Archaeological Geology
Three International Geological Correlation Programme projects (nos. 61,200 and 274) culminated two decades of research with an international symposium on Quaternary Coastal Evolution: Models, Processes and Local to Global Factors, held in Oostduinkerke-aam Zee, Belgium, in September 1993. Over the 20-year period, hundreds of geologists from more than 60 nations studied aspects of the Holocene epoch and the Quaternary period. The IGCP is an interdisciplinary effort sponsored by UNESCO and the International Union of Geological Sciences. The IGCP studies were closely related to collateral research by members of coastal subcommissions of the International Union for Quaternary Research. Findings from the research on changing climate, the evolution of shorelines, the nature of relative sea-level rise, ancient geographies, and other aspects of coastal research have a major impact upon the discipline of archaeological geology.
Climatological information may be applied regionally and specifically to the interpretation of archaeological sites. In the coastal zone, for example, we can now delineate past geographies with great precision. The nature of and reasons for the location of archaeological sites (or indeed the lack of sites) may be determined by analyzing paleoenvironmental factors at regional and specific sites, as well as in the immediate vicinity of artifacts.
Archaeological geologists are becoming more aware of the nuances of the historical and classical record. Legend, oral tradition, and mythology merit attention in a search for information about ancient events or the geographies of ancient times. Most successful interpretations have been the result of team research, using geological field and analytical techniques in concert with the expertise of archaeologists, historians, classicists, and scholars in many other disciplines. For example, history, oral tradition, and cartography tell us the details of major storm surges in the North Sea in the 14th and 17th centuries. These storms destroyed hundreds of low-lying towns and villages. Geologists and archaeologists can still study the remains of the settlements in the tidal flat regions. Increased storminess and the mining of low-lying peats, which deflated the coastal landscapes, led to catastrophe.
Marine transgressions are about to destroy a large medieval church on Poland’s Baltic coast. On the southwestern peninsula of Greece, a small sixth century Byzantine church has just fallen into the sea. Such examples remind us that a great portion of the evidence of human occupation of the Holocene coastal landscape is now long gone, destroyed or buried under the sea as transgression and inundation continue along 75 percent of the world’s coastal zone.
Also, humans, have caused major environmental and geographical changes since ancient times. A Mycenean dam was constructed during the Bronze Age in the Argoilid, Greece, to ameliorate flooding in the lower city of the fortification of Tiryns. The substrate of the lower city of Ephesus, which is on the marine embayment of the Cayster River (Köcük Menderes River), changed over a several thousand year period. The change was due to the alteration of harbor works that started a Hellenistic times (2,100 to 2,300 years before present), including urban renewal and landfill. Structures that were built over an ancient beach and the extant harbor (about A.D. 100) include a late Roman Empire-early Byzantine archbishop’s palace, Saint Mary’s Cathedral, and many other public works long the then-new harbor edge. At the same time, flood plain sands and silts were infilling what had once been a 25-kilometer-long coastal embayment. Ultimately, the long-lived, world-class harbor of Ephesus silted up, and the city was isolated inland. In another example, ancient Troy of the Iliad originally lay on the end of a cuesta in a marine embayment south of the Dardanelles. Thus, Troy was a major maritime power in prehistory, but now its remains lie buried inland, far from the sea.
Paleogeographic and paleoenvironmental analyses are the essence of archaeological geology. We can relate archaeological geologists’ work on paleogeographies to modern problems of coastal transgression, the nature of human occupancy of the coastal zone, projections of future land losses, adaptations to ever-changing coastal landscapes, and the need to fortify or restructure coastal cities. We can explain more precisely the reasons for the establishment and loci of ancient (and modern) cities and archaeological sites and their local and regional paleogeographies. We can also project where and why to search for unknown or missing historical and legendary cities. Our studies must include an amalgam of 3-D analysis of sedimentary environmental lithosomes and geomorphologies, applications of many traditional and newly developed analytical techniques, a continuing attempt to fit our interpretations to concepts of world eutasy, and the complexity of climatological cycles and changes throughout the Holocene - all considered within the context of peoples and their occupations of Earth.