Search publications of the members of the Royal Belgian institute of natural Sciences
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Dwarf traversodontids (Synapsida, Cynodontia) from the Late Triassic of Lorraine and Luxembourg
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Late Triassic vertebrates from Syren
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Walou Cave (Vesdre Basin, Begium). New palynological data for the Upper Pleistocene in Belgium
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Contribution de la paléobotanique a l'étude pluridisciplinaire des séquences sédimentaires dans les entrées de grottes et les abris-sous-roche en Belgique : le site de Walou
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New insight on the chronology of the Upper Palaeolithic in central and east Europe
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Climatic signature and chronology of the Late Pleistocene loess-palaeosol successions from Central and Eastern Europe
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Radiocarbon chronology and climatic signature of the middle pleniglacial loess from Danube to Yenisei: comparison with the marine and Greenland data
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Ancestors of domestic cats in Neolithic Central Europe: Isotopic evidence of a synanthropic diet
- Most of today’s domesticates began as farm animals, but cat domestication took a different path. Cats became commensal of humans somewhere in the Fertile Crescent, attracted to early farmers’ settlements by rodent pests. Cat remains from Poland dated to 4,200 to 2,300 y BCE are currently the earliest evidence for the migration of the Near Eastern wildcat to Central Europe. Tracking the possible synanthropic origin of that migration, we used stable isotopes to investigate the paleodiet. We found that the ecological balance was already changed due to the expansion of Neolithic farmlands. We conclude that among the Late Neolithic Near Eastern wildcats from Poland were free-living individuals, who preyed on rodent pests and shared ecological niches with native European wildcats.Cat remains from Poland dated to 4,200 to 2,300 y BCE are currently the earliest evidence for the migration of the Near Eastern cat (NE cat), the ancestor of domestic cats, into Central Europe. This early immigration preceded the known establishment of housecat populations in the region by around 3,000 y. One hypothesis assumed that NE cats followed the migration of early farmers as synanthropes. In this study, we analyze the stable isotopes in six samples of Late Neolithic NE cat bones and further 34 of the associated fauna, including the European wildcat. We approximate the diet and trophic ecology of Late Neolithic felids in a broad context of contemporary wild and domestic animals and humans. In addition, we compared the ecology of Late Neolithic NE cats with the earliest domestic cats known from the territory of Poland, dating to the Roman Period. Our results reveal that human agricultural activity during the Late Neolithic had already impacted the isotopic signature of rodents in the ecosystem. These synanthropic pests constituted a significant proportion of the NE cat’s diet. Our interpretation is that Late Neolithic NE cats were opportunistic synanthropes, most probably free-living individuals (i.e., not directly relying on a human food supply). We explore niche partitioning between studied NE cats and the contemporary native European wildcats. We find only minor differences between the isotopic ecology of both these taxa. We conclude that, after the appearance of the NE cat, both felid taxa shared the ecological niches.
