...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Earth and Planetary Science Letters: A Letter Journal Devoted to the Development in Time of the Earth and Planetary System >Tempo and scale of late Paleocene and early Eocene carbon isotope cycles: Implications for the origin of hyperthermals
【24h】

Tempo and scale of late Paleocene and early Eocene carbon isotope cycles: Implications for the origin of hyperthermals

机译：晚古新世和始新世碳同位素循环的速度和规模：对超高温起源的影响

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

The upper Paleocene and lower Eocene are marked by several prominent (>1‰) carbon isotope (δ~(13)C) excursions (CIE) that coincide with transient global warmings, or thermal maxima, including the Paleocene-Eocene Thermal Maximum (PETM). The CIE, which are recorded mainly in marine sedimentary sequences, have also been identified in continental sequences, occurred episodically, and yet appear to be paced or triggered by orbital forcing. To constrain the timing and scale of the CIE relative to long-term baseline variability, we have constructed a 4.52million year (myr) long, high-resolution (~3kyr) bulk sediment carbon isotope record spanning the lower Eocene to upper Paleocene (C25r-C24n) from a pelagic sediment section recovered at ODP Site 1262 in the southeast Atlantic. This section, which was orbitally-tuned utilizing high-resolution core log physical property and geochemical records, is the most stratigraphically complete upper Paleocene to lower Eocene sequence recovered to date. Time-series analysis of the carbon isotope record along with a high-resolution Fe intensity record obtained by XRF core scanner reveal cyclicity with variance concentrated primarily in the precession (21kyr) and eccentricity bands (100 and 400-kyr) throughout the upper Paleocene-lower Eocene. In general, minima in δ~(13)C correspond with peaks in Fe (i.e., carbonate dissolution), both of which appear to be in phase with maxima in eccentricity. This covariance is consistent with excess oceanic uptake of isotopically depleted carbon resulting in lower carbonate saturation during periods of high eccentricity. This relationship includes all late Paleocene and early Eocene CIE confirming pacing by orbital forcing. The lone exception is the PETM, which appears to be out of phase with the 400-kyr cycle, though possibly in phase with the 100-kyr cycle, reinforcing the notion that a mechanism other than orbital forcing and/or an additional source of carbon is required to account for the occurrence and unusual scale of this event.
机译：上古新世和下始新世以几个突出的（> 1‰）碳同位素（δ〜（13）C）偏移（CIE）为标志，与瞬时全球变暖或热最大值相吻合，包括古新世-始新世热最大值（PETM） ）。 CIE主要记录在海洋沉积层序中，也已在大陆序列中被识别出，发生在外地，但似乎是由轨道强迫引起的。为了限制CIE相对于长期基准线变化的时间和规模，我们构建了一个452万年长，高分辨率（〜3kyr）的大沉积物碳同位素记录，涵盖下始新世到上新世（C25r -C24n）来自东南大西洋ODP站点1262的浮游沉积物剖面。该部分是利用高分辨率岩心测井的物理性质和地球化学记录进行轨道调谐的，是迄今为止已恢复的地层最完整的上古新统至下新世序列。碳同位素记录的时间序列分析以及XRF核心扫描仪获得的高分辨率Fe强度记录揭示了周期性，其变化主要集中在整个上古新统上的旋进带（21kyr）和偏心带（100和400kyr）中。下新世。通常，δ〜（13）C中的最小值对应于Fe中的峰（即碳酸盐溶解），这两个峰似乎都与偏心率的最大值同相。这种协方差与海洋中过量吸收同位素消耗的碳相一致，从而导致在高离心率期间碳酸盐饱和度降低。这种关系包括所有新世晚期和始新世CIE通过轨道强迫确认起搏。唯一的例外是PETM，它似乎与400 kyr周期异相，尽管可能与100 kyr周期异相，从而强化了这样一种观念，即除了轨道强迫和/或其他碳源之外，还有其他机制需要考虑到此事件的发生和异常规模。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号