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Tree rings from a section of Prumnopitys taxifolia (matai) covering the period AD 1335-1745 have been radiocarbon dated and used to generate a 14C calibration curve for southern hemisphere wood. Comparison of this curve with calibration data for northern hemisphere wood does not show a systematic difference between 14C ages measured in the northern and southern hemispheres. A floating chronology covering 270 yr and terminating at the last Taupo (New Zealand) eruption, derived from a sequence of 10-yr samples of tree rings from Phyllocladus trichomanoides (celery pine, or tanekaha), is also consistent with the absence of a systematic north-south difference, and together with the matai data, fixes the date of the Taupo eruption at AD 232 ± 15.

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The El Tule fault extends southeastward from the Huachuca Mountains area of Arizona to run along the base of the Sierra San José in northern Sonora. This fault, with the Jurassic and Cretaceous strata that lie on either side of it, helps to link the geologic histories of the Sierra San José, the Huachuca Mountains, and the Mule Mountains. This fault was active during the Jurassic and formed part of the southern and southwestern limit of a small Jurassic basin that accumulated Glance Conglomerate and contains the type locality of that unit; it was also active during the time of deposition of the upper part of the Bisbee Group, i.e., the Morita, Mural, and Cintura formations. This fault is an important marker for the northern margin of the Cananea high.Three evidences suggest that a genetic distinction should be made between the basin that collected the Glance Conglomerate and the younger, wider, superposing basin that collected upper Bisbee rocks: (1) There was a depositional pause after active deposition of the Glance (and therefore after active opening of the Glance basin). (2) The subsequent, fi ner-grained upper Bisbee deposits do not extend entirely over the Cananea high, but are otherwise regional in extent, forming a thick blanket over the inactive fault basin and other similar basins elsewhere in the region. (3) The axial trends of the Jurassic fault basin(s) and the upper Bisbee basin do not coincide.We offer the hypothesis that the Jurassic fault basins were caused by the same crustal stresses that caused the Mojave-Sonora megashear (their ages of activity and orientations are similar), and that the upper Bisbee basin was the probable result of crustal thinning associated with formation of the extensional Jurassic basins, and of eustasy. We offer this in contrast to the current hypothesis that the Bisbee basin is a rift basin, that is, the product of a single, ongoing Mesozoic process.Large-scale mass-gravity deposits are signal features both of the Jurassic fault basin (a result of crustal extension) and of the overlying local Laramide basin (which McKee, J.W., McKee, M.B., and Anderson, T.H., 2005, Mesozoic basin formation, mass-gravity sedimentation, and inversion in northeastern Sonora and southeastern Arizona, in Anderson, T.

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