Abstract In this paper we review the main, long- and short-term geological and geotectonic processes that have controlled the development of Pleistocene landscapes in the Aegean region above and below the fluctuating sea level. We discuss the potential for further research on reconstruction of submerged landscapes of the continental shelf and beyond with the aim of addressing questions concerning Palaeolithic settlement. The geological, tectonic, morphological and hydrogeological background provides information for the assessment of the natural resources available to hominins. Along with the palaeogeographical evolution of the shallow coastal and shelf areas, they are examined in parallel with the terrestrial archaeological record in order to open windows to future work in a region that has remained marginal to human origins research. On the basis of the multi-variable tectonic evolution and geomorphological configuration of the coastal and shelf areas, we propose to divide the Aegean region into nine geographical units, each with its own geotectonic and morphological history and traits. These units can be further grouped to provide larger neighbouring and culturally meaningful regions, suitable for archaeological analysis, or subdivided to provide smaller target areas in which to work.

Abstract The Norwegian coast facing the Atlantic Ocean was ice free as early as the Allerød oscillation in the late Pleistocene. The landscape was probably habitable for humans. It has, therefore, been assumed by several scholars that this coastline was visited or inhabited from the Late Glacial period onwards. In part, this argumentation is based on the presumed proximity of the Norwegian mainland and Doggerland, which existed between present-day Denmark and Great Britain because of a much lower global sea level. The aim of this paper is to examine the 14 C dates available from the oldest Norwegian settlement sites, and to compare them to the Quaternary processes of deglaciation and sea-level change. The hypothesis is advanced that humans did not settle in present-day Norway before a sheltering passage of islands and peninsulas had developed between the Swedish west coast (Bohuslän) and the Oslo area. This happened in the second half of the Preboreal period, at approximately 9.3 cal ka BC, or in the final centuries of the tenth millenniun BC. Supplementary material: 14 C dates used in Figures 2, 4 and 9 are available at http://www.geolsoc.org.uk/SUP18779 .

Abstract The submerged sill in the Strait of Messina, which is located today at a minimum depth of 81 m below sea level (bsl), represents the only land connection between Sicily and mainland Italy (and thus Europe) during the last lowstand when the sea level locally stood at about 126 m bsl. Today, the sea crossing to Sicily, although it is less than 4 km at the narrowest point, faces hazardous sea conditions, made famous by the myth of Scylla and Charybdis. Through a multidisciplinary research project, we document the timing and mode of emergence of this land connection during the last 40 kyr. The integrated analysis takes into consideration morphobathymetric and lithological data, and relative sea-level change (both isostatic and tectonic), resulting in the hypothesis that a continental land bridge lasted for at least 500 years between 21.5 and 20 cal ka BP. The emergence may have occurred over an even longer time span if one allows for seafloor erosion by marine currents that have lowered the seabed since the Last Glacial Maximum (LGM). Modelling of palaeotidal velocities shows that sea crossings when sea level was lower than present would have faced even stronger and more hazardous sea currents than today, supporting the hypothesis that earliest human entry into Sicily most probably took place on foot during the period when the sill emerged as dry land. This hypothesis is compared with an analysis of Pleistocene vertebrate faunas in Sicily and mainland Italy, including a new radiocarbon date on bone collagen of an Equus hydruntinus specimen from Grotta di San Teodoro (23–21 cal ka BP), the dispersal abilities of the various animal species involved, particularly their swimming abilities, and the Palaeolithic archaeological record, all of which support the hypothesis of a relatively late land-based colonization of Sicily by Homo sapiens .

Abstract Past environments of equatorial SE Asia must have played a critical role in determining the timing and trajectory of early human dispersal into and through the region. However, very few reliable terrestrial records are available with which to contextualize human dispersal events. This circumstance, coupled with a sparse archaeological record and the likelihood that much of the archaeological record is now submerged, means we have an incomplete understanding of the role that geography, climate and environment played in shaping human pre-history in this region. From a review of the literature, we conclude that there must have been a substantial environmental barrier resulting in a genetic separation between east and west Sundaland that persisted even though a terrestrial connection was present for most of the Pleistocene. This barrier is likely to be a north–south corridor of open non-forest vegetation, and its existence may have encouraged the rapid dispersal of early humans through the interior of Sundaland and on to Sahul. We conclude that more reliable terrestrial palaeoenvironmental records are required to better understand the links between past environments and dispersal events. We highlight avenues of particular research value, such as focusing on eastern Sumatra, western/southern Borneo and the islands in the Java Sea, where the purported savanna corridor most probably existed, and including edaphic factors in palaeovegetation modelling.

