Réexamen du contexte géologique,chrono- et biostratigraphique du site de Moulin Quignon à Abbeville (Vallée de la Somme,France)

The geological context of the discoveries made by Boucher de Perthes at Moulin Quignon in 1863–1864 was examined through the testimonies left by himself, by his detractors, then by geologists and archaeologists who later worked on the alluvial deposits of the Somme at Abbeville. This critical approach has been completed by specific studies, through a restricted excavation performed at Carpentier Quarrya locality known since the end of the 19th century as a sequence analogous to Moulin Quignon, and by a series of new analyses (microvertebrate, malacofauna, dating). The main results of these studies confirm the fluvial nature of the ‘archaeological’ layers at Moulin Quignon that correspond to a high terrace of the Somme River, about 40 m above the current valley incision at Abbeville. Dating results provide an age of 584 ± 48 ka for the fluvial levels at Carpentier Quarry, in good agreement with the available biostratigraphic data, inferred from malacofaunas collected at both Moulin Quignon (Boucher de Perthes collection) and Carpentier Quarry, and from mammals fauna recovered since the end of the 19th century from the white marl at Carpentier Quarry which allow the allocation of these alluvial deposits to an interglacial stage of the second half of the Cromerian, the marine isotopic stage (MIS) 15. From these data and taking into account the identification of the human remains of Moulin Quignon as an anatomically modern man, the contemporaneity of these remains with the alluvial deposits of a high terrace of the Somme River is virtually impossible and supports the hypothesis of a hoax. Besides, it is possible that at least some of the lithic material collected at the time of the discovery by Boucher de Perthes could derive from fluvial levels dated of approximately 600,000 years. They would be then the oldest evidence of a human presence in the Somme Valley.     

Stratigraphie et chronologie du site de Gaolingpo dans le bassin de Bose,sud de la Chine

The Bose Paleolithic industry in the Bose Basin, Guangxi, South China is well known in the international scientific community for its bearing handaxes dated back to 803 ka. Seven terraces were developed in the basin and terrace 4 is the most important because handaxes and tektites were recovered from this terrace. Since the first site was discovered in 1973, additional sites of the Bose Paleolithic industry have been investigated and excavated, most of which are located on terrace 4. The previous studies concluded that there is only one phase within this industry and its age is 803 ka. However, before 2013, no attempt had been made to dig down to the basal gravels from the top of terrace 4 in archaeological excavations. Therefore, the stratigraphy and the layers from which the stone artifacts derive of terrace 4 are not clear. In 2013–2014, we conducted an excavation of 200 m² at the Gaolingpo site, which is one of the most important Paleolithic sites in the Bose Basin. We excavated to the basal gravel deposits from the top of this terrace, and a section of more than 7 meters thick deposit was exposed and clearly shows the stratigraphic layers of Pleistocene and Holocene deposits. Furthermore, features and about 800 stone artifacts including choppers, picks, scrapers, etc. were excavated from several stratigraphic layers, which are different in age and other aspects. Based on stratigraphy and the stone artifacts, three stages of Paleolithic cultural remains from the Gaolingpo site can be established. The first stage is in the age of at leat 803 ka. The second stage can be dated to 15 ka and the third stage to about 10 ka.     

Astronomical dating of the Xiantai, Donggutuo and Maliang Paleolithic sites in the Nihewan Basin (North China) and implications for early human evolution in East Asia

Magnetostratigraphic studies have established a first-order chronological framework for the Paleolithic sites in the Nihewan Basin (North China), which enabled tracking early human evolution in East Asia. However, to fully understand how well early humans were adapted to climate change, a truly precise dating of the Paleolithic sites is required. Here, we established a high-resolution astronomical timescale for the Xiantai and Donggutuo fluvio-lacustrine successions at the eastern margin of the Nihewan Basin employing low-field magnetic susceptibility (χ) as a climatic indicator, aiming to further refine the ages of the Xiantai, Donggutuo and Maliang Paleolithic sites. Starting from an initial age model constrained by geomagnetic reversals, larger-scale χ cycles were firstly tuned to orbital obliquity using an automatic orbital tuning method. This first-order tuning was followed by simultaneously tuning χ to both obliquity and precession. The finally tuned χ records can be correlated almost cycle-by-cycle with the quartz grain-size record of the Chinese loess sequence and the marine δ¹⁸O record. The astronomically estimated age of the Xiantai Paleolithic site is ca. 1.48 Ma, corresponding to paleosol layer S₂₀ of the Chinese loess sequences or marine oxygen isotope stage (MIS) 49, an interglacial period. The astronomical estimate for the Donggutuo Paleolithic site ranges from ~ 1.06 Ma to 1.12 Ma, corresponding to paleosol/loess layers S₁₁-S₁₂ or MIS 31-33, spanning both interglacial and glacial periods. The astronomically estimated age of the Maliang Paleolithic site is ~ 0.79 Ma, corresponding to loess layer L₈ or MIS 20, a glacial period. This astronomical finding further implies that early humans may have permanently occupied China as far north as 40^oN since at least 1.1 Ma, and before this time the occupation may be intermittent.     

