Constraining the timing and volume of sediment dispersal in an ancient sedimentary system is vital to understand a basin's infill history. One preferred method for a first-order approximation of ancient sediment load estimates, the BQART model, is based on empirical observations of modern river systems relating basin morphology, topography, climate, run-off and bedrock characteristics. Despite the popularity of such methods, a comprehensive assessment on the validity of using modern river observations to measure sediment load on geological timescales is lacking. Here, we investigate the uncertainties, sensitivities and practicalities surrounding the use of modern empirical observations in general and the BQART model in particular, to evaluate ancient sediment river loads. Although catchment area and relief are the least constrained parameters in an ancient sedimentary system, the temperature parameter may have an even more significant impact in the range of predicted sediment load estimates using a BQART approach. The applicability of BQART is most suitable for regional to continental scale source-to-sink systems that are based on robust paleogeographic and paleoclimatic models of cold (<2°C) or warm temperate (>8°C) climates. One further needs to consider the high amplitude discharge events that can dominate the stratigraphic record which are not captured by historical observations of sediment load over a 30-year period. In addition, our limited understanding of bedload material transport and an unknown pristine environment in the Anthropocene reduce the reliability of modern sediment load estimates for the ancient. Mass budget estimates in deep time based on empirical relationships of modern river systems can thus provide first-order estimates within an order of magnitude but need to consider the limitations imposed by extrapolating the modern to the ancient. Here, we present a framework to consider the suitability of the BQART method for ancient source-to-sink mass budget analyses.

中文翻译：

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评估古代源到汇质量预算计算的一阶 BQART 估计

限制古代沉积系统中沉积物扩散的时间和体积对于了解盆地的填充历史至关重要。古代沉积物负荷估计的一阶近似的一种首选方法，即 BQART 模型，是基于对与流域形态、地形、气候、径流和基岩特征相关的现代河流系统的经验观察。尽管这种方法很受欢迎，但缺乏对使用现代河流观测测量地质时间尺度上的沉积物负荷的有效性的综合评估。在这里，我们调查了围绕使用现代经验观察，特别是 BQART 模型来评估古代沉积物河流负荷的不确定性、敏感性和实用性。尽管集水区和地势是古代沉积系统中约束最少的参数，但温度参数可能对使用 BQART 方法预测的沉积物负荷估计范围产生更显着的影响。BQART 的适用性最适用于基于冷 (<2°C) 或暖温带 (>8°C) 气候的稳健古地理和古气候模型的区域到大陆尺度源汇系统。进一步需要考虑可以支配地层记录的高振幅排放事件，这些事件在 30 年期间的沉积物负荷历史观测中没有捕获到。此外，我们对沉积物物质运输的有限了解和人类世未知的原始环境降低了古代现代沉积物负荷估计的可靠性。因此，基于现代河流系统的经验关系的深层大规模预算估计可以提供一个数量级内的一阶估计，但需要考虑将现代外推到古代所施加的限制。在这里，我们提出了一个框架来考虑 BQART 方法在古代源到汇质量预算分析中的适用性。