Melilitolite: An ultramafic plutonic rock consisting essentially of melilite, pyroxene and olivine.
The melilitolites are classified according to their mineral content. Those with melilite < feldspathoid and with feldspathoid > 10% are classified as melilite foidolites. In a recent paper on the classification of melilitic rocks, Dunworth & Bell (1998) suggested that melilitolites with melilite > 65% be termed ultramelilitolites. Besides melilite, other principal mineral components include perovskite, olivine, hauyne, nepheline and pyroxene. If these minerals comprise > 10% of the rock and melilite is < 65% then the following names may be used:
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If a third mineral is present in amounts greater than 10% then it can be applied as a modifier, e.g. magnetite-pyroxene Melilitolite.
Melilitolite classification.
The calcite-leucite-melilitolite of Pian di Celle (San Venanzo) has been famous for over a century, and was previously called pegmatoid venanzite (Gallo et al., 1984). It contains tabular melilite up to 5 cm long, nepheline intergrowths associated with coarse-grained, intergranular, twinned leucite, nepheline and kalsilite as essential minerals. The interstices between these phases are filled with a fine-grained groundmass composed of Apatite, F-phlogopite, clinopyroxene, Zr-cuspidine, gotzenite, khibinskite, pyrrhotite, Co-Ni-westerveldite, bartonite, wollastonite and brown or green glass. Olivine and monticellite also occur. The interstitial material commonly contains carbonate ocelli with high Sr, B a and REE (Stoppa and Woolley, 1997).
Panoramic view of coarse-grained pegmatitic Venanzinte thin section. Image by Andy Tindle (Virtual Microscope). PPL image, field of view = 2.5cm.
Panoramic view of coarse-grained pegmatitic Venanzinte thin section. Image by Andy Tindle (Virtual Microscope). XPL image, field of view = 2.5cm.
Contact between coarse-grained pegmatitic venanzinte (melilitolite) and venanzite aphanitic lava at Pian di Celle lava flow, San Venanzo, Italy.
Contact between coarse-grained pegmatitic venanzinte (melilitolite) and venanzite aphanitic lava at Pian di Celle lava flow, San Venanzo, Italy.
Coarse-grained pegmatitic venanzinte (melilitolite) at Pian di Celle lava flow, San Venanzo, Italy.
• Stoppa, F., & Sforna, S. (1995). Geological map of the San Venanzo volcano (Central Italy): explanatory notes. Acta Vulcanologica, 7(1), 85-91.
• Stoppa, F. (1996). The San Venanzo maar and tuff ring, Umbria, Italy: eruptive behaviour of a carbonatite-melilitite volcano. Bulletin of Volcanology, 57(7), 563-577.
• Stoppa, F., & Cundari, A. (1998). Origin and multiple crystallization of the kamafugite-carbonatite association: The San Venanzo-Pian di Celle occurrence (Umbria, Italy). Mineralogical Magazine, 62(2), 273-289.
Foto
![sanvenanzo0140(3).jpg](/immagini/vulc/piccole/sanvenanzo0140(3).jpg)
Melilite (with anomalous, berlin blue colors) and olivine in a Melilitite, San Venanzo (Umbria, Italy). XPL image , 2x (Field of view = 7mm) |
![sanvenanzo0140(6).jpg](/immagini/vulc/piccole/sanvenanzo0140(6).jpg)
Melilite (with anomalous, berlin blue colors), Leucite (dark and twinned) and olivine in a Melilitite, San Venanzo (Umbria, Italy). XPL image , 2x (Field of view = 7mm) |
![sanvenanzo0140(8).jpg](/immagini/vulc/piccole/sanvenanzo0140(8).jpg)
