Different types of biogenic remains, ranging from siliceous algae to carbonate precipitates, accumulate in the sediments of lakes and other aquatic ecosystems. Unicellular algae called diatoms, which form a siliceous test or frustule, are an ecologically and biogeochemically important group of organisms in aquatic environments and are often preserved in lake or marine sediments. When diatoms accumulate in large numbers in sediments, the fossilized remains can form diatomite. In sedimentological literature, “diatomite” is defined as a friable, light-coloured, sedimentary rock with a diatom content of at least 50%, however, in the Quaternary science literature diatomite is commonly used as a description of a sediment type that contains a “large” quantity of diatom frustules without a precise description of diatom abundance. Here we pose the question: What is diatomite? What quantity of diatoms define a sediment as diatomite? Is it an uncompacted sediment or a compacted sediment? We provide a short overview of prior practices and suggest that sediment with more than 50% of sediment weight comprised of diatom SiO2 and having high (>70%) porosity is diatomaceous ooze if unconsolidated and diatomite if consolidated. Greater burial depth and higher temperatures result in porosity loss and recrystallization into porcelanite, chert, and pure quartz.

中文翻译：

---

什么是硅藻土？

不同类型的生物遗骸，从硅藻到碳酸盐沉淀物，积聚在湖泊和其他水生生态系统的沉积物中。称为硅藻的单细胞藻类形成硅质测试或硅藻壳，是水生环境中生态和生物地球化学重要的一组生物，通常保存在湖泊或海洋沉积物中。当硅藻大量积聚在沉积物中时，化石残骸可以形成硅藻土。在沉积学文献中，“硅藻土”被定义为一种易碎、浅色、硅藻含量至少为 50% 的沉积岩，然而，在第四纪科学文献中，硅藻土通常被用作对含有“大量”硅藻壳，但没有准确描述硅藻丰度。我们在这里提出问题：什么是硅藻土？多少硅藻将沉积物定义为硅藻土？它是未压实的沉积物还是压实的沉积物？我们简要概述了先前的做法，并建议沉积物重量超过 50% 的沉积物由硅藻 SiO2 组成2并且具有高（> 70％）孔隙率如果未固结是硅藻泥，如果固结是硅藻土。更大的埋藏深度和更高的温度导致孔隙度损失和再结晶成瓷石、燧石和纯石英。