Global Geodynamics in Relation to 2 Known and 3 Suspected Impacts on Earth.

2 Known and 3 Suspected Impacts on Earth, Crustal Plate Boundaries and Current Plate Motions Based on GPS Data
www.impacttectonics.org/Earth/5impacts.html

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Far-field strains from 2 known (Chicxulub and Chesapeake) and 3 suspected (Congo, Argentine, and Ordos) impact sites on Earth are shown below. Splash rings are shown using colored line traces at 1700 and 2900 km radius around each impact. Vectors show current, horizontal direction and magnitude of tectonic-plate motions based on NASA JPL GPS data. Vector lengths are variably-scaled with the horizontal velocity for each GPS station multiplied by 0.25 geographic degrees. The average horizontal velocity for the crustal plates is about 27 mm/yr based on time-series data for 778 GPS stations. Station points are color coded blue for those stations having negative vertical motions (subsidence) and brown for positive motions (uplift) respectively. Red-dashed lines originate at impact craters and trend northward in line with oblique descent paths of the different projectiles. Purple dashed lines on the sea-floor highlight some sea-floor spreading (SFS) shear zones having symmetry with respect to the Argentine event (Late Miocene?). Gray dashed lines trace SFS zones in the north central Atlantic showing curvature that reflect proposed far-field stains stemming from the Chicxulub (~65 mya) and Chesapeake (~35 mya) events. Tectonic-plate boundaries are shown as thick gray lines. The thin gray lines on the sea floor trace the M34 magnetic isochron.
2 Known and 3 Suspected Impacts, Plate Boundaries and Motions

Plate motions worldwide currently diverge northward away from the suspected Argentine impact located immediately north of the South Georgia and South Sandwich Islands in the Southwest Atlantic Basin. The only exceptions are plate motions associated with the Chicxulub impact and a suspected (Middle Paleozoic?) impact in the Ordos Basin, China. In both of these instances, plates pivot around earlier impact points. This may indicate that large impact events produce mantle and crustal welts resulting in subsequent, log-lasting geodynamic responses operating to dispel energy fluxes imparted by collisions. Moreover, most of these impacts show nearby plate fragmentation with plate triple junctions either occurring near craters or at suspected impact antipodes. Together, these strain responses show that large-bolide impacts drastically influence Earth geodynamics to a degree that we are only beginning to realize. The Argentine impact is probably of late Cenozoic age, perhaps occurring in the Late Miocene (~ 9 mya) based on the occurrence of melt-breccias and tektites in sedimentary deposits on the Argentine Pampas (Schultz and others, 2007). The distribution of tektites in the North American tektite strewn field also shows a remarkable spatial coincidence with the proposed foreland trajectory of the Argentine impact even though they reportedly stem from the Chesapeake impact of Eocene age (~34-35 mya).