Coastal geoarchaeology

Marine resource exploitation is documented for the central coast of Ecuador from 10.000 yr B.P., with a wide range of fishing techniques developing through time. Most recently, dozens of stone fishing structures have been identified at the Liguiqui archaeological locality, on the Manta Peninsula of Manabí Province. These resemble fish traps such as have been recorded worldwide, though no similar devices have previously been reported on the Pacific coast of tropical or subtropical South America. A preliminary study of the Liguiqui structures is presented here, assessing their geologic, environmental, cultural and chronological context. It is hypothesized that they could have had a double function as fish traps and as fish attractors/containers, and that they were most likely built during the Pre-Hispanic Manteño cultural period.

The extant terrestrial Paleoindian sites on the Delmarva Peninsula suggest a hunting emphasis.  Interpretations about Paleoindian lifestyles in the Middle Atlantic coastal plain are greatly biased by marine transgression.  Research conducted over the past two years at 44NH233 offers new insights into Paleoindian adaptations near the developing Chesapeake Bay.  The geologic investigations provide an opportunity to assess regional models explaining the formation of Mockhorn Island along the Atlantic coast of the Delmarva Peninsula.  The investigations at 44NH233 also offer a better appreciation of the natural processes impacting archaeological sites during the transition from a terrestrial environment to a sub-aqueous offshore setting.  (A detailed analysis of the stone tools found at this site will be published in 2016 as a book chapter.  The reference is:  Dennis Stanford, Darrin Lowery, Margaret Jodry, and Michael Frank;  Mockhorn Island and Insights into Paleoindian Coastal Adaptations, pp. 58-95.  Chapter to be included in the book entitled In The Eastern Fluted Point Tradition, Volume II, edited by Joseph A. M. Gingerich, University of Utah Press).

Located on Virginia's Eastern Shore, 44NH478 is a badly eroding Early Woodland (~1100 cal B.C.) shell midden periodically exposed by seasonal movement of sediments. Because of the threat of erosion, we conducted extensive excavations at the site from 2011-2012. Detailed faunal and artifact analysis, geomorphological research, and Accelerator Mass Spectrometry (AMS) radiocarbon dating demonstrate that 44NH478 is the oldest securely dated shell midden on the Eastern Shore and one of only a handful of Early Woodland shell middens in the broader Chesapeake Bay region. Vertebrate faunal remains, including modest amounts of deer and fish bones, were limited, but at least 12 shellfish species show that people were exploiting a wide variety of marine shellfish, especially compared to later sites in the region. The artifact assemblage is also diverse, producing a Meadowood point and blade, debitage, and several different ceramic types, including shell-tempered Waterlily and Mockley Wares 2 that were directly AMS radiocarbon dated to ~1100 cal B.C. These are the oldest securely dated shell-tempered ceramics in North America and roughly the same age as the earliest ceramics in the Chesapeake region. Our research at 44NH478 demonstrates diverse Early Woodland shellfish use and sophisticated artifact technologies, as well as the importance of comprehensive AMS radiocarbon dating, geomorphological studies, and faunal analysis of shell middens throughout the Chesapeake region.

The present geomorphology of the Mediterranean’s coasts is largely a product of an intricate long-term relationship between Nature and human societies. A cradle of ancient
civilizations, the Mediterranean has seen its shores occupied by Humans since Prehistory, and is, therefore, a particularly pertinent unit of analysis. The morphotectonic context and
other forcing agents (e.g., climate) shaped out a highly diversified coastal morphology and generated a sediment-supply regime potentially favourable to the formation of numerous open-coast deltas and bay-head deltas in infilled rias as sea level stabilised during the mid- Holocene. This supply of riverine sediment has also been the key agent in mediating human occupation of the Mediterranean’s clastic coasts.

Expressions of this relationship have been extensively archived in clastic coastal deposits, including base-level deltaic and estuarine sedimentary sinks, which comprise records to explore the interactions between geosystemsand the human environment. The stratigraphic sequences in these coastal sedimentary archives comprise, in many places, a clearly identified anthropogenic signature, notably in ancient harbours, some of which underwent extremely rapid silting up due to massive sediment sourcing generated by new agricultural practices from the Neolithic onwards.

