Detrital-zircon records of provenance are used to reconstruct paleogeography, sediment sources, and tectonic configuration. Recognition of biases in detrital-zircon records that result from grain-size-dependent processes adds new complexity and caution to the interpretation of these records. We begin by investigating possible size-dependent biases that may affect interpretation of detrital-zircon provenance records in an idealized sedimentary system. Our modeling results show that settling and selective entrainment can differentially affect detrital-zircon spectra if an initial size variation between source zircon populations exists. We then consider a case study: a detrital-zircon record from Ediacaran to Terreneuvian strata of Death Valley, USA, with a focus on the Rainstorm Member of the Johnnie Formation. The detrital-zircon record of the Rainstorm Member shows that despite its unusual, heavy-mineral-rich character, the provenance of the unit is like other units in the succession. Size and density measurements of the grains of the deposit suggest that its enriched heavy-mineral suite is best explained through concentration by selective entrainment and winnowing. The relationship between detrital-zircon grain size and age for samples from the Johnnie Formation are consistent with grain-size influence on the interpretation of provenance, especially for large Grenville-age (1.0–1.2 Ga) zircons. Grain size can exert significant bias on a provenance interpretation and must be accounted for in provenance studies.

中文翻译：

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埃迪卡拉纪碎屑锆石记录中的晶粒尺寸和输运偏差

碎屑锆石物源记录用于重建古地理、沉积物来源和构造构造。对碎屑锆石记录中由晶粒尺寸相关过程导致的偏差的识别为这些记录的解释增加了新的复杂性和谨慎性。我们首先调查可能的尺寸相关偏差，这些偏差可能会影响理想化沉积系统中碎屑锆石来源记录的解释。我们的建模结果表明，如果源锆石种群之间存在初始尺寸变化，沉降和选择性夹带会对碎屑锆石光谱产生不同的影响。然后我们考虑一个案例研究：从埃迪卡拉纪到美国死亡谷的 Terreneuvian 地层的碎屑锆石记录，重点是约翰尼组的暴雨段。暴雨成员的碎屑锆石记录显示，尽管其具有不同寻常的、富含重矿物的特征，但该单元的来源与该系列中的其他单元一样。对矿床颗粒的尺寸和密度测量表明，通过选择性夹带和风选浓缩，可以最好地解释其富含的重矿物组。约翰尼组样品的碎屑锆石晶粒尺寸和年龄之间的关系与晶粒尺寸对物源解释的影响一致，特别是对于大型 Grenville 年龄 (1.0-1.2 Ga) 锆石。颗粒大小会对来源解释产生重大偏差，必须在来源研究中加以考虑。对矿床颗粒的尺寸和密度测量表明，通过选择性夹带和风选浓缩，可以最好地解释其富含的重矿物组。约翰尼组样品的碎屑锆石晶粒尺寸和年龄之间的关系与晶粒尺寸对物源解释的影响一致，特别是对于大型 Grenville 年龄 (1.0-1.2 Ga) 锆石。颗粒大小会对来源解释产生重大偏差，必须在来源研究中加以考虑。对矿床颗粒的尺寸和密度测量表明，通过选择性夹带和风选浓缩，可以最好地解释其富含的重矿物组。约翰尼组样品的碎屑锆石晶粒尺寸和年龄之间的关系与晶粒尺寸对物源解释的影响一致，特别是对于大型 Grenville 年龄 (1.0-1.2 Ga) 锆石。颗粒大小会对来源解释产生重大偏差，必须在来源研究中加以考虑。约翰尼组样品的碎屑锆石晶粒尺寸和年龄之间的关系与晶粒尺寸对物源解释的影响一致，特别是对于大型 Grenville 年龄 (1.0-1.2 Ga) 锆石。颗粒大小会对来源解释产生重大偏差，必须在来源研究中加以考虑。约翰尼组样品的碎屑锆石晶粒尺寸和年龄之间的关系与晶粒尺寸对物源解释的影响一致，特别是对于大型 Grenville 年龄 (1.0-1.2 Ga) 锆石。颗粒大小会对来源解释产生重大偏差，必须在来源研究中加以考虑。