Humid phases on the southwestern Arabian Peninsula are consistent with the last two interglacials

Past environmental and climatic conditions within the Arabian Peninsula are key to understanding the setting for hominin dispersal across the Saharo-Arabian dryland belt. The tufa deposits within the volcanic harrats on the southwest coast of Saudi Arabia fill a significant spatial gap in the distribution of palaeoenvironmental records on the west coast of the Arabian Peninsula adjacent to the Red Sea. In the catchment of Wadi Dabsa in the Harrat Al Birk, there are widespread fossil palustrine to shallow-lacustrine tufa deposits with fluvial elements. Several phases of tufa accumulation, separated by fluvial downcutting, are observable within these powerful palaeoenvironmental proxies. U–Th dating of targeted dense, banded tufa facies, yield ages that are stratigraphically consistent at the landscape scale, and indicate that tufa accumulation occurred during distinct humid phases broadly coeval with the last two warm interglacial Marine Isotope Stages (MIS 7 and MIS 5). For the first time this shows humid intervals in southwest Arabia coincident with the southern coast. There is a simlar pattern emerging further north in the Arabian Peninsula, The Sinai and Levant and further on into continental Europe. Furthermore, tufa δ18O ranges from −14.6 to −1.9‰, covering a range similar to those reported for tufa from north African oasis sites and speleothems elsewhere on the Arabian Peninsula and The Levant. The lowest δ18O values are derived from MIS 5e samples, a pattern in agreement with speleothems in Yemen and Oman, and consistent with an isotopic-enabled climate model simulation for this time slice. The δ13C and Sr isotopic compositions of dated tufa samples indicate deposition from shallow-circulating meteoric water, with no geothermal influence. This, along with the δ18O values, suggest a freshwater supply that was a potable water source in this landscape. The δ13C signatures at Wadi Dabsa are more negative than for parts of north Africa, suggesting Wadi Dabsa may have experienced comparatively higher biomass, thicker soils and wetter conditions with lower evaporative losses. This new record of tufa deposition during the middle and late Pleistocene, suggests for the first time that the west coast of Arabia experienced a similar history of humid phases over the past 250 ka as southern Arabia and the Nefud in the northern interior. These regional changes in hydroclimatic regime occur at timescales coincident with hominin dispersals

The chronostratigraphy of the Haua Fteah cave (Cyrenaica, northeast Libya)

The 1950s excavations by Charles McBurney in the Haua Fteah, a large karstic cave on the coast of northeast Libya, revealed a deep sequence of human occupation. Most subsequent research on North African prehistory refers to his discoveries and interpretations, but the chronology of its archaeological and geological sequences has been based on very early age determinations. This paper reports on the initial results of a comprehensive multi-method dating program undertaken as part of new work at the site, involving radiocarbon dating of charcoal, land snails and marine shell, cryptotephra investigations, optically stimulated luminescence (OSL) dating of sediments, and electron spin resonance (ESR) dating of tooth enamel. The dating samples were collected from the newly exposed and cleaned faces of the upper 7.5 m of the w14.0 m-deep McBurney trench, which contain six of the seven major cultural phases that he identified. Despite problems of sediment transport and reworking, using a Bayesian statistical model the new dating program establishes a robust framework for the five major lithostratigraphic units identified in the stratigraphic succession, and for the major cultural units. The age of two anatomically modern human mandibles found by McBurney in Layer XXXIII near the base of his Levalloiso-Mousterian phase can now be estimated to between 73 and 65 ka (thousands of years ago) at the 95.4% confidence level, within Marine Isotope Stage (MIS) 4. McBurney’s Layer XXV, associated with Upper Palaeolithic Dabban blade industries, has a clear stratigraphic relationship with Campanian Ignimbrite tephra. Microlithic Oranian technologies developed following the climax of the Last Glacial Maximum and the more microlithic Capsian in the Younger Dryas. Neolithic pottery and perhaps domestic livestock were used in the cave from the mid Holocene but there is no certain evidence for plant cultivation until the Graeco-Roman period

Why do we see what we see where we see it? Geomorphological controls on archaeological narratives across space and time

