WebJun 1, 1990 · At a distance over ∽ 20 cm, the host peridotite displays the typical feature of cryptic metasomatism, i.e., selective LREE enrichment in otherwise anhydrous mineralogy. The chondrite-normalized REE patterns vary from U-shaped in the range 15–25 cm to strongly fractionated in the range 25–65 cm. These variations encompass the … WebFeb 17, 2007 · Under the rift shoulder spinel peridotites have undergone both cryptic and patent (modal) metasomatism, possibly during separate events, whereas the upper mantle under the rift axis has undergone only cryptic metasomatism by …

Metasomatism - an overview ScienceDirect Topics

WebAbundant amphibole lherzolites may form a matrix enclosing relict volumes of anhydrous lherzolites showing varying degrees of cryptic metasomatism. The overall pattern of trace-element enrichment in the mantle beneath Victoria will depend on the volumetric proportions of these rock types. WebMetasomatism is the prime process to create compositional heterogeneity of the upper mantle. Mineralogical and mineral chemical changes of the mantle triggered by … highline edmonton

Depletion, cryptic metasomatism, and modal metasomatism ...

WebCryptic metasomatism of mantle xenoliths from the Jemez lineament, a transition zone between the Rio Grande rift (RGR) and Colorado Plateau (CP), is manifested by LREE-enrichment and heterogeneous isotopic compositions. The timing and source of metasomatism is unclear. Dehydration of the subducted Farallon plate during flat-slab … WebJul 14, 2010 · Cryptic metasomatism frequently accompanies deformation. Metasomatic enrichment of incompatible trace elements can be observed not only in clinopyroxenes but also in coexisting orthopyroxenes.... WebIn cryptic metasomatism, mineral compositions are changed, or introduced elements are concentrated on grain boundaries and the peridotite mineralogy appears unchanged. In modal metasomatism, new minerals are formed. highline electric association annual report