During the Late Paleozoic Ice Age, the fault-bounded equatorial Cumberland Basin of Nova Scotia experienced rapid subsidence, accumulating kilometer-thick fluvial sedimentary units derived from two highlands to the northwest and southeast. Major variations are recorded in the paleosols exposed at the Joggins Fossil Cliffs, ranging from oxidized and well-drained paleosols with recognizable vertic features to highly reduced organic-rich paleosols. These different soil lithologies suggest alternating conditions between well-drained floodplain environments and water saturation associated with overall poor soil development. Although halokinetic subsidence of the Cumberland Basin is known to have been operative during deposition of these units, previous research favored glacio-eustatic processes as the primary forcing mechanism of sedimentation. A total of 474 fluvial aggradational cycles were identified within a kilometer-thick interval and show a fluctuating accommodation history with a very abrupt nature. The series of fluvial aggradational cycles was used to develop threshold autoregressive models based on 1) their thickness, 2) their paleosol thickness, 3) their sandstone content, and 4) their paleosol-to-sandstone ratio. For each model, results suggest no evidence of statistically significant cyclicity, contradicting the hypothesis that fluvial sedimentation was mainly driven by glacio-eustatic cyclothems. Additionally, a total of 7 lithologies were recognized through 1,655 beds. Evaluation of 8 spherical semivariograms suggests no evidence for cyclicity in the frequency, order, or distribution of the data based on lithologies, although some covariance was found at distances between 550 and 750 m suggesting similar processes controlling sedimentation in the lower and upper Joggins Formation. The Cumberland Basin is known to have been rapidly subsiding, mainly because of ductile deformation of salt deposits in the deeper basinal units. Our results suggest that Joggins records tectonically induced ponding of a part of the sedimentary basin, allowing more extensive preservation of abundant coal and organic-rich units, as well as still-standing fossil forests exposed along the cliffs. These new results suggest that tectonic subsidence of the Cumberland Basin during the Late Paleozoic Ice Age was a more important driver of fluvial sedimentation than previously thought. This novel application of the TAR methodology provides a mathematical description of the sediment accumulation history of terrestrial basins when applied to conformable sedimentary successions, along with the means of linking paleosol development to climatic processes.

中文翻译：

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缺乏加拿大新斯科舍省乔金斯石炭纪沉积物气候驱动循环的证据：盐分抽采构造对沉积和成岩作用的影响

在古生代末期的冰河时期，新斯科舍以断层为界的赤道坎伯兰盆地经历了快速沉降，堆积了由西北和东南两个高地衍生的千米厚的河流沉积单元。在乔金斯化石悬崖暴露的古土壤中记录了主要变化，范围从具有可识别的垂直特征的氧化和排水良好的古土壤到高度还原的富含有机物的古土壤。这些不同的土壤岩性表明，排水良好的洪泛区环境与含水饱和度之间的交替条件与总体土壤发育不良有关。尽管众所周知，坎伯兰盆地的晕动沉陷在这些单元的沉积过程中是有效的，但先前的研究倾向于将冰河共生过程作为沉积的主要推动机制。在一千米厚的时间间隔内，总共确定了474个河流的凝结周期，并显示出波动的适应性历史，且具有非常突然的性质。利用一系列河床凝结周期，基于以下条件建立阈值自回归模型：1）厚度，2）古土壤厚度，3）砂岩含量，4）古土壤与砂岩之比。对于每个模型，结果都表明没有统计上显着的周期性证据，这与河流沉降主要由冰川-欧共体旋回驱动的假设相矛盾。此外，通过1655张床共识别出7种岩性。对8个球形半变异函数的评估表明，没有证据表明基于岩性的数据的频率，顺序或分布具有周期性，尽管在550至750 m的距离上发现了一些协方差，这表明控制下部和上部乔金斯组沉积的相似过程。众所周知，坎伯兰盆地正在迅速沉降，这主要是由于深部盆地单元中盐沉积物的韧性变形所致。我们的研究结果表明，Joggins记录了沉积盆地一部分的构造诱发的淤积，从而可以更广泛地保存丰富的煤炭和富含有机物的单元，以及沿悬崖裸露的静止的化石森林。这些新结果表明，晚古生代冰期期间坎伯兰盆地的构造沉降是河流沉积作用的重要驱动力，比以前认为的要重要。