Staff Publications

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The Gediz River fluvial archive : A benchmark for Quaternary research in Western Anatolia
Maddy, D. ; Veldkamp, A. ; Demir, T. ; Gorp, W. van; Wijbrans, J.R. ; Hinsbergen, D.J.J. van; Dekkers, M.J. ; Schreve, D. ; Schoorl, J.M. ; Scaife, R. - \ 2017
Quaternary Science Reviews 166 (2017). - ISSN 0277-3791 - p. 289 - 306.
Buried river terraces - Fluvial archive - Gediz River - Pleistocene
The Gediz River, one of the principal rivers of Western Anatolia, has an extensive Pleistocene fluvial archive that potentially offers a unique window into fluvial system behaviour on the western margins of Asia during the Quaternary. In this paper we review our work on the Quaternary Gediz River Project (2001-2010) and present new data which leads to a revised stratigraphical model for the Early Pleistocene development of this fluvial system.In previous work we confirmed the preservation of eleven buried Early Pleistocene fluvial terraces of the Gediz River (designated GT11, the oldest and highest, to GT1, the youngest and lowest) which lie beneath the basalt-covered plateaux of the Kula Volcanic Province. Deciphering the information locked in this fluvial archive requires the construction of a robust geochronology. Fortunately, the Gediz archive provides ample opportunity for age-constraint based upon age estimates derived from basaltic lava flows that repeatedly entered the palaeo-Gediz valley floors. In this paper we present, for the first time, our complete dataset of 40Ar/39Ar age estimates and associated palaeomagnetic measurements. These data, which can be directly related to the underlying fluvial deposits, provide age constraints critical to our understanding of this sequence.The new chronology establishes the onset of Quaternary volcanism at ∼1320ka (MIS42). This volcanism, which is associated with GT6, confirms a pre-MIS42 age for terraces GT11-GT7. Evidence from the colluvial sequences directly overlying these early terraces suggests that they formed in response to hydrological and sediment budget changes forced by climate-driven vegetation change. The cyclic formation of terraces and their timing suggests they represent the obliquity-driven climate changes of the Early Pleistocene. By way of contrast the GT5-GT1 terrace sequence, constrained by a lava flow with an age estimate of ∼1247ka, span the time-interval MIS42 - MIS38 and therefore do not match the frequency of climate change as previously suggested. The onset of volcanism breaks the simple linkage of terracing to climate-driven change. These younger terraces more likely reflect a localized terracing process triggered by base level changes forced by volcanic eruptions and associated reactivation of pre-existing faults, lava dam construction, landsliding and subsequent lava-dammed lake drainage.Establishing a firm stratigraphy and geochronology for the Early Pleistocene archive provides a secure framework for future exploitation of this part of the archive and sets the standard as we begin our work on the Middle-Late Pleistocene sequence. We believe this work forms a benchmark study for detailed Quaternary research in Turkey.
Large scale pantelleritic ash flow eruptions during the Late Miocene in central Kenya and evidence for significant environmental impact
Claessens, L.F.G. ; Veldkamp, A. ; Schoorl, J.M. ; Wijbrans, J.R. ; Gorp, W. van; MacDonald, R. - \ 2016
Global and Planetary Change 145 (2016). - ISSN 0921-8181 - p. 30 - 41.
In the area south-east of Mount Kenya, four previously unrecorded peralkaline rhyolitic (pantelleritic) ash flow tuffs have been located. These predominantly greyish welded and non-welded tuffs form up to 12 m thick units, which are sometimes characterized by a basal vitrophyre. The four flow units yielded 40Ar/39Ar ages ranging from 6.36 to 8.13 Ma, indicating a period of ~ 1.8 Ma of pantelleritic volcanic activity during the Late Miocene in central Kenya. Tentative compositional and age correlations with other known tuff deposits suggest that the pantelleritic tuffs originally covered 40,000 km2 in central Kenya, extending much further than earlier recorded Pliocene tuffs. This newly identified magmatic phase occurred between the phonolitic flood eruptions (16–8 Ma) and the Pliocene tuff eruptions (6–4 Ma). The occurrence of multiple ash flow tuff deposits up to 150 km away from the inferred eruptive center(s) in the central sector of the Kenya Rift, indicates multi-cyclic peralkaline supereruptions during the Late Miocene. By analogy with more recent pantelleritic eruptions, the tuffs are thought to have been sulfur-rich; during eruption, they formed stratospheric aerosols, with significant environmental impact. The timing of the eruptions coincides with the shift towards more savannah-dominated environments in East Africa.
