Natrocarbonatite is a rare carbonatite lava which erupts from the Ol Doinyo Lengai volcano in Tanzania within the East African Rift of eastern Africa. Natrocarbonatite lavas were first documented in 1962, by J. B. Dawson.

2019年4月15日 · Earth’s only active natrocarbonatite volcanism, occurring at Oldoinyo Lengai (OL), Tanzania, suggests that natrocarbonatite melts are formed through a unique geological process.

Data from experiments with natrocarbonatite and related synthetic systems indicate that Na−K−Ca carbonatite magmas which crystallize calcite cannot fractionate to nyerereite+gregoryite +liquid assemblages. Natrocarbonatites plot in the liquidus field of nyerereite, and minor fractionation of nyerereite to produce the erupted lavas is indicated.

2012年9月1日 · These carbonatites, known as natrocarbonatites or gregoryite–nyerereite carbonatites, are unusual in most aspects of their mineralogical, geochemical and petrological characteristics and are distinguished from other carbonatites as extremely alkali-rich rocks.

2020年7月29日 · Located in the remote Maasai lands of northern Tanzania, Ol Doinyo Lengai is one of the most unusual volcanoes in the world. Eruptions cycle between violent explosions of silicate magma and passive...

钠碳酸岩（natrocarbonatite）又称碳酸熔岩 (lengaite)。 是一种罕见的碳酸熔岩。 仅见于坦桑尼亚伦盖火山 (Lungai)。 1960年伦盖火山喷发出的一种碳酸熔岩。 岩石由Na Ca K碳酸盐矿物组成，包括尼碳钠钙石（尼雷尔石）和格碳钠石 (gregoryite) 是一种罕见的碳酸熔岩。 仅见于坦桑尼亚伦盖火山 (Lungai)。 1960年伦盖火山喷发出的一种碳酸熔岩。 岩石由Na Ca K碳酸盐矿物组成,包括尼碳钠钙石 (尼雷尔石)和格碳钠石 (gregoryite) 钠碳酸岩（natrocarbonatite）又称碳酸熔岩 …

2006年10月1日 · The natrocarbonatite lavas of the Oldoinyo Lengai volcano, East African Rift, Tanzania, consist of the water-soluble phenocryst minerals nyerereite and gregoryite, groundmass sylvite and halite and are black to dark grey.

2023年6月19日 · Major-element calculations show that crystallization of 32% gregoryite and 18% nyerereite from the type natrocarbonatite composition can reproduce the aphyric natrocarbonatite composition (50% crystallization is indicated by the gray line).

The best interpretation of the Oldoinyo Lengai natrocarbonatite involves expulsion of a cognate, mobile, alkaline, and CO 2-rich fluid condensate. The activity at Oldoinyo Lengai can be divided into three main types: (1) dormant stage; (2) carbonatite stage, and (3) Plinian stage.

A carbonatite composed essentailly of sodium +/-potassium +/-calcium carbonate minerals. A lava known from only one locality currently. Please feel free to link to this page. Peterson, Tony D. (1990) Petrology and genesis of natrocarbonatite. Contributions to Mineralogy and Petrology, 105 (2) 143-155 doi:10.1007/bf00678981.

2013年10月30日 · Here we report a detailed chemical investigation of melt inclusions associated with intrusive (plutonic) calcite-rich carbonatites from the ~120 Ma carbonatite complex of Oka (Canada). Melt...

No natural silicate magma is known to produce natrocarbonatite compositions by liquid immiscibility. The best interpretation of the Oldoinyo Lengai natrocarbonatite flows involves expulsion of a cognate, mobile, alkaline, and CO2-rich fluid condensate.

2008年8月1日 · Three major processes, mineral dissolution, metasomatic replacement and crystallization from solution, alter the natrocarbonatite to pirssonite carbonatite, shortite carbonatite and calcite carbonatite. Nyerereite – pirssonite – calcite relationships depend on variations in P(H 2 O) and P(CO 2).

1997年12月1日 · Porphyritic natrocarbonatite lavas erupted from the Oldoinyo Lengai volcano (Tanzania) on 17 October 1995 and 15-19 December 1995 differ from previously studied lavas in that they preserve textures indicative of groundmass carbonate-carbonate immiscibility.

A carbonatite composed essentailly of sodium +/-potassium +/-calcium carbonate minerals. A lava known from only one locality currently. https://www.mindat.org/min-48026.html Please feel free to link to this page. Peterson, Tony D. (1990) Petrology and genesis of natrocarbonatite.

The chemical relationships of the natrocarbonatite component in the spheroids to the dominant silicate fraction are consistent with liquid immiscibility, as are the multiple stages of unmixing. These direct observations confirm the intimate relationship between natrocarbonatite and wollastonite nephelinite inferred both from the field ...

2018年10月9日 · A natrocarbonatite is a special variety of carbonatite consisting mainly of Na–K–Ca carbonates, such as nyerereite [(Na,K) 2 Ca(CO 3) 2] and gregoryite [(Na,K,Ca x) 2–x (CO 3)], known from Ol Doinyo Lengai volcano (Tanzania).

The trace element signature of natrocarbonatite as compared with the more common alkali-poor carbonatites shows that Lengai lavas represent exotic compositions so far restricted to this volcano, and cannot be used to model petrogenetic schemes for carbonatites in general.

2021年10月1日 · Carbonatites are unique, enigmatic, and controversial rocks directly sourced from, or evolved from, mantle melts. Mineral proportions and chemical compositions of carbonatites are highly variable and depend on a wide range of processes: melt generation, liquid immiscibility, fractional crystallization, and post-magmatic alteration.

Natrocarbonatite is a rare carbonatite lava which erupts from the Ol Doinyo Lengai volcano in Tanzania and is part of the volcanic system of the Great Rift Valley in eastern Africa.