With 18 figures ZusammenfassungUntersucht wurden Profile yon Kohlenstotf-Isotopen mariner Karbonate aus dem Oberperm und der Untertrias der Tethys-Region aus 20 Lokalit~iten in Jugoslawien, Griechentand, der Tfirkei, der Sowjet-Republik Arrnenien, dem Iran, Pakistan, Indien, Nepal und China. Die oberpermischen Proben zeigen dieselben hohen positiven 613C Werte, wie sie vorher auch aus den oberpermiscben Beeken NWEuropas und dem Westen der USA berichtet wurden. Anhand yon vollstandigeren Abschnitten der Tethys kann dargelegt werden, dai~ die 6 13C Werte yon der Murgabium-bis zur Dzhulfium-Phase des Oberperms abnehmen und dann innerhalb der letzten zwei Biozonen des Dorashamiums abrupt gegen Null verlaufen. Diese 6 13C Niveaus sind repr~-sentativ ffir die Tethys und den Weltozean. Sie gelten auSerdem ffir alle Wassertiefen, wie durch ~ihnliche Werte aus Tiefsee-Sedimenten yon Salamis (Griechenland) bes6itigt wird. Unsere Annahme ist, dag die hohen 6 13C Werte auf sp~itpal~iozoische Speicherung organiscben Kohlenstoffs zuriickzuffihren ist. Die Abnahme stellt episodische Sedimentationsschwankungen des organischen Materials dar, w~ihrend der die organischen Substanzen fiber einen Zeitraum yon mehreren Millionen Jahren zum Tel1 aufoxidiert wurden. Das Kohlenstoff-Isotop Profil entspricht parallelisiert in etwa dem Muster des Massen-Aussterbens w~ih-rend des Oberperms. AbstractProfiles of carbon isotopes were studied in marine limestones of Late Permian and Early Triassic age of the Tethyan region from 20 sections in Yugoslavia, Greece, Turkey, Armenian SSR,

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The fossiliferous section at Meishucun of Yunnan, China, is a candidate stratotype section for the Precambrian–Cambrian boundary. Early diagenetic dolomites and phosphorites have been sampled across the boundary interval here, and in the correlated section at Maidiping in Sichuanand Valiabad in Iran, for comparison of their carbon and oxygen isotopes. This is the first such study that is calibrated by biostratigraphy in the interval from the earliest (pre-Tommotian) skeletal fossils to trilobites. Although negative oxygen isotopes indicate a diagenetic signal in the Zhongyicun Member and basal Badaowan Member phosphorites, two carbon-isotope cycles are clearly present and can be correlated in dolomitic rocks between the two sections. The first appearance datum (FAD) of the earliest skeletal assemblage (zone I, Marker A), FAD of diverse micromolluscs (zone II, Marker B) and FAD of Chinese trilobites (zones IV, V) and Marker C appear at similar points on the carbon-isotope curve in the two Chinese sections. Integrated carbon-isotope and early skeletal fossil biostratigraphy is shown to have the potential to correlate further afield, with sections in Iran, as well as with India, Siberia, Morocco and Australia. We suggest that a distinctive positive excursion provides a global marker for the interval between Marker B and C in China and just below the Tommotian Stage of Siberia.

Mount Sedom is a salt diapir, on the southwestern shore of the Dead Sea, which has been rising above the local base level throughout the Holocene. Karst development within the salt body has kept pace with the rise forming subhorizontal cave passages with vertical shafts. Wood fragments found embedded in flood sediments that were deposited in the cave passages yielded 14C ages ranging from c. 7100 to 200 BP. A palaeoclimatic sequence was constructed, based on parameters that include: relative abundance of plant types or floral communities, the elevations of the corresponding cave passages and the ratio of their width to present passage width. The results were correlated to the Holocene sedimentary sequence of the Dead Sea Basin, and other features associated with shifting lake levels. Moister climatic stages are indicated by relatively abundant wood remains, by wide cave passages and by elevated outlets indicating high Dead Sea level. Arid periods are marked by a scarcity of wood remains, by narrow cave passages and by low-level outlets. The Holocene sequence of Mount Sedom is subdivided into 10 climatic stages: A moist stage in the early Holocene, older than 7000 BP, and nine subsequent stages of drier climate, fluctuating between conditions that are somewhat drier, up to somewhat moister than those of today. The Dead Sea level dropped from c. -300 MSL during the early moist period to -400 MSL or lower during the subsequent arid periods.

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A 34.5 m borehole, which was drilled near the Dead Sea coast (altitude -394 m) in the southern part of the fan delta of Wadi Zeelim, reveals the geological history of that area from the latest Pleistocene to present. The depositional time frame is based on six 14C dates and two U-Th dates. An erosional (or nondepositional) period is implied by the hiatus between 21,100 yr B.P. (U-Th age, depth 33 m) and 11,315 yr B.P. (14C age, depth 32 m). A subsequent arid phase is recorded by a 6.5-m-thick layer of halite; based on 14C dates this phase relates to the abrupt Younger Dryas cold period reported in temperate to polar regions. The fragility of the environment in this region is indicated by the fact that the region experienced such a severe, short aridification phase (less than 1000 yr), evidence of which is found widely in the desert fringes of the Middle East and North Africa. The aragonite found in most of the Holocene section indicates that the well site was covered by the lake for most of the Holocene. Exceptions are the intervals at 0-3 and 10-14 m depths which represent low stands of the lake.

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The isotopic composition of rainwater near Nahariya, Israel, was measured in 12 individual storms during the winter months of 1980/1981. Rains most depleted in the heavy stable isotopes and enriched in tritium are associated with air masses which come from North East Europe and have a short, intense interaction with the East Mediterranean Sea. Storms most enriched in 18O and D and depleted in tritium are associated with air masses which come from the Atlantic Ocean and enter the Mediterranean Sea on its western part, travelling along the North African Coast, sometimes with a southerly shift. A relatively high correlation coefficient was found between the stable isotopic content of precipitation and the 800 mb temperature.