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Spiders in Galapagos – diversity, biogeography and origin
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First records of Eulophidae from Cambodia (Hymenoptera: Chalcidoidea)
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A surprisingly short early Holocene humid spell inferred from remnant shorelines and palaeolake deposits in northern Arabia
- Early Holocene greening of the Sahara has been inferred from many sedimentary archives (e.g. Hoelzmann et al., 2001). Likewise, over the last two decades similar reconstructions of lakes and a more humid climate have been established for the southern Arabian Peninsula (e.g. Fleitmann et al., 2007; Engel et al., 2017) and the Levant (Bar-Matthews et al., 2003). Such evidence also exists for northern Arabia (Schulz and Whitney, 1986; Crassard et al., 2013; Zielhofer et al., 2018), but is limited in sufficiently robust proxy data and chronological resolution, hampering our understanding of the scarce archaeological record of that time (Hilbert et al., 2014). In this paper, we present latest results of the ongoing DFG-funded project CLEAR, which explores the highly resolved palaeolake record of the sabkha basin in the oasis of Tayma, northern Arabia. Today only flooded episodically after rainfall events, the endorheic basin is encircled by a ring of isolated shoreline deposits in an altitudinal corridor of only a few metres, consisting almost entirely of Melanoides tuberculatus and Hydrobia sp. shells, Amphibalanus amphitrite carapaces, foraminifers, and ostracods, with minor amounts of siliciclastic sand (Engel et al., 2012; Pint et al., 2017). These deposits have recently been mapped and dated by 14C and OSL, and indicate the presence of an early Holocene lake with a depth of up to 17 m and an area of up to 22 km². They correlate with partly varved lake sediments of the central basin according to the 14C-(pollen concentrates), varve- and cryptotephra-based chronology (Dinies et al., 2015; Neugebauer et al., 2017). In the framework of CLEAR, the palaeolake sequence was subjected to detailed sedimentological, geochemical and micropalaeontological analyses (grain-size distribution, XRD, µXRF, thin- section studies, foraminifera, ostracods, diatoms, pollen, stable isotopes, C/N, lipid biomarkers). Current results indicate increasing moisture at Tayma from c. 9300 cal. yrs. BP with pronounced humid conditions only over the second half of the 9th millennium BP, represented by an annually varved sequence of aragonite-, diatom-, and clastic silt- dominated laminae. After 7950 cal. yrs. BP, aridification set in, leading to sabkha development at c. 4200 cal. yrs. BP and the accumulation of aeolian sand. The rather short period of increased moisture availability contrasts with adjacent records from southern Arabia and the Levantine region (Bar-Matthews et al., 2003; Fleitmann et al., 2007), which reflect more humid conditions over several millennia during the early to mid-Holocene. This is a contribution to the research project “CLEAR – Holocene Climatic Events of Northern Arabia” (DFG PL 535/2-1; FR 1489/5-1; EN 977/2-1); see also contribution Pint et al. (this conference) and project website https://clear2018.wordpress.com. References: Bar-Matthews, M, et al., Geochim. Cosmochim. Acta 67, 3181–3199 (2003); Crassard, R., et al., PLOS ONE 8, e68061 (2013); Dinies, M., et al., Quat. Int. 382, 293–302 (2015); Engel, M., et al., 2012, Quat. Int. 266, 131–141 (2012); Engel, M., et al., Global Planet. Change 148, 258–267 (2017); Fleitmann, D., et al., Quat. Sci. Rev. 26, 170–188 (2007); Hilbert, Y.H., et al., J. Archaeol. Sci. 50, 460–474 (2014); Hoelzmann, P., et al., Palaeogeogr. Palaeocl. 169, 193–217 (2001); Neugebauer, I., et al., Quat. Sci. Rev. 170 269–275 (2017); Pint, A., et al., J. Foram. Res. 42, 175–187 (2017); Schulz, E., Whitney, Hydrobiologia 143, 175–190 (1986); Zielhofer, C., et al., Quat. Int. 473, 120–140 (2018).
