Tracing Competing Paradigms - Mapping Scientific Frontiers: The Quest for Knowledge Visualization - page 211

Tabl e 6. 3 Landmark articles in the top three specialties of mass extinctions (Citations 50)
Factor loadings

Name Year Source Volume Page

KT impact
0.964 Smit J 1980 Nature 285 198

0.918 Hildebrand AR 1991 Geology 19 867

0.917 Keller G 1993 Geology 21 776

0.887 Glen W 1994 Mass Extinction Deba

0.879 Sharpton VL 1992 Nature 359 819

0.877 Alvarez LW 1980 Science 208 1,095

Periodicity
0.898 Patterson C 1987 Nature 330 248

0.873 Raup DM 1986 Science 231 833

0.859 Raup DM 1984 P Natl Acad Sci-Biol 81 801

0.720 Jablonski D 1986 Dynamics Extinction 183

0.679 Benton MJ 1985 Nature 316 811

0.629 Davis M 1984 Nature 308 715

0.608 Jablonski D 1986 Science 231 129

Permian extinction
0.812

Magaritz M 1989 Geology 17 337

0.444 Renne PR 1995 Science 269 1,413

0.436 Stanley SM 1994 Science 266 1,340

0.426 Erwin DH 1994 Nature 367 231

0.425 Wignall PB 1996 Science 272 1,155

6.3.2.2 The Periodicity of Mass Extinctions

The second largest area in the visualization landscape highlights the theme of
the periodicity of mass extinctions. The periodicity frame in Fig. 6.9 shows two
predominant landmarks, both from David Raup and John Sepkoski. The one on the
left is their 1984 article published in the Proceedings of the National Academy of
Sciences of the United States of America - Biological Sciences, entitled Periodicity
of extinctions in the geologic past . They showed a graph of incidences of extinction
of marine families through time, in which peaks coincided with the time of most
major extinction events, and suggested that mass extinctions occurred every 26
million years. The one on the right is their 1982 article in Science , entitled Mass
extinctions in the marine fossil record .
The catastrophism was one of the major beneficiaries of the periodicity paradigm
because only astronomical forces are known to be capable of producing such a
precise periodic cycle. There were also hypotheses that attempted to incorporate
various terrestrial extinction-making events such as volcanism, global climatic
change, and glaciations. There was even a theory that each time an impact triggered
the volcanic plume, but supporting evidence was rather limited. A few landmark
articles in the periodicity frame addressed the causes of the periodicity of mass
extinctions using the impact paradigm with a hypothesis that asteroids or comets
strike the earth catastrophically every 26 million years.