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New CU-Boulder led research effort dates oldest petroglyphs known in North America

By Guest PostAugust 17, 2013Environmentarchaeologists, benjamin aleck, boulder, boulders, carbonate coating, cave in oregon, elevation, emerson pass, eugene hattori, fossilized human excrement, lahontan basin, larry benson, limestone, maximum height, native american artifacts, North America, northeast of reno, oldest petroglyphs, pyramid lake, university of colorado, water level, western nevada, winnemucca lake, winnemucca lake petroglyphs, winnemucca lake subbasin

A new high-tech analysis led by a University of Colorado Boulder researcher shows the oldest known petroglyphs in North America, which are cut into several boulders in western Nevada, date to at least 10,500 years ago and perhaps even as far back as 14,800 years ago.

The petroglyphs located at the Winnemucca Lake petroglyph site 35 miles northeast of Reno consist of large, deeply carved grooves and dots forming complex designs on several large limestone boulders that have been known about for decades, said CU-Boulder researcher Larry Benson, who led the new effort. Although there are no people, animals or handprint symbols depicted, the petroglyph designs include a series of vertical, chain-like symbols and a number of smaller pits deeply incised with a type of hard rock scraper. (more…)

Droughts are Pushing Trees to the Limit

By Guest PostSeptember 8, 2012Environmentaerial surveys, atmospheric sponge, borderland, carbon dioxide, catastrophic disruption, climate change, deficit, drought, ecological disturbance, elevation, embolism, forest service, four corners, greenhouse experiment, growing season, high plains, index, jeremy weiss, jonathan overpeck, julio betancourt, leaf water, Mexico, moisture, mountainous terrain, photosynthesis, plant growth, precipitation, regional warming, southwest, stomates, temperatures rise, university of arizona, US, vapor pressure, vicious circle, weather data, wildfires

Droughts in the Southwest made more severe by warming temperatures are putting plants in stressful growing conditions, a new study has found, identifying an increasingly water-thirsty atmosphere as a key force that sucks moisture from plants, leading to potentially higher stress – especially in mid and low elevations.

As temperatures rise and droughts become more severe in the Southwest, trees are increasingly up against extremely stressful growing conditions, especially in low to middle elevations, University of Arizona researchers report in a study soon to be published in the Journal of Geophysical Research Biogeosciences.

Lead author Jeremy Weiss, a senior research specialist in the UA department of geosciences, said: “We know the climate in the Southwest is getting warmer, but we wanted to investigate how the higher temperatures might interact with the highly variable precipitation typical of the region.” (more…)

Climate Change Boosts Then Quickly Stunts Plants, Decade-long Study Shows

By Guest PostApril 12, 2012Environmentarizona, atmosphere, bruce hungate, climate change, ecologist, ecosystem feedback, elevation, george koch, global warming, grassland ecosystem, great basin desert, greenhouse, national science foundation, nau, nitrogen gas, northern arizona university, nsf, nutrient cycle, paul dijkstra, plant communities, san francisco peaks, saran twombly, warming environment, zhuoting wu

*Global warming may initially make the grass greener, but not for long*

Global warming may initially make the grass greener, but not for long, according to new research results.

The findings, published this week in the journal Nature Climate Change, show that plants may thrive in the early stages of a warming environment but then begin to deteriorate quickly.

“We were really surprised by the pattern, where the initial boost in growth just went away,” said scientist Zhuoting Wu of Northern Arizona University (NAU), a lead author of the study. “As ecosystems adjusted, the responses changed.” (more…)

Tag Archives: elevation

New CU-Boulder led research effort dates oldest petroglyphs known in North America

Droughts are Pushing Trees to the Limit

Climate Change Boosts Then Quickly Stunts Plants, Decade-long Study Shows