Increasing human influence, especially over the last 3000 years, has been, in turn, an important driver of changes in sediment supply, strongly modulating deltaic development.
Pulses of sediment supply from catchments rendered vulnerable by human perturbations during the Roman period resulted in a new cycle of inception of many other deltas and in
rapid delta growth (e.g. the Ebro, the Po, the Arno and the Ombrone). Another progradation dynamic during the Little Ice Age, at a time of strong rural population growth, river discharge
increases, technological developments, and urbanisation, further consolidated delta growth.

Understanding the life cycle of these deltas since their initial formation is, in turn, key to unravelling the relative role of natural and anthropogenic forcing agents. Rapid climate
changes are deemed to have contributed through both the stripping of landscapes rendered fragile by human activities and active fluvial sediment transport to the coast, but
disentangling climate change effects from human impacts in the Mediterranean remains a challenge.

The patterns of subsequent deltaic growth and delta morphodynamics reflect adaptations to pulsed sediment supply, river discharge variations, the microtidal, fetchlimited
context of the Mediterranean, and direct engineering interventions. The progradation dynamic of the Roman period and Little Ice Age contrasts markedly with the situation of common coastal destabilisation over the last two centuries, particularly well documented for the last 50 years. This period has been characterised by reduced sediment flux to base-level geosystems due to catchment reforestation, retenion within reservoirs, fluvial regulation and dredging, resulting in the erosion of deltas and barrier-lagoon and beach-dune systems. Large stretches of shoreline and narrow coastal plains have been massively engineered for coastal defence and protection against erosion, but also for the construction of marinas, leisure harbours and artificial beaches, resulting in the emergence of veritable artificial seafronts. These interventions have, collectively and progressively, raised societies to a pervasive and overarching position in the geomorphic stabilityinstability of the Mediterranean’s coasts, a situation that will be exacerbated by pressures from sea-level rise, paving the way for rampant coastal erosion and delta destruction.

Human records of short-term, catastrophic, geological processes, mainly in coastal or fluvial environments, and related phenomena in historic and prehistoric times have to be considered as functions of event intensities and impacts (and damages) caused on ancient human settlements and lives. Catastrophic events, such as, floods, earthquakes, volcanic eruptions, tsunamis, and the collapse of ancient cultures, in particular, those allied to the birth of myths and legends, are the subject of long-lasting, vivid debate. Longer-term, more-or-less consecutive, geological processes and climatic fluctuations have a more pronounced effect on human history. Historical accounts provide many descriptions about cultural evolution in a recurrent manner. The geoarchives (geology, sedimentology, and geomorphology) and the human record (archaeology and history) are considered documentary evidence of these past events. Astronomical causes have introduced severe phenomena (warming, heavy precipitation, monsoons, droughts) imposed on ancient societies, including catastrophic meteor impact. Terrestrial upheavals and astronomical impacts have introduced a nonlinear character of a quasiperiodic nature in transforming human cultural evolution and reshaping the earth's surface. The transient nature of geological, geophysical, and proxy climatic indices, as well as, astronomical phenomena within the solar system, exhibit a wide spectrum of quasiperiodic frequencies as variable and effective environmental factors, which, in addition to anthropogenic factors, reshape the human context. Several conspicuous examples have been reported on mythological deluges and their relation to natural catastrophes. The Anthropocene sea level rise and climatic episodes have had a decisive and prominent role on coastlines and human settlements. Alluvial sediments, sedimentary deposits, and land modifications have drastic effects on settlements. These effects were memorized as floods, deluges, and fallen sky. World examples of disasters derived from the coastal Mediterranean, the Great Flood of Gun-Yu in China, and those from South America, Mesopotamia, and the Middle East and others, were critically assessed with scientific methods.

The economy is one of the areas in which more progress has been completed in last decades regar- ding to the study of transition processes operated within punic (or western phoenician) communities after the an- nexation of the Straits of Gibraltar by the Roman Republic. Similarly, has been also relatively recent the rise in the area of paleogeographic debate and the crystallization of specialized teams and projects in this issues, whose scopes are helping significantly to change our current perception of the scenario where these processes took place. In this paper we focus on the specific case of the island of Gadir/Gades, and particularly the Atlantic coast, attempting to provide a new overview of transformations of settlement patterns and industrial exploitation in combination with some new paleogeographic data closely related.

