camel, llama, horse, mountain sheep, pronghorn antelope, wolves, weasels, badgers, coyotes, II–2 Nevada Water Basin Information and Chronology Series DIVISION OF WATER PLANNING Humboldt River Chronology—Part II lizards, bats and birds. The oldest bone fragments have been carbon-dated back to about 42,000 years ago; however, only the cave’s upper sediment layers have thus far been excavated. The cheetah bones provided scientists with one possible explanation of why the pronghorn antelope developed such speed. The predators that used the cave had a high vantage point from which to spot their prey moving about in relatively open land below as they crossed the Baily Pass just to the east of the cave. Research suggests that the climate during this period was considerably cooler and wetter than today with extensive grassland areas, thereby supporting the proliferation of large grazing animals prevalent during this period.14 11,200 Years Ago (Prehistoric Human Occupation) The record of man’s existence around Lake Lahontan, including the lower Humboldt, Truckee and Carson River Basins, began at Fishbone Cave, located on the eastern shore of the dry lake bed of Winnemucca Lake in the Truckee River Basin. Excavation of the cave produced bones of horses, camels, and marmots, as well as burned human bones. Little else has been revealed about these Paleo-Indians who lived on the shores of Lake Lahontan and its remnant bodies of water near the end of the Pleistocene Epoch. This period of time corresponds to the approximate period when the last land bridge existed between Siberia and Alaska. For extended periods during the late Pleistocene’s Wisconsin Age, a period that lasted from 75,000 to 10,000 years ago, the world’s oceans were approximately 300 to 330 feet lower than they are today. During certain intervals within this period, namely approximately 40,000 to 35,000 years ago, 28,000 to 23,000 years ago, and finally at about 13,000 to 10,000 years ago, the Asian and North American continents were connected by a land bridge and migrations of prey and pursuing hunters were possible along a route down the Pacific coastline, which was relatively free of ice fields and glaciers.15 7,000 Years Ago The two vast sinks of the Humboldt and Carson River drainage systems, the marshy remnants of Ice Age Lake Lahontan, along with the lower Humboldt River Basin’s Humboldt and Toulon Lakes, served as life-sustaining resources of food and materials for prehistoric man. Generations of prehistoric peoples occupied caves located on the lower slopes of the Humboldt Mountain Range in the lower Humboldt River Basin.