Global Change Abstracts The Swiss Contribution - SCNAT

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178 Global Change Abstracts – The Swiss Contribution | Past Global Changes to 11.2 ka. M1-5 is highly correlated to the Dongge Cave record from 15.5-11 ka, suggesting much of the Indian Ocean monsoon region responded similarly to the major climate changes of the last deglaciation. The transitions into the Younger Dryas and to a lesser extent the Bolling are remarkably gradual in M1-5, as they are in all other Asian speleothem records, occurring over several centuries. These gradual transitions are in striking contrast to high-resolution records from around the North Atlantic basin where the transitions are extremely abrupt and generally occur in under a century. This spatially variable pattern of climate change is consistent with an Atlantic origin for these deglacial climate events. Earth and Planetary Science Letters, 2007, V259, N3-4, JUL 30, pp 442-456. 08.1-369 Climate changes and volcanic signals during the Bronze Age: A stalagmite record Siklosy Z, Demeny A, Vennemann T W, Hegner E, Kramers J D, Leel Ossy Sz Hungary, Switzerland Geochemistry & Geophysics , Geology , Paleontology Geochimica et Cosmochimica Acta, 2007, V71, N15, AUG, SS, p A936. 08.1-370 Hyalinea marmarica, a new species of benthic foraminifera from the sea of Marmara (Turkey) Spezzaferri S, Yanko Hombach V Switzerland, Canada Paleontology , Marine & Freshwater Biology Traditionally, the benthic foraminifera Hyalinea balthica (Schroter) has been considered a species with high intraspecific variability, possibly related to climatic changes, and, therefore, a potential indicator of paleoclimate in the Mediterranean Sea. However, a stable and characteristic morphology very different from the syntype of the species can be observed in specimens from the Sea of Marmara. By identification and documentation of this morphology and a subsequent comparison to specimens similar to the type species, clear differences between the two groups have been established. Hyalinea marmarica n. sp. is proposed as an example of possible environment- related speciation in benthic foraminifera. It differs from H. balthica in having less numerous chambers in the last whorl (maximum of eight), depressed sutures at least in the last four chambers, a moderate increase in chamber size as added, a subacute profile and accessory apertures on the peripheral margin. Speciation could have occurred between 14 and 12 ka. At this time, increasingly efficient connections were progressively established between the Sea of Marmara and the Eastern Mediterranean Sea, allowing Hyalinea balthica to migrate into the Sea of Marmara. Here this species might have modified its morphology in response to the extreme environmental conditions. Journal of Foraminiferal Research, 2007, V37, N4, OCT, pp 309-317. 08.1-371 Mesolithic agriculture in Switzerland? A critical review of the evidence Tinner W, Nielsen E H, Lotter A F Switzerland, Netherlands Paleontology , Agriculture, Soil Sciences , Plant Sciences , Ecology Accumulating palaeobotanical evidence points to agricultural activity in Central Europe well before the onset of the Neolithic, commonly dated at ca 5500-5200 cal BC. We reinvestigated an existing pollen profile from Soppensee with refined taxonomical resolution by further subdividing the Cerealia pollen type into Triticum t. and Avena t. because the sediments at this site currently provide the highest temporal resolution and precision for the period of interest among all sites in Switzerland. Our new results are in agreement with previous high-resolution investigations from Switzerland showing scattered but consistent presence of pollen of Cerealia, Plantago lanceolata, and other cultural plants or weeds during the late Mesolithic period (6700-5500 cal BC). Chronologically, this palynological evidence for sporadic agricultural activities coincides with a major break in material culture at ca 6700 cal BC (i.e. the transition from early to late Mesolithic). Here, we review possible arguments against palaeobotanical evidences of Mesolithic agriculture (e.g. chronological uncertainties, misidentification, contamination, long-distance transport) and conclude that none of these can explain the consistent pollen pattern observed at several sites. The palynological evidence can, of course, not prove the existence of pre-ceramic agriculture in Central Europe. However, it is so coherent that this topic should be addressed by systematic archaeolbotanical analyses in future archaeological studies. If our interpretation should turn out to be true, our conclusions would have fundamental implications for the Neolithic history of Europe. Currently, it is intensely debated whether Central European agriculture developed locally under the influence of incoming ideas from areas where Neolithic farming had already developed earlier (e.g. southeastern Europe) or whether it was in-
