USING GPS TO HELP UNRAVEL CENOZOIC-RECENT CARIBBEAN-SOUTH AMERICAN AND ADRIA-EURASIA PLATE MOTIONS AND PLATE BOUNDARY ZONE TECTONICS
GPS data show that near Trinidad and Venezuela the Caribbean plate currently moves ~eastward at ~20 mm/yr (SAωCA=57.6°N, 69.3°W, 0.233°/m.y.). Fossil Cenozoic foreland fold-thrust belt structures are overprinted by active right-stepping transforms that are connected by well-developed pull-apart basins (Gulf of Paria, Gulf of Cariaco). Trinidad contains a major transpressive restraining transform segment, the Central Range Fault, that is oblique (N75°E) to plate motion, currently aseismic, and probably elastically locked. Geology indicates that Caribbean-South American relative plate motion probably changed from oblique collision to transform at about 10Ma.
GPS data show that lithosphere in the northern Adriatic now moves as an independent, rigid microplate (Adria), currently rotating slowly ccw relative to Eurasia about a pole (pivot point) in northern Italy (EUωAD=46.2°N, 11.5°E, 0.680°/m.y.). Rates of motion and seismic moment release are lowest near the pole (e.g., Slovenia, northern Italy) and increase systematically southward away from it (Croatia, central Italy). Earlier in the Cenozoic, Adriatic lithosphere was subducting as an African (Nubian) promontory that was largely swallowed up beneath the Alps, Apennines, and Dinarides. The Adriatic microplate was probably torn off of Africa via slab break-off beneath the Apennines and born within just the past ~1 m.y.