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Simulation of boulder transport in a flume comparing cuboid and complex-shaped boulder models
- Coasts around the world are affected by high-energy wave events like storm surges or tsunamis depending on their regional climatological and geological settings. Coarse clasts (boulders to fine blocks) deposited on the shore can provide evidence for hazard-prone areas and physical characteristics of the flooding event. In order to better understand the process of boulder transport by tsunamis and to calibrate numerical hydrodynamic models, we conducted physical boulder transport experiments in a Froude-Scale of 1:50 utilizing idealized boulder shapes (cuboids) as well as realistic, complex boulder shapes based on real-world data. Comparing the behaviour of natural shaped with idealized boulders, allows identifying how the boulder shape influences the transport process in terms of transport mode (sliding, shifting, saltation), path and distance. Experiments are conducted in a 33 m long and 1 m wide flat wave flume ending on an ascending coastal profile. The gradient angle of the ramp changes from 11◦ to 4◦ ending on a flat elevated platform resulting in a total length of 4.5 m. The complex shaped boulder model (17.4x9.6x7.6 cm3) is constructed from photogrammetric data of a coastal boulder on Bonaire in the Dutch Caribbean (BOL2 in Engel and May, 2012), which is assumed to be transported by a tsunami. A cuboid boulder model of equivalent volume and weight (14x8x6 cm3) is created for comparison. The tsunami is modelled as a broken bore generated by two computer-controlled pumps. Each experimental run set-up was repeated for at least three times. The results show a significant influence of the boulder shape, in particular regarding the area of the contact surface when the bore approaches the boulder. With increasing contact surface higher transport distances occur. Due to the shape of the complex boulder tends slightly towards a rough ovoid, which is more streamlined than the idealized shape, the effectively acting drag force decreases and leads to reduced transport distances. The predominant transport mode during the experiments was sliding combined with gentle rotating around the vertical axis. However, in several experimental cases the complex boulder significantly rotates while the idealized does not. Recognizing that the transport distance, presumably due to decreasing ground contact and therefore less friction, increases during rotational transport, it is remarkable that the complex boulder still does not reach the transport distances of the idealized one. Experiments for boulder-boulder interactions generally show reduced transport distances. The bore-facing boulder generates a “flow shield” preserving the latter boulder from movement. In consequence, the bore-facing boulder hits its neighbour and stops moving. Within the range of our experiments, this boulder-boulder impact does not exceed a necessary energy-threshold for dislocating the second boulder. Beside further results regarding the influence of the initial water level, increased bottom friction and exper- iment sensitivity, insights into a numerical model based on these experiments will be presented. Engel, M.; May, S.M.: Bonaire’s boulder fields revisited: evidence for Holocene tsunami impact on the Leeward, Antilles. Quaternary Science Reviews 54, 126–141, 2012.
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The Early Holocene Humid Period in N Arabia – proxy evidence from a unique varved lake record
- There is growing interest in deciphering the hydroclimatic dynamics on the Northern Arabian Peninsula during and after the Early Holocene Humid Period (EHHP) as a key for better understanding the role of climate in driving neolithisation and the evolution of new lifestyles in the poorly studied Arabian Desert. However, our knowledge about the magnitude, timeframe and sources of increased moisture in Northern Arabia during the EHHP is limited due to a lack of robust proxy data. Here we provide the first high-resolution and precisely dated multi-proxy reconstruction of the hydroclimatic variability during the EHHP for northern Arabia, retrieved from annually laminated (varved) sediments of the Tayma palaeolake record. We found pronounced seasonal variability during the lake’s evolution, which we reconstructed through micro-facies analyses of the varved sediments. Changing lake water evaporation and the lake-internal productivity was inferred using stable oxygen and carbon isotope compositions (δ18O and δ13C) of carbonates. The compound-specific hydrogen isotope composition of plant-wax n-alkanes (δDwax) was used as a proxy for changing moisture supply. Our robust age model is well constrained by a floating varve chronology anchored through 14C dating of pollen concentrates and the well-dated ‘S1’ cryptotephra. Our results show that slightly wetter conditions started at Tayma at ca. 9300 yrs BP. The highest moisture availability was only achieved during a ca. 600 years lasting deep-lake phase from ca. 8500 to 7900 yrs BP, when varves formed in the lake. This implies that the EHHP was comparably short in northern Arabia. Furthermore, we found a complex regional hydrological pattern during the EHHP on centennial time-scales, which we discuss with respect to alternative moisture sources and mechanisms that led to the observed hydroclimatic signature at Tayma. This study is a contribution to the research project “CLEAR – Holocene Climatic Events of Northern Ara- bia” (https://clear2018.wordpress.com/).
