An important interval for reef evolution occurs in the Triassic Period. However, Late Triassic reefs along the edge of the Panthalassa Ocean receive much less attention than their Tethys region counterpart. To improve our understanding of reef evolution along the Panthalassa, we present a quantitative microfacies analysis to characterize reef facies types from a central Nevada locality. We point counted thin sections to quantitatively assess the relative abundance of reef and interstitial components from six Carnian reef mounds. Reef mound formation occurs at three different stratigraphic intervals. Each interval records a different reef mound size and shape. The oldest stratigraphic interval consists of four separate reef mounds; each mound is approximately 3–12 m wide and 2–4 m high. The second youngest stratigraphic interval consists of one large ~ 10-m wide and 15.5-m high domal reef mound. The third, and youngest, reef mound is smaller in comparison (i.e., 1-m wide and 1.5-m high). We recognize two reef facies types within these reef mounds. Different calcareous sponges, bound together by microproblematica and clotted micrite, form the overall reef framework. We suspect that changes in relative sea level affect the initial colonization, different growth capacities, and overall preservation of the South Canyon reef mounds. When South Canyon reefs are compared to other Panthalassa reefs, it seems that “Wetterstein-type” reef–sponge bindstone facies containing biogenic crusts dominate and corals are less abundant and persist generally in both shallow and deeper water environments. However, significant differences in primary and secondary framebuilder abundances exist due to differences in where the reefs grew in relation to fair-weather wave base (FWWB). Thus, changes in relative sea level may affect the initial colonization, different growth capacities, and overall preservation of reef but water depth may also control the primary and secondary reef builders. Consequently, quantitative assessment of reef ecosystems within a sequence stratigraphic framework undoubtedly facilitates fewer problematic comparisons between reefs but it also enhances our understanding of reef development.

中文翻译：

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来自内华达州中部南峡谷的上三叠纪（卡尼阶）海绵礁丘

三叠纪是生物礁演化的重要时期。然而，沿着 Panthalassa 洋边缘的晚三叠世珊瑚礁比它们的 Tethys 地区受到的关注要少得多。为了提高我们对 Panthalassa 沿线珊瑚礁演化的理解，我们提出了定量微相分析，以表征内华达州中部地区的珊瑚礁相类型。我们指向计数的薄片以定量评估来自六个卡尼安礁丘的礁石和间隙成分的相对丰度。礁丘形成发生在三个不同的地层间隔。每个间隔记录不同的礁丘大小和形状。最古老的地层层段由四个独立的礁丘组成；每个土墩大约 3-12 m 宽，2-4 m 高。第二个最年轻的地层层段由一个约 10 米宽、15.5 米高的圆顶礁丘组成。相比之下，第三个也是最年轻的礁丘较小（即 1 米宽和 1.5 米高）。我们在这些礁丘中识别出两种礁相类型。不同的钙质海绵，由 microproblematica 和凝结的泥晶结合在一起，形成了整体的珊瑚礁框架。我们怀疑相对海平面的变化会影响南峡谷礁丘的初始殖民化、不同的生长能力和整体保存。当将南峡谷珊瑚礁与其他 Panthalassa 珊瑚礁进行比较时，似乎“Wetterstein 型”珊瑚礁 - 含有生物结壳的海绵粘结岩相占主导地位，珊瑚数量较少，通常在浅水和深水环境中持续存在。然而，由于与晴天波基 (FWWB) 相关的珊瑚礁生长位置不同，因此初级和次级框架建造者丰度存在显着差异。因此，相对海平面的变化可能会影响珊瑚礁的初始殖民、不同的生长能力和整体保存，但水深也可能控制主要和次要的珊瑚礁建造者。因此，在层序地层框架内对珊瑚礁生态系统进行定量评估，很容易减少珊瑚礁之间有问题的比较，但它也增强了我们对珊瑚礁发育的理解。和珊瑚礁的整体保存，但水深也可能控制主要和次要的珊瑚礁建造者。因此，在层序地层框架内对珊瑚礁生态系统进行定量评估无疑有助于减少珊瑚礁之间的问题比较，但也增强了我们对珊瑚礁发育的理解。和珊瑚礁的整体保存，但水深也可能控制主要和次要的珊瑚礁建造者。因此，在层序地层框架内对珊瑚礁生态系统进行定量评估无疑有助于减少珊瑚礁之间的问题比较，但它也增强了我们对珊瑚礁发育的理解。