{"title":"探地雷达的技术挑战和成果:以新斯科舍省约金斯为例","authors":"T. Kelly, G. Wach, D. O'Connor","doi":"10.3934/GEOSCI.2021002","DOIUrl":null,"url":null,"abstract":"The Carboniferous Joggins Formation is known for its complete succession of fossil-rich, coal-bearing strata, deposited in a fluvial meanderbelt depositional setting. Hence, the Joggins Formation outcrop is an excellent analogue for studying the 2D geological complexities associated with meanderbelt systems. In this research, a conventional ground-penetrating radar system was tested with the intent of imaging near-surface, dipping, strata of the Joggins Formation (potentially with subsequent repeats as annual erosion provides new visual calibrations). The survey was unsuccessful in its primary goal, and for future reference we document the reasons here. However, the overlying near-surface angular unconformity was successfully imaged enabling mapping of the approximately 8 m of overlying glacial till. A successful outcome would have allowed observations from the 2D outcrop to be extended into 3D space and perhaps lead to an increased understanding of the small (e.g., bedform baffles and barriers) and large (e.g., channel bodies) scale architectural elements, meanderbelt geometry, and aspect ratios. The study comprises a 42-line, 3.46 km ground-penetrating radar survey using a Sensors and Software pulseEKKO Pro SmartCart system. It was combined with a real-time kinematic differential global positioning system for the georeferencing of survey lines. The 50 MHz antenna frequency, with a 1 m separation, was chosen to maximize the depth of penetration, while still maintaining a reasonable resolution. The results show that many of the lines are contaminated with diffraction hyperbolae, possibly caused from buried objects near or under the survey lines or surface objects near the survey lines. A total of thirteen unique radar reflectors are described and interpreted from this work. The thick clay-rich soil overlying the Joggins Formation probably contributed to significant signal attenuation and the nature of the Carboniferous strata (dip of the beds, pinching and swelling of the beds, bed thickness, etc.) also contributed to imaging difficulties.","PeriodicalId":43999,"journal":{"name":"AIMS Geosciences","volume":null,"pages":null},"PeriodicalIF":0.9000,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"1","resultStr":"{\"title\":\"The technical challenges and outcomes of ground-penetrating radar: A site-specific example from Joggins, Nova Scotia\",\"authors\":\"T. Kelly, G. Wach, D. O'Connor\",\"doi\":\"10.3934/GEOSCI.2021002\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"The Carboniferous Joggins Formation is known for its complete succession of fossil-rich, coal-bearing strata, deposited in a fluvial meanderbelt depositional setting. 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引用次数: 1
摘要
石炭系约金斯组以其完整的富化石、含煤地层序列而闻名,沉积在河流曲流带沉积环境中。因此,Joggins组露头是研究与蜿蜒带系统相关的二维地质复杂性的极好模拟。在这项研究中,测试了传统的探地雷达系统,目的是对Joggins组近地表倾斜地层进行成像(后续可能会重复进行,因为每年的侵蚀提供了新的视觉校准)。该调查未能实现其主要目标,为了将来参考,我们在这里记录了原因。然而,对上覆的近地表角不整合进行了成功的成像,从而绘制了大约8米的上覆冰碛物。一个成功的结果将使二维露头的观测扩展到三维空间,并可能增加对小型(例如,河床挡板和障碍物)和大型(例如,河道体)规模建筑元素、曲流带几何形状和纵横比的理解。该研究包括42线,3.46公里的探地雷达测量,使用传感器和软件pulseEKKO Pro SmartCart系统。它与实时运动差分全球定位系统相结合,用于测量线的地理参考。选择50 MHz的天线频率,间隔1 m,以最大限度地提高穿透深度,同时仍然保持合理的分辨率。结果表明,许多线被衍射双曲线污染,这可能是由于测量线附近或以下的埋藏物体或测量线附近的表面物体造成的。从这项工作中,共描述和解释了13种独特的雷达反射器。Joggins组上覆较厚的富粘土层可能导致信号明显衰减,石炭系地层的性质(地层的倾角、地层的挤压和膨胀、地层厚度等)也导致成像困难。
The technical challenges and outcomes of ground-penetrating radar: A site-specific example from Joggins, Nova Scotia
The Carboniferous Joggins Formation is known for its complete succession of fossil-rich, coal-bearing strata, deposited in a fluvial meanderbelt depositional setting. Hence, the Joggins Formation outcrop is an excellent analogue for studying the 2D geological complexities associated with meanderbelt systems. In this research, a conventional ground-penetrating radar system was tested with the intent of imaging near-surface, dipping, strata of the Joggins Formation (potentially with subsequent repeats as annual erosion provides new visual calibrations). The survey was unsuccessful in its primary goal, and for future reference we document the reasons here. However, the overlying near-surface angular unconformity was successfully imaged enabling mapping of the approximately 8 m of overlying glacial till. A successful outcome would have allowed observations from the 2D outcrop to be extended into 3D space and perhaps lead to an increased understanding of the small (e.g., bedform baffles and barriers) and large (e.g., channel bodies) scale architectural elements, meanderbelt geometry, and aspect ratios. The study comprises a 42-line, 3.46 km ground-penetrating radar survey using a Sensors and Software pulseEKKO Pro SmartCart system. It was combined with a real-time kinematic differential global positioning system for the georeferencing of survey lines. The 50 MHz antenna frequency, with a 1 m separation, was chosen to maximize the depth of penetration, while still maintaining a reasonable resolution. The results show that many of the lines are contaminated with diffraction hyperbolae, possibly caused from buried objects near or under the survey lines or surface objects near the survey lines. A total of thirteen unique radar reflectors are described and interpreted from this work. The thick clay-rich soil overlying the Joggins Formation probably contributed to significant signal attenuation and the nature of the Carboniferous strata (dip of the beds, pinching and swelling of the beds, bed thickness, etc.) also contributed to imaging difficulties.