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Metagenomics of tsunami deposits
- Onshore deposits of tsunamis provide information on the long-term frequency-magnitude patterns of events, which may not be covered by historical or instrumental records. Such information is crucial to assess coastal hazards and mitigation measures against the loss of life and assets. The identification of tsunami deposits in the coastal sedimentary record and the reconstruction of flooding processes requires reliable proxies, which are based on studies of recent tsunami deposits. Microfossils (e.g. foraminifera, ostracods, diatoms) are often applied to recognize tsunami deposits and differentiate them from storm deposits. In terms of foraminifera, tsunami deposits mostly contain allochthonous associations dominated by benthic intertidal to inner shelf taxa. Specimens may originate from outer shelf to bathyal depths; even planktonic forms may occur. Furthermore, changes in test numbers, taphonomy, size or adult/juvenile ratios compared to background sedimentation are common (Engel et al., 2016). However, dissolution of microfossils often prevents identification and reduces their value as a proxy (e.g. Yawsangratt et al., 2012). We address the problem of post-depositional dissolution of foraminiferal tests in tsunami deposits by applying high- throughput metagenomic sequencing techniques to identify foraminiferal associations based on DNA remains. Metagenomics (or environmental genomics) is related to sequencing DNA directly from the sediment record, where the genetic material may persist for tens of thousands of years. Among the broad range of organisms tackled in metagenomic studies so far, foraminifera (single-celled protists) were chosen as they show a water depth-related zonation in subtidal environments and were the first group to have been identified successfully in palaeo-tsunami deposits by their DNA (Szczuciński et al., 2016). The core study area are the Shetland Islands, exposed to the mega-tsunami triggered by the early Holocene Storegga submarine slide off the coast of Norway. Tsunami run-up of more than 25 m left a distinct landward-thinning sand layer with an erosive lower contact, locally large rip- up clasts, fining-upward sequences and marine diatoms in coastal lakes and peat lowlands. In addition to Storegga tsunami deposits, two younger tsunami deposits dated to c. 5 and 1.5 ka (Bondevik et al., 2005) were sampled during a field campaign in March 2018. Preliminary microscope analysis reveals rich foraminiferal associations in the shallow subtidal muddy sands of protected fjords, which represent the main source area for tsunami deposits. The onshore tsunami deposits, however, vertically confined by ubiquitous dystrophic peat, are void of any carbonate, which seems to have quickly dissolved after deposition in the low-pH environment. This setting paves the way for developing a new eDNA-based proxy to support the identification of tsunamis in the sedimentary record. Funding by a BELSPO BRAIN-be pioneer grant (BR/175/PI/GEN-EX) is gratefully acknowledged. References: Bondevik, S., Mangerud, J., Dawson, S., Dawson, A., Lohne, Ø., 2005. Evidence for three North Sea tsunamis at the Shetland Islands between 8000 and 1500 years ago. Quat. Sci. Rev. 24, 1757–1775. Engel, M., Oetjen, J., May, S.M., Brückner, H., 2016. Tsunami deposits of the Caribbean – Towards an improved coastal hazard assessment. Earth Sci. Rev. 163, 260–296. Szczuciński, W., Pawłowska, J., Lejzerowicz, F., Nishimura, Y., Kokociński, M., Majewski, W., Nakamura, Y., Pawlowski, J., 2016. Ancient sedimentary DNA reveals past tsunami deposits. Mar. Geol. 381, 29–33. Yawsangratt, S., Szczuciński, W., Chaimanee, N., Chatprasert, S., Majewski, W., Lorenc, S., 2012. Evidence of probable paleotsunami deposits on Kho Khao Island, Phang Nga Province, Thailand. Nat. Hazards 63, 151–163.
