Most earthen burial mounds of eastern North America have been destroyed—or have they? We review geophysical methods for assessing whether leveled mounds retain intact deposits or features. Magnetic survey holds promise for locating and evaluating leveled mounds because it is rapid and sensitive to magnetic variations associated with anticipated features such as pits and deposits of mound fill. As a case study, we discuss our magnetic survey of the Gast Farm site (13LA12) in eastern Iowa. The survey covered 8.64 ha, encompassing loci of one previously reported mound and possible geometric earthworks as well as Middle and Late Woodland habitation areas. Interpretation of survey results incorporated quantitative differentiation of magnetic anomaly types using GIS techniques, along with standard visual inspection. We found no evidence of geometric earthworks but identified at least six leveled mounds. Displaced mound fill appears to account for the earthwork-like features. We conclude that leveled mounds are detectable and may retain subsurface integrity. Their associated features, including burials, may be identifiable even when above-ground evidence has disappeared.

北美东部的大多数土葬土墩都被摧毁了，或者是吗？我们审查了地球物理方法，以评估平整的土丘是否保留完整的沉积物或特征。磁力勘测对定位和评估平整的土丘具有广阔的前景，因为它对与预期特征（例如坑和土堆填充物）相关的磁变化迅速且敏感。作为案例研究，我们讨论了对爱荷华州东部的Gast农场场址（13LA12）进行的磁测量。这项调查占地8.64公顷，涵盖了一个先前报道的土丘和可能的几何土方以及中，晚林地的栖息地。调查结果的解释结合了使用GIS技术对磁异常类型的定量区分以及标准的目视检查。我们没有发现几何土方的证据，但确定了至少六个平整的土丘。位移的土堆填充似乎可以解释类似土方的特征。我们得出的结论是，平整的土墩是可检测的，并且可以保留地下完整性。即使地面上的证据已经消失，它们的相关特征（包括埋葬）也可能是可识别的。