Melilite (with anomalous, berlin blue colors), Leucite (dark and twinned) and olivine in a Melilitite, San Venanzo (Umbria, Italy). XPL image , 2x (Field of view = 7mm) |
![sanvenanzo0140(14).jpg](/immagini/vulc/piccole/sanvenanzo0140(14).jpg)
Melilite (with anomalous, berlin blue colors), Leucite (dark and twinned) and olivine in a Melilitite, San Venanzo (Umbria, Italy). XPL image , 2x (Field of view = 7mm) |
![sanvenanzo0140(15).jpg](/immagini/vulc/piccole/sanvenanzo0140(15).jpg)
Melilite (with anomalous, berlin blue colors), Leucite (dark and twinned) and olivine in a Melilitite, San Venanzo (Umbria, Italy). XPL image , 2x (Field of view = 7mm) |
![sanvenanzo0140(16).jpg](/immagini/vulc/piccole/sanvenanzo0140(16).jpg)
Melilite (with anomalous, berlin blue colors), Phlogopite, Leucite (dark and twinned) and olivine in a Melilitite, San Venanzo (Umbria, Italy). XPL image , 2x (Field of view = 7mm) |
![sanvenanzo0140(18).jpg](/immagini/vulc/piccole/sanvenanzo0140(18).jpg)
Melilite (with anomalous, berlin blue colors), Leucite (dark and twinned) and olivine in a Melilitite, San Venanzo (Umbria, Italy). XPL image , 2x (Field of view = 7mm) |
![sanvenanzo0140(19).jpg](/immagini/vulc/piccole/sanvenanzo0140(19).jpg)
Melilite (with anomalous, berlin blue colors), Leucite (dark and twinned) and olivine in a Melilitite, San Venanzo (Umbria, Italy). XPL image , 2x (Field of view = 7mm) |
![sanvenanzo0140(20).jpg](/immagini/vulc/piccole/sanvenanzo0140(20).jpg)
Melilite (with anomalous, berlin blue colors), Leucite (dark and twinned) and olivine in a Melilitite, San Venanzo (Umbria, Italy). XPL image , 2x (Field of view = 7mm) |
![venanzitepegmatoide(2).jpg](/immagini/vulc/piccole/venanzitepegmatoide(2).jpg)
Melilite (beige), Leucite and olivine (colorless) and Phlogopite (brown) in a Melilitite, San Venanzo (Umbria, Italy). PPL image , 2x (Field of view = 7mm) |
![venanzitepegmatoide(3).jpg](/immagini/vulc/piccole/venanzitepegmatoide(3).jpg)
Melilite (with anomalous, berlin blue colors), Phlogopite, Leucite (dark and twinned) and olivine in a Melilitite, San Venanzo (Umbria, Italy). XPL image , 2x (Field of view = 7mm) |
![venanzitepegmatoide(4).jpg](/immagini/vulc/piccole/venanzitepegmatoide(4).jpg)
Melilite (beige), Leucite and olivine (colorless) and Phlogopite (brown) in a Melilitite, San Venanzo (Umbria, Italy). PPL image , 2x (Field of view = 7mm) |
![venanzitepegmatoide(5).jpg](/immagini/vulc/piccole/venanzitepegmatoide(5).jpg)
Melilite (beige), Leucite and olivine (colorless) and Phlogopite (brown) in a Melilitite, San Venanzo (Umbria, Italy). PPL image , 2x (Field of view = 7mm) |
![venanzitepegmatoide(6).jpg](/immagini/vulc/piccole/venanzitepegmatoide(6).jpg)
Melilite (with anomalous, berlin blue colors), Phlogopite, Leucite (dark and twinned) and olivine in a Melilitite, San Venanzo (Umbria, Italy). XPL image , 2x (Field of view = 7mm) |
![venanzitepegmatoide(7).jpg](/immagini/vulc/piccole/venanzitepegmatoide(7).jpg)
Melilite (beige), Leucite and olivine (colorless) and Phlogopite (brown) in a Melilitite, San Venanzo (Umbria, Italy). PPL image , 2x (Field of view = 7mm) |
![venanzitepegmatoide(8).jpg](/immagini/vulc/piccole/venanzitepegmatoide(8).jpg)
Melilite (with anomalous, berlin blue colors), Leucite (dark and twinned) and olivine in a Melilitite, San Venanzo (Umbria, Italy). XPL image , 2x (Field of view = 7mm) |
![venanzitepegmatoide(9).jpg](/immagini/vulc/piccole/venanzitepegmatoide(9).jpg)