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Reef-top platform coral boulders of Eastern Samar demonstrate the long-term coastal hazard of extreme waves
- The Eastern Visayas region in the Philippines experiences some of the most violent tropical cyclones on Earth, exemplified by Typhoon Haiyan (7–9 November 2013) or Typhoon Hagupit (6–8 December 2014). Moreover, strong earthquakes along the Philippine Trench have triggered tsunamis in the past, both implying significant hazards of coastal flooding through extreme waves for the Pacific coast of the island of Samar. Due to the very short and fragmented historical record of the region, not much is known about frequency-magnitude relationships and maximum magnitudes on centennial and millennial scales, which can be derived from geological traces and which should be considered in coastal hazard management. We studied a large boulder field along the north coast of Eastern Samar distributed over an elevated reef platform to understand mechanisms of boulder transport and to derive implications for the maximum spatial extent, depth and velocity of coastal flooding. In this paper, we compare the field observations to physical experiments of boulder transport by extreme waves currently undertaken in a flume of the Methods: (i) Documentation of location, shape, morphological features, length, orientation of main axes of >250 boulders (1.5 m<a-axes<11.9 m) in the field; (ii) UAV-based 2D/3D- mapping; (iii) creation of SfM-based models of prominent boulders; (iv) interviewing elders of the local community for past events; (v) inverse modelling of coastal flooding and comparison with Deft3D-based numerical models of Haiyan and Hagupit; (vi) multi-temporal analyses of Pléiades and Worldview-3 scenes to reconstruct boulder movement during recent events; (vii) estimate the age of the carbonate platform and the timing of transport through 230U/Th dating. Preliminary results: (i) the platform’s age is mid-/late Holocene and formed through relative sea-level fall; boulder transport occurred over the late Holocene; (ii) Haiyan and Hagupit shifted boulders up to 115 t in steps of <32 m only at the seaward margin of the boulder field; (iii) transport during Haiyan and Hagupit clearly reflects the individual approaching angle of waves; (iv) size-distance relationships of the entire boulder field are unclear (r2=0.46 at best) and large clasts are located up to 1.3 km from the platform edge indicating that also major long-period waves (infragravity waves, tsunamis) have occurred in the past; (vi) flow velocities of up to 6–7 m/s were inferred for Hagupit, while largest clasts more inland (up to 11.9x8.1x4.2 m3; 433 t) require minimum values >10 m/s.
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Anthropogenic and environmental controls of barchan dune dynamics in Qatar
- Barchan dunes are crescentic aeolian landforms of loose, mostly well-sorted sand with a convex side directed upwind and two horns pointing downwind. Their migration is mainly controlled by sand supply, dune size, wind patterns, vegetation cover and human impact. In Qatar, their distribution is limited to the southeastern part of the peninsula, where they play an important role for tourism and camping activities among locals. We investigate the variability of dune migration in Qatar over a time period of 50 years using high-resolution satellite and aerial imagery. We then explore its relation to the regional Shamal wind system (NNW–SSE), teleconnection patterns, and limitations in sand supply associated with the transgression of the Arabian Gulf, which explain the fact that Qatar is gradually being stripped from aeolian landforms with a remaining dune population in the southeast. Strong size-dependent differences in migration rates of individual dunes as well as significant decadal variability on a dune-field scale are detected, the latter closely correlating with summer Shamal activity. The summer Shamal itself is mainly driven by pressure differences between the stationary anticyclone over the eastern Mediterranean and the established summer heat low over Iran and adjacent areas. It seems to be related to the intensity of the North Atlantic Oscillation and the Indian Summer Monsoon, in particular during years of relatively strong (weak) summer Shamals. High uncertainties associated with the extrapolation of migration rates back into the Holocene, however, do not permit further refining of the timing of the loss of sand supply and the onset of the mid-Holocene relative sea-level (RSL) highstand. For the youngest phase considered in this study (2006–2015), human impact has significantly accelerated dune migration under a more or less stable Shamal regime through systematic sand mining and excessive vehicle traffic upwind of the core study area, which started in 2007.
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Micro-and Macrofossils as indicators of Early Holocene palaeoenvironmental changes in the northwestern Saudi Arabia
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GEN-EX - Metagenomics of Extreme-Wave Events
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Megaclasts of Eastern Samar (Philippines)–Implications for the long-term hazard of extreme waves
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CARTS - the database of CARibbean Tsunami depositS
