FIRE OR ICE IN CALIFORNIA. A new study shows that episodic volcanism and glaciation have alternated in holding sway over the California-Nevada borderlands during the past 800,000 years. Scientists at the University of North Carolina and Duke, who examined 112 different geological ages in documenting their study, suggest that the anti-correlation comes about because of climate-related issues, including perhaps the loading effect of lakes or overlying ice (300 m thick in places) or the stress on the lithosphere by changes in atmospheric circulation. (Glazner et al., Geophysical Research Letters, 15 June.)