Sodalite Syenite Research Articles

Preliminary account of the geology of the Kvanefjeld Area of the Ilímaussaq Intrusion, South Greenland

The Kvanefjeld area is situated in the northernmost part of the nimaussaq intrusion. The area represents a section through the roof zone of this intrusion. The roof is composed of sandstone, basaltic lavas, sheets of gabbro and dykes of dolerite and trachyte. Large masses of anorthosite are also found in the roof zone, The oldest members of the intrusion are augite syenite and alkali syenite which together with large masses of naujaite (poikilitic sodalite syenite) are enclosed in various types of fine-grained lujavrite. The lujavrite also intrudes the lavas of the roof. The bodies and veins of lujavrite are mainly located in zones of deformation in the rocks of the roof zone. The lavas of the roof are strongly altered in contact with the lujavrite and are locally enriched in epistolite-murmanite minerals. The latest member of the intrusion is a medium- to coarsegrained lujavrite which forms sheets and veins in most of the abovementioned rocks. The earlier fine-grained lujavrites and the contactmetasomatized lavas have concentrations of steenstrupine, monazite and thorite (?) in contact with the medium- to coarse-grained lujavrite and may contain up to 0.3 % U and three to four times this amount of thorium. This mineralization has been studied by mineralogical, geochemical and radiometric methods and in a number of drill holes. Analcime-rich veins rich in niobium and beryllium minerals are of widespread occurrence. The present paper gives a preliminary account of the geology of this region with special reference to the structural geology. A detailed examination of the economic geology of the Kvanefjeld area is currently being undertaken.

Chalcothallite - A new sulphide of copper and thallium from the Ilímaussaq alkaline intrusion, South Greenland

The new mineral chalcothallite, CU3TlS2 was discovered in a hydrothermal ussingite vein in poikilitic sodalite syenite (naujaite) in the Ilímaussaq intrusion, South Greenland. The new mineral is associated with ussingite, analcime, sodalite, epistolite and chkalovite. The mineral forms lamellar aggregates. The colour is lead grey to iron black with metallic lustre. There are three mutually perpendicular cleavages. The specific gravity is 6.6, the hardness is 61-90 kg/mm2. The chemical composition is: TI-38.07, Cu- 40.58, Ag-0.19, Pb-0.13, Fe - 3.79, S -12.06, Sb - 3,93, insoluble 1.52; total 100.27. The d-values of the strongest lines of the x-ray powder diagram are: 3.93, 3.75, 3.49, 3.07, 2.48, 2.32, 2.19, 1.930. Like chalcocite, chalcothallite is easily subject to transformation and recrystallization. There are inclusions of native silver, chalcocite, vrbaite and avicennite (?).

The Lovozero minerals - nenadkevichite, gerassimovskite and tundrite - from Ilímaussaq, South Greenland

Nenadkevichite NaCaTiNbSi4O14.4H20, gerassimovskite NbTi(OH) 9 and tundrite Na2Ce2TiSiO8.4H2O, which until now have been found only in the Lovozero alkaline massif in the Kola peninsula have also been found in the nepheline-sodalite syenites of the Ilímaussaq massif (South Greenland). Nenadkevichite and gerassimovskite occur in hydrothermaI veins in the poikilitic sodalite syenites (naujaites) as alteration products of epistolite. Tundrite was found in pegmatites in nepheline syenites (kakortokites). A new formula of tundrite is suggested.

Differentiation trends in the Ice River complex, British Columbia

Four phases of the complex (jacupirangite, ijolite, nepheline syenite, and sodalite syenite) were studied from the viewpoint of their chemical variation. If one goes from the first-formed jacupirangite to the last-formed sodalite syenite, CaO, FeO, Fe ~2~ O ~3~ , MgO, and TiO ~2~ decrease, whereas SiO ~2~ , Al ~2~ O ~3~ , Na ~2~ O, K ~2~ O, and volatile content increase. A tentative diagram for the system SiO ~2~ -NaAlSiO ~4~ -KAlSiO ~4~ at a water pressure of 1,000 kg ^2^ /cm. ^2^ is used to study the differentiation path. Jacupirangite lies well above the diagram due to its high CaO and MgO content. Ijolite is at or near the liquidus of the system, and nepheline syenite falls in the cotectic trough between the feldspar and nepheline fields. Sodalite syenite does not appear to lie at the ternary eutectic in the position expected of the last differentiate.

Phase petrology in the Cortlandt complex, New York

Research Article| March 01, 1942 Phase petrology in the Cortlandt complex, New York S. JAMES SHAND S. JAMES SHAND Search for other works by this author on: GSW Google Scholar GSA Bulletin (1942) 53 (3): 409–428. https://doi.org/10.1130/GSAB-53-409 Article history received: 30 Jun 1941 first online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Twitter LinkedIn Tools Icon Tools Get Permissions Search Site Citation S. JAMES SHAND; Phase petrology in the Cortlandt complex, New York. GSA Bulletin 1942;; 53 (3): 409–428. doi: https://doi.org/10.1130/GSAB-53-409 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract The Cortlandt complex, near Peekskill, New York, is formed of rocks that range from peridotite and pyroxenite through norite to diorite. G. S. Rogers mapped 14 species of these rocks and added syenite and sodalite syenite to the list. Robert Balk made a structural survey of the complex and showed it to be a funnel-shaped pluton within which three smaller funnels are developed. If these funnels mark channels through which magma ascended, the various species ought to be grouped more or less symmetrically about the funnels; yet Rogers’ petrographic map shows little correspondence with Balk’s structural map. The explanation lies in the indefinite character of Rogers’ species, which grade into one another in every respect. Progress in understanding the complex requires the abandonment of “species petrology” in favor of “phase petrology” or the mapping of critical mineral phases. The most instructive phase is hornblende, which occurs in two forms, one primary and the other a poikilitic replacement of plagioclase and pyroxene. The first is confined to the marginal zone; the second is found all through the central region, extending far beyond the boundary of Rogers’ “hornblende-norite.” Balk’s central funnel falls entirely within this enlarged hornblende field. The marginal zone of the pluton is characterized by primary hornblende, by the frequent appearance of biotite in large poikilitic plates, and by the occasional development of poikilitic garnets, orthoclase, and micropegmatite. The occurrence of sodalite syenite is not confirmed. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

II.—On a Sodalite Syenite (Ditroite) from Ice River Valley, Canadian Rocky Mountains

In the year 1886 the late Dr. G. M. Dawson gave an account of a syenitic rock, rich in a beautiful blue sodalite, which he had discovered when exploring the district near Hector Pass, on the watershed of the Canadian Rocky Mountains, and an analysis of the mineral was afterwards published by Professor Harrington. The place was visited last Summer by Mr. E. Whymper during his examination of the district south of the Canada Pacific Railway, when he collected a number of specimens, which he showed to me on his return. The rock is hardly less beautiful than lapis lazuli, and as no description of its microscopic structure has been published, as far as I can ascertain, I give the results of my examination, together with a condensed account of its mode of occurrence. I am much indebted to Mr. Whymper for placing his specimens at my disposal, to Mr. L. Fletcher, Keeper of the Mineral Collection in the British Museum, for the opportunity of examining specimens of sodalite rock not in my own cabinet, and to Mr. L. J. Spencer, of that department, for giving me his kind assistance and valuable references to papers about the mineral.

A sodalite syenite and other rocks from Montana

A sodalite syenite and other rocks from Montana