汉水上游汉中盆地新发现的旧石器及其年代

2009~2012年,在秦岭南麓汉水上游汉中盆地梁山周围新发现何家梁和窑厂湾2处旷野类型旧石器地点,采集石制品252件。早期人类加工石制品的原料来自于河流堆积物中的石英、火山岩、石英岩、硅质灰岩和砂岩等砾石,采取硬锤直接打击法和砸击法剥片。石制品种类包含石锤、石核、石片、修理的工具和断块。工具类型以砍砸器、石球、重型刮削器、手斧和手镐等重型器物为主。汉中盆地梁山周围以龙岗寺等地点为代表的旧石器地点群是含阿舍利(Acheulian)类型器物的石器工业。何家梁和窑厂湾地点分别位于汉江右岸第二和第三级阶地上,通过对窑厂湾地点黄土地层剖面进行回授光释光(TTOSL)方法测年,结合古地磁测试和对比黄土高原标准黄土地层序列测年结果,证实汉中盆地古人类活动的时代最晚在60万年前就已经开始,而何家梁地点的地层测年数据则表明距今7、8万年左右存在另外一个古人类活动繁盛的阶段,早期人类在汉中盆地活动有较长的时间跨度。以前汉中盆地发现的旧石器地点没有独立的年代数据,极大地限制了学术界对其石器工业技术和人类行为的深入研究,这是首次获得的汉中盆地埋藏旧石器地点地层的独立年代数据,是对汉中盆地旧石器遗址年代学认识上的一大突破。本研究结合可靠的测年数据,分析石器组合及加工技术,对建立中更新世以来秦岭山区的旧石器文化序列,理解我国南北方旧石器工业的发展演化以及东西方旧石器工业技术比较具有重要的参考价值。     

Stress physiologique et état de santé des plus anciens Hommes anatomiquement modernes du sud-est de l’Europe (données dentaires,couche 6-1, Buran-Kaya III,Crimée)

Buran-Kaya III site, in Crimea, provides an exceptional stratigraphic sequence, extending from Middle Paleolithic to Neolithic. Among the archaeological layers allocated to the Gravettian (sensu lato), more than 170 anthropological remains have been discovered in the layer 6-1. They represent the oldest Upper Paleolithic modern humans from Eastern Europe in a well-documented archaeological context. The aim of this article, based on dental remains and enamel dental hypoplasias in particular, is to evaluate the health of the modern humans, which lived more than 32,000 years BP ago in Crimea. This study puts into the light the low frequency of hypoplasias (occurring in the two youngest individuals). This article complete the rare studies concerning the presence of this physiological stress during the Early Upper Paleolithic and confirm the scarcity of enamel dental hypoplasias and dental pathologies, such as caries, at this period.     

Le site Paléolithique de Suyanggae, Corée

The Suyanggae site is an open-air site in central part of South Korea. This site was discovered in 1980 and seven excavations have been carried out from 1983 to 1996. As a result, many stone artefacts were unearthed and 49 stone tool workshops were known. This site contains 5 cultural layers and the most important one is the Upper Paleolithic layer. This layer is dated to be 16,400 ~ 18,630 BP by ¹⁴C dating. It shows a massive blade production and microblade technique. It is one of the crucial sites for understanding the Upper Paleolithic of Korea.     

Environnement et archéologie durant le Paléolithique final dans la région du Rhin moyen (Rhénanie, Allemagne) : conclusions des 15 dernières années de recherches

The Laacher See volcano erupted at 10,966 cal BC covered the whole Central Rhineland with huge tephra layers which are exploited now for some 150 years. During the last 15 years of research several new find locations exhibiting tree trunks of the hemi-boreal woodland, leaf imprints and animal tracks preserved in pumice and ashes reveal detailed insights into the (younger) Allerød environment. Five final Paleolithic (Federmessergruppen) habitation sites without any evident settlement structures but providing exogenous raw materials from outcrops in distances up to 170 km demonstrate the highly mobile mode of life of these hunter-gatherers groups some 13,000 years ago.     

