Airborne electromagnetic, magnetic, and radiometric survey, upper East River and surrounding watersheds near Crested Butte, Colorado, 2017

This data release consists of 1,984 line-kilometers of airborne electromagnetic (AEM), magnetic data and radiometric data collected from October to November 2017 in the upper East River and surrounding watersheds in central Colorado. The U.S. Geological Survey contracted Geotech Ltd. to acquire these data as part of regional investigations into the geologic structure and hydrologic framework of the area. The AEM data have been inverted to produce a series of regional cross-sections that constrain the electrical properties of the subsurface to a depth of approximately 500m. Data were acquired using the VTEM ET time-domain helicopter-borne electromagnetic system along flight lines that cross important geological structures over a 483 square kilometer area. In addition to magnetic and radiometric data, this data release includes minimally processed AEM data, processed AEM data used in the development of resistivity and induced polarization (IP) models, and laterally constrained inverse models for resistivity and IP parameters along all flight lines. Data that intersected cultural infrastructure have been removed from the processed AEM data prior to inversion.

本数据集发布包含1984航测线千米的航空电磁（airborne electromagnetic, AEM）、磁法及放射性数据，采集于2017年10月至11月，覆盖科罗拉多州中部东河上游及周边流域。美国地质调查局（U.S. Geological Survey）委托Geotech Ltd.采集本套数据，作为该区域地质构造与水文框架区域性调查的组成部分。航空电磁数据已完成反演处理，生成一系列区域性剖面，可将地下电性属性约束至约500米深度。本次数据采集采用VTEM ET时域直升机载电磁系统，沿穿越重要地质构造的航测线在483平方千米范围内开展作业。除磁法与放射性数据外，本数据集还包含经轻度预处理的航空电磁数据、用于构建电阻率与激发极化（induced polarization, IP）模型的已处理航空电磁数据，以及沿所有航测线生成的电阻率与IP参数横向约束反演模型。在反演前，已从已处理航空电磁数据中剔除了与人工设施相交的测段数据。