Catchment response to lava damming: integrating 1 field observation, geochronology and landscape evolution modelling.
Gorp, W. van; Schoorl, J.M. ; Temme, A.J.A.M. ; Reimann, T. ; Wijbrans, J.R. ; Maddy, D. ; Demir, T. ; Veldkamp, A. - \ 2016
Earth Surface Processes and Landforms 41 (2016)11. - ISSN 0197-9337 - p. 1629 - 1644.
Combining field reconstruction and landscape evolution modelling can be useful to investigate the relative role of different drivers on catchment response. The Geren Catchment (~45 km2) in western Turkey is suitable for such a study, as it has been influenced by uplift, climate change and lava damming. Four Middle Pleistocene lava flows (40Ar/39Ar- dated from 310 to 175 ka) filled and dammed the Gediz River at the Gediz–Geren confluence, resulting in base-level fluctuations of the otherwise uplift-driven incising river. Field reconstruction and luminescence dating suggest fluvial terraces in the Geren Catchment are capped by Middle Pleistocene aggradational fills. This showed that incision of the Geren trunk stream has been delayed until the end of MIS 5. Subsequently, the catchment has responded to base-level lowering since MIS 4 by 30 m of stepped net incision. Field reconstruction left us with uncertainty on the main drivers of terrace formation. Therefore, we used landscape evolution modelling to investigate catchment response to three scenarios of base-level change: (i) uplift with climate change (rainfall and vegetation based on arboreal pollen); (ii) uplift, climate change and short-lived damming events; (iii) uplift, climate and long-lived damming events. Outputs were evaluated for erosion–aggradation evolution in trunk streams at two different distances from the catchment outlet. Climate influences erosion–aggradation activity in the catchment, although internal feedbacks influence timing and magnitude. Furthermore, lava damming events partly control if and where these climate-driven aggradations occur. Damming thus leaves a legacy on current landscape evolution. Catchment response to long-duration damming events corresponds best with field reconstruction and dating. The combination of climate and base level explains a significant part of the landscape evolution history of the Geren Catchment. By combining model results with fieldwork, additional conclusions on landscape evolution could be drawn.
Upland catchment response to base level lowering, climate and dam events. A combined field and modelling approach
Gorp, W. van; Schoorl, J.M. ; Temme, A.J.A.M. ; Reimann, T. ; Wijbrans, J. ; Maddy, D. ; Demir, T. ; Veldkamp, A. - \ 2015
Homo erectus at Trinil on Java used shells for tool production and engraving
Joordens, J.C.A. ; d’Errico, F. ; Wesselingh, F.P. ; Munro, S. ; Vos, J. de; Wallinga, J. ; Ankjaergaard, C. ; Reimann, T. ; Wijbrans, J.R. ; Kuiper, K.F. ; Mücher, H.J. ; Coqueugniot, H. ; Prié, V. ; Joosten, I. ; Os, B. van; Schulp, A.S. ; Panuel, M. ; Haas, V. van der; Lustenhouwer, W. ; Reijmer, J.J.G. ; Roebroeks, W. - \ 2015
Nature 518 (2015). - ISSN 0028-0836 - p. 228 - 231.
quartz osl ages - luminescence signals - south-africa - indonesia - sediments - reliability - sangiran - record - rates
The manufacture of geometric engravings is generally interpreted as indicative of modern cognition and behaviour1. Key questions in the debate on the origin of such behaviour are whether this innovation is restricted to Homo sapiens, and whether it has a uniquely African origin1. Here we report on a fossil freshwater shell assemblage from the Hauptknochenschicht (‘main bone layer’) of Trinil (Java, Indonesia), the type locality of Homo erectus discovered by Eugène Dubois in 1891 (refs 2 and 3). In the Dubois collection (in the Naturalis museum, Leiden, The Netherlands) we found evidence for freshwater shellfish consumption by hominins, one unambiguous shell tool, and a shell with a geometric engraving. We dated sediment contained in the shells with 40Ar/39Ar and luminescence dating methods, obtaining a maximum age of 0.54 ± 0.10 million years and a minimum age of 0.43 ± 0.05 million years. This implies that the Trinil Hauptknochenschicht is younger than previously estimated. Together, our data indicate that the engraving was made by Homo erectus, and that it is considerably older than the oldest geometric engravings described so far4, 5. Although it is at present not possible to assess the function or meaning of the engraved shell, this discovery suggests that engraving abstract patterns was in the realm of Asian Homo erectus cognition and neuromotor control.
The earliest securely-dated hominin artefact in Anatolia?
