This point, although untested in the Lehigh and Schuylkill River basins, raises concerns regarding

the legacy of anthropogenic events. How long does an anthropogenic event, like the MCE, impact the depositional environment? How do we classify post-MCE effects on the U0126 environment? How do we differentiate actual MCE deposits from post-MCE remobilization? These legacy-based questions have direct implications for land-use and land management strategies. Every continent on Earth contains coal beds and many have historically been mined (Tewalt et al., 2010 and Gregory, 2001). This extensive range of potential anthropogenic (MCE) source material allows us to propose the following hypothesis–stratigraphic equivalents of the MCE are present on a global scale. This hypothesis is locally valid where evidence of the Mammoth Coal Event is documented throughout the North Branch, Susquehanna River Valley, mapped as the Nanticoke allomember (Thieme, 2003). The Nanticoke allomember, AD 1468–1899, includes a laminar sand and anthracite particle lithofacies consisting of laminated sediment with woody detritus and coal silt, largely originating from forest clearance and coal mining in the Northern Anthracite Field (Fig. 1). The original age range of the Nanticoke allomember was based on a single calibrated radiocarbon age and

likely does not reflect the true age range. Because the mining histories of the Northern, Central and Southern Anthracite MLN0128 Fields were approximately coeval, we assume here that the anthracite particle lithofacies unit within the Nanticoke allomember has a similar minimum age of deposition to that of the MCE, ∼1820 AD (Fig. 6). Bituminous coal regions within the Appalachian basin of eastern USA also harbor a legacy of mining and production. A stratigraphic

equivalent of the MCE occurs along the Chattanooga Creek Alanine-glyoxylate transaminase floodplain in southeastern, Tennessee (Dickerson, 2005). Laminated sand and coal alluvial sediment underlie a 137Cs peak, which likely dates to ∼1959 AD (Fig. 3C). Also near this location a distinct increase in Polycyclic Aromatic Hydrocarbons (PAHs) was documented in soil associated with a coal-gasification plant in Tennessee (Vulava et al., 2007). At least one coal-gasification plant was in operation in the Delaware River basin during the time which the MCE occurred. Therefore, PAHs may also serve as a source for determining the magnitude and extent of the coal production on the stratigraphic record. Like the Gibraltar soil series within the anthracite region of eastern Pennsylvania, the Nelse series, also a Mollic Udifluvent, forms on recent alluvial coal wash in the West Virginia and Kentucky region (Soil Survey Staff, 2012a and Soil Survey Staff, 2012b). These data further suggest that in addition to anthracite coal, bituminous coal alluvium is also likely preserved in the event stratigraphic record.