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Gregoryite - complete list of mineral names Mineral specimens of Nyerereite* and Gregoryite* from Oldoinyo Lengai volcano, Maasai Steppe, East Africa Rift Valley, Tanzania available for sale from John Betts, crystal and minerals dealer in NY, NY. Euhedral to acicular grains are phenocrysts of "nyerereite", anhedral grains are "gregoryite", both Na-K-Ca carbonates... nearly pure alkali carbonate minerals (nyerereite and gregoryite) occur in lavas with chemical compositions not... www.absoluterocknet.com /complete_list_of_mineral_and_crystal_names/Gregoryite.asp   (427 words)

LookSmart - Search results for "Nyerereite"   (Site not responding. Last check: 2007-10-19) Analyse the chemical properties, relationship of nyerereite to other species, crystallography, formula, optical data, and the mineral classification. Delve into two outlines that show the factors needed to determine the nyerereite mineral structure. Analysis of Chaos Crags showed it to be very rich in crystals of nyerereite and gregoryite, the typical minerals of natrocarbonatite. www.looksmart.com /r_search?look=&key=Nyerereite   (339 words)

Nyerereite at AllExperts Nyerereite is a very rare sodium calcium carbonate mineral with formula Na Ca(CO It forms colorless, platey pseudohexagonal orthorhombic crystals that are typically twinned. Nyerereite is not stable in contact with the atmosphere and rapidly breaks down. Collection specimens must be kept in a sealed argon environment. en.allexperts.com /e/n/ny/nyerereite.htm   (283 words)

The activity of Oldoinyo Lengai in 1993 More details about the activity of 1993 are given in Nyamweru (1993, 1997). Analysis of Chaos Crags showed it to be very rich in crystals of nyerereite and gregoryite, the typical minerals of natrocarbonatite. However it also contained 8 to 10% by weight of spheroids (up to 2 mm in diameter) of dominantly silicate material. it.stlawu.edu /~cnya/lenweb6b.htm   (781 words)

Oldoinyo Lengai Photographs   (Site not responding. Last check: 2007-10-19) Close-up of an active vent eruping carbonatite lava, Oldoinyo Lengai crater, northern Tanzania. Thin section of natrocarbonatite viewed by cathodoluminescence (CL) microscopy (CLM) showing phenocrysts of hexagonal gregorite (Gr; dark brown) and orthorhombic nyerereite (Ny; orange) in a groundmass of acicular (needle-like) nyerereite (orange), fluorite (dark blue), and sylvite (light blue). Manganese is the element that activates the colors shown by nyerereite and gregorite. web.umr.edu /~rhagni/OLphotos.html   (288 words)

Global Volcanism Program | Ol Doinyo Lengai | Monthly Reports   (Site not responding. Last check: 2007-10-19) Lava samples from the crater floor were analyzed and found to be natrocarbonatite, consisting almost entirely of nyerereite and gregoryite. A thin section showed clear tabular nyerereite and cloudy rounded gregoryite phenocrysts in a finely crystalline groundmass that was primarily carbonate minerals (Hay). The lava flows, fl when active, had whitish edges 24 hours after they stopped advancing, and their surface was entirely whitish after 48 hours of cooling. www.volcano.si.edu /world/volcano.cfm?vnum=0202-12=&volpage=var   (16813 words)

main   (Site not responding. Last check: 2007-10-19) This means that in addition to so-called silicate magmas a sodium-calcium rich carbonate, called natrocarbonatite, has been observed. It is mineralogically mainly composed of nyerereite (named for former Tanzanian president Julius Nyerere) and gregoryite (named for geologist John Walter Gregory). Ol Doinyo Lengai natrocarbonatite lavas have been proved controversial, because although these are the only carbonatite lavas worldwide that have been observed to erupt, natrocarbonatite seems to be absent from other, older carbonatite volcanoes. www.africantravelreview.co.tz /ancient_hills.htm   (848 words)

A Miracle of Science: Ad astra per aspera!   (Site not responding. Last check: 2007-10-19) Natrocarbonatite is composed mostly of two minerals, one of which is called nyerereite. Nyerereite is named for the same man Chief Nyerere is - Julius Nyerere, the first president of Tanzania. It strikes me that I haven't used my picture of a frog in a while. project-apollo.net /mos/mos075.html   (169 words)

