If there is more plagioclase than there is K-feldspar, the rock is either a plagioclase arkose, a plagioclase subarkose or a lithic plagioclase arkose, respectively.
2.
Within the lower subarkose of the Shinumo Sandstone, a basal lag of conglomerate, which contains basement clasts up to across, lies on the eroded surface that forms this disconformity.
3.
First, the Hance Rapids ( lower ) member consists of purple to reddish-purple mudstone, interbedded sandy siltstone, and rare occurrences of thin-bedded subarkose-to quartz arenite.
4.
If there is more K-feldspar than there is plagioclase, or if it is too difficult to make a distinction between the feldspars, the name stays as arkose, subarkose or lithic arkose, respectively.
5.
If the abundances of quartz, feldspars and rock fragments indicate that the rock is an arkose, a subarkose or a lithic arkose, one must then normalize the abundance of feldspars to 100 % and attempt to identify the relative abundances of K-feldspars to plagioclase in the sample.
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