ANTHROPOCENE SEQUENCE STRATIGRAPHY

The Danish philosopher Søren Kierkegaard wrote, "Life can only be understood backwards; but it must be lived forwards." The stratigraphic record is analogous: the record is interpreted from observations looking backwards, but processes march forward. This doesn't negate the idea of some predictive capacity. The Anthropocene is a proposed epoch that relates geologic time with the notable impacts of humans on Earth. It has generated considerable debate concerning the effects of the industrial revolution on climate change, and especially, according to the Working Group on the Anthropocene, recognition of a radionuclide spike at the near-synchronous dawn of the nuclear age. While establishing a golden spike for this GSSP may serve an important function from a geochronologic perspective, the application of sequence stratigraphy and chronostratigraphy is more problematic because humans have been and likely will continue to be capable of generating tremendous erosional disturbances of an unprecedented scale, prior to a highly anticipated, climate-induced base-level rise that threatens to inundate coastal areas globally. These disturbances, assuming they will be preserved, will rival and surpass those recognized at megasequence boundaries with perhaps the exception of the sub-Cambrian unconformity.

Most unconformities, sequence boundaries, are associated with base-level fall, so the sub-Anthropocene unconformity likely will pose a perplexing problem for future sentient beings of Earth. Most unconformities are defined by superposed strata. Some local unconformities, such as road cuts, borrow pits, quarries, cut-and-fill along transportation corridors, and mountain-top removal practices in mining may be quasi-contemporaneous, but other anthropogenic erosional features such as excavations, burrows and borings, as well as superposed constructions or deposits show marked diachroneity over several thousand years, as do overlying constructions. The oldest mining at Ngwenya, Swaziland dates back to 41,000 – 43,000 years BP (late Pleistocene). The oldest known complex structures date to approximately 3,500 BCE on Malta. Younger examples include the ziggurats of Iraq to Egyptian and New World pyramids, and ultimately contemporary high-rise steel-frame structures and colossal impoundments.