Melilite (beige), Leucite and olivine (colorless), pyroxene (green) and Phlogopite (brown) in a Melilitite, San Venanzo (Umbria, Italy). PPL image , 2x (Field of view = 7mm) |
![venanzitepegmatoide(10).jpg](/immagini/vulc/piccole/venanzitepegmatoide(10).jpg)
Melilite (with anomalous, berlin blue colors), Leucite (dark and twinned), pyroxene and olivine in a Melilitite, San Venanzo (Umbria, Italy). XPL image , 2x (Field of view = 7mm) |
![venanzitepegmatoide(11).jpg](/immagini/vulc/piccole/venanzitepegmatoide(11).jpg)
Melilite (with anomalous, berlin blue colors), Leucite (dark) and Kalsilite (gray). XPL image , 10x (Field of view = 2mm) |
![venanzitepegmatoide(12).jpg](/immagini/vulc/piccole/venanzitepegmatoide(12).jpg)
Melilite (with anomalous, berlin blue colors), Leucite (dark) and Kalsilite (gray). XPL image , 10x (Field of view = 2mm) |
![venanzitepegmatoide(13).jpg](/immagini/vulc/piccole/venanzitepegmatoide(13).jpg)
Melilite (with anomalous, berlin blue colors) and Leucite (dark). XPL image , 10x (Field of view = 2mm) |
![venanzitepegmatoide(14).jpg](/immagini/vulc/piccole/venanzitepegmatoide(14).jpg)
Melilite (with anomalous, berlin blue colors) and Leucite (dark). XPL image , 10x (Field of view = 2mm) |
![venanzitepegmatoide(15).jpg](/immagini/vulc/piccole/venanzitepegmatoide(15).jpg)
Melilite (with anomalous, berlin blue colors) and Leucite (dark). XPL image , 10x (Field of view = 2mm) |
![venanzitepegmatoide(16).jpg](/immagini/vulc/piccole/venanzitepegmatoide(16).jpg)
Melilite (with anomalous, berlin blue colors). XPL image , 10x (Field of view = 2mm) |
![venanzitepegmatoide(17).jpg](/immagini/vulc/piccole/venanzitepegmatoide(17).jpg)
Melilite (with anomalous, berlin blue colors). XPL image , 10x (Field of view = 2mm) |
![venanzitepegmatoide(18).jpg](/immagini/vulc/piccole/venanzitepegmatoide(18).jpg)
Melilite (with anomalous, berlin blue colors), Leucite (dark and twinned) and Phlogopite in a Melilitite, San Venanzo (Umbria, Italy). XPL image , 2x (Field of view = 7mm) |
![venanzitepegmatoide(19).jpg](/immagini/vulc/piccole/venanzitepegmatoide(19).jpg)
Melilite (with anomalous, berlin blue colors), Leucite (dark and twinned) and Phlogopite in a Melilitite, San Venanzo (Umbria, Italy). XPL image , 2x (Field of view = 7mm) |
![sanvenanzooo(2).jpg](/immagini/vulc/piccole/sanvenanzooo(2).jpg)
Melilite (beige), Leucite and olivine (colorless), pyroxene (green) and Phlogopite (brown) in a Melilitite, San Venanzo (Umbria, Italy). PPL image , 2x (Field of view = 7mm) |
![sanvenanzooo(3).jpg](/immagini/vulc/piccole/sanvenanzooo(3).jpg)
Melilite (with anomalous, berlin blue colors), Leucite (dark and twinned), pyroxene and olivine in a Melilitite, San Venanzo (Umbria, Italy). XPL image , 2x (Field of view = 7mm) |
![sanvenanzooo(5).jpg](/immagini/vulc/piccole/sanvenanzooo(5).jpg)
Melilite (with anomalous, berlin blue colors), Leucite (dark and twinned), pyroxene and olivine in a Melilitite, San Venanzo (Umbria, Italy). XPL image , 2x (Field of view = 7mm) |
![sanvenanzooo(17).jpg](/immagini/vulc/piccole/sanvenanzooo(17).jpg)
Melilite (with anomalous, violet-yellow and berlin blue colors) and Leucite (dark and twinned) in a Melilitite, San Venanzo (Umbria, Italy). XPL image , 2x (Field of view = 7mm) |
![sanvenanzomelilite(9).jpg](/immagini/vulc/piccole/sanvenanzomelilite(9).jpg)
Melilite (with anomalous, berlin blue colors), Leucite (dark and twinned) and olivine in a Melilitite, San Venanzo (Umbria, Italy). XPL image , 2x (Field of view = 7mm) |
