R: radar technique radio wave radioactive decay radioactive element radioactivity radiocarbon dating radioisotope radiolaria radiolarian chert radiometric radiometric age radiometric age dating radiometric dating radiometric time scale rain rain erosion rain forest rain shadow rainfall rainstorm Rancho La Brea rapid current rare mineral rate of sedimentation ravine Rayleigh wave reaction series recharge area recrystallization recurrence interval Red Cross Red Eye Crossing Red River Red Sea reef reflection reflection seismogram reflection seismology refraction region regional metamorphism regression regression analysis rejuvenation relative age dating relative gravity relative time scale relief organization remote sensing renewable resource replenishment reptile research method reserve reservoir residual resistivity resource resource extraction return period reverse fault reverse polarity rhyolite Richard Hazlett Richter Scale Richter scale Rick Aguayo ridge Ridge Basin rift rift zone right lateral right-lateral rim of fire Ring of Fire rip up fragment ripple ripple mark river river bed river channel river delta River Seine riverbank riverside road Robert Dietz Robert Douglas Robert Fiske Griggs Robert O. Burford Robert Palmer Robert Tilling robot rock rock age rock avalanche rock color rock composition rock coring rock cycle rock formation rock forming mineral rock hammer rock layer rock origin rock planet rock slab rock type Rockies rockslide rocky debris Rocky Mountain System Roman root rubidium isotope decay rupture front rupture velocity Russia rust
U.S. Department of the Interior | U.S. Geological Survey URL: http://walrus.wr.usgs.gov/infobank/programs/html/school/R_keywords.html Page Contact: InfoBank staff Page Last Modified: Tue Dec 16 06:27:35 PST 2008 (wcs)