PETER ROBINSON’S IMPACT ON NEW ENGLAND AND APPALACHIAN GEOLOGY (Invited Presentation)

Peter Robinson was both an outstanding scientist and person. His career was marked by significant contributions to metamorphic petrology (MP), structural geology, geologic mapping (GM), and lastly to mineral physics. He was a superb field geologist and teacher, doubtlessly augmented by his artistic abilities ranging from precise geologic cross sections and 3D syntheses (e.g., the “ruptured bra”) to cartoons needling professional colleagues. It was an honor to be the object of one of his cartoons. Some remember Pete for his lasting contributions to New England (NE) geology, while others will recall him as a superb MP. His approach to geology, however, was always based in the field with ideas derived from solid, integrated field and laboratory data that drove new discoveries.

These principles have been employed in the southern Appalachians (APs) to build several islands of ground truth—detailed (quantitative, reproducible) GM—that laid the foundations for laboratory-driven research in modern petrology, geochemistry, structural geology, geophysics, and geochronology (GC). These islands have revealed major faults, suspect and exotic terranes (TERRs), and modern GC has yielded ages of plutons, faults/TERR boundaries, timing of metamorphism, provenance of TERRs from detrital zircons, which acquitted several that were previously suspect, and timing of orogenies.

These data, coupled with modern data from elsewhere in the AP orogen, have facilitated formulation of new tectonic models throughout the orogen that are internally more consistent with existing data. We now know that Gander terrane extends farther south through southern NE and effects of the Alleghanian orogeny were more widespread here than previously thought. Mid- Paleozoic westward subduction of Avalon beneath NE contrasts with opposite subduction polarity of Carolina subduction in the southern-central APs, requiring a previously unrecognized mid-Paleozoic transform at the NE-central APs junction (credit A. J. Merschat).