Maddy, D. ; Schreve, D. ; Demir, T. ; Veldkamp, A. ; Wijbrans, J.R. ; Gorp, W. van; Hinsbergen, D.J.J. van; Dekkers, M.J. ; Scaife, R. ; Schoorl, J.M. ; Stemerdink, C. ; Schriek, T. van der - \ 2015
Quaternary Science Reviews 109 (2015). - ISSN 0277-3791 - p. 68 - 75.
geomagnetic secular variation - river terrace staircase - western turkey - gediz river - volcanic field - dmanisi - georgia - kula - dispersal - caucasus
Anatolia lies at the gateway from Asia into Europe and has frequently been favoured as a route for Early Pleistocene hominin dispersal. Although early hominins are known to have occupied Turkey, with numerous finds of Lower Palaeolithic artefacts documented, the chronology of their dispersal has little reliable stratigraphical or geochronological constraint, sites are rare, and the region's hominin history remains poorly understood as a result. Here, we present a Palaeolithic artefact, a hard-hammer flake, from fluvial sediments associated with the Early Pleistocene Gediz River of Western Turkey. This previously documented buried river terrace sequence provides a clear stratigraphical context for the find and affords opportunities for independent age estimation using the numerous basaltic lava flows that emanated from nearby volcanic necks and aperiodically encroached onto the contemporary valley floors. New 40Ar/39Ar age estimates from these flows are reported here which, together with palaeomagnetic measurements, allow a tightly-constrained chronology for the artefact-bearing sediments to be established. These results suggest that hominin occupation of the valley occurred within a time period spanning ~1.24 Ma to ~1.17 Ma, making this the earliest, securely-dated, record of hominin occupation in Anatolia.
Edifice growth and collapse of the Pliocene Mt. Kenya: Evidence of large scale debris avalanches on a high altitude glaciated volcano
Schoorl, J.M. ; Veldkamp, A. ; Claessens, L.F.G. ; Gorp, W. van; Wijbrans, J.R. - \ 2014
Global and Planetary Change 123 (2014)Part A. - ISSN 0921-8181 - p. 44 - 54.
african climate-change - mount kenya - tectonic evolution - gregory rift - east-africa - deposits - geochronology - uplift - pleistocene - himalaya
The cyclic growth and destruction of the Late Cenozoic Stratovolcano Mt. Kenya have been reconstructed for its southeastern segment. At least three major debris avalanche deposits have been reconstructed and dated. The oldest deposits indicate an edifice collapse around 4.9 Ma (40Ar/39Ar), followed by a larger event around 4.1 Ma (40Ar/39Ar). The last and best preserved debris avalanche deposit, with still some morphological expression covering the whole 1214 km2 SE sector, occurred around 2.83 Ma (40Ar/39Ar). This very large debris avalanche event must have truncated the whole top of Mt. Kenya. Of the original typical hummocky relief, only local topographical depressions are still best visible and preserved. Using known geometric empirical parameters of the 3 preserved debris-avalanche deposits, the height of the sector collapse is estimated to be in the range of 5100–6500 m above the current height of 1000 m a.s.l. near the end lobe of the VDA deposits. This demonstrates that Mt. Kenya attained impressive altitudes during its main activity in the Pliocene, being one of the highest mountains in that time and was most probably covered by an ice cap. Correcting for the known net eastward tilting post eruptive uplift of approximately 500 m of the Mt. Kenya summit, our reconstruction indicates that an at least 5.6 to 7 km a.s.l. high active Mt. Kenya existed in the Pliocene landscape between 5.1 and 2.8 Ma. This volcano must have significantly contributed to regional environmental change, by catching rain on its eastern slopes and projecting a rain shadow towards the Kenya Rift valley in the west. The last major edifice collapse event around 2.8 Ma coincides with a major change in regional vegetation. This suggests that the truncating of Mt. Kenya may have caused significant changes in the local climate surrounding Mt. Kenya with possible implications for environmental change in the central Kenya Rift valley, the cradle of hominin evolution.
