Improved Age Calibration of the O-25 Ma (Miocene- Pleistocene) Geomagnetic Polarity Time Scale

小行星9405347 该项目的目的是大大提高0 - 25 Ma年龄范围（中新世-更新世）的地磁极性时标（GPTS）的时间校准。 目前，GPTS在这一时间段的校准是基于三个放射性同位素结合点：2.8 Ma、14.8 Ma和23.8 Ma。 我们建议在这个时间间隔内从各种各样的limcations和地质环境，包括地中海，东非，冰岛和北美获得20到30个高精度的40 Ar/39 Ar日期。 该项目部分是PI正在进行的几项研究工作的产物和综合，其整合将提高获得准确放射性同位素连接点的效率和及时性，将首次产生基于可获得的最高质量40 Ar/39 Ar年龄的GPTS，能够严格测试中新世/上新世边界之外的轨道调谐时间尺度。 这种相互比较将有助于评估全球气候变化的原因和时间，也将有助于评估年龄的40 Ar/39 Ar年龄，一个能够严格测试轨道调谐的时间尺度以外的中新世/上新世边界。 这种相互比较将有助于评估全球气候变化的原因和时间，也将有助于评估40 Ar/39 Ar定年标准的年龄，以便在本项目涵盖的时间范围之外应用。

9405347 Swisher This project is intended to greatly improve the temporal calibration of the geomagnetic polarity time scale (GPTS) in the O- 25 Ma age range (Miocene-Pleistocene). Currently, calibration of the GPTS in this time interval is based on three radioisotopic tie- points; 2.8 Ma, 14.8 Ma and 23.8 Ma. We propose to obtain between twenty and thirty high-precision 40Ar/39Ar dates for specific reversals in this time interval from a variety of lmcations and geologic settings, including the Mediterranean, East Africa, Iceland, and North America. This project is partly an outgrowth and synthesis of several ongoing research efforts by the PI's whose integration will increase the efficiency and timeliness of obtaining accurate radioisotopic tie-points will produce, for the first time, a GPTS based on the highest quality 40Ar/39Ar ages obtainable, one that is capable of rigorously testing orbitally- tuned time scales beyond the Miocene/Pliocene boundary. This intercomparison will help evaluate the causes and timing of global climate change, and will also be useful in assessing the ages of 40Ar/39Ar ages obtainable, one that is capable of rigorously testing orbitally-tuned time scales beyond the Miocene/Pliocene boundary. This intercomparison will help evaluate the causes and timing of global climate change, and will also be useful in assessing the ages of 40Ar/39Ar dating standards for application well beyond the time range covered by this project.