吉林和龙柳洞2004年发现的旧石器

吉林和龙柳洞旧石器地点于2002年5月发现,2004年5月对其进行了复查。该地点位于图们江流域第2级阶地上,在地表和灰黄色土层中发现石制品142件,包括石核、石片、石叶和工具(石砧、使用石片、刮削器、砍砸器、雕刻器、尖状器和琢背小刀);原料以黑曜岩为主,占93.66%。遗址应属于晚更新世晚期,即旧石器时代晚期。     

Évolution des caractères technologiques et typologiques des industries lithiques dans la stratigraphie de la Caune de l'Arago

The thick Quaternary deposits of the Caune de l’Arago (Pyrénées-Orientales, France) are dated to between 690 000 and 90 000 years old. At least fifteen different archeostratigraphical units have been identified within these deposits, each corresponding to distinct prehistoric occupations. Numerous stone tools made from several different rock types, have been discovered in each unit. The tools present specific characteristics concerning the choice of raw materials, the typology, and the technology used to produce them. Morpho-technological study of the different components of the assemblage contributes to a better understanding of the debitage methods used for their production. Each raw material is considered individually in order to ascertain its origin in the environment, its typological role and the technology applied during its exploitation. Defining production systems leads to the characterisation of the assemblages from each unit. When compared, they reveal common elements, as well as differences, suggesting evolutionary trends. Some observations are also made concerning the extent to which changing uses of the site may have influenced the general morphology of each assemblage, therefore taking into account exterior factors. Analysis of this rich stone tool assemblage helps to situate the Caune de l’Arago industry within the larger evolutionary context of the Lower Paleolithic in Mediterranean Europe.     

Madonna dell'Arma (San Remo, Italie) : expression locale de la végétation ligure au cours du Paléolithique moyen

Pollen analysis of Madonna dell’Arma cave inside part (Liguria, Italy) allowed us to reconstitute, at local scale, the Ligurian coastal vegetation between the end of the last interglacial period and the beginning of the pleniglacial. This transition period shows an important representation of arboreal cover and a persistence of thermophilous elements that allowed us to considerate the western Liguria as a periglacial refuge. During the end of the last interglacial, xerophytic, halophytic herbs and shrubs taken over from a Mediterranean pre-forest unit in the first slopes constituted the coastal zone. The nearness of Argentina torrent and the Armea influenced, in the coast, the existence of marshy zones colonized by hygrophilous trees. In the Ligurian lowlands spread out sclerophyllous and mesophilous forests according to altitude. The beginning of the pleniglacial is indicated in the sequence by increases of Pinus, Cupressaceae and Artemisia in the context of a decline in the thermophilous components. This picture of vegetation has become integrated into the multidisciplinary studies of the site and contributed to the elaboration of palaeoclimatic hypothesis similar as those revealed by the fauna.     

L’art bourgeois de la fin du XIX siècle face à l’art mobilier Paléolithique

On the occasion of the centenary of the Emile Cartailhac’s « Mea culpa d’un sceptique”, we want to reflect on one of the main questions of our discipline: Why has so-called « cave art” only been accepted as Paleolithic art in 1902, whereas the so-called « mobiliary art” had been accepted as Paleolithic art at the beginning of 1860s? In this paper, we want to suggest a definition of the conception of primitive art during the last third of the 19th century in order to understand: (A) Why Paleolithic paintings in the walls of some caves (Niaux, Chabot, Altamira) were not accepted as Paleolithic art between 1860 and 1902. (B) Given that what we now call mobiliary art is the same artistic phenomenon that prehistorians of the late 19th century thought of as primitive art, this article allows us to suggest a genealogy of mobiliary art. This genealogy will enable us to show that this concept not only defines a wide variety of forms, from engraving stones to carving in antler or ivory, but hides a multiplicity of meanings and connotations which originated in the period between 1860 and 1900.     