GEOMORPHOLOGY AND GEOARCHAEOLOGICAL TYPOLOGY OF ANCIENT HARBOURS IN LAGOONAL CONTEXTS

In coastal areas, under a context of relative sea-level stability during the past 6,000 years, one important question relates to
the impact of environmental conditions on human settlements around lagoons. Historiography has developed a number of
deterministic models but how do these fair in the light of recent palaeo-environmental data? What was the impact of these occupations on the evolution of the coastline? How did ancient societies use and overcome, or not, the environmental potentialities and specific constraints linked to the occupation of lagoonal environments, including accessibility, navigation conditions, sediment infilling and the draught depth. Here we present a number of multidisciplinary case study examples of lagoonal harbours. We attempt to estimate the weight of natural forcing agents on the different harbour sites and underline the important roles of coastline changes and the sedimentary infilling of the lagoons at different spatial scales. These processes impacted upon the infrastructure and the viability
of the lagoonal harbours to varying degrees. We present five main types of lagoonal harbour that show the great diversity of these environments, their potentiality and also their constraints:
(1) artificially-dug lagoonal harbours, known in the ancient literature as “cothons”
(2) infilled lagoonal harbours in deltaic contexts
(3) lagoonal harbours still in water
(4) estuarine harbours
(5) mixed lagoon systems.

Kuumbi Cave is one of a group of caves that underlie a flight of marine terraces in Pleistocene limestone in eastern Zanzibar (Indian Ocean). Drawing on the findings of geoarchaeological field survey and archaeological excavation, we discuss the formation and evolution of Kuumbi Cave and its wider littoral landscape. In the later part of the Quaternary (last ca. 250,000 years?), speleogenesis and terrace formation were driven by the interplay between glacioeustatic sea level change and crustal uplift at rates of ca. 0.10-0.20 mm/yr. Two units of backreef/reef limestone were deposited during ‘optimal’ (highest) highstands, tentatively correlated with MIS 7 and 5; (mainly) erosive marine terraces formed in these limestones in ‘suboptimal’ highstands. Kuumbi and other sub-terrace caves developed as flank margin caves, in the seaward portion of freshwater lenses during such ‘suboptimal’ highstands. Glacioeustacy-induced fluctuations of the groundwater table may have resulted in shifts from vadose (with deposition of well-developed speleothems) to phreatic/epiphreatic conditions in these caves. At Kuumbi, Late Pleistocene (pre-20,000 cal. BP) ceiling collapse initiated colluvial deposition near-entrance and opened the cave to large plants and animals, including humans. A phase of terminal Pleistocene human occupation ca. 18,500-17,000 cal. BP resulted in the deposition of a dense assemblage of Achatina spp. landsnails, alongside marine molluscs and mammal remains (including zebra, buffalo and other taxa now extinct on Zanzibar). The Holocene part of the cave stratigraphy near-entrance records phases of abandonment and intensified late Holocene human use.

Sea-level rise, human impacts and climate change have deeply affected coastal environments during the Holocene. These forcing factors are studied using the Lower H erault valley, which constitutes a very representative Mediterranean case study because of (i) its very early, intense and continuous land use since Neolithic times, and (ii) its sensitivity to sea-level rise and Mediterranean climate changes over a relatively small watershed. 34 cores and 61 AMS radiocarbon dates, associated with biological and geochemical analyses, have allowed us to precisely reconstruct the Holocene evolution of the lower valley. Until 6500 cal yr BP, a wave-dominated morphology and retrogradational dynamics were reconstructed. During this phase, ephemeral channels and successive river mouths formed and were rapidly submerged by sea-level rise. The progradational phase began after 6500 cal yr BP, and the alluvial plain gradually built seawards with the formation of a beachridge system outside the valley. Growth of the fertile alluvial plain was coeval with the development of Neolithic agriculture. This alluvial progradation gradually filled the estuary with advances of the mouths, several shallow lagoons and sandbar. The high density of information collected allows us to recognize, for the first time, a pronounced fluvial-dominated deltaic morphology, especially 3000 years ago, during the Bronze Age. Lagoonal and coastal shores were continually inhabited. Human land use continually adapted to geomorphological and environmental changes. Around 300 years ago, the delta shifted to a wave-dominated system.

