Authigenic sphene in these two sandstones occurs commonly as cement, often on altered detrital biotites; it may develop prismatic or sphenoidal forms. SEM photographs and microprobe analyses are presented and relatively high Al (Al2O3 2.04-4.82%), and smaller Fe (Fe2O3 0.08-1.39%) and Mg (MgO 0.04-0.28%) contents reported. The sphenes show etched surfaces and are associated with leucoxene when they occur in calcite cement, but those that occur in quartz cement have smooth faces and better crystal morphology. Compared with the sphene in low-grade metamorphic rocks and in some igneous rocks, it has a specific chemical composition. -R.A.H.
|Number of pages||10|
|Journal||Neues Jahrbuch fur Mineralogie, Monatshefte|
|Publication status||Published - Jan 1 1986|
ASJC Scopus subject areas
- Geochemistry and Petrology