From the Bay of Naples to the River Don: the Campanian Ignimbrite eruption and the Middle to Upper Paleolithic transition in Eastern Europe

The Campanian Ignimbrite (CI) eruption, dated by ⁴⁰Ar/³⁹Ar and various stratigraphic methods to ca. 39,000 cal BP, generated a massive ash plume from its source in southern Italy across Southeastern and Eastern Europe. At the Kostenki-Borshchevo open-air sites on the Middle Don River in Russia, Upper Paleolithic artifact assemblages are buried below, within, and above the CI tephra (which is redeposited by slope action at most sites) on the second terrace. Luminescence and radiocarbon dating, paleomagnetism, and soil and pollen stratigraphy provide further basis for correlation with the Greenland and North Atlantic climate stratigraphy. The oldest Upper Paleolithic occupation layers at Kostenki-Borshchevo may be broadly correlated with warm intervals that preceded the CI event and Heinrich Event 4 (HE4; Greenland Interstadial: GI 12-GI 9) dating to ca. 45,000-41,000 cal BP. These layers contain an industry not currently recognized in other parts of Europe. Early Upper Paleolithic layers above the CI tephra are correlated with HE4 and warm intervals that occurred during 38,000-30,000 cal BP (GI 8-GI 5), and include an assemblage that is assigned to the Aurigancian industry, associated with skeletal remains of modern humans.     

广西百色盆地高岭坡遗址的地层及年代

广西百色盆地旧石器工业因含有众多的手斧且年代早到803 kaBP而闻名于世。盆地内发育有7级河流阶地,其中第IV级阶地发现有手斧和玻璃陨石。自从1973年第一个石器地点被发现,越来越多的遗址或地点被调查发现和发掘。以前研究认为,百色盆地旧石器只出自网纹红土层,年代均为803 kaBP。2013年以前,通常只在土状堆积的上部发掘,从来没有人对第IV级阶地的沉积物从地表到底部砾石层进行系统发掘,因此关于第IV级阶地的整体地层堆积情况及含石器层位很模糊。2013-2014年,广西文物保护与考古研究所会同田东县博物馆对百色盆地最重要的旧石器遗址之一——田东高岭坡遗址进行了系统的考古发掘。此次发掘从遗址的地表往下一直发掘到砾石层,揭露出厚度超过7m的完整地层序列,发现1处小型石器制造场和1处用火遗迹。在不同地层中发现石制品800多件,包括砍砸器、手镐、刮削器等。涵盖旧石器和新石器两个时代。根据地层对比和石制品的特征及测年结果,我们把旧石器时代文化遗存可分为3期:第一期的年代早于或等于803 kaBP,第二期为15 kaBP,第三期约为10 kaBP。     

Les derniers Homo heidelbergensis et leurs descendants les néandertaliens : datation des sites d’Orgnac 3, du Lazaret et de Zafarraya

This article presents the dating results recently obtained on three archaeological sites in Europe. At Orgnac 3 (Ardèche, France) from where the last Homo heidelbergensis fossils are associated with the first evidence of levallois technique, two speleothem formations from the 5b–6–7^th layers were U-Th dated with MC-ICPMS, giving an age range of 319–255 ka (2σ) (MIS 8–9), while the volcanic ash-bearing second layer was dated by ⁴⁰Ar/³⁹Ar, obtaining a preliminary date of 308.2 ± 6.8 ka (2σ). The combined ESR/U-Th dating of red deer enamel teeth from Lazaret cave (Alpes-Maritimes, France) attributed ages of 120–190 ka to the Acheulean and pre-Mousterian layers (MIS 6), which is in agreement with previous TIMS U-Th dates between 108 and 44 ka on calcite samples from the overlying TRA trench (MIS 5, 4, 3). At Zafarraya (Andalousie, Espagne), a number of ¹⁴C measurements on charcoal samples as well as combined ESR/U-Th dates on Capra and Equus dental enamels assigned the Mousterian artefacts and neandertalian fossils-bearing deposits an age interval between 42 and 34 ka (MIS 3).     

