نتایج جستجو برای: aureole
تعداد نتایج: 193 فیلتر نتایج به سال:
Introduction: Olympus Mons is the largest volcano on Mars, rising over 25 km above the surrounding plains and with a basal diameter greater than 600 km. It is surrounded by a basal escarpment up to 6 km tall. Extending up to 1000 km beyond this scarp are lobes of ridged materials known as the aureole [1, 2]. Superimposed upon the west and northwest aureole deposits at the base of the escarpment...
Archean supracrustal sequences of pelitic, quartzitic, calcareous and mafic compositions in the central Laramie Mountains, Wyoming, have been affected by two metamorphic events: a 1.78 Ga amphibolitegrade regional metamorphism, and a 1.43 Ga contact metamorphism resulting from the intrusion of the Laramie Anorthosite Complex (LAC). Rb–Sr whole-rock isotopic data from both outside and within the...
Intrusion of the Alvand plutonic complex into the pelitic and sim-pelitic rocks of the Tuyserkan area has caused the development of a thermal aureole in the Sarabi area. The rocks within the aureole are thermally metamorphosed and formed different types of hornfelses. High-grade metamorphic rocks with chemically suitable compositions were melted adjacent to the contact due to the heat from the ...
in order to assess the presence or absence of fluids under peak metamorphic conditions within the inner aureole of the etive igneous complex in west scotland, eight suitable metabasic hornfels samples and one suitable pelitic hornfels were used to calculate water activities using a mineral equilibria. calculated activities for water are lower than unity in the pelitic sample and extremely low i...
the relations of fibrolite-biotite are discussed by presenting data from the ardara aureole, nw ireland. biotite-fibrolite intergrowths are developed in all three aureole zones including: the outer kyanite-bearing andalusite zone, the middle kyanite-free andalusite zone and the inner prismatic sillimanite zone. a strain-assisted mechanism is proposed for the fibrolitisation of biotite in the ar...
In order to assess the presence or absence of fluids under peak metamorphic conditions within the inner aureole of the Etive igneous complex in west Scotland, eight suitable metabasic hornfels samples and one suitable pelitic hornfels were used to calculate water activities using a mineral equilibria. Calculated activities for water are lower than unity in the pelitic sample and extremely low i...
Paleotopography and flexural modeling are here used to constrain the formation history and eruption rates of Olympus Mons, the tallest shield volcano on Mars. The timing of the initiation of significant edifice construction is constrained using lava flows whose paths deviate significantly from the downslope direction of the present-day flexural trough, and thus are classified as topographically...
The formation of atoll garnet in the Ardara aureole, NW Ireland, is discussed using the textural, chemical and Electron Backscatter Diffraction (EBSD) data. Textural evidence suggests the possibility of incipient of garnet replacement from the core. In addition, the presence of staurolite and andalusite in the core of small atoll garnets as well as the occurrence of sillimanite in the core of l...
The mechanisms by which Cordilleran plutons are emplaced vary widely. However, the present authors have examined a series of plutons ranging from 2–35 km emplacement depth that have many common features, which suggest that downward transport of host rock is the most important mechanism during magma ascent and pluton emplacement. Many of these Cordilleran plutons preserve gently dipping, unfault...
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