Feldspars oligoclase

Plagioclase feldspars Albite, oligoclase, andesine, labradorite, bytownite, anorthite... 

It should be noted that in the above examples significant energy migration can occur between thermal stimulation and recombination since the electron is free to diffuse throughout the sample. Other electron-hole recombination processes occur, however, in which the excited states of the charge carrier are not to be found in the delocalized bands. An example of this, recently noted in the literature, concerns the TL emission from oligoclase feldspar in which the thermal stimulation involves the transition of the electron to a localized, intermediate state - see Figure 8... 

Figure 8. The Localized Transition Model for TL emission from oligoclase feldspar. The TL signal appears near 280°C.

FarquharM. L., Wogelius R. A., and Tang C. C. (1999a) In situ synchrotron x-ray reflectivity study of the oligoclase feldspar mineral-fluid interface. Geochim. Cosmochim. Acta 63, 1587-1594. 

The major portion of the dissolved silica in the stream is derived from the brealcdown of oligoclase feldspar even though quartz is the major silica mineral in the rock. 

In granodiorite, the plagioclase is oligoclase or andesine and is at least double the amount of potash feldspar present, the latter forming 8 to 20% of the rock. The plagioclases are nearly always euhedral (minerals completely bounded by crystal faces), as may be biotite and hornblende. These minerals are set in a quartz-potash feldspar matrix. 

Aluminium group Feldspar group Silicates group Aualcime Andesine Anorthite Bytownite Kaolinite Labradorite Montmoiillonite Oligoclase... 

Feldspar group (Framework silicates) Albite Andesine Anorthite Anorthoclase Bytownite Labradorite Microcline Oligoclase Orthoclase. 

At a concentration of 1 mM and moderately acidic conditions, oxalate has no effect on the dissolution rate of oligoclase feldspar, but a significant effect on more calcic feldspars (Mast and Drever 1987 Amrhein and Suarez 1988 Oxburgh 1991). Swoboda-Colberg and Drever (unpubl.) measured the effect of ImM oxalate on the dissolution rate at pH 4 and 4.5 of the 75-150//m size fraction of natural soil minerals from a Spodosol in Maine. 

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