ABSTRACT
As one might expect, most fossils are destroyed during metamorphism by deformation and recrystallization. In unusual circumstances, however, fossils can survive in recognizable form even to high metamorphic grade. At the very least, such circumstances generally require minimal deformation of the fossil-bearing rock. Fossil preservation might occur by happenstance, such as a situation in which the fossil-bearing rock is preserved in less-deformed fold hinges. Deformation might also be limited if reactions early in the metamorphic history produced minerals that strengthened the fossil-bearing rock, allowing it to resist deformation. For example, an impure dolomite might react early during metamorphism to form a calc-silicate assemblage strong enough to resist deformation, if surrounding rocks were more ductile (e.g., Boucot and Thompson, 1963; Boucot and Rumble, 1978; brachiopods in sillimanite grade calcsilicate rock). Another possibility is that the fossils themselves were originally stronger than the host rock (e.g., Elbert et al., 1988, apatite conodonts in garnet grade marble).
