Dioritoid
A rock classification type
This page is currently not sponsored. Click here to sponsor this page.
About Dioritoid
A field term for coarse-grained crystalline normal igneous rocks with <90% mafic minerals and the felsic minerals containing <20% quartz, <10% felspathoids and plagioclase being >65% of total feldspars. The plagioclase is sodium rich, in contrast to gabbroids, which have calcium rich plagioclase. The group includes diorite, quartz diorite, quartz monzodiorite, foid- bearing diorite, foid- bearing monzodiorite and monzodiorite.
Unique Identifiers
Mindat ID:
48224
Long-form identifier:
mindat:1:1:48224:6
Similar Names
| Dioritite | A rock subtype |
Classification of Dioritoid
float='left'>Dioritic rocks are in sections 9,9*,9â,10,10* and 10' of the QAPF diagram.
Sub-divisions of Dioritoid
Mineralogy of Dioritoid
Essential minerals - these are minerals that are required within the classification of this rock:
| Feldspar > Plagioclase | (Na,Ca)[(Si,Al)AlSi2]O8 |
Non-essential minerals - these minerals are common, sometimes major components, but are not always present:
| Amphibole > Hornblende | AnCa2(Z2+5-mZ3+m)(Si8-(n+m)Al(n+m))(OH,F,Cl)2 |
| Mica > Biotite | K(Fe2+/Mg)2(Al/Fe3+/Mg/Ti)([Si/Al/Fe]2Si2O10)(OH/F)2 |
Age distribution
Recorded ages:
Phanerozoic : 275.2 Âą 1.2 Ma to 97.0 Âą 3.1 Ma - based on 7 recorded ages.
Sample ages:
| Sample ID | Recorded age | Geologic Time | Dating method |
|---|---|---|---|
| 1 | 97.0 Âą 3.1 Ma | Late/Upper Cretaceous | K-Ar |
| 2 | 131.7 Âą 1.4 Ma | Early/Lower Cretaceous | LA-ICP-MS zircon U-Pb |
| 3 | 185.4 Âą 2.0 Ma | Early Jurassic | Rb-Sr isochron |
| 4 | 275.2 Âą 1.2 Ma | Cisuralian |
Sample references:
Chemical Analysis
Oxide wt%:
| 1 | 2 | 3 | |
|---|---|---|---|
| SiO2 | 43.35 % | 45.95 % | 41.61 % |
| Al2O3 | 16.56 % | 16.47 % | 13.09 % |
| TiO2 | 3.15 % | 3.38 % | 4.39 % |
| Fe2O3 | 2.00 % | 2.00 % | 2.00 % |
| FeO | 7.87 % | 8.69 % | 12.73 % |
| MgO | 3.44 % | 4.05 % | 6.44 % |
| MnO | 0.27 % | 0.22 % | 0.19 % |
| Na2O | 6.07 % | 5.1 % | 3.89 % |
| CaO | 10.75 % | 10.17 % | 11.59 % |
| K2O | 2.8 % | 2.4 % | 2.1 % |
| P2O5 | 0.87 % | 0.6 % | 0.56 % |
| Total: | 97.13 % | 99.03 % | 98.59 % |
Sample references:
| ID | Locality | Reference | Notes |
|---|---|---|---|
| 1 | Mont Royal, MontrÃĐal, QuÃĐbec, Canada | Wet chemical analysis by G. Woussen and B.M.Gunn. The Fe2O3 percentage is arbitrarily set to 2%. | |
| 2 | " " | Wet chemical analysis by G. Woussen and B.M.Gunn. The Fe2O3 percentage is arbitrarily set to 2%. | |
| 3 | " " | Wet chemical analysis by G. Woussen and B.M.Gunn. The Fe2O3 percentage is arbitrarily set to 2%. |
Synonyms of Dioritoid
Internet Links for Dioritoid
mindat.org URL:
https://www.mindat.org/min-48224.html
Please feel free to link to this page.
Please feel free to link to this page.
References for Dioritoid
Reference List:
TeletÃn quarry, KrÅany, BeneÅĄov District, Central Bohemian Region, Czech Republic