Joseph (Joe) Kirschvink

Research

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:

• Magnetofossils, from Mars to Earth?
• Magnetite-Based Magnetoreceptors
• The Snowball Earth Hypothesis: (Possibly the worst climatic disasters in Earth history)
• The Cambrian Evolutionary Explosion, and the Inertial Interchange True Polar Wander Hypothesis
• The Grand Unified Theory of Biomineralization

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. As promised, a 28 MB Powerpoint file of the slides from this lecture is now available at CarlSaganLecture.ppt, the 14 MB video clip of the pulse-remagnetization experiment for the magnetotactic bacteria is at bacteria.avi (this file should be in the same directory to run properly), and a 96kb Adobi Acrobat PDF file of Koseki's cut-out model of the Martian Magnetofossil is also posted. Also as promised, the 33 MB powerpoint presentation from the 2003 Caltech GPS Alumni College, "Snowballs, True polar Wander, and the Cambrina Explosion", is now posted here, as is the ~ 14 MB movie (iitpw.mov) of the proposed Inertial Interchange event.

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.

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. Cody Nash
Mr. Robert Kopp

Major research projects by current and former students are described in several other home pages:

* High resolution records of geomagnetic reversals
* Late Precambrian climate, tectonics and paleomagnetism
* Magnetic study of Martian Meteorite ALH84001
* Paleomagnetism of Vancouver Island & the Baja BC controversy