The upper Silurian of South China records the first, and perhaps the only occurrence of widespread (spanning over 1400 km), thick to very thick bedded facies (TVTFs) after the Late Ordovician mass extinction. However, the palaeobiological, palaeoecological features and potential significance of these facies are yet to be demonstrated. A case study at northwestern Hunan Province, middle to upper Yangtze Block, reports the occurrence of TVTFs in a storm dominated open marine succession of the upper Silurian Xiaoxi Formation, which can be further assigned to lower offshore, upper offshore, offshore transition to distal lower shoreface, and proximal lower to middle shoreface settings. The regular changes of bioturbation intensity and maximum penetrating depth from various settings suggest that local energy levels, especially frequency of storms could have controlled the development of , while their burrow sizes were generally confined by population densities. The facies could have been constructed by unknown crustaceans, which generally conducted a deposit-feeding strategy. The return of widespread TVTFs in the tropical oceans of South China during the late Silurian could reflect a restored primary productivity, an elevated oxygen level, and a final recovery of benthic ecosystem to pre-extinction level after the Late Ordovician mass extinction. TVTFs could have remarkably shaped the late Silurian benthic environment in view of their high abundance, large burrow sizes, nature of deep tiered burrow systems and a deposit-feeding strategy.

中文翻译：

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华南上志留统广泛分布的Thalassinoides相——以湘西北、中上扬子地块为例

华南志留统上层记录了晚奥陶世大灭绝之后第一次、也许是唯一一次广泛（跨越1400多公里）厚层到特厚层状相（TVTF）的出现。然而，这些相的古生物学、古生态特征和潜在意义仍有待证实。以湖南省西北部扬子中上游地块为例，报道了志留统小溪组上段风暴主导的开阔海相序列中出现了TVTF，可进一步划分为近海下层、近海上层、近海过渡到远下层。岸面，以及近端中下岸面设置。不同环境下生物扰动强度和最大穿透深度的规律变化表明，当地的能量水平，特别是风暴的频率可能控制了它们的发展，而它们的洞穴大小通常受到人口密度的限制。这些相可能是由未知的甲壳类动物构成的，它们通常采取沉积物供给策略。志留世晚期华南热带海洋广泛的TVTF的恢复可能反映了晚奥陶世大规模灭绝后初级生产力的恢复、氧气水平的升高以及底栖生态系统最终恢复到灭绝前的水平。鉴于TVTF的高丰度、大洞穴尺寸、深层洞穴系统的性质和沉积物供给策略，TVTF可能显着塑造了志留世晚期的底栖环境。