Magnetic record of deglaciation using FORC‐PCA, sortable‐silt grain size, and magnetic excursion at 26 ka, from the Rockall Trough (NE Atlantic)
Magnetic record of deglaciation using FORC‐PCA, sortable‐silt grain size, and magnetic excursion at 26 ka, from the Rockall Trough (NE Atlantic)
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使用 FORC-PCA、可分选淤泥颗粒尺寸和来自罗卡尔海槽（大西洋东北部）的 26 ka 磁偏移进行冰消蚀的磁记录
DOI：
10.1002/2016gc006300
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发表时间：
2016
期刊：
影响因子：
3.7
通讯作者：
["Jet Channell
中科院分区：
文献类型：
--
作者：
["Jet Channell
罗卡尔海槽的MD 04 - 2822岩芯在末次冰消期（终止I）的表观沉积速率为1.01 m/kyr。分量磁化方向表明，磁漂移在16.3米深度的核心，对应的年龄为26.5 ka，这意味着偏移的持续时间为350年。在终端I，可分选粉砂的平均粒度意味着新仙女木和海因里希体育场（HS）-1A的底流速度降低，而在Bølling-Allerød温暖时期的速度增加。标准的体磁参数意味着从新仙女木中期（约12 ka）到约18 ka的磁性晶粒尺寸变细。使用脊提取分析一阶反转曲线（FORC），以区分单域（SD）和背景（碎屑）组分。然后使用主成分分析（FORC-PCA）来区分对应于SD、伪单畴（PSD）和多畴（MD）磁铁矿的三个端元。从12到8 ka的大块磁性晶粒尺寸的细化是由于碎屑（PSD + MD）磁铁矿的浓度减少，叠加在由趋磁细菌产生的SD磁铁矿的相对均匀的浓度。PSD+MD磁铁矿浓度从12 ka降低到8 ka与底栖δ 13 C的增加同步，并与主要（约70 m）区域海平面上升同步，因此可能与陆架上的碎屑源有关，这些碎屑源随着海平面上升而影响减少，并与底层水重组有关，因为北方水源（NSW）取代了南方水源（SSW）。
Core MD04‐2822 from the Rockall Trough has apparent sedimentation rates of ∼ 1 m/kyr during the last deglaciation (Termination I). Component magnetization directions indicate a magnetic excursion at 16.3 m depth in the core, corresponding to an age of 26.5 ka, implying an excursion duration of ∼350 years. Across Termination I, the mean grain size of sortable silt implies reduced bottom‐current velocity in the Younger Dryas and Heinrich Stadial (HS)−1A, and increased velocities during the Bølling‐Allerød warm period. Standard bulk magnetic parameters imply fining of magnetic grain size from the mid‐Younger Dryas (∼12 ka) until ∼ 8 ka. First‐order reversal curves (FORCs) were analyzed using ridge extraction to differentiate single domain (SD) from background (detrital) components. Principal component analysis (FORC‐PCA) was then used to discriminate three end members corresponding to SD, pseudo‐single domain (PSD), and multidomain (MD) magnetite. The fining of bulk magnetic grain size from 12 to 8 ka is due to reduction in concentration of detrital (PSD + MD) magnetite, superimposed on a relatively uniform concentration of SD magnetite produced by magnetotactic bacteria. The decrease in PSD+MD magnetite concentration from 12 to 8 ka is synchronized with increase in benthic δ13C, and with major (∼70 m) regional sea‐level rise, and may therefore be related to detrital sources on the shelf that had reduced influence as sea level rose, and to bottom‐water reorganization as Northern Source Water (NSW) replaced Southern Source Water (SSW).
影响因子：
5.3
作者：
Channell, J. E. T.;Hodell, D. A.;Kesler, M. S.
通讯作者：
Kesler, M. S.
影响因子：
5.3
作者：
Roberts, Andrew P.;Florindo, Fabio;Gerald, John D. Fitz
通讯作者：
Gerald, John D. Fitz