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

改进的 O-25 Ma（中新世-更新世）地磁极性时标的年龄校准

• 批准号: 9405347
• 负责人: Carl Swisher
• 金额: $ 21.09万
• 依托单位: Berkeley Geochronology Center
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1994
• 资助国家: 美国
• 起止时间: 1994-09-15 至 1998-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9405347&HistoricalAwards=false
• 关键词: Improved; Age; Calibration; 25; Ma

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.

9405347 Swisher这个项目旨在大大改善O-25 MA年龄范围内（中新世 - 普遍）的地磁极性时间尺度（GPTS）的时间校准。 当前，在此时间间隔中，GPT的校准基于三个放射性分析点。 2.8 MA，14.8 MA和23.8 MA。 我们建议在此时间间隔中获得二十至30个高精度的40AR/39AR日期，以从各种LMCATION和地质环境（包括地中海，东非，冰岛和北美）获得特定的逆转日期。 该项目部分是PI的几项正在进行的研究工作的生长和综合，其整合将提高获得准确的放射性分析点的效率和及时性，这将首次产生基于最高质量40AR/39AR年龄的GPTS可获得的，能够严格测试中新世/上新世边界以外的轨道测试时间尺度。 该比较将有助于评估全球气候变化的原因和时机，并且在评估可获得40AR/39AR年龄的年龄也将很有用，该年龄可以严格测试超过中新世/上新世边界以外的轨道调整时间尺度。 该比较将有助于评估全球气候变化的原因和时机，并且对于评估40AR/39AR约会标准的应用程序也将很有用，远远超出了该项目所涵盖的时间范围。