نتایج جستجو برای: uplift and magmatism
تعداد نتایج: 16828102 فیلتر نتایج به سال:
The Himalayan mountains are dissected by some of the deepest and most impressive gorges on Earth. Constraining the interplay between river incision and rock uplift is important for understanding tectonic deformation in this region. We report here the discovery of a deeply incised canyon of the Yarlung Tsangpo River, at the eastern end of the Himalaya, which is now buried under more than 500 met...
The Greenland GPS Network (GNET) uses the Global Positioning System (GPS) to measure the displacement of bedrock exposed near the margins of the Greenland ice sheet. The entire network is uplifting in response to past and present-day changes in ice mass. Crustal displacement is largely accounted for by an annual oscillation superimposed on a sustained trend. The oscillation is driven by earth's...
[1] Three-dimensional models of the uplift of Beta Regio caused by a mantle plume satisfy constraints on gravity, topography, rheology, and the uplift rate substantially better than two-dimensional models. In particular, the uplift time of Beta Regio is reduced to an acceptable 800 million years. Three-dimensional models give the plume formation depth around 3000 km, which approximately corresp...
Concentrations of cosmogenic Al and Be in cave sediments and bedrock surfaces, combined with studies of landscape morphology, elucidate the topographic history of the southern Sierra Nevada over the past 5 Ma. Caves dated by Al/Be in buried sediments reveal that river incision rates were moderate to slow between c. 5 and 3 Ma (≤0·07 mm a), accelerated between 3 and 1·5 Ma (c. 0·3 mm a−), and th...
In this paper, we develop a new axisymmetric analytic model of surface uplift upon sills and laccoliths, based on the formulation of a thin bending plate lying on an elastic foundation. In contrast to most former models also based on thin bending plate formulation, our model accounts for (i) axi-symmetrical uplift, (ii) both upon and outside the intrusion. The model accounts for shallow intrusi...
Patterns of late Palaeogene mammalian evolution appear to be very different between Eurasia and North America. Around the Eocene-Oligocene (EO) transition global temperatures in the Northern Hemisphere plummet: following this, European mammal faunas undergo a profound extinction event (the Grande Coupure), while in North America they appear to pass through this temperature event unscathed. Here...
The Anthocoris nemorum group belongs to the Anthocoridae (Hemiptera), and is an important group of predators of agricultural pests. A phylogeny was constructed in conjunction with dispersal-vicariance analysis of the Anthocoris nemorum group species in order to discern the relationships between the phylogeographical structuring of A. nemorum group species, and the effects of the Qinghai-Tibet p...
Mitochondrial Cytochrome Oxidase Subunit I DNA sequences are a good discriminative marker for phylogenetic studies in crustaceans and especially in amphipoda. In the present study, molecular and morphological data were analyzed to test whether Gammarus lobifer authority and Gammarus balutchi authority which one or two geographically separated but morphologically similar species. The analyses pr...
The Central Andes represent the archetypical Cordilleran orogenic system, with a well-developed continental volcanic arc and some of thickest crust on Earth. Yet relative contributions shortening magmatic additions to crustal thickening remain difficult quantify, which hinders understanding processes evolution in arcs. Cerro Aconcagua, highest mountain Americas relict Miocene stratovolcano rest...
An ongoing enigma for the standard geological community is why all the high mountain ranges of the world—including the Himalayas, the Alps, the Andes, and the Rockies—experienced most of the uplift to their present elevations in what amounts to a blink of the eye, relative to the standard geological time scale. In terms of this time scale, these mountain ranges have all undergone several kilome...
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