黄河中游晋陕峡谷延安段新发现的石制品

2018年6月,我们在黄河中游晋陕峡谷陕西一侧延安段新发现5处旷野石器地点,采集石制品556件,部分石制品暴露于黄土地层的剖面上。古人类加工石制品的原料来自于黄河河床和阶地的砾石层,岩性以石英岩为主,其次为石英。除上述两种原料之外,燧石、硅质岩、硅质灰岩、石英砂岩、细砂岩、蛋白石、玛瑙、火成岩等也有少量使用。石制品类型包括石锤、石核、石片、工具、断块和碎片屑,尺寸以小型为主。石核和石片以自然砾石台面者居多。剥片主要采用锤击法直接剥片,少量使用砸击法,可能偶而使用碰砧法和锐棱砸击法。工具多为以石片为毛坯加工而成的中小型刮削器,有少量以砾石为毛坯加工而成的砍砸器。伏羲村、苏亚河、高家畔、延水关4个地点发现的石制品原生埋藏地层为黄河第二级阶地上覆的马兰黄土堆积,该套地层形成于晚更新世晚期,石制品属简单的石核-石片工业,可能属于旧石器时代晚期。衣锦滩地点的石制品分别埋藏于黄河第二级阶地上覆的马兰黄土堆积和黄河第一级阶地上覆的土状堆积中,时代分属于旧石器时代晚期和新石器时代。本次新发现的旧石器地点进一步扩大了黄河晋陕峡谷地区旧石器遗存的分布范围,丰富了该地区旧石器文化的内涵,为未来的研究工作提供...     

La variabilité graphique du Molí del Salt (Vimbodí, Catalogne, Espagne) et l'art mobilier de la fin du Paléolithique supérieur à l'est de la Péninsule Ibérique

The Upper Paleolithic of Catalonia has been so far characterized by a very weak presence of artistic representations. This scarcity was especially surprising if we take into account the huge number of discoveries from other zones of the Iberian Peninsula (Valencia, the Cantabrian region). In this paper we present four objects of portable art found at the Molí del Salt site (Vimbodí, Conca de Barberà, Tarragona). Below a mesolithic layer, dated to 8 ka BP, there is an Upper Magdalenian sequence with several dates between 10.8 and 12.5 ka BP. These magdalenian levels have yielded four plaques of schist with engravings, including several animal figurines and one human representations. Once the objects are described, we will place them in the context of the portable art from the Late Upper Paleolithic of Mediterranean Spain. From these data, the chronocultural successions based on the Upper Magdalenian-Microlaminar Epipaleolithic distinction will be discussed.     

Microrefugia and Shifts of Hippophae tibetana (Elaeagnaceae) on the North Side of Mt. Qomolangma (Mt. Everest) during the Last 25000 Years

Microrefugia at high altitudes or high latitudes are thought to play an important role in the post-glacial colonization of species. However, how populations in such microrefugia have responded to climate changes in alternating cold glacial and warm interglacial stages remain unclear. Here we present evidence to indicate the Rongbuk Valley of the Mt. Qomolangma (Mt. Everest) area, the highest region on earth, had microrefugia for Hippophae tibetana and discuss how this low shrub was adapted to the extreme climate fluctuations of the last 25,000 years by shifts. By integrating geological, glaciological, meteorological, and genetic information, we found that the Rongbuk Valley was not only a glacial microrefugium but also an interglacial microrefugium for H. tibetana: the former was located on the riverbank below 4800 m above sea level (asl) or lower area and the latter at ∼5000 m asl. Our results show that after the Last Glacial Maximum (LGM), H. tibetana in the valley has undergone upward and downward migrations around ∼5000 m driven by climate fluctuations and the population in the glacial microrefugium has suffered extinction or extreme contraction. Moreover, with the rise of temperature in the last four decades, the upper limit of H. tibetana has shifted at least 30 m upward. Combining population history and recent range shift of this species is important in predicting the fate of this endemic species to future climate changes.     

Last interglacial reef limestones, northeastern St. Croix, US Virgin Islands—evidence of tectonic tilting and subsidence since MIS 5.5

Most last interglacial (MIS 5.5) coral reef deposits in the Caribbean are emergent. However, in St. Croix, these are found mainly at depth, underneath Holocene material and confirmed by TIMS U–Th dated corals from eight cores through Holocene reefs. The only emergent MIS 5.5 marine deposit peaks at +1.5 m MSL at the northwestern end of the island. The Late Pleistocene surface decreases at least 9.25 m (based on reef crest elevations) in elevation over 15 km along a 0.62 m/km eastward (alongshore) slope. Neither differential erosion nor a naturally sloping deposit is likely, thus the directional elevation decrease requires the influence of tectonic processes. Platform tilting or differential subsidence increasing in rate to the east probably operated both during and since the last interglacial and created progressively greater accommodation space for increasingly thicker overlying Holocene reefs in an eastward direction. Rates of subsidence since MIS 5.5 increase from west to east, from 0.02 mm/year to 0.1 mm/year, assuming a MIS 5.5 +6-m sea level and +4 m initial reef elevation. St. Croix’s association with extensional shelf faulting from the northern part of the Virgin Islands Basin, the Anegada Fault to the east and the Puerto Rico Trench to the north may be significant in terms of identifying mechanisms for, or past events resulting in, directional tilting. Identification of differential elevations of MIS 5.5 reefs adds substantially to the information on Late Quaternary tectonism of the area.     

