The study of glacial evidence in the Gran Sasso Massif of the Central Apennines, Italy, has allowed the last maximum advance and the subsequent stadial phases to be dated and the mean annual temperature and quantity of precipitation in the form of snow to be assessed for a number of periods. The glaciers probably reached their maximum extension (Campo Imperatore Stade) ca. 22,600 14C yr B.P. and started to retreat ca. 21,000 yr B.P., leaving behind three recessional moraines. After a first interstade (Fornaca Interstade), the Fontari Stade appears to have taken place shortly after 16,000 yr ago. Ca. 15,000 yr ago the glacier started retreating, leaving behind four more recessional moraines. An interstade (Venacquaro Interstade) preceded the Mount Aquila Stade, datable at ca. 11,000 yr B.P. A strong correlation is evident between the glacial phases on land and the isotopic variations in cores from the Tyrrhenian Sea.
BackgroundApproximately two hundred human burials were discovered on the edge of a paleolake in Niger that provide a uniquely preserved record of human occupation in the Sahara during the Holocene (∼8000 B.C.E. to the present). Called Gobero, this suite of closely spaced sites chronicles the rapid pace of biosocial change in the southern Sahara in response to severe climatic fluctuation.Methodology/Principal FindingsTwo main occupational phases are identified that correspond with humid intervals in the early and mid-Holocene, based on 78 direct AMS radiocarbon dates on human remains, fauna and artifacts, as well as 9 OSL dates on paleodune sand. The older occupants have craniofacial dimensions that demonstrate similarities with mid-Holocene occupants of the southern Sahara and Late Pleistocene to early Holocene inhabitants of the Maghreb. Their hyperflexed burials compose the earliest cemetery in the Sahara dating to ∼7500 B.C.E. These early occupants abandon the area under arid conditions and, when humid conditions return ∼4600 B.C.E., are replaced by a more gracile people with elaborated grave goods including animal bone and ivory ornaments.Conclusions/SignificanceThe principal significance of Gobero lies in its extraordinary human, faunal, and archaeological record, from which we conclude the following: The early Holocene occupants at Gobero (7700–6200 B.C.E.) were largely sedentary hunter-fisher-gatherers with lakeside funerary sites that include the earliest recorded cemetery in the Sahara.Principal components analysis of craniometric variables closely allies the early Holocene occupants at Gobero with a skeletally robust, trans-Saharan assemblage of Late Pleistocene to mid-Holocene human populations from the Maghreb and southern Sahara.Gobero was abandoned during a period of severe aridification possibly as long as one millennium (6200–5200 B.C.E).More gracile humans arrived in the mid-Holocene (5200–2500 B.C.E.) employing a diversified subsistence economy based on clams, fish, and savanna vertebrates as well as some cattle husbandry.Population replacement after a harsh arid hiatus is the most likely explanation for the occupational sequence at Gobero.We are just beginning to understand the anatomical and cultural diversity that existed within the Sahara during the Holocene.
We present a synthesis of geological, stratigraphic, geomorphological and stable isotope data collected from continental archives to highlight the environmental and climatic differences between the first and second half of the Holocene of central and southern Italy. The beginning of the Holocene is marked by rapid environmental change. In Mediterranean Italy, between c. 9500 cal. BP and c. 6000—5500 cal. BP, average temperatures were probably higher and environmental conditions were generally stable; between c. 9000 and 7000 cal. BP, meteoric precipitation was at its highest. The end of the wetter period seems to occur later, at c. 6000—5000 cal. BP. Since c. 6000—5000 cal. BP, rapid climatic excursions are apparent in different palaeoclimate proxies, with both variability in meteoric precipitation and temperature evident. Of particular relevance is the event occurring at c. 4200 cal. BP. This event heralds a period of significant environmental change in the Apennines and, more generally, in central Italy. Following this event, environmental variability appears most pronounced and frequent. Some environmental changes during the early Holocene and after 4200 cal. BP seem to be in phase with IRD events in the North Atlantic, which suggest: (1) teleconnections between North Atlantic and Mediterranean areas; and (2) a possible influence of North Atlantic meridional overturning circulation in controlling the advection of moisture over the central Mediterranean basin via westerly air masses. The archives used in this review allow us to consider climate evolution as a driver of most of the observed environmental changes.
The major climatic variations that have affected the summit slopes of the higher Apennine massifs in the last 6000 yr are shown in alternating layers of organic matter-rich soils and alluvial, glacial and periglacial sediments. The burial of the soils, triggered by environmental–climatic variations, took place in several phases. For the last 3000 yr chronological correlations can be drawn between phases of glacial advance, scree and alluvial sedimentation and development of periglacial features. During some periods, the slopes were covered by vegetation up to 2700 m and beyond, while in other phases the same slopes were subject to glacial advances and periglacial processes, and alluvial sediments were deposited on the high plateaus. Around 5740–5590, 1560–1370 and 1300–970 cal yr B.P., organic matter-rich soils formed on slopes currently subject to periglacial and glacial processes; the mean annual temperature must therefore have been higher than at present. Furthermore, on the basis of the variations in the elevation of the lower limit reached by gelifraction, it can be concluded that the oscillations in the minimum winter temperatures could have ranged between 3.0°C lower (ca. 790–150 cal yr B.P.) and 1.2°C higher (ca. 5740–5590 cal yr B.P.) than present minimum winter temperatures. During the last 3000 yr the cold phases recorded by the Calderone Glacier advance in the Apennines essentially match basically the phases of glacial advance in the Alps.
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