Impact Tectonics Google Earth ver. 012015

A set of Google Earth (GE) graphic lments and embedded imagery that emphasize tectonic strains on Earth stemming from known and suspected, hyper-velocity, large-bolide impacts.

Download GCH Impact Tectonics 01-2015.kmz file (7.3 MB). 

Click on the image for more detail.

Three views of Earth showing far-field impact strains with respect to two known and six suspected
impact events. Far-field strains include impact-generated, far-field crustal fractures,  faults,  crustal welts
and troughs that are circumferential to impact craters. Tectonic-plate-motion vectors are included based
on 13 years of GPS-crustal movement. Lines are drawn from the center of each crater that depict interpreted
bolide-decent paths. These paths extend into foreland regions and bisect symmetrical strain fields. The
views include gray-shade sea-floor physiography and continental crustal ages that are color-coded by
geologic Era (yellow-Cretaceous, green-Mesozoic, pink-Paleozoic, gray-Precambrian).
 

Contents of the KMZ File

This file includes three folders containing GE lines, polygons, annotated points, embedded imagery, and hyperlinks that help demonstrate hypothetical, far-field crustal and body strains occurring on Earth that developed in response to large, hyper-velocity bolide (asteroid and comet) impacts. This is a working hypothesis that has not yet been throughly scrutinized by the general scientific community.

The strain effects are separated into two folders for two known and seven suspected impact events. The known impacts includethe  Chicxulub and Chesapeake events of ~65 Ma and ~35 Ma respectively, located on the North American plate. The seven suspected impact events reamin unproven, are located around the Earth and their timing is interetped to span the Paleozoic to late Cenzoic eras. Each of these events are hypothesized to deeply fracture the lithosphere and some possibly perturb tectonic-plate motions. 

The far-field body strains include circumferential crustal welts and seismic zones, foreland shear fractures and thrust-faults, and hinterland extension fractures and normal faults that are systematically disposed about craters. Foreland compression paths are illustrated using line that parallel each bolide's descent trajectorys. Many of these events are thought to be single impacts, but others involve multiple strikes, spalled projectiles, and strewn fields. Many of these features were mapped using Lambert equal-area, azimuthal projections about each crater using a geographic information system. Other strain features are mapped using GE. Each crater is named and assigned an estimated age based on preliminary geological studies including the use of data from deep-sea (DSDP) and ocean-drilling (ODP) projects.  Ancillary data within a third folder inlcude plate boundary models, continental geology by era imagery, ocean-floor isochrons (Müller and others, 1997, 2008), and crustal-motion vectors from global, ground-based GPS data (NASA JPL). Vector size is scaled relative to velocity (factored by 0.1 degree for display in geographic space).  

This revision includes a report of newly suspected major impact in the Amazon basin near the Xingu River, Brazil. This is the 7th, large one mapped, and it's delineation benefits greatly from detailed studies of crustal thickness across the region (Tassara and others, 2007). Please read Far-Field Bolide-Impact Strains on Earth for a brief summary of prior work.  

References

Müller, R.D., Roest, W.R., Royer, J.-Y., Gahagan, L.M. and Sclater, J.G., 1997. Digital isochrons of the world's ocean floor. Journal of Geophysical Research, 102: 3211-3214. o GE

Müller, R.D., Sdrolias, M., Gaina, C. and Roest, W.R., 2008. Age, spreading rates and spreading asymmetry of the world's ocean crust. Geochem. Geophys. Geosyst., 9(Q04006): doi:10.1029/2007GC001743.

Tassara A., Swain C., Hackney R., Kirby J., 2007, Elastic thickness structure of South America
estimated using wavelets and satellite derived gravity data. Earth Pl. Sci. Lett., 253, 17-36.

 

 

Warning. This KMZ application can crash a computer with less than 1 GB RAM. Be careful not to overload your computer by having all layers on at once if you have less than 1 GB RAM.

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