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106 results on '"Hoek, Wim Z."'

101. Validation of climate model-inferred regional temperature change for late-glacial Europe

Author

Veski, Siim, Samartin, Stéphanie, Lotter, André F., Heiri, Oliver, Bedford, Alan, Tonkov, Spassimir, Amon, Leeli, Seppä, Heikki, Ilyashuk, Boris, Muñoz Sobrino, Castor, Van Asch, Nelleke, Renssen, Hans, Watson, Jenny E., Tinner, Willy, Hazekamp, Marjolein, Toth, Monika, Kuiper, Saskia, Mortensen, Morten F., Hoek, Wim Z., Lang, Barbara, Kirilova, Emiliya, Lammertsma, Emmy, Brooks, Stephen J., Birks, Hilary H., Jeffers, Elizabeth S., Magyari, Enikö, Millet, Laurent, Birks, H. John B, and Verbruggen, Frederike

Subjects
13. Climate action, 580 Plants (Botany)
Abstract

Comparisons of climate model hindcasts with independent proxy data are essential for assessing model performance in non-analogue situations. However, standardized palaeoclimate data sets for assessing the spatial pattern of past climatic change across continents are lacking for some of the most dynamic episodes of Earth’s recent past. Here we present a new chironomid-based palaeotemperature dataset designed to assess climate model hindcasts of regional summer temperature change in Europe during the late-glacial and early Holocene. Latitudinal and longitudinal patterns of inferred temperature change are in excellent agreement with simulations by the ECHAM-4 model, implying that atmospheric general circulation models like ECHAM-4 can successfully predict regionally diverging temperature trends in Europe, even when conditions differ significantly from present. However, ECHAM-4 infers larger amplitudes of change and higher temperatures during warm phases than our palaeotemperature estimates, suggesting that this and similar models may overestimate past and potentially also future summer temperature changes in Europe.

102. The Lateglacial to early Holocene tephrochronological record from Lake Hämelsee, Germany: a key site within the European tephra framework

Author

Jones, Gwydion, Lane, Christine S., Brauer, Achim, Davies, Siwan M., De Bruijn, Renée, Engels, Stefan, Haliuc, Aritina, Hoek, Wim Z., Merkt, Josef, Sachse, Dirk, Turner, Falko, Wagner-Cremer, Friederike, Jones, Gwydion, Lane, Christine S., Brauer, Achim, Davies, Siwan M., De Bruijn, Renée, Engels, Stefan, Haliuc, Aritina, Hoek, Wim Z., Merkt, Josef, Sachse, Dirk, Turner, Falko, and Wagner-Cremer, Friederike

Abstract

Here we present the results of a detailed cryptotephra investigation through the Lateglacial to early Holocene transition, from a new sediment core record obtained from Lake Hämelsee, Germany. Two tephra horizons, the Laacher See Tephra (Eifel Volcanic Field) and the Saksunarvatn Ash (Iceland), have been previously described in this partially varved sediment record, indicating the potential of the location as an important Lateglacial tephrochronological site in northwest Europe. We have identified three further tephra horizons, which we correlate to: the c. 12.1 ka BP Vedde Ash (Iceland), the c. 11 ka BP Ulmener Maar tephra (Eifel Volcanic Field) and the c. 10.8 ka BP Askja-S tephra (Iceland). Three additional cryptotephra deposits have been found (locally named HÄM_T1616, HÄM_T1470 and HÄM_T1456-1455), which cannot be correlated to any known eruption at present. Geochemical analysis of the deposits suggests that these cryptotephras most likely have an Icelandic origin. Our discoveries provide age constraints for the new sediment records from Lake Hämelsee and enable direct stratigraphical correlations to be made with other tephra-bearing sites across Europe. The new tephrostratigraphical record, within a partially varved Lateglacial sediment record, highlights the importance of Lake Hämelsee as a key site within the European tephra lattice.

