Nico and Marilyn Van Wingen Professor of Geobiology
B.S., M.S., Caltech, 1975; M.A., Princeton University, 1978; Ph.D., 1979. Assistant Professor, Caltech, 1981-87; Associate Professor, 1987-92; Professor, 1992-2004; Van Wingen Professor, 2004-.
Science progresses by a process called hypothesis testing, which involves proposing an idea and then subjecting it to experimental tests. However, someone has to initially propose scientifically plausible hypotheses for this process to work. Prof. Kirschvink has originated several such ideas aimed at increasing our understanding of how biological evolution has influenced, and has been influenced by, major events on the surface of the Earth. In more-or-less chronological order, the major contributions include: (1) the idea that biogenic magnetite produced by the magnetotactic bacteria ("magnetofossils") might be responsible for the magnetization of some sedimentarty rocks; these magnetofossils now provide the strongest evidence for early life on the planet Mars. (2) Another major idea is that the magnetic field sensitivity in animals might be due to small chains of the same biogenic magnetite functioning as specialized sensory organelles; this work has provided a solid biophysical basis for understanding magnetic effects on animal behavior, and has actually led to the discovery of these new sensory organs in higher animals. (3) An idea that is generating much interest recently is that the entire Earth may have actually frozen over several times in Earth history, resembling a "Snowball", potentially causing some of the most severe criseses is history of life on Earth and perhaps stimulating evolution. (4) Another original concept is that the Cambrian Evolutionary explosion may have been precipitated in part by large burst of true polar wander, in which the Earth's rotational axis moved to the equator in a geologically short interval to of time, and (5) that the burst of biomineralization observed in the fossil record at the Cambrian Explosion may have resulted from the evolutionary exaptation of the magnetite biomineralization system. A common thread in all of these efforts is the study of paleomagnetism and rock magnetism, for which the Kirschvink group maintains laboratories dedicated to the study of weakly magnetic biological and geological materials. Several home pages (currently under construction) describe these major contributions and facilities in more detail:
Prof. Kirschvink delivered the Carl Sagan Memorial Lecture at the 2001 American Geophysical Union Fall meeting in San Francisco, a webcast of which is posted on the AGU www site. Click here for the current location of Asteriod 27711 Kirschvink, a member of the Phocaea family with an unusually high eccentricity, orbiting between Mars and Jupiter, with a magnitude of 15, about 3 km in diameter.
Joe is also the real Iron Man!. Additional contributions include various studies in rock- and paleomagnetism and Biomagnetism, and those from recent or current students:
Prof. Robert Ripperdan Prof. David A. Evans Dr. John Holt Prof. Benjamin Weiss Mr. Robert Kopp Mr. Cody Nash
Ge 104. Introduction to Geobiology.9 units (3-0-6); second term, 2019-20.
Lectures about the interaction and coevolution of life and Earth surface environments. We will cover essential concepts and major outstanding questions in the field of geobiology, and introduce common approaches to solving these problems. Topics will include biological fractionation of stable isotopes; history and operation of the carbon and sulfur cycles; evolution of oxygenic photosynthesis; biomineralization; mass extinctions; analyzing biodiversity data; constructing simple mathematical models constrained by isotope mass balance; working with public databases of genetic information; phlyogenetic techniques; microbial and molecular evolution.
Instructors: Fischer, Kirschvink
Ge 11 b. Introduction to Earth and Planetary Sciences: Earth and the Biosphere.9 units (3-3-3); second term, 2019-20.
Systematic introduction to the origin and evolution of life and its impact on the oceans, atmosphere, and climate of Earth. Topics covered include ancient Earth surface environments and the rise of atmospheric oxygen. Microbial and molecular evolution, photosynthesis, genes as fossils. Banded iron stones, microbial mats, stromatolites, and global glaciation. Biological fractionation of stable isotopes. Numerical calibration of the geological timescale, the Cambrian explosion, mass extinctions, and human evolution. The course usually includes one major field trip and laboratory studies of rocks, fossils, and geological processes. Although Ge 11 abcd is designed as a sequence, any one term may be taken as a standalone course. Biologists are particularly welcome.
Instructors: Fischer, Kirschvink
Ge 136 abc. Regional Field Geology of the Southwestern United States.3 units (1-0-2); first, second, or third terms, by announcement, 2019-20.
Includes approximately three days of weekend field trips into areas displaying highly varied geology. Each student is assigned the major responsibility of being the resident expert on a pertinent subject for each trip. Graded pass/fail.
Instructor: Kirschvink
Ge/Bi 244. Paleobiology Seminar.6 units (3-0-3); third term, 2019-20.
Critical reviews and discussion of classic investigations and current research in paleoecology, evolution, and biogeochemistry.
Instructor: Kirschvink
Research Website