Global Change Abstracts – The Swiss Contribution | Past Global Changes troduced by immigrating farmers. On the basis of our results, we suggest that agriculture developed locally throughout the late Mesolithic and Neolithic. Mesolithic trading networks connecting Southern and Central Europe also support the hypothesis of a slow and gradual change towards sessile agriculture, probably as a result of incoming ideas and regional cultural transformation Quaternary Science Reviews, 2007, V26, N9-10, MAY, pp 1416-1431. 08.1-372 Signal strength and climate calibration of a European tree-ring isotope network Treydte K, Frank D, Esper J, Andreu L, Bednarz Z, Berninger F, Boettger T, Dalessandro C M, Etien N, Filot M, Grabner M, Guillemin M T, Gutierrez E, Haupt M, Helle G, Hilasvuori E, Jungner H, Kalela Brundin M, Krapiec M, Leuenberger M, Loader N J, Masson Delmotte V, Pazdur A, Pawelczyk S, Pierre M, Planells O, Pukiene R, Reynolds Henne C E, Rinne K T, Saracino A, Saurer M, Sonninen E, Stievenard M, Switsur V R, Szczepanek M, Szychowska Krapiec E, Todaro L, Waterhouse J S, Weigl M, Schleser G H Switzerland, Spain, Poland, Canada, Germany, Italy, France, Austria, Finland, Sweden, Wales, Lithuania, England Plant Sciences , Instruments & Instrumentation , Paleontology We present the first European network of tree ring delta C-13 and delta O-18, containing 23 sites from Finland to Morocco. Common climate signals are found over broad climatic-ecological ranges. In temperate regions we find positive correlations with summer maximum temperatures and negative correlations with summer precipitation and Palmer Drought Severity Indices (PDSI) with no obvious speciesspecific differences. Regional delta C-13 and delta O-18 chronologies share high common variance in year-to-year variations. Long-term variations, however, exhibit differences that may reflect spatial variability in environmental forcings, age trends and/or plant physiological responses to increasing atmospheric CO 2 concentration. Rotated principal component analysis (RPCA) and climate field correlations enable the identification of four sub- regions in the delta O-18 network - northern and eastern Central Europe, Scandinavia and the western Mediterranean. Regional patterns in the delta C-13 network are less clear and are timescale dependent. Our results indicate that future reconstruction efforts should concentrate on delta O-18 data in the identified European regions. Geophysical Research Letters, 2007, V34, N24, DEC 19 ARTN: L24302. 179 08.1-373 Oncoid growth and distribution controlled by sea-level fluctuations and climate (Late Oxfordian, Swiss Jura Mountains) Vedrine S, Strasser A, Hug W Switzerland Paleontology , Meteorology & Atmospheric Sciences , Geology Abundant lagoonal oncoids occur in the Late Oxfordian Hauptmumienbank Member of the Swiss Jura Mountains. Four oncoid types are observed in the studied sections and classified according to the oncoid surface morphology, the structure and composition of the cortex, and the texture and fauna of the encasing sediment. Micrite-dominated oncoids (types 1 and 2) have a smooth surface. Type 1 has a rather homogeneous cortex and occurs in moderate-energy environments. Type 2 presents continuous or discontinuous micritic laminae. It is associated with a low-diversity fauna and occurs in high-energy facies. Bacinella and Lithocodium oncoids (types 3 and 4) display a lobate surface. They are dominated by microencrusters (Bacinella irregularis and Lithocodium aggregatum) and are found in low-energy facies. The stratigraphic and spatial distribution of these oncoid types shows a correlation with the sequence-stratigraphic evolution of the studied interval, and thus with relative sea-level fluctuations. It can be shown that these sea-level fluctuations were controlled by orbital cycles with 100- and 20-kyr periodicities. At the scale of 100- and 20-kyr sequences, types 1 and 2 oncoids are preferentially found around sequence boundaries and in transgressive deposits, while types 3 and 4 oncoids are preferentially found around maximum floodings and in highstand deposits. This implies that changes of water energy and water depth were direct controlling factors. Discrepancies in oncoid distribution point to additional controlling factors. Platform morphology defines the distribution and type of the lagoon where the oncoids flourished. A low accumulation rate is required for oncoid growth. Additionally, humidity changes in the hinterland act on the terrigenous influx, which modifies water transparency and trophic level and thus plays a role in the biotic composition and diversity in the oncoid cortex. Facies, 2007, V53, N4, NOV, pp 535-552.
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