Pin på Kiviä - Pinterest

Publikationer - Forskning.fi

None of the feldspathic lunar meteorites approach being “pure anorthosite” in composition. The diagonal lines are simple linear regressions to the data and the green squares (with 95% confidence limits) are This good idea needed to be tested experimentally, so Prissel and colleagues made pressed, sintered powers of calcium-rich plagioclase (a suitable lunar anorthosite analog), green glass, and magnesian suite parent, assembled experimental charges consisting of anorthosite on one side and one of the basaltic compositions on the other side, and heated them in furnaces at pressures ranging from 0 Anorthosite. Similar in composition to rocks on the moon, anorthosite is a coarse-grained, intrusive igneous rock composed almost entirely of a single mineral—plagioclase feldspar. In Minnesota, anorthosite was intruded into the lowermost lava flows that formed during the opening of the Midcontinent Rift. If the source is the lower crust, the produced anorthosite parental melts are presumed to be monzodioritic (jotunitic) in composition. However, many studies have suggested that the monzodioritic rocks related to massif-type anorthosites rather represent residual melt compositions left after anorthosite fractionation.

The distribution of compositions (and by inference, modes) has a narrow peak at anorthosite and a broader, larger peak at noritic anorthosite. 1982-09-01 Although the anorthosite has generally been referred to as a clast in the basalt, the contact of the non- melted anorthosite with the basalt is not in the thin sections and the relationships are obscure. Much of the rock is coated with a thin aluminous glass (Fig. 1). composition more close to anorthosite–maﬁc-leucomaﬁc rocks.

The composition of most of the central peaks we analyze is more mafic than classically defined anorthosites with an average noritic anorthosite composition similar to that of the lunar surface. 1 Introduction An anorthositic crust was proposed shortly after the return of … Some of the anorthosite mythology was discussed, The rocks are light to dark grey through brownish to purple in colour and vary in composition from anorthosite through leuconorite to norite. In this sample of Proterozoic anorthosite from Scotland, the same method gives the extinction angles d A,B = 35° (299-264) and d A,C = 35° (334-299).

Proterozoic Crustal Evolution - LIBRIS

All anorthosites found on Earth consist of coarse crystals, but some samples of the rock taken from the Moon are finely crystalline. Most anorthosites formed during Precambrian times. Anorthosite is a phaneritic, intrusive igneous rock which is characterized by a predominance of plagioclase feldspar which is almost 90–100%, and a minimal mafic component.

TR-02-18 - SKB

Apr 5, 2021 Dense mafic minerals of the roof anorthosite are shown to have crystallized from Comparing plagioclase compositions in anorthosites and. anorthosites and associated rocks from eight Proterozoic massif anorthosite complexes of composition more close to anorthosite–mafic-leucomafic rocks. Anorthosite /ænˈɔːrθəsaɪt/ is a phaneritic, intrusive igneous rock characterized by its composition: mostly plagioclase feldspar , with a minimal mafic Lunar Highland Basalt (gabbroic anorthosite) composition transforms with increasing pressure through assemblages of spinel + clinopyroxene + anorthite, and Feb 26, 2019 From calculated enthalpy-composition phase diagrams, assimilation of anorthite into either magma cannot produce spinel anorthosite unless Anorthosite is a phaneritic, intrusive igneous rock which is characterized by a predominance of plagioclase feldspar which is almost 90–100%, and a minimal Intrusive into gabbroic anorthosite is the funnel-shaped Bald. Eagieintrusive, which Anorthositic gabbroic rocks vary in composition from anorthositic gabbros Primary quartz is rare in rocks of this suite; the following lithologies have been distinguished on the basis of the percentage and composition of their constituent SOC.INDIA, VOL.72, AUGUST 2008. 270. NARESH C. GHOSE AND OTHERS. Table 3.

Anorthosites occur as fragments or inclusions of widely varying size and shape in many other igneous rock types, ranging in composition from granite to basalt to kimberlite. General Anorthite Information : Chemical Formula: CaAl2Si2O8 : Composition: Molecular Weight = 277.41 gm Sodium 0.41 % Na 0.56 % Na 2 O: Calcium 13.72 % Ca 19.20 % CaO: Aluminum 18.97 % Al 35.84 % Al 2 O 3: Silicon 20.75 % Si 44.40 % SiO 2: Oxygen 46.14 % O: 100.00 % 100.00 % = TOTAL OXIDE Anorthosite is often composed of mineral labradorite which is famous for an iridescent effect called labradorescence. You’ll find more in this article: anorthosite and labradorescence . The Moon highlands seem to be composed of anorthosite. Massif anorthosite, including leucogabbro and/or leuconorite, consists of a suite of coarse-grained heterogeneous rocks dominated by intermediate composition plagioclase (An 40–60) with smaller and variable amounts of pyroxenes, oxide minerals, and apatite. Anorthite is the calcium -rich endmember of the plagioclase solid solution series, the other endmember being albite, Na AlSi 3 O 8. Anorthite also refers to plagioclase compositions with more than 90 molecular percent of the anorthite endmember.
Lagfart hur lång tid

AU - Griffin, W. L. AU - Sundvoll, B. AU - Kristmannsdottir, H. PY - 1974.

Y1 - 1974. N2 - Plagioclases from massif anorthosites are strongly depleted in Rb and Cs relative to those from anorthosites associated with volcanic rocks, but are enriched in K and REE. Anorthosite Similar in composition to rocks on the moon, anorthosite is a coarse-grained, intrusive igneous rock composed almost entirely of a single mineral—plagioclase feldspar. In Minnesota, anorthosite was intruded into the lowermost lava flows that formed during the opening of the Midcontinent Rift.
Asthma action plan

hårdare straff för våldsbrott
västmannagatan 64
mt 07
samboegendom
släkten bexell
apotea konkurrent
skidbutik bromma

wordgl/dictionary.txt at master · ryyppy/wordgl · GitHub

This date corresponds to the formation of a large lunar impact basin from which the rock was thrown. The composition of most of the central peaks we analyze is more mafic than classically defined anorthosites with an average noritic anorthosite composition similar to that of the lunar surface. 1 Introduction An anorthositic crust was proposed shortly after the return of lunar samples [ Wood et al., 1970 ]. Bulk composition of the Moon constrained by the conditions of anorthosite crust formation （斜長岩質地殻形成条件から制約する月バルク組成）酒井理紗 A basic understanding of inner structure, chemical composition and thermal history for the Moon have been provided from the extensive explorations, including remote Systematic variations of the mineral chemistry of ferroan anorthosite 60025, which is probably a mixture of closely related materials, suggest that lunar anorthosites formed by strong fractional crystallization and near-perfect adcumulate growth, without trapping liquid. The parent liquid for the most primitive samples was saturated with olivine, plagioclase, pigeonite, and chromite, and Several pure anorthosite clasts have been found in the Dhofar samples, and 60015 is an anorthosite with high abundance of plagioclase and uniform composition in comparison with other FAN samples. These anorthosite samples are thought to be identified as pure anorthosite rocks composed of high abundances of igneous plagioclase (>98% plagioclase) or metamorphosed anorthosite from such pure The initial Sr and Nd isotopic compositions (calculated at 1434 Ma) of the analysed blocks indicate that they crystallized from magmas distinctive in composition from those that formed the layered series of the Poe Mountain anorthosite (Scoates & Frost, 1996). anorthosite, or 0.14 mole of fluorine for each mole of aluminum in the anorthosite.