![sanvenanzooo(16).jpg](/immagini/vulc/piccole/sanvenanzooo(16).jpg)
Melilite (with anomalous, berlin blue colors), Leucite (dark and twinned) and olivine in a Melilitite, San Venanzo (Umbria, Italy). XPL image , 2x (Field of view = 7mm) |
![vvenanzitee(40).jpg](/immagini/vulc/piccole/vvenanzitee(40).jpg)
Melilite (with anomalous, berlin blue colors), Leucite (dark and twinned), Phlogopite, and olivine in a Melilitite, San Venanzo (Umbria, Italy). XPL image , 2x (Field of view = 7mm) |
![vvenanzitee(42).jpg](/immagini/vulc/piccole/vvenanzitee(42).jpg)
Melilite (with anomalous, berlin blue colors) and Phlogopite in a Melilitite, San Venanzo (Umbria, Italy). XPL image , 2x (Field of view = 7mm) |
![vvenanzitee(43).jpg](/immagini/vulc/piccole/vvenanzitee(43).jpg)
Melilite (with anomalous, berlin blue colors) and Leucite (dark and twinned) in a Melilitite, San Venanzo (Umbria, Italy). XPL image , 2x (Field of view = 7mm) |
![vvenanzitee(44).jpg](/immagini/vulc/piccole/vvenanzitee(44).jpg)
Melilite (with anomalous, berlin blue colors), Phlogopite, Kalsilite (gray) in a Melilitite, San Venanzo (Umbria, Italy). XPL image , 2x (Field of view = 7mm) |
![vvenanzitee(45).jpg](/immagini/vulc/piccole/vvenanzitee(45).jpg)
Melilite (with anomalous, berlin blue colors) and Phlogopite in a Melilitite, San Venanzo (Umbria, Italy). XPL image , 2x (Field of view = 7mm) |
![vvenanzitee(46).jpg](/immagini/vulc/piccole/vvenanzitee(46).jpg)
Melilite (with anomalous, berlin blue colors), Phlogopite, Kalsilite (gray) in a Melilitite, San Venanzo (Umbria, Italy). XPL image , 2x (Field of view = 7mm) |
![vvenanzitee(47).jpg](/immagini/vulc/piccole/vvenanzitee(47).jpg)
Melilite (with anomalous, berlin blue colors) in a Melilitite, San Venanzo (Umbria, Italy). XPL image , 10x (Field of view = 2mm) |
![vvenanzitee(48).jpg](/immagini/vulc/piccole/vvenanzitee(48).jpg)
Melilite (with anomalous, berlin blue colors) in a Melilitite, San Venanzo (Umbria, Italy). XPL image , 10x (Field of view = 2mm) |
![vvenanzitee(49).jpg](/immagini/vulc/piccole/vvenanzitee(49).jpg)
Melilite (beige) and Phlogopite in a Melilitite, San Venanzo (Umbria, Italy). PPL image , 10x (Field of view = 2mm) |
![vvenanzitee(50).jpg](/immagini/vulc/piccole/vvenanzitee(50).jpg)
Melilite (with anomalous, berlin blue colors) in a Melilitite, San Venanzo (Umbria, Italy). XPL image , 10x (Field of view = 2mm) |
![vvenanzitee(51).jpg](/immagini/vulc/piccole/vvenanzitee(51).jpg)
Melilite (with anomalous, berlin blue colors) and Leucite in a Melilitite, San Venanzo (Umbria, Italy). XPL image , 10x (Field of view = 2mm) |
![vvenanzitee(52).jpg](/immagini/vulc/piccole/vvenanzitee(52).jpg)
Melilite (with anomalous, berlin blue colors) and Leucite in a Melilitite, San Venanzo (Umbria, Italy). XPL image , 10x (Field of view = 2mm) |
![vvenanzitee(53).jpg](/immagini/vulc/piccole/vvenanzitee(53).jpg)
Melilite (beige) and Phlogopite in a Melilitite, San Venanzo (Umbria, Italy). XPL image , 10x (Field of view = 2mm) |
![vvenanzitee(54).jpg](/immagini/vulc/piccole/vvenanzitee(54).jpg)
Melilite (with anomalous, berlin blue colors) in a Melilitite, San Venanzo (Umbria, Italy). XPL image , 10x (Field of view = 2mm) |
![vvenanzitee(55).jpg](/immagini/vulc/piccole/vvenanzitee(55).jpg)
Melilite (beige), Magnetite and Phlogopite in a Melilitite, San Venanzo (Umbria, Italy). PPL image , 10x (Field of view = 2mm) |
![melilitolite(27).jpg](/immagini/vulc/piccole/melilitolite(27).jpg)
