General Chronological Criteria
It is common practice to assume that in igneous or metamorphic rocks, a given mineral 1 is older than some mineral 2 if 1 is either partly or completely included in 2 (Fig. 3.1A). The relative ages of 2 and 1 can usually be determined by general petrogenetic analysis and by studying the local geological context. In some cases, the form and distribution of 1 and 2 can give an idea of the time lapse between the formation of the first and that of the second mineral.
KeywordsMetamorphic Rock Polycrystalline Aggregate Native Crystal Geometrical Lattice Prefer Nucleation Site
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