A Cenozoic record of seawater uranium in fossil corals
A Cenozoic record of seawater uranium in fossil corals
复制标题
珊瑚化石中海水铀的新生代记录
DOI：
10.1016/j.gca.2019.01.039
复制
发表时间：
2019
影响因子：
5
通讯作者：
Bender, Michael L.
中科院分区：
文献类型：
--
作者：
Gothmann, Anne M.;Higgins, John A.;Adkins, Jess F.;Broecker, Wally;Farley, Kenneth A.;McKeon, Ryan;Stolarski, Jarosław;Planavsky, Noah;Wang, Xiangli;Bender, Michael L.
我们测量了U/Ca比率、4He浓度、234U/238U和238U/235U，这是Gothmann等人（2015）之前描述的保存完好的文石硬核珊瑚化石子集。测量的化石珊瑚He/U年龄与地层年龄的比较表明，保存完好的珊瑚文石将其大部分或全部放射性成因He保留了数千万年。这些样本必须在很大程度上或完全没有改变，包括新形态。234u /238U和238U/235U的测量进一步有助于表征原始U浓度的保真度。化石珊瑚U/Ca分析表明，早新生代至今，海水U/Ca比值上升了4-5倍。对观测到的增加的可能解释包括：(1)由于海水[CO32−]的增加，海水中U的稳定，以及由此导致的uo2 - co3络合的增加，这是Broecker（1971）最初提出的；(2)早新生代至今低温热液蚀变速率降低，导致U汇减少，海水升高[U]；(3)还原性沉积物中铀的去除率降低，再次导致海水浓度升高[U]。
We measured U/Ca ratios,4He concentrations,234U/238U, and238U/235U in a subset of well-preserved aragonitic scleractinian fossil corals previously described by Gothmann et al. (2015). Comparisons of measured fossil coral He/U ages with the stratigraphic age demonstrate that well-preserved coral aragonite retains most or all of its radiogenic He for 10’s of millions of years. Such samples must be largely or entirely free of alteration, including neomorphism. Measurements of234U/238U and238U/235U further help to characterize the fidelity with which the original U concentration has been preserved. Analyses of fossil coral U/Ca show that the seawater U/Ca ratio rose by a factor of 4–5 between the Early Cenozoic and today. Possible explanations for the observed increase include (1) the stabilization of U in seawater due to an increase in seawater [CO32−], and a resulting increase in UO2-CO3complexation as originally suggested by Broecker (1971); (2) a decrease in the rate of low-temperature hydrothermal alteration from Early Cenozoic to present, leading to a diminished U sink and higher seawater [U]; or (3) a decrease in uranium removal in reducing sediments, again leading to higher seawater [U].
登录
查看更多内容
影响因子：
56.9
作者：
R. Anderson;M. Bacon;P. Brewer
通讯作者：
R. Anderson;M. Bacon;P. Brewer
影响因子：
5.2
作者：
Hain, Mathis P.;Sigman, Daniel M.;Haug, Gerald H.
通讯作者：
Haug, Gerald H.
影响因子：
5
作者：
COCHRAN, JK;CAREY, AE;SURPRENANT, LD
通讯作者：
SURPRENANT, LD
海水pH值对石珊瑚冷水珊瑚Lophelia pertusa U/Ca比值的影响
影响因子：
4.9
作者：
Raddatz;Rüggeberg;Flögel;Hathorne;Liebetrau;Eisenhauer;W.-Chr.
通讯作者：
W.-Chr.
影响因子：
5
作者：
BENDER, ML
通讯作者：
BENDER, ML