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103. The Lateglacial to early Holocene tephrochronological record from Lake Hämelsee, Germany: a key site within the European tephra framework

Author

Jones, Gwydion, Lane, Christine S., Brauer, Achim, Davies, Siwan M., De Bruijn, Renée, Engels, Stefan, Haliuc, Aritina, Hoek, Wim Z., Merkt, Josef, Sachse, Dirk, Turner, Falko, Wagner-Cremer, Friederike, Jones, Gwydion, Lane, Christine S., Brauer, Achim, Davies, Siwan M., De Bruijn, Renée, Engels, Stefan, Haliuc, Aritina, Hoek, Wim Z., Merkt, Josef, Sachse, Dirk, Turner, Falko, and Wagner-Cremer, Friederike

Abstract

Here we present the results of a detailed cryptotephra investigation through the Lateglacial to early Holocene transition, from a new sediment core record obtained from Lake Hämelsee, Germany. Two tephra horizons, the Laacher See Tephra (Eifel Volcanic Field) and the Saksunarvatn Ash (Iceland), have been previously described in this partially varved sediment record, indicating the potential of the location as an important Lateglacial tephrochronological site in northwest Europe. We have identified three further tephra horizons, which we correlate to: the c. 12.1 ka BP Vedde Ash (Iceland), the c. 11 ka BP Ulmener Maar tephra (Eifel Volcanic Field) and the c. 10.8 ka BP Askja-S tephra (Iceland). Three additional cryptotephra deposits have been found (locally named HÄM_T1616, HÄM_T1470 and HÄM_T1456-1455), which cannot be correlated to any known eruption at present. Geochemical analysis of the deposits suggests that these cryptotephras most likely have an Icelandic origin. Our discoveries provide age constraints for the new sediment records from Lake Hämelsee and enable direct stratigraphical correlations to be made with other tephra-bearing sites across Europe. The new tephrostratigraphical record, within a partially varved Lateglacial sediment record, highlights the importance of Lake Hämelsee as a key site within the European tephra lattice.

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104. The Lateglacial to early Holocene tephrochronological record from Lake Hämelsee, Germany: a key site within the European tephra framework

Author

Jones, Gwydion, Lane, Christine S., Brauer, Achim, Davies, Siwan M., De Bruijn, Renée, Engels, Stefan, Haliuc, Aritina, Hoek, Wim Z., Merkt, Josef, Sachse, Dirk, Turner, Falko, Wagner-Cremer, Friederike, Jones, Gwydion, Lane, Christine S., Brauer, Achim, Davies, Siwan M., De Bruijn, Renée, Engels, Stefan, Haliuc, Aritina, Hoek, Wim Z., Merkt, Josef, Sachse, Dirk, Turner, Falko, and Wagner-Cremer, Friederike

Abstract

Here we present the results of a detailed cryptotephra investigation through the Lateglacial to early Holocene transition, from a new sediment core record obtained from Lake Hämelsee, Germany. Two tephra horizons, the Laacher See Tephra (Eifel Volcanic Field) and the Saksunarvatn Ash (Iceland), have been previously described in this partially varved sediment record, indicating the potential of the location as an important Lateglacial tephrochronological site in northwest Europe. We have identified three further tephra horizons, which we correlate to: the c. 12.1 ka BP Vedde Ash (Iceland), the c. 11 ka BP Ulmener Maar tephra (Eifel Volcanic Field) and the c. 10.8 ka BP Askja-S tephra (Iceland). Three additional cryptotephra deposits have been found (locally named HÄM_T1616, HÄM_T1470 and HÄM_T1456-1455), which cannot be correlated to any known eruption at present. Geochemical analysis of the deposits suggests that these cryptotephras most likely have an Icelandic origin. Our discoveries provide age constraints for the new sediment records from Lake Hämelsee and enable direct stratigraphical correlations to be made with other tephra-bearing sites across Europe. The new tephrostratigraphical record, within a partially varved Lateglacial sediment record, highlights the importance of Lake Hämelsee as a key site within the European tephra lattice.

