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Two Death Valleys in One: Travels in Death Valley Version 1.0

17 hours agoAcademics / Geology : Geotripper

It's certainly not the first time I've talked about Death Valley, Version 1.0 (see this post, for instance), but it's also a story of unending fascination. The deep and very long fault graben that forms the main axis of Death Valley National Park is only the latest in a series of fault valleys that have formed here over millions of years. Show More Summary

The marine terrace of Clinton, lengthwise

A few years back I showed you a view across the flat marine terrace where the old town of Clinton once sat, back in the 1850s. To really get a sense of it, walk the length of the terrace some time. Here it is on the geologic map, marked “Qmt.” The photos below (1000 pixels) […]

Spring is Coming, and Flowers are Awakening in the Sierra Nevada Mother Lode

It's still a bit early to see the awesomeness to come, but the spring wildflowers are beginning to make a splash of color in the Sierra Mother Lode. With the record and near record amounts of rain in Northern California, the slopes are...Show More Summary

The Roan Cliffs Again, This Time with Some Contacts

After seeing Ron Schott's awesome and enlightening GigaPan of the Roan Cliffs, I decided I had to mark some contacts on the photos from my last post (and partly because what I said or implied about the formations were a little off).Show More Summary

New Exhibit at the Great Valley Museum: Homo Naledi and MJC's Dr. Debi Bolter

If you've read my blog for any amount of time, you know that I work in a wonderful Science Community Center, which has a the marvelous Great Valley Museum (the GVM) taking up most of the bottom floor. The museum has existed for more than thirty years, but spent most of that time in a cramped 1930's vintage house. Show More Summary

AZGS funding bill (SB1184) comes before AZ House Appropriations Committee - 15 March

Phil Pearthree examining columnar basalt, Verde River headwaters. Tucson. Senate Bill 1184 (SB1184), introduced by Senator Gail Griffin, would provide a state appropriation to fund the AZGS at the same level we were funded as a separate state agency. Show More Summary

Rubbing rocks

Rocks interact with animals of all kinds. Obviously, lizards and voles and snakes and woodchucks live on rocks and/or dig under them. Humans paint on rocks and move them around and blow them up. Today, however, I’m going to talk about animals that scratch themselves against rocks — rather, rocks that animals have rubbed for […]

Liveblogging the Deluge: It Ain't Over 'til the Fat River Drains...A Six Month Flood is in Process

The flooding in California hasn't been in the news all that much of late, but that doesn't mean the threat is over. The atmospheric river storms that have been hitting the state like an out-of-control fire hose have been turned off for...Show More Summary

A Place Where Water Once Was But Was No Longer, But Once Again Was (sort of) - Travels in Death Valley

Yes, I used that silly title a few weeks ago, but today it is in a very different context. We were continuing our exploration of the Death Valley region, and we were still dealing with the effects of the Bombogenesis storm that dropped so much precipitation across Southern California. Show More Summary

LARA Committee passes AZGS' funding bill (SB1184 ) 7-0

Sen. Gail Griffin testifying before LARA The Arizona House Land, Agriculture and Rural Affairs Committee passed SB 1184, AZGS' funding bill, 7-0 this morning. Senator Griffin introduced and defended the bill. Arizona Rock Products Association's executive director, Steve Trussell, was on hand to voice his support. Show More Summary

From the Road: Bedding and Talus in the Roan Cliffs of Colorado

Getting back to my October-November road trip (last seen here), I stopped to get some fuel in Parachute, CO, on what was Day 7 of the trip, and I ended up taking a few photos (surprise!), partly thinking that the cliffs show good examples of bedding, and also because I was becoming fascinated by the exceptional talus slopes coming off the cliffs. Show More Summary

A previously unrecognized high-temperature impactite from the Steen River impact structure, Alberta, Canada

Here, we report a previously unrecognized impactite from the Steen River impact structure in Alberta, Canada, which was intersected by continuous diamond drill core into the allochthonous proximal deposits of this buried 25-km-diameter complex crater. Show More Summary

Recurrent hierarchical patterns and the fractal distribution of fossil localities

Understanding the spatial structure of fossil localities is critical for interpreting Earth system processes based on their geographic distribution. Coordinates of marine and terrestrial sites in the conterminous United States for 17 time bins were analyzed using point pattern statistics. Show More Summary

Seismic array constraints on reach-scale bedload transport

Measurements and mechanical models of heterogeneous bedload transport in rivers remain basic challenges for studies of landscape evolution and watershed management. A 700 m reach of the Trinity River (northern California, USA), a large...Show More Summary

The control of the tropical North Atlantic on Holocene millennial climate oscillations

Changes in ocean dynamics in the northern North Atlantic affect the thermohaline circulation that controls global climate. During glacial and deglaciation periods these dynamics are enhanced due to large variations in the surface ocean density caused by changes in glacier volumes. Show More Summary

Controls and feedbacks in the coupling of mountain channels and hillslopes

Mountain channels can be strongly coupled with adjacent hillslopes, exchanging both mass and energy. However, hypotheses of the underlying cause and effect relations are based on indirect observations that do not resolve the mechanics of channel-hillslope coupling at the process scale. Show More Summary

Block-controlled hillslope form and persistence of topography in rocky landscapes

Rocky hillslopes dotted with boulder-sized blocks and covered by a thin, nonuniform soil are common in both steep landscapes and arid environments on Earth, as well as on other planets. While the evolution of soil-mantled, convex-upward...Show More Summary

Pore fluids in Dead Sea sediment core reveal linear response of lake chemistry to global climate changes

Pore fluids extracted from a 456 m sediment core, recovered within the framework of a multinational and International Continental Scientific Drilling Program (ICDP) co-sponsored effort at the bottom of the terminal Dead Sea, recorded the chemical variations in the deep lake over the past 220 k.y. Show More Summary

Aragonitic scleractinian corals in the Cretaceous calcitic sea

Changes in seawater chemistry have affected the evolution of calcifying marine organisms, including their skeletal polymorph (calcite versus aragonite), which is believed to have been strongly influenced by the Mg/Ca ratio at the time these animals first emerged. Show More Summary

Sediment cycling on continental and oceanic crust

Sedimentary rocks are often described as declining in quantity with increasing age due to the cumulative effects of crustal deformation and erosion. One important implication of such a model is that the geological record becomes progressively less voluminous and less complete with increasing age. Show More Summary

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