LATE PALEOZOIC -TRIASSIC CORAL WANDERING CURVES

Permian strata in western North America bearing corals and fusulinids constitute 3 faunal realms: that of cratonal North American, the McCloud belt, and the Tethyan belt. It is clear that all three belts occupied tropical to subtropical waters, and statistical studies, involving study of distribution of modern corals, suggest that in the Permian the terranes of the McCloud belt lay several thousand kilometers west of North America and that the terranes bearing Tethyan faunas were considerably more distant.

In recent decades interpretations of distance between the three faunal belts in the Permian generally have been based on large numbers of taxa. The focus here, in contrast, is on individual taxa (species and genera) in the context of the entire fauna. This approach may aid in interpretation of the paleogeography, which undoubtedly changed with time.

Using data, mostly from corals, we can interpret the Cache Creek terrane to have been in the Tethyan realm, but isolated from any continent, from Late Carboniferous into Guadalupian time. The McCloud belt was separated from cratonal North America by several thousand km in Late Carboniferous and early Wolfcampian time, perhaps moving closer to North America starting in the late Wolfcampian. In the Guadalupian, some Tethyan terranes had moved close enough to the McCloud belt to share a few members of its fauna. By Late Triassic time, some of the Tethyan fragments had been amalgamated to part of the McCloud belt, which probably was then converging upon North America.

Thus, these fossils can be used to interpret the general positions of the North American terranes in which they occur at different times during Late Carboniferous to Late Triassic time. The movements of these terranes through time define paths I am here calling coral wandering curves.