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首页> 外文期刊>Palaeontographica Canadiana >Trilobite taphonomy of the Latham Shale(Lower Cambrian; Dyeran), Mojave Desert, California: An Inner Detrital Belt Burgess Shale-type deposit of western Laurentia
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Trilobite taphonomy of the Latham Shale(Lower Cambrian; Dyeran), Mojave Desert, California: An Inner Detrital Belt Burgess Shale-type deposit of western Laurentia

机译：加利福尼亚州莫哈韦沙漠的Latham页岩（下寒武统; Dyeran）的三叶虫垂体：西部Laurentia的内部碎屑带Burgess页岩型矿床

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摘要

A sample of >800 specimens from the Lower Cambrian Latham Shale of California shows that among the most abundant trilobite species are Olenellus cf. clarki, O. nevadensis, Mesonacis fremonti, and Bristolia bristolensis, although abundance rank of species frequently varies by individual pit. Modal size for all olenelloids in the sample is comparable to several other deposits of similar age, and the size frequency distributions of the specimens indicates little or no size sorting. The trilobites of the Latham Shale demonstrate one of the lowest frequencies of articulation of any Cambrian deposit in the region. Cephalon orientation data on trilobite specimens indicate no statistically significant up-down trend, and azimuth orientations of the long axis of the glabella show no obvious preferred trend. Taphonomic results suggest that the Latham Shale trilobites were deposited in a shallow marine shelf with little turbulence, a low sedimentation rate, low oxygen levels, a moderate degree of shallow bioturbation, and possibly long bottom-exposure times for trilobite sclerites. Anoxic events and relatively rapid burial did sometimes converge to preserve soft-bodied taxa such as algae, worms and anomalocaridids.
机译：从加利福尼亚的下寒武统Latham页岩中提取的800多个标本样本显示，最丰富的三叶虫物种是Olenelluscf。 clarki，O。nevadensis，Mesonacis fremonti和Bristolia bristolensis，尽管物种的丰富度等级经常因单个窖而不同。样品中所有油样的模态尺寸可与相似年龄的其他几种沉积物相比，并且样品的尺寸频率分布表明几乎没有或没有尺寸分类。 Latham页岩的三叶虫表现出该地区任何寒武纪沉积物的最低成矿频率之一。三叶虫标本的头孢定向数据表明没有统计学上显着的上下趋势，而眉间长轴的方位方向没有明显的优选趋势。谱学结果表明，Latham页岩三叶虫沉积在一个浅海相架中，湍流少，沉积速率低，氧含量低，浅度生物扰动程度适中，并且三叶虫巩膜的底部暴露时间可能较长。缺氧事件和相对快速的埋葬有时确实会聚在一起，以保存软体类群，例如藻类，蠕虫和异位龙类。

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