Problems with proxies? Cautionary tales of calcareous nannofossil paleoenvironmental indicators
Problems with proxies? Cautionary tales of calcareous nannofossil paleoenvironmental indicators
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代理有问题吗？
DOI：
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发表时间：
2005
期刊：
影响因子：
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通讯作者：
E. Mattioli
中科院分区：
文献类型：
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作者：
J. Lees;P. Bown;E. Mattioli
许多与长期全球变化和气候变化有关的研究依赖于化石和地球化学的代用数据来重建古环境。这些数据也有助于我们了解生物多样性的时间。在这方面，钙质超微化石是一个很好的代理资源，一些类群已成为古温度和/或古肥力的指标。然而，尽管大多数识别这些超微化石代理的原始作品基本上是合理的，但代理在不同的古环境条件和时间间隔中应用于更广泛的场景，开始挑战我们最初的一些假设。因此，越来越需要对这些代理人的地位进行更准确的评估。此外，还有一些超微化石分类群具有替代潜力，但需要重点研究，以确定其效用的程度。在这里，我们指出了一些最常用的中生代超微化石代理类群（Watznaueria spp.，Biscutum constans，Zeugrhabdotus erectus，Nannoconus spp.），并引入分类群Micula作为潜在的生育力代理，凭借其在特定环境中的高丰度。此外，我们概述了一个程序，正在进行中，涉及地球化学的“指纹”结合超微化石的统计数据，个别类群，这应该使我们能够更好地了解这些类群的古生态偏好，从而帮助恢复这些代理人的信心，并提供更好地了解其潜在的局限性。
Many studies relating to long-term global change and climate variability rely on proxy data from fossils and geochemistry to reconstruct paleoenvironments. Such data can also contribute to our understanding of biodiversity through time. In this respect, calcareous nannofossils are an excellent proxy resource, with a number of taxa having become established as indices of paleotemperature and/or paleofertility. However, although the majority of the original works that identified these nannofossil proxies are basically sound, the application of the proxies to a widening range of scenarios, in differing paleoenvironmental situations and time-intervals, is beginning to challenge some of our original assumptions. Consequently, there is a growing need for more precise evaluations of the status of these proxies. In addition, there are a number of nannofossil taxa which have proxy potential but which require focused study to determine the extent of their utility. Here, we point to the problems associated with some of the most commonlyused Mesozoic nannofossil proxy taxa (Watznaueria spp., Biscutum constans, Zeugrhabdotus erectus, Nannoconus spp.), and introduce the taxon Micula as a potential fertility proxy, by virtue of its high abundance in particular environments. Further to this, we outline a program that is in progress , involving geochemical 'finger-printing' of individual taxa combined with nannofossil statistical data, that should enable us to better understand the paleoecological preferences of these taxa and so help in restoring confidence in these proxies and provide a better understanding of their potential limitations.