The Oligocene Haynes Creek Flora Of Eastern Idaho

This flora of 70 species is dominated by deciduous trees, many with descendants in China. Precipitation was 890 mm, mean annual temperature 12.5°C, the annual range 10°C, and freezing rare. Elevation was about 1000 meters. Comparison with the Horse Prairie flora, 30 miles east and across the present continental divide, indicates that the divide was then low and discontinuous, with warmer climate to the east.

This flora of 70 species is dominated by deciduous trees, many with descendants in China. Precipitation was 890 mm, mean annual temperature 12.5°C, the annual range 10°C, and freezing rare. Elevation was about 1000 meters. Comparison with the Horse Prairie flora, 30 miles east and across the present continental divide, indicates that the divide was then low and discontinuous, with warmer climate to the east.

Volume 66 of Reviews in Mineralogy and Geochemistry is based on a two day short course entitled Paleoaltimetry: Geochemical and Thermodynamic Approaches held prior to the Geological Society of American annual meeting in Denver, Colorado (October 26-27, 2007). This meeting and volume were sponsored by the Geochemical Society, Mineralogical Society of America, and the United States Department of Energy. Contents: The Significance of Paleotopography Stable Isotope-Based Paleoaltimetry: Theory and Validation Paleoelevation Reconstruction Using Pedogenic Carbonates Stable Isotope Paleoaltimetry in Orogenic Belts – The Silicate Record in Surface and Crustal Geological Archives Paleoaltimetry from Stable Isotope Compositions of Fossils A Review of Paleotemperature–Lapse Rate Methods for Estimating Paleoelevation from Fossil Floras Paleoaltimetry: A Review of Thermodynamic Methods Paleoelevation Measurement on the Basis of Vesicular Basalts Stomatal Frequency Change Over Altitudinal Gradients: Prospects for Paleoaltimetry Thermochronologic Approaches to Paleotopography Terrestrial Cosmogenic Nuclides as Paleoaltimetric Proxies

This is a study of the Miocene Carmel flora of California, an evergreen laurel–oak forest that grew in a mild temperate (mean annual temperature of 15 degrees C), frost-free climate, with annual precipitation of about 760 mm (30 in.). Collectively, the Carmel and other Miocene floras like the San Pablo and Temblor (broad-leafed deciduous trees, with few evergreen species), the Puente (evergreen oak forest with chaparral species), the Mint Canyon, Ricardo, and Tehachapi (numerous arid subtropical scrub associated with oak woodland and chaparral species) suggest they foreshadowed a similar distribution of the different California vegetation zones today.

The author describes forty-two fossil taxa recovered during a study of the San Timoteo Badlands that used magnetobiostratigraphy to develop a temporal framework for addressing the tectonic evolution of southern California over the last 6 million years. For the Pliocene, small mammals are an effective means of correlating a magnetostratigraphy to the Geomagnetic Polarity Time Scale when radioisotopic dates are unobtainable.

The Florissant formation's fossil beds and petrified forest are interesting in themselves but also shed light on questions of paleoecology, macroevolution, and taphonomy (the study of the process of fossilization). Meyer (National Park Service. Florissant Fossil Beds National Monument, Colorado) and Smith (U. of Colorado Museum of Natural History--Paleontology/geological sciences, UC, Boulder) introduce 11 papers examining Florissant fossil flora, fauna, mineralogy and geochemistry through different periods and via a model of the role of microbial mats in its preservation. An integrated database/Web site to further related research is also discussed. The monograph is well-illustrated with geologic maps and images of historical figures in the field and specimens, but is not indexed.