Cyclostratigraphical analysis of the foraminiferal assemblages from the Early Toarcian at the Mochras Farm Borehole (Wales) was conducted in order to evaluate the incidence of cyclic palaeoenvironmental changes on the foraminiferal community. Different variables such as type of morphogroup, evolutionary strategy, habitat, particular taxa, diversity and abundance were studied using the Lomb–Scargle periodogram implemented in the computer program SLOMBS. A well‐developed cyclostratigraphical pattern is recognized, with the presence of several cycles (in metres) at 3.4–4/7.2–7.5/10.1–10.6/32.1–33.3/104.2–111.2/128.2/166.7, belonging to the high‐, middle‐, middle‐/low‐, and low‐frequency bands. The incidence and relevance of the cycles is found to be related to particular variables marking the global and local character of the involved processes. Cyclic changes in the organic matter input are found to be the most relevant palaeoenvironmental factor, oxygenation being secondary. A correspondence with specific Milankovitch cycles is, at present, difficult to determine.

中文翻译：

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Mochras农场钻孔（威尔士）早期Toarcian期间的循环环境变化：有孔虫群落的变化响应

为了评估有孔虫群落周期性古环境变化的发生率，对Mochras农场钻孔（威尔士）早期Toarcian的有孔虫组合进行了地层地层学分析。使用计算机程序SLOMBS中实现的Lomb-Scargle周期图，研究了不同的变量，例如形态群类型，进化策略，栖息地，特定分类群，多样性和丰度。人们认识到一种完善的旋回地层学模式，在3.4–4 / 7.2–7.5 / 10.1–10.6 / 32.1–33.3 / 104.2–111.2 / 128.2 / 166.7处存在几个周期（以米为单位），属于高，中，中/低和低频段。发现周期的发生率和相关性与标记所涉及过程的整体和局部特征的特定变量有关。发现有机物输入中的循环变化是最相关的古环境因子，而氧合是次要的。目前，很难确定与特定米兰科维奇循环的对应关系。