Loess is common in the Mid-Atlantic region of the United States south of the Late Wisconsinan glacial border particularly along rivers draining the glaciated areas of Pennsylvania, New Jersey, and New York. The broadest deposits occur on the flat landscapes of the Delmarva Peninsula in Maryland where two episodes of deposition have been identified. The earlier Miles Point Loess has a limited distribution and is buried by the more widespread Paw Paw Loess. OSL and 14C dates place deposition of the Miles Point Loess during MIS 3. The well developed paleosol formed in the Miles Point Loess acts as a stratigraphic marker. The Paw Paw Loess buries Clovis age cultural materials which date deposition to the end of the Pleistocene. Loess deposits and paleosols are critical in understanding regional landscape evolution, Late Pleistocene environments, and early North American cultural history. Mapping the extent of loess in the Mid-Atlantic using the Natural Resources Conservation Service's gSSURGO database overrepresents loess in some areas and underrepresents in others.

The famous Greek geographer Strabo wrote in the fi rst century A.D., that Piraeus was formerly an island and lay ‘over against’ the mainland, from which it got its name. To validate Strabo’s hypothesis, cartographic and historical data were compiled with multiproxy paleoenvironmental analyses and radiocarbon dating from a series of boreholes drilled in
the Cephissus coastal plain, southwest of Athens, Greece. The results of this interdisciplinary geoarchaeological research demonstrate the reliability of Strabo’s text by revealing that
Piraeus was indeed an island. In early Holocene time, the rocky hill of Piraeus was linked to the mainland of Attica. During the late to fi nal Neolithic Period (4850–3450 B.C.), Piraeus became an island in a shallow marine bay, due to sea-level rise in the Holocene. Between 2850 and 1550 B.C., in the Early and Middle Bronze Age, Piraeus was separated from the mainland by a wide lagoon. In the fi fth century B.C., Themistocles, Cimon, and then Pericles connected Athens to Piraeus by building two “long walls” partly built on a residual coastal marsh called the Halipedon. This study reveals an impressive example of past landscape evolution.

A multifaceted, multidisciplinary research strategy was employed to  reconstruct the taphonomy and environmental history of a late Holocene coastal archaeological site (20LU115) at Sleeping Bear Point on the north-east coast of Lake Michigan, USA. Our case study shows how interdisciplinary examination of coastal processes that impact archaeological site preservation and destruction can beneficially integrate human settlement into an evolving landscape. We contextualize coastal site taphonomy in to an environmental framework that includes changing Lake Michigan lake levels and coastlines, vegetation regimes, and eolian activation and stabilization cycles during the past 2,000 years. Chronology for this framework derives from 10 radiocarbon and 12 Optically Stimulated Luminescence dates from beach ridges, dunes, paleosols, and human occupation hori-zons at or near the site. Such research outcomes, however, are not possible without focusing on the site as part of a larger landscape history, and could not have been realized without a multidisciplinary design that integrates geologists, physical geographers, environmental archaeologists, and cultural resources managers.

Au Sud-Est de l'île de Chypre, sur les rives de la baie de Larnaca, ouverte vers le levant, l'antique cité de Kition fut fondée au 13ème siècle avant J.-C. Installée sur une ancienne terrasse marine et entourée par un mur d'enceinte cyclopéen, la cité se distingue au Sud-Est (quartier de Bamboula) par la présence d'un port militaire d'époque classique abritant des rampes de hallages très bien préservées (Yon, 2000 ; Morhange et al., 2000 ; Sourisseau et al., 2003). Au Nord de la cité, le quartier de Kathari, situé en face d'une nécropole classique de la ville, abrite une zone de temples ainsi que des ateliers de travail du cuivre. L'organisation interne des ports phéniciens laisse à penser que la cité pouvait abriter un port de commerce éventuellement localisé au pied du quartier de Kathari dans une ancienne petite baie aujourd'hui colmaté. Afin de reconstituer l'évolution paléo-environnementale du littoral dans ce secteur et de comprendre l'organisation de la cité phénicienne, nous avons réalisé une série de 9 carottages répartis dans l'ancienne baie de Kathari. Les résultats bio-sédimentologiques révèlent une mobilité des rivages dictée par les apports sédimentaires fluviaux du Tremithos. Vers le 5ème siècle avant J.-C., des apports sédimentaires grossiers sont responsables de la transformation de la baie de Kathari en un milieu lagunaire, évoluant ensuite progressivement en un marais d'eau douce. Cet environnement lagunaire protégé naturellement par ce cordon de galets a donc favorisé l'installation d'une activité portuaire militaire à Bamboula et probablement commerciale à Kathari.