Geoarchaeological research captures dimensions of the past at an unprecedented level of detail and multiple spatial and temporal scales. The record of the past held by soils and sediments is an archive for past environments, climate change, resource use, settlement lifeways, and societal development and resilience over time. When the McDonald Institute was established at Cambridge, geoarchaeology was one of the priority fields for a new research and teaching environment. An opportunity to develop the legacy of Charles McBurney was bestowed upon Charles French, whose ‘geoarchaeology in action’ approach has had an enormous impact in advancing knowledge, principles and practices across academic, teaching and professional sectors. Many journeys that began at Cambridge have since proliferated into dozens of inspired geoarchaeologies worldwide. This volume presents research and reflection from across the globe by colleagues in tribute to Charly, under whose leadership the Charles McBurney Laboratory became a beacon of geoarchaeology

Anti-VEGF treatment in neovascular age-related macular degeneration: A treat-and-extend protocol over 2 years

Purpose: To evaluate 2-year visual acuity outcome of a treat-and-extend protocol of anti&#8211;vascular endothelial growth factor treatment in age-related macular degeneration. Methods: In this prospective cohort study, 120 age-related macular degeneration patients with choroidal neovascularization received 3 initial monthly ranibizumab or bevacizumab injections; monthly injections were continued until there was no choroidal neovascularization activity (subretinal/intraretinal fluid, loss of >5 letters, or persistent/recurrent retinal hemorrhage). When there was no choroidal neovascularization activity, the interval to the next visit/injection was extended by 2 weeks to a maximum of 12 weeks. In the presence of choroidal neovascularization activity, this interval was shortened by 2 weeks. Main outcome measures included the percentage losing <15 letters and the mean visual acuity change after 12 months and 24 months. Results: Mean baseline visual acuity was 51.2 &#0177; 12.1 Early Treatment Diabetic Retinopathy Study scores. Mean visual acuity change from baseline was +9.5 &#0177; 10.9 and +8.0 &#0177; 12.9 letters after 12 months and 24 months, respectively, with, on average, 8.6 &#0177; 1.1 visits/injections in the first year and 5.6 &#0177; 2.0 in the second year. After 12 months and 24 months, 97.5% and 95.0% of patients, respectively, lost <15 letters. Conclusion: The &#8220;inject-and-extend&#8221; protocol&#8212;with fewer injections and visits&#8212;delivered outcomes comparable to those of the pivotal clinical trials of monthly ranibizumab

Afromontane foragers of the Late Pleistocene: site formation, chronology and occupational pulsing at Melikane Rockshelter, Lesotho

This paper provides a preliminary chronostratigraphic and palaeoenvironmental framework for the Late Pleistocene archaeological sequence at Melikane Rockshelter in mountainous eastern Lesotho. Renewed excavations at Melikane form part of a larger project investigating marginal landscape use by Late Pleistocene foragers in southern Africa. Geoarchaeological work undertaken at the site supports in-field observations that Melikane experienced regular, often intensive, input of groundwater via fissures in the shelter’s rear wall. This strong hydrogeological connection resulted in episodic disturbances of the sedimentary sequence, exacerbated by other processes such as bioturbation. Despite this taphonomic complexity, a robust chronology for Melikane has been developed, based on tightly cross-correlated accelerator mass spectrometry (AMS)14C with acid-base-wet oxidation stepped-combustion (ABOx-SC) pretreatment and single-grain optically stimulated luminescence (OSL) dating. The results show that human occupation of Melikane was strongly pulsed, with episodes of Late Pleistocene occupation at ~80, ~60, ~50, ~46e38 and ~24 ka. At least three additional occupational pulses occurred in the Holocene at w9 ka, w3 ka and in the second millennium AD, but these are dealt with only briefly in this paper. Implications of the Late Pleistocene pulsing for the colonisation of high elevations by early modern humans in Africa ahead of dispersals into challenging landscapes beyond the continent are discussed

The chronostratigraphy of the Haua Fteah cave (Cyrenaica, northeast Libya)

The 1950s excavations by Charles McBurney in the Haua Fteah, a large karstic cave on the coast of northeast Libya, revealed a deep sequence of human occupation. Most subsequent research on North African prehistory refers to his discoveries and interpreta