Page 16 - Global Tectonics

HISTORICAL PERSPECTIVE 3

Figure 1.2 Taylor’s mechanism for the formation of Cenozoic mountain belts by continental drift (after Taylor, 1910).

thought, the proponents of continental drift still The pioneer of the theory of continental drift is
resorted to catastrophic events to explain the separation generally recognized as Alfred Wegener, who as well as
of the continents. Thus, George Darwin in 1879 and being a meteorologist was an astronomer, geophysicist,
Oswald Fisher in 1882 associated drift with the origin and amateur balloonist (Hallam, 1975), and he devoted
of the Moon out of the Pacifi c. This idea persisted well much of his life to its development. Wegener detailed
into the 20th century, and probably accounts in part for much of the older, pre-drift, geologic data and main-
the reluctance of most Earth scientists to consider the tained that the continuity of the older structures, for-

concept of continental drift seriously during the fi rst mations and fossil faunas and floras across present
half of the 20th century (Rupke, 1970). continental shorelines was more readily understood on
A uniformitarian concept of drift was fi rst suggested a pre-drift reconstruction. Even today, these points are
by F.B. Taylor, an American physicist, in 1910, and the major features of the geologic record from the con-
Alfred Wegener, a German meteorologist, in 1912. For tinents which favor the hypothesis of continental drift.
the fi rst time it was considered that drift is taking place New information, which Wegener brought to his thesis,
today and has taken place at least throughout the past was the presence of a widespread glaciation in Permo-
100–200 Ma of Earth history. In this way drift was Carboniferous times which had affected most of the
invoked to account for the geometric and geologic southern continents while northern Europe and Green-
similarities of the trailing edges of the continents land had experienced tropical conditions. Wegener pos-
around the Atlantic and Indian oceans and the forma- tulated that at this time the continents were joined into
tion of the young fold mountain systems at their leading a single landmass, with the present southern continents
edges. Taylor, in particular, invoked drift to explain the centered on the pole and the northern continents strad-
distribution of the young fold mountain belts and “the dling the equator (Fig. 1.3). Wegener termed this con-
origin of the Earth’s plan” (Taylor, 1910) (Fig. 1.2 and tinental assembly Pangea (literally “all the Earth”)
Plate 1.1 between pp. 244 and 245). although we currently prefer to think in terms of A. du