Long term response to lava damming: landscape evolution of an upland catchment in Western Turkey
Gorp, W. van; Schoorl, J.M. ; Veldkamp, A. ; Temme, A.J.A.M. ; Maddy, D. ; Demir, T. ; Reimann, T. ; Wijbrans, J. - \ 2014
Abstract We investigated landscape evolution of the Geren catchment, a small upland tributary of the Gediz river in Western Turkey. This highly gullied catchment is not only responding to gradual incision of the Gediz, but it has also been aperiodically dammed by lava flows since the middle Pleistocene. Fieldwork and dating demonstrated that lava damming of the Gediz and Geren catchment occurred at least three and possibly five times between 310 ka and 3.0 ka. Middle Pleistocene (> 140 ka) aggradational limestone-capped ridges consist of fluvial gravels proximal to a limestone scar and fine down to fine layered sands and silts downstream. These fills can be correlated to the 310-175 ka period of repeated damming. Subsequent erosion and aggradation sequences indicate how the Geren catchment has responded to base level lowering by stepped incision, leaving terrace remnants at MIS 4, 2 and 1. Especially terraces of MIS 2 and 1 show significant aggradation of fine sands and silts. We conclude that response of such an upland catchment to gradual base level lowering, punctuated damming, and climate, is complex and spatially diverse and cannot be unravelled using fieldwork alone. Landscape evolution modelling will be pursued to better understand catchment response to these different driving factors.
Fluvial response to Holocene volcanic damming and breaching in the Gediz and Geren rivers, Western Turkey. EGU2013-12277
Gorp, W. van; Veldkamp, A. ; Temme, A.J.A.M. ; Maddy, D. ; Demir, T. ; Schriek, T. van der; Reimann, T. ; Wallinga, J. ; Wijbrans, J. ; Schoorl, J.M. - \ 2013
Fluvial response to Holocene volcanic damming and breaching in the Gediz and Geren rivers, western Turkey
Gorp, W. van; Veldkamp, A. ; Temme, A.J.A.M. ; Maddy, D. ; Demir, T. ; Schriek, T. van der; Reimann, T. ; Wallinga, J. ; Wijbrans, J. ; Schoorl, J.M. - \ 2013
Geomorphology 201 (2013). - ISSN 0169-555X - p. 430 - 448.
pleistocene lava-dam - grand-canyon - luminescence signals - terrace staircase - natural dams - k-feldspars - new-zealand - evolution - arizona - uplift
This study discusses the complex late Holocene evolution of the Gediz River north of Kula, western Turkey, when a basaltic lava flow dammed and filled this river valley. Age control was obtained using established and novel feldspar luminescence techniques on fluvial sands below and on top of the flow. This dating constrained the age of the lava flow to 3.0–2.6 ka. Two damming locations caused by the lava flow have been investigated. The upstream dam caused lake formation and siltation of the upstream Gediz. The downstream dam blocked both the Gediz and a tributary river, the Geren. The associated lake was not silted up because the upstream dam already trapped all the Gediz sediments. Backfillings of the downstream lake are found 1.5 km upstream into the Geren valley. The downstream dam breached first, after which the upstream dam breached creating an outburst flood that imbricated boulders of 10 m3 size and created an epigenetic gorge. The Gediz has lowered its floodplain level at least 15 m since the time of damming, triggering landslides, some of which are active until present. The lower reach of the Geren has experienced fast base level lowering and changed regime from meandering to a straight channel. Complex response to base level change is still ongoing in the Geren and Gediz catchments. These findings are summarized in a diagram conceptualizing lava damming and breaching events. This study demonstrates that one lava flow filling a valley floor can block a river at several locations, leading to different but interrelated fluvial responses of the same river system to the same lava flow.
Mount Kenya volcanic activity and the Late Cenozoic landscape reorganisation in the upper Tana fluvial system
Veldkamp, A. ; Schoorl, J.M. ; Wijbrans, J.R. ; Claessens, L.F.G. - \ 2012
Geomorphology 145-146 (2012). - ISSN 0169-555X - p. 19 - 31.
