نتایج جستجو برای: volcanism
تعداد نتایج: 2423 فیلتر نتایج به سال:
Introduction: The globally extensive smooth plains of Mercury are believed to be mostly volcanic in origin [1]. Widespread effusive volcanism on Mercury is thought to have ended by ~3.5 Ga due to secular cooling of the planet’s interior, and contraction of its lithosphere [2]. As the planet cools and contracts, melt should be produced at a slower rate and in smaller volumes, so it will stall de...
The end-Triassic extinction is characterized by major losses in both terrestrial and marine diversity, setting the stage for dinosaurs to dominate Earth for the next 136 million years. Despite the approximate coincidence between this extinction and flood basalt volcanism, existing geochronologic dates have insufficient resolution to confirm eruptive rates required to induce major climate pertur...
[1] Abstract: The subducting Nazca Plate shows a high degree of along-strike heterogeneity in terms of intermediate-depth seismicity ( 70–300 km), orientations of slab stress, and volcanism. We compile the intermediate-depth earthquakes of South America from the Harvard Centroid Moment Tensor (CMT) catalogue to determine along-strike dip variations, and we explore the variable level of correlat...
Widespread basaltic volcanism occurred in the region of the West Siberian Basin in central Russia during Permo-Triassic times. New 40Ar/39Ar age determinations on plagioclase grains from deep boreholes in the basin reveal that the basalts were erupted 249.4 +/- 0.5 million years ago. This is synchronous with the bulk of the Siberian Traps, erupted further east on the Siberian Platform. The age ...
[1] We use the identification of volcanism on Mercury, together with lobate, flow-front like topography, crustal composition information and data on the stress state and history of the lithosphere, to derive a new model for the ascent and eruption of magma on Mercury. We find that extrusion is likely to be dominated by high-effusion rate events. Initial emplacement of dikes in the crust and ext...
Magraatism and volcanism exhibit spatial and temporal clustering on a wide range of scales. Using the spatial pair-correlation function, the number of pairs of magmatic orvolcanic events whose separation is between r« Ar and r + « Ar per unit area, we quantify the spatial clustering of raagraatism and volcanism in several data sets. Statistically self-similar clustering characterized by power l...
Extension and calc-alkaline volcanism of the submerged orogen of alpine age (OAA) initiated in Early Oligocene (~33/32 Ma) and reached the stage of oceanic opening in Early-Miocene (Burdigalian), Late-Miocene and Late-Pliocene. In the Burdigalian (~20-16 Ma) period of widespread volcanism of calcalkaline type on the margins of oceanic domain, seafloor spreading originated the deep basins of nor...
[1] We investigated the possibility of significant variations in the rates and styles of volcanism and rifting during the time postdating the formation of regional plains on Venus. We analyzed the age relations of all known impact craters 30 km in diameter (183 craters) with the neighboring geologic units. Of these we selected 164 craters which were superposed on regional plains and determined ...
volcanic landform can be as terrain legacies from the past to the present era be considered. these heritage of land in terms of their unique characteristics can be considered as geomorphosite in the scientific community and the public. the evaluation of resources is one of the most important tasks of geotourism research.and thereby become profitable and thriving tourism industry in their own di...
Resolving the time–space (and compositional) evolution of volcanism along long-lived South Atlantic hotspot trails is important to understanding the connection between hotspot volcanism and mantle plumes. Ar=Ar ages are reported here for rocks dredged from a line of five individual seamounts along an 3⁄4290 km northeast to southwest line extending from the vicinity of Saint Helena Island, and a...
نمودار تعداد نتایج جستجو در هر سال
با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید