Zircon dating metamorphic rocks
O., Rullkötter, J., A Comparative Study of Molecular Paleosalinity Indicators: Chromans, Tocopherols and C20 Isoprenoid Thiophenes in Miocene Lake Sediments (Nördlinger Ries, Southern Germany), Aquatic Geochemistry, v. B., Transformation of planetary material in high-speed collisions (in Russian). Routine U-Th-Pb dating and analysis of low abundance trace elements of thin zircon overgrowths was unavailable until our laser rim-piercing technique was developed at ANU where we have an Excimer laser (193 nm wavelength; long focal length) attached to an Agilent 7500S Q-ICP-MS.
If you are not on our list, but would like to receive the Empire State Geogram (it's free), send us your name and address. Replies should be sent to: Geogram Mailing List Geological Survey Room 3140, Cultural Education Center Albany, New York 12230 A complete list of Survey publications on the geology of New York, their availability, price, and ordering instructions was printed in Volume 28, Number 2, 1992 of the Empire State Geogram. Loaned materials are shipped by registered mail (registered air mail outside of North America). If the rim is wider than 5 microns a precise age can be measured.Moreover, even if the rim is not preserved, and the core not encountered, the Pb loss zone if wide enough (~15 mcirons) can be used to construct a discordia on that single grain with moderately precise lower and upper intercept ages. The "E-collections" will gradually shrink as specimens are integrated into the stratigraphic collections or are illustrated as new types. Clarke and include a large number of Lower and Middle Paleozoic species from classic localities in North America, Britain, and western and central Europe. Proceedings of the National Academy of Sciences, v.