Large detrital zircon data set investigation and provenance mapping: Local versus regional and continental sediment sources before, during, and after Ancestral Rocky Mountain deformation
Large detrital zircon data set investigation and provenance mapping: Local versus regional and continental sediment sources before, during, and after Ancestral Rocky Mountain deformation
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大型碎屑锆石数据集调查和物源测绘：祖先落基山变形之前、期间和之后的局部与区域和大陆沉积物来源
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发表时间：
2023
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通讯作者：
K. Sundell
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作者：
Tyson M. Smith;J. Saylor;T. Lapen;R. Leary;K. Sundell
碎屑地质年代学数据集的数量和规模不断增加，为提高沉积物路线模型的精度和分辨率提供了新的机会。然而，新的机遇伴随着大数据集成和可视化方面的挑战。我们通过概述两种有助于分析和解释大量碎屑地质年代学数据集的新方法来应对这些挑战：(1)自下而上和自上而下相结合的碎屑锆石源区模拟；(2)沉积物来源图。结合源区模拟方法，可为识别碎屑状锆石经验来源和确定源区比例提供指导。物源图综合了模拟结果和补充的地质数据(如古水流、古地理和地层厚度图)的来源比例，以通过数据稀少或不明确的地区推断物源信息，从而缓解了数据分布不均的问题。沉积物来源图还提供了数据的概括性视图，与碎屑锆石来源建模一起，有助于避开对包含数百个样本的数据集的个别年龄模式的冗长描述，这可能会掩盖数据中的潜在趋势。
我们将这一方法应用于晚古生代−早中生代地层，利用329个已发表的和新的U-Pb碎屑锆石样品，记录了西劳伦蒂亚板内变形核心带(即原始落基山脉(ARM))的5个沉积径流事件。这些时期之间的转变是由沉积物来源分布的变化来确定的，这由物源图说明，该图显示了(1)ARM盆地与横贯大陆沉积物来源隔离的程度和程度，以及(2)ARM驱动的横贯大陆沉积物输送系统的变化。我们绘制了ARM核心周围远端衍生沉积物的可能沉积路径图，说明ARM隆起使板块内强烈变形区域周围的横贯大陆系统改道。此外，西部劳伦西亚地区在ARM变形之前、期间和之后的沉积路径演变提供了横贯大陆的沉积物路径与板内变形之间相互作用的一个例子。
The increasing number and size of detrital geochronology data sets offer new opportunities for increased accuracy and resolution of sediment routing models. However, the new opportunities come coupled with challenges in large data integration and visualization. We address these challenges by outlining two novel approaches that aid in analyzing and interpreting large detrital geochronology data sets: (1) combination of bottom-up and top-down detrital zircon source modeling, and (2) sediment provenance mapping. Combining source-modeling methods provides guidance in identifying empirical detrital zircon sources and determining source proportions. Provenance mapping integrates source proportions from modeling results and complimentary geologic data (e.g., paleocurrents, paleogeography, and stratal thickness maps) to extrapolate provenance information through areas with sparse or ambiguous data, thus mitigating issues of data distribution heterogeneity. Sediment provenance maps also provide a synoptic view of data that, along with detrital zircon source modeling, aids in circumventing lengthy descriptions of individual age modes for data sets containing hundreds of samples, which can obscure underlying trends in the data.
We apply this approach to late Paleozoic−early Mesozoic strata, using 329 published and new U-Pb detrital zircon samples, and document five sediment-routing episodes in the core zone of intraplate deformation in western Laurentia (i.e., the Ancestral Rocky Mountains (ARM)). The transitions between these episodes are defined by changes in sediment source distribution, which are illustrated by provenance maps that show (1) the degree and extent of ARM basin isolation from transcontinental sediment sources and (2) ARM-driven changes in transcontinental sediment routing systems. We map possible sediment pathways of distally derived sediment around the ARM core, illustrating that ARM uplifts diverted transcontinental systems around areas of intense intraplate deformation. Further, the evolution of sediment routing in western Laurentia before, during, and after ARM deformation provides an example of the interaction between transcontinental sediment routing and intraplate deformation.