Melilite (beige-white), Magnetite, green pyroxene and Phlogopite in a Melilitite, San Venanzo (Umbria, Italy). PPL image , 2x (Field of view = 7mm) |
![melilitolite(34).jpg](/immagini/vulc/piccole/melilitolite(34).jpg)
Melilite (beige-white), Magnetite, green pyroxene and Phlogopite in a Melilitite, San Venanzo (Umbria, Italy). PPL image , 2x (Field of view = 7mm) |
![melilitolite(33).jpg](/immagini/vulc/piccole/melilitolite(33).jpg)
Melilite, Magnetite, pyroxene and Phlogopite in a Melilitite, San Venanzo (Umbria, Italy). XPL image , 2x (Field of view = 7mm) |
![melilitolite(6).jpg](/immagini/vulc/piccole/melilitolite(6).jpg)
Melilite (with anomalous, berlin blue colors), Phlogopite and Leucite in a Melilitite, San Venanzo (Umbria, Italy). XPL image , 2x (Field of view = 7mm) |
![melilitolite(8).jpg](/immagini/vulc/piccole/melilitolite(8).jpg)
Melilite (with anomalous, berlin blue colors), Olivine, Phlogopite and Leucite in a Melilitite, San Venanzo (Umbria, Italy). XPL image , 2x (Field of view = 7mm) |
![melilitolite(47).jpg](/immagini/vulc/piccole/melilitolite(47).jpg)
Melilite (with anomalous, berlin blue colors), Phlogopite and Calcite in a Melilitite, San Venanzo (Umbria, Italy). XPL image , 2x (Field of view = 7mm) |
![melilitolite(15).jpg](/immagini/vulc/piccole/melilitolite(15).jpg)
Pyroxene and Kalsilite (gray). XPL image , 10x (Field of view = 2mm) |
![melilitolite(20).jpg](/immagini/vulc/piccole/melilitolite(20).jpg)
Pyroxene and Kalsilite (colorless, rectangular crystals). PPL image , 10x (Field of view = 2mm) |
![melilitolite(21).jpg](/immagini/vulc/piccole/melilitolite(21).jpg)
Pyroxene and Kalsilite (gray). XPL image , 10x (Field of view = 2mm) |
![melilitolite(23).jpg](/immagini/vulc/piccole/melilitolite(23).jpg)
Phlogopite and Kalsilite (gray). XPL image , 10x (Field of view = 2mm) |
![melilitolite(25).jpg](/immagini/vulc/piccole/melilitolite(25).jpg)
Phlogopite and Kalsilite (gray). XPL image , 10x (Field of view = 2mm) |
![melilitolite(41).jpg](/immagini/vulc/piccole/melilitolite(41).jpg)
Pyroxene and Kalsilite (gray). XPL image , 10x (Field of view = 2mm) |
![melilitolite(53).jpg](/immagini/vulc/piccole/melilitolite(53).jpg)
Leucite, Phlogopite and Kalsilite (gray) and Calcite. XPL image , 10x (Field of view = 2mm) |
![melilitolite(31).jpg](/immagini/vulc/piccole/melilitolite(31).jpg)
Phlogopite and Calcite. XPL image , 10x (Field of view = 2mm) |
![melilitolite(54).jpg](/immagini/vulc/piccole/melilitolite(54).jpg)
Green glass between Phlogopite crystals. PPL image , 10x (Field of view = 2mm) |
![melilitolite(2).jpg](/immagini/vulc/piccole/melilitolite(2).jpg)
Green glass between Phlogopite crystals. The small, fibrous colorless crystals are Cuspidine. PPL image , 10x (Field of view = 2mm) |
![melilitolite(4).jpg](/immagini/vulc/piccole/melilitolite(4).jpg)
Green glass between Phlogopite and Kalsilite (square) crystals. The small, fibrous colorless crystals are Cuspidine. PPL image , 10x (Field of view = 2mm) |
![melilitolite(3).jpg](/immagini/vulc/piccole/melilitolite(3).jpg)
Green glass between Phlogopite crystals. The small, fibrous colorless crystals are Cuspidine. PPL image , 10x (Field of view = 2mm) |
![melilitolite(5).jpg](/immagini/vulc/piccole/melilitolite(5).jpg)
Green glass between Phlogopite and Kalsilite (square) crystals. The small, fibrous colorless crystals are Cuspidine. PPL image , 10x (Field of view = 2mm) |