Abstract The carcinogenic potential of erionite has sparked concern about human exposure in areas where it is present in regional bedrock. The Arikaree Formation in western North Dakota contains altered tuffaceous units with authigenic zeolites. We sampled stratigraphic profiles in the Killdeer Mountains, Dunn County, North Dakota, to determine the distribution and chemical composition of zeolites. Powder X-ray diffraction, SEM/EDS and electron microprobe analyses were carried out on sample concentrates. Only samples stratigraphically in or below the distinctive burrowed marker unit were found to contain zeolites. Erionite and offretite were the most common zeolites identified, with offretite being more abundant based on frequency of measured Mg/(Ca+Na) ratios. Intermediate chemical compositions could be natural or due to intimate intergrowths of the two minerals. A better understanding is needed of the potential toxicity across the range of erionite and offretite compositions.

中文翻译：

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来自美国北达科他州邓恩县 Killdeer 山脉的毛沸石和软铁矿

摘要毛沸石的致癌潜力引发了人们对它存在于区域基岩中的地区的人类暴露的担忧。北达科他州西部的 Arikaree 组包含具有自生沸石的蚀变凝灰质单元。我们对北达科他州邓恩县 Killdeer 山脉的地层剖面进行了采样，以确定沸石的分布和化学成分。对样品浓缩物进行粉末 X 射线衍射、SEM/EDS 和电子探针分析。仅在地层学上在独特的洞穴标记单元中或下方的样品被发现含有沸石。毛沸石和钙沸石是最常见的沸石，根据测量的 Mg/(Ca+Na) 比率的频率，钙沸石的含量更高。中间化学成分可能是天然的，也可能是由于两种矿物的密切共生。需要更好地了解毛沸石和粗沸石成分范围内的潜在毒性。