To these succeeded during the Pliocene epoch still more highly silicated rocks of trachytic type, consisting of sanidine and oligoclase trachytes.
It is remarkable for the large crystals of sanidine (glassy felspar) which it contains, and has a rude columnar structure.
In the dacites felsitic groundmasses are by no means rare, but microcrystalline types consisting of plagioclase and sanidine with quartz are more prevalent.
Sanidine occurs with considerable frequency, but not in notable amount.
Sanidine usually is found in volcanic ash falls and has been important in the establishment of the geologic time scale, as we shall see.
Sanidine Still another good system is the rare feldspar, sanidine, which is excellent for both potassium-argon and rubidium-strontium age determination.
Monoclinic felspar does, however, occur in some of these rocks; but the difficulty of ascertaining the precise character of microliths renders it unsafe to speculate on the amount of sanidine which may be present.
In some of these lavasSanidine is also present, but it is always subordinate to the plagioclase, and does not, as a rule, appear to play a part sufficiently prominent to entitle the rock to the appellation Trachy-dolerite.
The texture of rhyolite is often more or less distinctly porphyritic, having a finely crystalline or granular matrix, with interspersed crystals of sanidine and quartz.
The composition is sometimes partially revealed where a portion of the sanidine comes out in distinct crystals porphyritically interspersed through the glass.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "sanidine" in a variety of sentences. We hope that you will now be able to make sentences using this word.