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105. The Lateglacial to early Holocene tephrochronological record from Lake Hämelsee, Germany: a key site within the European tephra framework

Author

Jones, Gwydion, Lane, Christine S., Brauer, Achim, Davies, Siwan M., De Bruijn, Renée, Engels, Stefan, Haliuc, Aritina, Hoek, Wim Z., Merkt, Josef, Sachse, Dirk, Turner, Falko, Wagner-Cremer, Friederike, Jones, Gwydion, Lane, Christine S., Brauer, Achim, Davies, Siwan M., De Bruijn, Renée, Engels, Stefan, Haliuc, Aritina, Hoek, Wim Z., Merkt, Josef, Sachse, Dirk, Turner, Falko, and Wagner-Cremer, Friederike

Abstract

Here we present the results of a detailed cryptotephra investigation through the Lateglacial to early Holocene transition, from a new sediment core record obtained from Lake Hämelsee, Germany. Two tephra horizons, the Laacher See Tephra (Eifel Volcanic Field) and the Saksunarvatn Ash (Iceland), have been previously described in this partially varved sediment record, indicating the potential of the location as an important Lateglacial tephrochronological site in northwest Europe. We have identified three further tephra horizons, which we correlate to: the c. 12.1 ka BP Vedde Ash (Iceland), the c. 11 ka BP Ulmener Maar tephra (Eifel Volcanic Field) and the c. 10.8 ka BP Askja-S tephra (Iceland). Three additional cryptotephra deposits have been found (locally named HÄM_T1616, HÄM_T1470 and HÄM_T1456-1455), which cannot be correlated to any known eruption at present. Geochemical analysis of the deposits suggests that these cryptotephras most likely have an Icelandic origin. Our discoveries provide age constraints for the new sediment records from Lake Hämelsee and enable direct stratigraphical correlations to be made with other tephra-bearing sites across Europe. The new tephrostratigraphical record, within a partially varved Lateglacial sediment record, highlights the importance of Lake Hämelsee as a key site within the European tephra lattice.

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106. Holocene vegetation succession and forest history in the upper Monts du Forez, Massif Central, France.

Author

van der Knaap, Willem O., Kalis, Arie J., van Leeuwen, Jacqueline F.N., Bos, Johanna A.A., Camping, Jeroen R., Hoek, Wim Z., Marbus, Marlies, Schorn, Erik A., Swertz, Charlotte A., and Janssen, C. Roel

Subjects
*FOREST succession, *EUROPEAN beech, *HOLOCENE Epoch, *SILVER fir, *FOREST plants, *TREE-rings
Abstract

On the basis of seven palynological records, we reconstruct the forest-limit composition and dynamics during the second part of the Holocene, in the upper montane and subalpine zones of the Monts du Forez in the north-eastern Massif Central, using a 2 km long, elevational transect of sites at 1335–1590 m elevation. All sites are mires today, varying in size from 2 to <0.1 ha. The chronology of the pollen diagrams is based on calibrated radiocarbon dating combined with pollen-stratigraphic correlation among the diagrams using the regional pollen component. Corylus avellana forest with Ulmus developed in the study region soon after the start of the Holocene. Soon after Fagus sylvatica arrived in the study area and expanded after ca. 3500 BC (5450 cal yr BP) to full abundance within a few centuries at the cost of Corylus. Abies alba expanded slowly within the Fagus forest after ca. 3300 BC (5250 cal yr BP), taking two millennia to reach its final abundance. During ca. 800–650 BC (2750–2600 cal yr BP) Fagus and Abies had reached similar overall abundances and formed forests only minimally affected by prehistoric human impact, which could serve as a natural baseline condition for extant forest management. We hypothesise that during this period dense Abies – Fagus krummholz had an upper limit of 1570 m, with scattered Abies trees above this and open woodland of Sorbus , Betula and Acer up to the summit (1634 m a.s.l.). A varied cultural landscape was in place in medieval times, with cereal cultivation and grasslands in a predominantly forested landscape. A baseline condition of this kind of cultural landscape could be found in late medieval times. During the last several centuries major deforestations took place and planted Pinus sylvestris replaced much of the originally natural Abies – Fagus forest. Crop cultivation increased in the cultural landscape. All diagrams have hiatuses (missing peat layers), which in most cases could be attributed to domesticated animals damaging the mire surface. For mire protection we therefore recommend a limited grazing pressure by cattle. The major phases in settlement history from the Neolithic to medieval times can be recognized in the pollen diagrams. [ABSTRACT FROM AUTHOR]

Published
2022
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