Constraining the eruption rates of flood basalt lava flows remains a significant challenge despite decades of work. One potential observable proxy for eruption rates is flood basalt lava-flow lobe thicknesses, a topic that we tackle here quantitatively. In this study, we provide the first global compilation of pāhoehoe lava-lobe thicknesses from various continental flood basalt provinces (∼ 3,800 measurements) to compare characteristic thicknesses within and between provinces. We refer to thin lobes (∼ ≤5 m), characteristic of “compound” lavas, as hummocky pāhoehoe lava flows or flow-fields. Conversely, we term thicker lobes, characteristic of “simple” flows, as coming from sheet-lobe-dominated flows. Data from the Deccan Traps and Columbia River flood-basalt provinces are archetypal since they have the most consistent datasets as well as established chemo- and litho-stratigraphies. Examining Deccan lobe thicknesses, we find that previously suggested (and disputed) distinct temporal and regional distributions of hummocky pāhoehoe and sheet-lobe-dominated flow fields are not strongly supported by the data and that each geochemically defined formation displays both lobe types in varying amounts. Thin flow-lobes do not appear to indicate proximity to source. The modal lobe thickness of Deccan formations with abundant “thin” lava-lobes is 8 m, while the mode for sheet-lobe-dominated formations is only 17 m. Sheet-lobes up to 75–80 m are rare in the Deccan and Columbia River Provinces, and ones >100 m are exceptional globally. For other flood basalt provinces, modal thickness plots show a prevalence toward similar lobe thicknesses to Deccan, with many provinces having some or most lobes in the 5–8 m modal range. However, median values are generally thicker, in the 8–12 m range, suggesting that sheet-lobes dominate. By contrast, lobes from non-flood basalt flow-fields (e.g., Hawai’i, Snake River Plain) show distinctly thinner modes, sub-5 m. Our results provide a quantitative basis to ascertain variations in gross lava morphology and, perhaps, this will in future be related to emplacement dynamics of different flood basalt provinces, or parts thereof. We can also systematically distinguish outlier lobes (or regions) from typical lobes in a province, e.g., North American Central Atlantic Magmatic Province lava-lobes are anomalously thick and are closely related to feeder-intrusions, thus enabling a better understanding of conditions required to produce large-volume, thick, flood basalt lava-lobes and flows.

尽管进行了数十年的工作，但限制玄武岩熔岩流的爆发速度仍然是一项重大挑战。玄武岩熔岩流波瓣厚度是​​潜在的可观测喷发率的代表，这是我们在此定量解决的一个话题。在这项研究中，我们提供了来自各个大陆洪水玄武岩省的帕霍霍熔岩裂片厚度的第一个全球汇总数据（约3,800个测量值），以比较各省内部和各省之间的特征厚度。我们将细叶（〜≤5 m）称为“复合”熔岩的特征，称为丘状phoehoe熔岩流或流场。相反，我们称较厚的裂片为“简单”流动的特征，它来自以片状裂片为主的流动。来自Deccan Traps和Columbia River洪水玄武岩省的数据是原型数据，因为它们具有最一致的数据集以及已建立的化学地层和岩石地层。通过检查Deccan瓣厚度，我们发现先前提出的（和有争议的）山楂phoehoe和片状叶为主的流场在时间和区域上的独特分布并没有得到数据的强烈支持，并且每个地球化学定义的地层均以不同的量显示两种叶型。细的波瓣似乎没有表明与源的接近。具有丰富的“稀薄”熔岩裂片的Deccan地层的模态波瓣厚度为8 m，而以片裂片为主的地层的模态波瓣厚度仅为17 m。在德干和哥伦比亚河省，极少见到高达75–80 m的表叶，而在全球范围内，超过100 m的表叶是罕见的。对于其他洪水玄武岩省，模态厚度图显示了与德干地区相似的裂片厚度流行，许多省的部分或大部分裂片在5-8 m模态范围内。但是，中值通常较厚，在8-12 m范围内，表明表叶为主。相比之下，来自非洪水玄武岩流场（例如，夏威夷，蛇河平原）的裂片表现出明显更薄的模式，低于5 m。我们的研究结果为确定总熔岩形态的变化提供了定量依据，也许在将来，这可能与不同洪水玄武岩省或其部分地区的进驻动态有关。我们还可以系统地将离群的裂片（或区域）与某省的典型裂片区分开，例如，