Millennial-scale oscillations are documented from lake deposits, which have been explained by streamflow pulses lasting several decades and separated by several centuries. These pulses were intense enough to increase inflow but not so long-lasting to raise water levels to overflow. Some lake level changes may have been too short to leave detectable shoreline deposits. Gypsum concentrations show strong 600 years long and weaker 350 and 250 years long cycles. The slow changes in the continental ice sheets cannot explain short-term changes in the lake, and other causal mechanisms have been sought. Solar cycles such as the Gleissberg solar cycle have been proposed as explanation for these fluctuations. Holocene Beach terraces and other beach deposits were emplaced early in the Holocene; after about 8,500 years before present Lake Estancia dried up. La Niña conditions during the Holocene reduced water inflow into the lake, which owing to high evaporation rates could not be compensated by summer precipitation. After Lake Estancia dried up, two separate wind deflation events took place, the first is dated to either 4,000 or 7,000 years ago and the second to either 4,000 or 2,000 years ago. The deflation removed Quaternary sediments thus exposing their internal structure. The deflation also generated the playa basins and the "Willard soil" during the Altithermal climate phase. Dunes developed during hot and dry conditions of the middle Holocene. After the middle Holocene the climate became wetter again, reducing dune activity. The existence of a "Lake Meinzer" with a depth of and an area of after the Altithermal has been inferred. Presently, dry lakes occur on the bed of Lake Estancia and are fed by groundwater. Geography and geomorphology Lake Estancia developed within the Estancia Valley, a closed basin in central New Mexico's Torrance County. The settlements of Estancia, Moriarty and Willard lie within the valley, which is about southeast of Albuquerque. Interstate 40 crosses the northernmost parts of the lakebed of Lake Estancia, and New Mexico State Road 41 and U.S. Route 60 pass over the western and southern lakebed, respectively; formerly the tracks of the New Mexico Central Railroad and the Atchison, Topeka and Santa Fe Railway also traversed the lake bed. The lowest units of the Salinas Pueblo Missions National Monument are located close to the shorelines of former Lake Estancia. Estancia Valley covers an area of and is flanked to the east by the Pedernal Hills, to the northwest by