inage divide intersections are more stable and more difficult to erode, thus leading to the formation of pyramid-shaped peaks. This observation implies that the location of high peaks is a function of drainage network. For example, Mount Everest occurs where it does because major divides intersect there; there may be nothing else special about the rocks or tectonics of that location. The association of peaks and drainage divide intersections also implies that mountain peaks are anchor points in the landscape. Peaks may exert a previously unrecognized feedback on long-term landscape evolution, which limits the migration of drainage divides and valleys and thus stabilizes the topography. As a result, the drainage divide structure and the distribution of elevation along ridges are relevant characteristics that both influence and record how mountain landscapes evolve.
Coupling meteoric 10Be with pedogenic losses of 9Be to improve soil residence time estimates on an ancient North American interfluve
Allan R. Bacon et al., University Program in Ecology, and Nicholas School of the Environment, Duke University, Box 90328, Durham, North Carolina 27708, USA. Posted online 29 June 2012; doi: 10.1130/G33449.1.
Soils are like ledgers -- while residing on Earth's surface, they record transactions of energy and material between Earth's plants, rocks, water, and atmosphere. Deciphering these records and estimating how far back in time they go is not only a challenge, it is also important because understanding how plants, rocks, water, and our atmosphere have interacted in the past (under different climatic conditions) may help us predict how they will interact in the future. To take a step toward deciphering the records stored in the soils of the Southeastern United States, Allan R. Bacon and colleagues asked a simple question: How long have these soils been residing at Earth's surface? To answer this question, they combined analyses and interpPage: 1 2 3 4 5 6 7 8 9 10 Related biology news :1
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