We have developed a new experimental procedure in order to study the role of water content in the acquisition of post‐depositional detrital remanent magnetism by a sediment. The procedure leads to the determination of the magnetic direction recorded by a sediment as a function of the water content present when that sediment experiences a change in the direction of an applied magnetic field. Experiments with a variety of sediments indicate that in most cases, regardless of the water content, the sediment does not become remagnetized. Such behavior requires a re‐assessment of the importance of the theoretical notion that at high water contents the magnetic carriers remain mobile within fluid‐filled voids and hence are able to realign along a new applied field. Analysis of the magnetic properties of sediment samples initially stirred in zero and non‐zero magnetic fields leads to the conclusion that the magnetization of the sediments may arise from small‐scale, shear‐induced liquefaction.

This paper classifies the karst landscapes of the Petén Plateau and defines the Mirador-Calakmul Karst Basin by illustrating the distribution of its karst hydrologic features. Archaeological and spatial research of the Mirador-Calakmul area of Guatemala and Mexico has shown it to be a karst basin with geopolitical implications. Current research characterizes the karst landscapes of the Petén Plateau, maps the distribution of karst hydrologic features, and delineates the basin in geomorphological terms. To further this aim, multiple forms of remote sensing data including orthophotographs, a satellite Digital Elevation Model, satellite multispectral images, and Light Detection and Ranging (LiDAR) data have been integrated to interpret the karst features in the study area. Outcrop study and thin section analysis of the upper Buena Vista Formation document that the dominant lithologies are a shallow water algal boundstone interbedded with terrestrial caliche. Karst landforms have been mapped over the Petén Plateau and we identify five karst landscapes, the largest of which is a fluviokarst landscape dominated by karst valleys. We further map karst hydrologic features including seasonal swamps, dolines, intermittent lakes, intermittent streams, solution-enhanced fractures, and springs all of which are characteristic of drainage basins. Boundaries of the karst basin are mapped from multiple lines of evidence including distribution of the karst valleys, a line of springs along the western boundary of the fluviokarst landscape, and a surface drainage analysis. We capture and classify hydrologic data points and develop a regional groundwater map that indicates subsurface flow from east to west within the basin. A drainage map illustrates the extensive system of karst valleys, boundaries, and inferred groundwater flow paths of the Mirador-Calakmul Karst Basin. It was within this geomorphological setting that the ancient Maya developed an extensive civilization during the Middle and Late Preclassic periods (1000 BCE-150 CE).

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