The geological development of Panama’s isthmus resulted from intermittent magmatism and oceanic plate interactions over approximately the past 100 m.y. Geochemical data from ~300 volcanic and intrusive rocks sampled along the Cordillera de Panama document this evolution and are used to place it in a tectonic framework. Three distinct trace-element signatures are recognized in the oldest basement rocks: (1) oceanic basement of the Caribbean large igneous province (CLIP basement) displays flat trace-element patterns, (2) CLIP terranes show enriched ocean-island basalt (OIB) signatures, and (3) CLIP rocks exhibit arc signatures. The Chagres igneous complex represents the oldest evidence of arc magmatism in Panama. These rocks are tholeiitic, and they have enriched but highly variable fluid-mobile element (Cs, Ba, Rb, K, Sr) abundances. Ratios of these large ion lithophile elements LILEs) to immobile trace elements (e.g., Nb, Ta, middle and heavy rare earth elements) have a typical, but variably depleted, arc-type character that was produced by subduction below the CLIP oceanic plateau. These early arc rocks likely comprise much of the upper crust of the Cordillera de Panama and indicate that by 66 Ma, the mantle wedge beneath Panama was chemically distinct (i.e., more depleted) and highly variable in composition compared to the Galapagos mantle material, from which earlier CLIP magmas were derived. Younger Miocene andesites were erupted across the Cordillera de Panama from 20 to 5 Ma, and these display relatively uniform trace-element patterns. High field strength elements (HFSEs) increase from tholeiitic to medium-K arc compositions. The change in mantle sources from CLIP basement to arc magmas indicates that enriched sub-CLIP (i.e., plume) mantle material was no longer present in the mantle wedge by the time that subduction magmatism commenced in the area. Instead, a large spectrum of mantle compositions was present at the onset of arc magmatism, onto which the arc fluid signature was imprinted. Arc maturation led to a more homogeneous mantle wedge, which became progressively less depleted due to mixing or entrainment of less-depleted backarc mantle through time. Normal arc magmatism in the Cordillera de Panama terminated around 5 Ma due to the collision of a series of aseismic ridges with the developing and emergent Panama landmass. Younger heavy rare earth element–depleted magmas (younger than 2 Ma), which still carry a strong arc geochemical signature, were probably produced by ocean-ridge melting after their collision.

Global Positioning System (GPS) measurements suggest the existence of a rigid Panama-Costa Rica microplate that is moving northward relative to the stable Caribbean plate. Northward motion of Central America relative to the Caribbean plate is independently suggested by the April 1991 Costa Rica earthquake, active folding in the North Panama deformed belt, and a south-dipping Wadati-Benioff zone beneath Panama. Panama may also be continuing to collide eastward with the northern Andes. Rapid subduction is occurring at the Middle America (72 mm/yr), Ecuador (70 mm/yr), and Colombia (50 mm/yr) trenches. The northern Andes are moving northeastward relative to stable South America. Preliminary GPS results also suggest Caribbean-North Andean convergence and an independent North Nazca plate. About 6 Ma the Panama-Choco island arc collided with the northwestern margin of South America, eventually forming a land bridge between the Americas; closed the Pacific-Caribbean seaway, changing ocean circulation patterns and perhaps the world’s climate; folded the East Panama deformed belt; and uplifted the Eastern Cordillera of Colombia. An interpretation of the paleo-Romeral suture in southern Colombia as a low-angle fault dipping to the west into the lower crust under the Cordillera Occidental is compatible with seismic velocity and gravity data. During the Late Cretaceous the Western Cordillera oceanic terrane was obducted eastward on the fault system over continental crust.