McGill SEG: activities These unusual lavas have viscosities approaching that of water (1-5 Pa.s) and erupt at considerably lower temperatures (500-600 oC) than any other lavas; basaltic lavas such as those in Hawaii typically extrude at temperatures in excess of 1000 oC. When crystallized, natrocarbonatite consists primarily of large crystals of nyerereite [Na2Ca(CO3)2] (a mineral that takes its name from the first president of Tanzania, Julius Nyereri) and gregoryite [(Na,K,Ca)2CO3] set in an extremely fine-grained groundmass consisting of these and a variety of other carbonate, sulphate and sulphide minerals. On February 25, our group ascended this volcano in the early morning, and spent 24 hours in the active summit crater at around 2800 metres above sea level, observing a variety of volcanic features and processes. www.eps.mcgill.ca /~seg/activities/index.php   (1722 words)

AMCSD Search Results Nyerereite: A new volcanic carbonate mineral from Oldoinyo Lengai, Tanzania Note: only half of the O atoms have been located Multiple datasets can be concatenated into a single downloadable file by selecting the datasets and then hitting the "Download Selected Data" button. rruff.geo.arizona.edu /AMS/result.php?mineral=Nyerereite   (71 words)

A Miracle of Science: Ad astra per aspera!   (Site not responding. Last check: 2007-10-19) Natrocarbonatite is composed mostly of two minerals, one of which is called nyerereite. Nyerereite is named for the same man Chief Nyerere is - Julius Nyerere, the first president of Tanzania. It strikes me that I haven't used my picture of a frog in a while. www.project-apollo.net /mos/mos075.html   (169 words)

LookSmart - Directory - Guides to Nyerereite   (Site not responding. Last check: 2007-10-19) Save a personal copy of any page on the Web and quickly find it again with Furl.net. Guides to Nyerereite - Browse resources regarding the chemical and physical attributes of this mineral. Join the Zeal community and help build the "Guides to Nyerereite" Directory Category. lsxml.looksmart.com /p/browse/us1/us317914/us263953/us330812/us553452/us10214930/us10182874/us10182896   (206 words)

Calcite - amphibole - clinopyroxene rock from the Afrikanda Complex, Kola Peninsula, Russia: mineralogy and a possible ... Abstract: Carbonate – amphibole – clinopyroxene rocks and carbonatites from the Afrikanda complex, in the Kola Peninsula, Russia, contain a number of oxysalt minerals, including major calcite (15–95 vol.%), subordinate hydroxylapatite, ancylite-(Ce), calcio-ancylite-(Ce), and minor burbankite, khanneshite, nyerereite, shortite, bradleyite, strontianite, britholite-(Ce) and barite. The presence of nyerereite, shortite, bradleyite, burbankite and khanneshite as solid inclusions in the early-crystallized minerals (primarily oxides and hydroxylapatite) indicates initially high activities of Na in the system. The transition from nyerereite (inclusions in magnetite) to shortite (in perovskite) signifies evolution of the carbonatite system toward Ca-enriched compositions. pubs.nrc-cnrc.gc.ca /mineral/tcm-10340-1.html   (595 words)

Liquid immiscibility in the join NaAlSiO4-NaAlSi3O8-CaCO3 at 1 GPa: implications for crustal carbonatites Path (1) then corresponds to the silicate-calcite liquidus field boundary, and a stage is reached where the carbonate-rich liquids will precipitate large amounts of calcite and fractionate toward alkali carbonates (not necessarily matching natrocarbonatite compositions). In path (2) the high-temperature immiscible carbonate liquid precipitates only silicates through a temperature interval until it reaches the silicate-carbonate liquidus field boundary, where it may precipitate calcite or nyerereite or gregoryite. Sovites are readily explained as cumulates, with residual alkali-rich melts causing fenitization. library.iem.ac.ru /j-petr/9-3897/381113.sgm.abs.html   (556 words)

Tanzanian Luxury Maasai Lodge - E Unoto Retreat It is the only volcano in the entire world that extrudes natrocarbonatite (volcanic material containing a large proportion of carbonates- such as calcium and sodium carbonates- chemicals commonly occurring as chalk and baking soda, respectively). The natrocarbonatite at this volcano is made up of largely two minerals, nyerereite (named after Julius Nyerere, the first president of independent Tanzania and who is referred to as the “father of the nation”) and gregoryite (named after J.W. Gregory, mentioned earlier). Lavas from this volcano are fl initially, but turn white in a few weeks. www.maasaivillage.com /pressrelease.htm   (1593 words)