Habitat et mode de vie des chasseurs paléolithiques de la Caune de l'Arago (600 000-400 000 ans)

Several human occupations have been identified within the deposits of the Caune de l’Arago Cave site, dated from 700 000 years to 100 000 years old. The exceptional wealth of these archeological levels provides an opportunity for the study of different types of habitat and behavioral patterns of Paleolithic hunters between 600 000 and 400 000 years ago. Results from preliminary studies, carried out over the last 30 years on these archeological levels, allow for the proposition of a typology for cave habitats during the Middle Pleistocene in the south of France. In fact, four types of habitat were identified and defined. They have been described according to different characteristics such as, the thickness of the archeological accumulation, the animal species represented, the season during which the animals were hunted, the state of conservation of the fossils discovered, the morpho-technological and typological characteristics of the lithics, the categories of raw materials used and the territory exploited by the hominids inhabiting the cave, as defined by the raw materials represented. The four habitation types defined are: the long duration habitat, where the cave was used as a home base; the temporary seasonal habitat, in which case the cave served as a secondary campsite; the hunting stopover and the bivouac, during which the cave was used as a refuge for short term stays. Behavioral patterns appear to be directly related to the type of habitat and oriented towards a principal activity: hunting. The activities performed by the inhabitants of the cave seem to be more diversified during prolonged or seasonal occupations, whereas they appear to be reduced or very specialised during brief stays. Generally, The characteristics studied show that the Caune de l’Arago Cave site had multiple uses over time for Anteneandertalian family groups and hunters who left traces of their activities, allowing us to better understand their lifestyle.     

Reef demise and back-stepping during the last interglacial, northeast Yucatan

The elevation of reefs and coastal deposits during the last Interglaciation (MIS-5e) indicates that sea level reached a highstand of as much as 6 m above the present, but it is uncertain how rapidly this level was attained and how it impacted reef development. To investigate this problem, I made a detailed sedimentological analysis of a well-dated reef from the northeast coast of the stable Yucatan Peninsula. Two linear reef tracts were delineated which are offset and at different elevations. The lower reef tract crops out along northern shore for 575 m and extends from below present mean sea level to +3 m. The reef crest facies consists of large Acropora palmata colonies dispersed within a coral boulder-gravel and is flanked by an A. cervicornis-dominated reef-front and a large area of lagoonal framework formed by coalesced patches of A. cervicornis and Montastraea spp. Constituents in the upper centimetre of the lower tract are heavily encrusted by a cap of crustose corallines and, in places, are levelled by a discontinuous marine-erosion surface. The upper reef tract crops out ~150 m inland up to an elevation of +5.8 m and parallels the southern section of shore for ~400 m. It also consist of an A. palmata-dominated crest facies flanked by reef-front, back-reef and lagoonal frameworks. In this case, however, lagoonal frameworks are dominated by a sediment-tolerant assemblage of branching coralline algae. Also different is the lack of encrustation by corallines, and the infiltration of upper tract facies by beach-derived shell-gravels from regressive shoreface deposits above. These results indicate that the lower reef tract and lagoonal patch-reefs formed at a sea level of +3 m. Final capping by crustose corallines and discontinuous marine erosion indicates that the lower tract was terminated by the complete demise of corals on the crest but only patchy demise in the lagoon. Areas of continuous framework accretion between the lagoonal patch reefs and the upper reef-tract, however, require that the demise of this reef was ecologically synchronous with initiation of the upper reef-tract, which had back-stepped 100 m into the lagoon. In this new position, the upper tract developed a reef crest that corresponded to a final sea-level position of +6 m. Reef flat development at +5 m and large in-place colonies of A. palmata at the base of the crest unit indicate, however, that sea level must have risen rapidly from +3 to more than +5 m to accommodate back-stepping. This sea-level jump created a higher energy wave field that mobilized back-reef and lagoonal sediments, and the resulting high sediment flux eroded lagoonal framework and prevented the recovery of the submerged lower reef crest. So this single jump in sea level was responsible not only for reef demise and back-stepping but also for marine erosion and suppression of subsequent reef development—features that elsewhere have been used to support multiple sea-level excursions during the last interglacial.