Relationship between d 18 O and minor element composition of Terebratalia transversa
Relationship between d 18 O and minor element composition of Terebratalia transversa
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d 18 O与Terebratalia transversa微量元素组成的关系
DOI：
10.1017/s1755691008075671
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发表时间：
2007
影响因子：
1.2
通讯作者：
Cusack M
中科院分区：
文献类型：
--
作者：
Cusack M
凭借其广泛的化石记录和稳定的低镁方解石的外壳，rhynchonelliform腕足动物是有吸引力的气候信息来源，通过海水温度代理，如稳定的氧同位素组成。在Terebratalia transversa（Sowerby）有一个进展，走向氧同位素平衡的方解石的最内层的第二层。本研究证实，缺乏任何影响T。横向，甚至在最里面的次级层的专门区域中。方解石Mg/Ca比值具有不受盐度影响的优点，是另一个潜在的海水温度指标。通过电子探针分析测量的镁浓度表明，与氧同位素平衡的逐渐转变相关，镁浓度在朝向内部次级层的方向上没有随之降低。镁分布是不均匀的整个壳和相关的硫，这可能是一个代理的有机成分，这表明，一些镁可能不是在方解石晶格。因此，必须确定镁离子的化学环境，以避免在腕足动物或任何其他方解石生物矿物中的任何错误的温度外推。
With their extensive fossil record and shells of stable low-Mg calcite, rhynchonelliform brachiopods are attractive sources of climate information via seawater temperature proxies such as stable oxygen isotope composition. In Terebratalia transversa (Sowerby) there is a progression towards oxygen isotope equilibrium in the calcite of the innermost secondary layer. This study confirms the lack of any vital effects influencing oxygen isotope composition of T. transversa, even in specialised areas of the innermost secondary layer. Calcite Mg/Ca ratio is another potential seawater temperature proxy, that has the advantage of not being influenced by salinity. Mg concentrations measured by electron microprobe analyses indicate that there is no concomitant decrease in Mg concentration towards the inner secondary layer, associated with the progressive shift towards oxygen isotope equilibrium. Mg distribution is heterogeneous throughout the shell and correlates with that of sulphur, which may be a proxy for organic components, suggesting that some of the Mg may not be in the calcite lattice. It is essential therefore, to determine the chemical environment of the magnesium ions to avoid any erroneous temperature extrapolations in brachiopods or any other calcite biomineral.