The authors gratefully acknowledge funding for this research from the Ministerio de Economía y Competitividad of Spain (MINECO HAR2012-35022).Dating agricultural terraces is a notoriously difficult problem for archaeologists. The frequent occurrence of residual material in terrace soils and the potential for post-depositional disturbance mean that conventional artefactual and lab-based dating methods often provide unreliable dates. In this paper we present a new technique using luminescence field profiling coupled with OSL dating to produce complete (relative) sequences of dates for sedimentary stratigraphies associated with agricultural terraces and earthworks. The method is demonstrated through a series of case-studies in western Catalonia, Spain, in which we reconstruct the formation sequence of earthwork features from the Middle Ages through to the present day. OSL profiling at the time of archaeological survey and excavation permitted spatially and temporally resolved sediment ‘chronologies’ to be generated, and provides the means to interpret the environmental and cultural archives contained in each. The case-studies presented here show that luminescence approaches are a valuable tool to reconstruct landscape histories.Publisher PDFPeer reviewe

The history of agricultural terraces remains poorly understood due to problems in dating their construction and use. This has hampered broader research on their significance, limiting knowledge of past agricultural practices and the long-term investment choices of rural communities. The authors apply OSL profiling and dating to the sediments associated with agricultural terraces across the Mediterranean region to date their construction and use. Results from five widely dispersed case studies reveal that although many terraces were used in the first millennium AD, the most intensive episodes of terrace-building occurred during the later Middle Ages (c. AD 1100–1600). This innovative approach provides the first large-scale evidence for both the longevity and medieval intensification of Mediterranean terraces.

Plio-Pleistocene sediments exposed around the ophiolitic Troodos Massif document spectacular uplift from below sea level to a maximum height of c . 2000 m. Sedimentation reflects a dominant control of focused tectonic uplift, modified by the effects of glacio-eustatic sea-level change and climatic change. Understanding the uplift and controls on deposition has been hindered by an inadequate age model. Here, we present a preliminary investigation of the polarity of remanent magnetizations recorded within the upper part of the Pliocene succession in the Pissouri and Mesaoria basins and from the Pleistocene marine terrace deposits that border the Troodos Massif. When integrated with available lithostatigraphic and biostratigraphic data, the main results are as follows. Focused uplift of the Troodos Massif began during the Late Pliocene, either between 2.14 and 1.95 Ma or immediately prior to 1.77 Ma. Shallow-marine, ophiolite-derived clastic and bioclastic sediments accumulated in both the Mesaoria and Pissouri basins, implying that the Troodos Massif was uplifted as a single tectonic entity. Non-marine, deltaic and fluvial facies prograded into both of the basins during the Pleistocene (1.77 Ma–recent). Marine terraces in SW and south Cyprus were cut and covered by littoral sediments from <0.78 Ma, suggesting that high rates of uplift of the Troodos Massif persisted into mid- and late Pleistocene time.

The gravel-sand transition (GST) is commonly observed along rivers. It is characterized by an abrupt reduction in median grain size, from gravel- to sand-size sediment, and by a shift in sand transport mode from wash load–dominated to suspended bed material load. We documented changes in channel stability, suspended sediment concentration, flux, and grain size across the GST of the Karnali River, Nepal. Upstream of the GST, gravel-bed channels are stable over hundred- to thousand-year time scales. Downstream, floodplain sediment is reworked by lateral bank erosion, particularly during monsoon discharges. Suspended sediment concentration, grain size, and flux reveal counterintuitive increases downstream of the GST. The results demonstrate a dramatic change in channel dynamics across the GST, from relatively fixed, steep gravel-bed rivers with infrequent avulsion to lower-gradient, relatively mobile sand-bed channels. The increase in sediment concentration and near-bed suspended grain size may be caused by enhanced channel mobility, which facilitates exchange between bed and bank material. These results bring new constraints on channel stability at mountain fronts and indicate that temporally and spatially limited sediment flux measurements downstream of GSTs are more indicative of flow stage and floodplain recycling than of continental-scale sediment flux and denudation rate estimates.

Doggerland was a landmass occupying an area currently covered by the North Sea until marine inundation took place during the mid-Holocene, ultimately separating the British landmass from the rest of Europe. The Storegga Event, which triggered a tsunami reflected in sediment deposits in the northern North Sea, northeast coastlines of the British Isles and across the North Atlantic, was a major event during this transgressive phase. The spatial extent of the Storegga tsunami however remains unconfirmed as, to date, no direct evidence for the event has been recovered from the southern North Sea. We present evidence of a tsunami deposit in the southern North Sea at the head of a palaeo-river system that has been identified using seismic survey. The evidence, based on lithostratigraphy, geochemical signatures, macro and microfossils and sedimentary ancient DNA (sedaDNA), supported by optical stimulated luminescence (OSL) and radiocarbon dating, suggests that these deposits were a result of the tsunami. Seismic identification of this stratum and analysis of adjacent cores showed diminished traces of the tsunami which was largely removed by subsequent erosional processes. Our results confirm previous modelling of the impact of the tsunami within this area of the southern North Sea, and also indicate that these effects were temporary, localized, and mitigated by the dense woodland and topography of the area. We conclude that clear physical remnants of the wave in these areas are likely to be restricted to now buried, palaeo-inland basins and incised river valley systems.