african climate-change - western turkey - sediment yield - gregory rift - debris flows - east-africa - pleistocene - evolution - river - uplift
Volcanic–fluvial landscape interaction of the late Cenozoic Mt Kenya region in the upper Tana catchment has been reconstructed. The oldest newly dated phonolite flow is 5.78 Ma (40Ar/39Ar), placing the initiation of Mt Kenya volcanic activity within the Late Miocene, much earlier than reported before, 3–3.5 Ma (K/Ar). The main body of the stratovolcano was already in existence around 4.22–5.27 Ma (40Ar/39Ar) supplying lahars to its lower footslopes. The final recorded volcanic main vent phase in the study area produced multiple phonolitic flows and lahars around 2.8 Ma (40Ar/39Ar). There is evidence of at least two major Pliocene drainage blocking events between 3.89 and 2.81 Ma (40Ar/39Ar) causing lava dammed lakes in which volcanic tuff deposits accumulated. Around this time the river Tana did not incise much and shaped an extensive fluvial plain, whose remnants can now be found around 1150 m altitude. This fluvial plain has been incising during the last 2.8 Ma, whereby the incision rate changed in time due to changing uplift rate and volcanic events. A flood basalt eruption covering 1150 km2, estimated to be 5 km3, on the south flank of Mt Kenya of the Thiba basalts at 0.80 Ma (40Ar/39Ar) plugged the Upper Tana basin and caused significant drainage reorganisation. The Tana was diverted southwards abandoning its former valley. The terrace record in the Tana valley downstream the Thiba basalts appears to register this event as a post 0.8 Ma accelerated incision. Current Thiba valley morphology is relatively young and appears to register uplift controlled terraces with interbedded lahars for the last 300 ka only, indicating a delayed fluvial response of approximately 0.5 Ma. The landscape reconstruction demonstrates that the Tana was well able to compensate for many volcanic events such as lahars and lava flows. Only the build-up of a stratovolcano body and a large flood basalt caused prolonged impact on fluvial landscape development
Late Cenozoic dynamics of the upper Tana river in response to the volcanic activity of Mount Kenya
Veldkamp, A. ; Schoorl, J.M. ; Wijbrans, J.R. ; Claessens, L. - \ 2010
In: Long term River evolution and fluvial dynamics, Abstracts, Fluvial Archives Group (FLAG) Biennial Meeting, Vila Velha de Rodao, Castelo Branco, Portugal, 5-10 September 2010. - Fluvial Archives Group (FLAG) - p. 40 - 40.
Late Cenozoic fluvial dynamics of the River Tana, Kenya, an uplift dominated record
Veldkamp, A. ; Buis, E. ; Wijbrans, J.R. ; Olago, D.O. ; Boshoven, E.H. ; Maree, M. ; Berg van Saparoea, R.M. van den - \ 2007
Quaternary Science Reviews 26 (2007)22-24. - ISSN 0277-3791 - p. 2897 - 2912.
african climate-change - east-africa - terrace stratigraphy - quaternary volcanism - environmental-change - mount kenya - rift - geochronology - history - lahars
The Late Cenozoic development of the River Tana in Kenya has been reconstructed for its central reach near its confluence with the River Mutonga, which drains the Mount Kenya region. Age control for this system has been provided by K-Ar and Ar-Ar dating. Between 3.21 and 2.65 Ma a major updoming occurred, in relation to the formation of the Kenyan rift valley. The tilting related to this doming has been reconstructed from lava flows that preserve former river gradients. Linear projection of these trends to the current rift valley rim suggests a net updoming of the eastern Gregory Rift valley by at least similar to 1 km during 3.21-2.65 Ma. In contrast, since 2.65 Ma the Tana system has been mainly subject to relatively minor epeirogenic uplift. Changing climatic conditions combined with continuing uplift yielded a typical staircase of strath terraces with at least 10 distinct levels. A more detailed reconstruction of the incision rates since 215 ka has been made, by correlating mineralogically fingerprinted volcaniclastic Tana deposits with dated tephras in a lake record. These volcaniclastic sediments were deposited during glacial periods, contemporaneous with lahars. The reconstructed incision rates for the three youngest terraces are similar to 0.1-0.2 mm a(-1), thus considerably faster than the overall average rate of valley incision since the Mid-Pliocene, of 0.06 mm a(-1). A plausible uplift history has been reconstructed using the estimated ages of the Tana terraces and marine terraces on the Indian Ocean coastline. The result suggests an increase in the rate of incision by the River Tana at similar to 0.9 Ma, an observation typical in most European river terrace staircases. The reconstructed Late Quaternary development of Tana valley indicates that a similar Quaternary uplift mechanism has operated in both Europe and East Kenya, suggesting a globally applicable process. (c) 2007 Elsevier Ltd. All rights reserved.
Voederwortelen : I. de indeling en de beschrijving van het in Nederland geteelde assortiment
Wijbrans, J.R. - \ 1953
Euphytica 2 (1953)2. - ISSN 0014-2336 - p. 149 - 156.
voedergewassen - akkerbouw - penen - beschrijvingen - landrassen - rassenlijsten - fodder crops - arable farming - carrots - descriptions - landraces - descriptive list of varieties
Het sortiment van de in Nederland verbouwde voederwortelen vertoont een veelheid van vormen. Er is getracht deze te ordenen in een aantal duidelijk omschreven typen. Ten dele zijn deze typen te beschouwen als het gemiddelde beeld van enige naverwante vormen, ten dele dekken zij bestaande vormen. Er komt nog materiaal in de handel, waaraan weinig kweekwerk is verricht en dat wegens geringe uniformiteit soms moeilijk tot een of ander type is te rekenen
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