Term
|
Definition
Extrusive often rich in glass. Alkali feldspar 15-75%; sodic plagioclase 0-30%; felspathoids 10-40%; mafics 35-10%. Divided into two varities:
Sodic Phonolite -dominant felsic minerals are sodic, e.g., nepheline, sanidine, anorthoclase
Potassic Phonolite -principle or sole felspathoid is leucite |
|
|
Term
|
Definition
| Extrusive, different varities depending on mineralogy |
|
|
Term
|
Definition
Plagioclase abundant
Alkali feldspar - 10-25% of total feldspar
Felspathoids absent or in small amounts |
|
|
Term
|
Definition
Resembling trachbasalts but with conspicuous modal feldspathoids (>10%)
Olivine, augite, calcic plagioclase, nepheline or leucite |
|
|
Term
|
Definition
| Similar to basanites but lacking olivine |
|
|
Term
|
Definition
| One or more feldspathoids abundant to point of virtual or complete exclusion of feldspar of any kind, e.g. augite + nepheline or leucite +- olivine |
|
|
Term
|
Definition
| Porphyritic rocks with abundant phenocrysts of phlogopite, and microphenocrysts of diopdidic augite set in a groundmass of euhedral or subhedral leicite, magnophorite, diopside and apatite |
|
|
Term
|
Definition
| Diverse group of dark colored basic and ultrabasic rocks usually ocurring in swarms of narrow dikes; all relatively rich in alkalis (Na2O + K2O), and in (FeO + MgO). Porphyritic with two generations of mafic minerals, each generation in the form of euhedral crystals; feldspars confined to the groundmass. |
|
|
Term
| Calc-alkaline and Shoshonitic Lamprophyres |
|
Definition
Have Post-Orgenic complexes or shoshonitic rocks; Ocelli normally absent; xenoliths of granitic and sedimentary rocks are very common.
Kersanite, Spessartite, Minette, and Vogesite |
|
|
Term
|
Definition
| Augite +- Biotite as phenocrysts and common in groundmass; mafic minerals >25-35%. Plagioclase +- K-feldspar; Olivine pseudomorph or quartz as groundmass and minor minerals |
|
|
Term
|
Definition
| Diopsidic augite and Horneblende (green-brown) as phenocrysts and common in groundmass; mafic minerals >25-35%. Plagioclase +- K-feldspar; Olivine pseudomorph or quartz as groundmass and minor minerals |
|
|
Term
|
Definition
| Diopsidic augite +- Biotite as phenocrysts and common in groundmass; mafic minerals >25-35%. K-feldspar +- Plagioclase; Olivine pseudomorph or quartz as groundmass and minor minerals |
|
|
Term
|
Definition
| Diopsidic augite and Hornblende (green-brown) as phenocrysts and common in groundmass; mafic minerals >25-35%. K-feldspar +- Plagioclase; Olivine pseudomorph orquartz as groundmass and minor minerals |
|
|
Term
|
Definition
| Similar to alkali basalts, nephelinites - with alkaline complexes or carbonites. Ocelli very common; xenocrysts of alkali feldspar, kaersutite common; Iherzolite xenoliths rare |
|
|
Term
|
Definition
| Titan-Augite, Barkevikite, Kaersutite, Ti Biotite and/or Olivine as phenocrysts and common in groundmass; Mafic minerals >40%. Plagioclase +- K feldspar, +- Feldspathoid or zeolites;olivine as groundmass and minor minerals. |
|
|
Term
|
Definition
| Titan-Augite, Barkevikite; Kaersutite, Ti-Biotite and/or Olivine as phenocrysts and common in groundmass; mafic minerals >40%. K feldspar +- plagioclase, +- Feldspathoid or zeolites, and olivine as groundmass and minor minerals. |
|
|
Term
|
Definition
| Titan-Augite, Barkevikite, Kaersutite, Ti-Biotite and/or olivine as phenocrysts and common in groundmass; mafic minerals >40%. Glass or possibly analcime or nepheline and/or zeolites as groundmass and minor minerals. |
|
|
Term
|
Definition
| With alkaline complexes or carbonitites |
|
|
Term
|
Definition
| Titan-Augite or other Cpx and Biotite as phenocrysts and common in groundmass; mafic minerals >90%. Melilite +- olivine, perovskite, or a feldspathoid as groundmass and minor minerals. |
|
|
Term
|
Definition
| Titan-Augite or other Cpx and Biotite as phenocrysts and common in groundmass; mafic minerals 70-90%. Melilite + a feldspathoid such as nepheline or hauyne +- olivine, perovskite as groundmass and minor minerals. |
|
|