Geology Picture of the Week, August 11-17, 2002   (Site not responding. Last check: 2007-10-19) Expansion of a shield volcano....they say human birth is a miracle,but the birth of land never ceases to amaze me. Let's give everyone a clue-- nyerereite and gregoryite are the principle minerals in this type of pyroclast. Hadn't heard it referred to as the Hershey mine, but the mineral names pretty much nail it down. www.freerepublic.com /focus/chat/731846/posts   (711 words)

Oldoinyo Lengai   (Site not responding. Last check: 2007-10-19) Lengai is made of alternating layers of silicate and carbonate volcanic products. High carbon dioxide (CO2) contents feature in many of the rift volcanos, often expressed as carbonate minerals like calcite; at Lengai nearly pure alkali carbonate minerals (nyerereite and gregoryite) occur in lavas with chemical compositions not disimilar to washing soda! Isotopic measurements show that this alkali carbonate magma comes fomr the mantle, yet samples of the mantle brought to the surface as xenoliths (accidental fragments) in adjacent volcanos (eg Deeti) contain very little CO2. www.earthsciences.ucl.ac.uk /research/petrology/Lengai.html   (339 words)

Oldoinyo Lengai   (Site not responding. Last check: 2007-10-19) Lengai is made of alternating layers of silicate and carbonate volcanic products. High carbon dioxide (CO2) contents feature in many of the rift volcanos, often expressed as carbonate minerals like calcite; at Lengai nearly pure alkali carbonate minerals (nyerereite and gregoryite) occur in lavas with chemical compositions not disimilar to washing soda! Isotopic measurements show that this alkali carbonate magma comes fomr the mantle, yet samples of the mantle brought to the surface as xenoliths (accidental fragments) in adjacent volcanos (eg Deeti) contain very little CO2. www.es.ucl.ac.uk /research/petrology/Lengai.html   (339 words)

v31a in fm99 Olivine phenocrysts in the phoscorites and carbonatites contain abundant crystallised melt inclusions. The primary melt inclusions, 5-200 micron in length, are composed of the following daughter phases: Fe-rich mica (tetraferriphlogopite), clinohumite, magnetite, dolomite, Na-Ca carbonates (including nyerereite), Na-Mg carbonates and mixed salts (eitelite, bradleyite and northupite) with minor calcite. Unlike many silicate melt inclusions heating, homogenisation and quenching does not produce glasses and bulk compositions can not be estimated by homogenisation runs. www.agu.org /cgi-bin/SFgate/SFgate?&listenv=table&multiple=1&range=1&directget=1&application=fm99&database=/data/epubs/wais/indexes/fm99/fm99&maxhits=200&="V31A"   (4557 words)

Nuffieldite   (Site not responding. Last check: 2007-10-19) [263] [264] · Nullaginite [265] [266] · Nyerereite [267] [268] · Nchwaningite [259] [260] · Nuffieldite [261] [262] · Nukundamite Nsutite [266]; Nyerereite [267] [268]; [264]; Nullaginite [265]... List of specified cards with unique numbers under unique name. nuffielditezxug.picaaegp.bepasztp.info   (296 words)

Nyerereite Mineral Data McKie D, Frankis E J, Zeitschrift fur Kristallographie, 145 (1977) p.73-95, Nyerereite: A new volcanic carbonate mineral from Oldoinyo Lengai, Tanzania, Note: low-temperature polymorph that inverted from the high-temperature polymorph, Note: only half of the O atoms have been located, Locality: Oldoinyo Lengai, Tanzania Pseudo Hexagonal - Crystals show a hexagonal outline. Print or Cut-and-Paste your Nyerereite Specimen Label here : webmineral.com /data/Nyerereite.shtml   (308 words)

Do you have more information about the composition of the lava from this volcano?   (Site not responding. Last check: 2007-10-19) Oldoinyo Lengai erupts carbonate lavas (mostly carbon and oxygen). The carbonate minerals in the lava are nyerereite Here is a chemical analysis of one flow: volcano.und.edu /vwdocs/frequent_questions/grp8/question209.html   (190 words)

Do you have more information about the composition of the lava from this volcano? Oldoinyo Lengai erupts carbonate lavas (mostly carbon and oxygen). The carbonate minerals in the lava are nyerereite Here is a chemical analysis of one flow: www.volcanoworld.org /vwdocs/frequent_questions/grp8/question209.html   (190 words)

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