Comparisons of Be TCN ages within sample sets on individual surfaces most closely approximate to the age of landforms that are younger than ~ 70 ka.
Alluvial fan surfaces older than ~ 70 ka have begun to undergo sufficient erosion such that the majority of Be TCN ages for beach bars near Beatty Junction and shorelines ~ 8 km south of Furnace Creek is large, ranging from ~ 119 ka to ~ 385 ka and ~ 109 ka to ~ 465 ka, respectively.
The uniform stratigraphy at the TM localities allowed us to use absolute ages from both TM 266, where Toumaï was discovered, and TM 254 to assign an age to Toumaï.
It was hoped that the tephra layer would contain material datable by the Be associates with continental particles, where it decays with a half-life of ≈1.4 million years.cranium level were 6.83 ± 0.45 Ma for the overlying level and 7.12 ± 0.31 Ma for the underlying level.
of Earth Sciences, Environmental Earth Science Projects Lawrence Berkeley National Laboratory, The Berkeley Laboratory Isotopes Project, Exploring the Table of Isotopes. USGS Periodic Table - Beryllium von Blanckenburg, F., M.
A comparison of the measured nuclide concentrations with those expected to be produced in the corals by nuclear interactions of energetic cosmic radiation shows that (i) the radionuclides 26Al and 36Cl are derived from in situ cosmic ray interactions in the corals after their formation, but that (ii) the radionuclide 10Be owes its provenance in the coralline lattice primarily due to incorporation of dissolved beryllium in seawater in the lattice structure of the corals. The arid environment punctuated by wet periods during which a large shallow lake formed both provided Holocene sediments with which to determine the (Abel, KT 12) sampled for calibration purpose indicates that the Koro Toro fossiliferous locality is at least 3.3 Ma old, an age that is in the range of the biochronological estimation by using the mammal evolutive degree (3, 4, 36).This new absolute dating constraint shows that , the earliest known hominid (1, 2, 40), is probably very close in time to this divergence contrary to the unlikely “provocative explanation,” which recently suggested a “possible hybridization in the human-chimp lineage before finally separating less than 6.3 Ma” (41).Cosmogenic production at the earth's surface Si and mu-meson capture.The rate of this production is dependent on cosmic-ray flux, which increases with latitude and elevation.