BY PETER J. SMITH
Department of Earth Sciences
Milton Keynes, U.K.
" Seismic reflection studies in the North Atlantic, southwest of Bermuda, show that the oceanic crust is not as uniform as hitherto supposed. In particular, dipping reflectors in the lower crust indicate either major fault zones or, more probably, chemical signatures of magma chambers once active on the mid-Atlantic ridge, note the authors of a new study.
J. McCarthy, J.C. Mutter, J.L. Morton, N.H. Sleep, G.A. Thompson, “Relic magma chamber structures preserved within the Mesozoic North Atlantic crust?,” Geological Society of America Bulletin, 100 (9), 1423-36, September 1988.
" The characteristics of the Caledonian orogenic belts, ophiolotes, sediments, and faunal provinces in Britain and Scandinavia indicate ocean-margin terrane processes rather than the opening and closing of a major ocean. The supposed lapetus, or Proto-Atlantic, Ocean may never have existed.
R. Mason, “Did the Iapetus...