Abstracts with Programs - Geological Society of America

den Wiederkehrperioden einmal in 10 Jahren, einmal in 10 –50 Jahren, einmal in 50 – 200
Jahren und seltener als 200 Jahre.
Zur Kategorisierung der Sturm- und Erdbebenexposition dienen die Karten der einschlägigen
DIN-Regelwerke. Georisikozonen für Erdrutsch und Erdfall werden auf Basis von Informationen
der Geologischen Landesämter bzw. Landesämter für Umwelt ermittelt.
Zur Risikoexposition von Gewerbe- und Industriebetrieben kann ein Geoinformationssystem
allerdings nur allgemeine Informationen liefern. Komplexe Risiken dieser Art erfordern
regelmäßig individuelle Bewertungen auf Basis von Orts- und Betriebsbesichtigungen. Dabei
geht es nicht nur um Gebäude, sondern um Schäden an Inventar, Vorräten und Produkten, ggf.
sind sogar Folgeschäden wie Produktions- und Lieferausfälle abzusichern.
24-7 12:30 Schmidt-Thomé, Philipp
NATURAL HAZARDS AND CLIMATE (CHANGE) ADAPTATION - EXAMPLES OF
INTERDISCIPLINARY GEOSCIENCE - DECISION MAKER COOPERATION
SCHMIDT-THOMÉ, Philipp, Geological Survey of Finland, Betonimiehenkuja 4,
Espoo 02150 Finland, philipp.schmidt-thome@gtk.fi
The rising costs caused by natural hazards are often attributed to climate change impacts.
Meanwhile it is currently not possible to prove climate change impacts as the cause for rising
costs it is a fact that most of the increasing damages can be attributed to inappropriate landuse.
The correct communication of climate change scenarios and their uncertainties are most
crucial for later application of adaptation measures in decision making processes.
Projects related to natural hazards, climate change and regional development conducted
under the European Spatial Planning Observation Network (ESPON) have supported the
development of hazard and climate change oriented policy recommendations1; 2 . Regional
Development projects in the Baltic Sea Region have been more concrete in stakeholder
communication and have led to concrete decision making3; 4; 5 .
The scenarios developed under these projects comprise, among others, sea level rise
and changing flood prone areas, salinization of aquifers and drought impacts, all of which
were analyzed in interdisciplinary cooperation. Examples of successful results comprise the
mentioning of these projects in international documents (e.g. the Territorial Agenda of the
European Union; the EU Green paper on climate change adaptation, 4th IPCC report). Several
cities and municipalities have cooperated in the development of participatory process design for
the development of adaptation measures. The mentioned projects have contributed to concrete
decisions and actions to adapt to potential impacts of natural hazards and climate change.
1Natural and technological hazards affecting the spatial development in Europe (http://www.
gtk.fi/projects/espon)
2Climate change and territorial effects on regions and local economies (www.espon-climate.
eu)
3Sea Level Change Affecting the Spatial Development of the Baltic Sea Region (http://www.
gtk.fi/slr)
4Developing Policies and Adaptation Strategies to Climate Change in the Baltic Sea Region
(http://www.astra-project.org)
5Climate Change: Impacts, Costs and Adaptation in the Baltic Sea Region (http://www.
baltcica.org)
24-8 14:00 Schlager, Wolfgang
HOW DEEP WERE THE HALLSTATT BASINS OF THE NORTHERN CALCAREOUS ALPS?
SCHLAGER, Wolfgang, Earth & Life Sciences, Vrije Univ. Amsterdam, De Boelelaan 1085,
Amsterdam, 1081HV, Netherlands, w.schlager@vu.nl, KRYSTYN, Leopold, Institute of
Palaeontology, University of Vienna, Vienna, 1090, Austria, and KENTER, Jeroen A.M.,
Chevron Energy Technology Company, 6001 Bollinger Canyon Rd, San Ramon, CA
94583-232
The Northern Calcareous Alps (NCA) are the cradle of important stratigraphic and
sedimentologic concepts but the intensive deformation of the allochthon frequently hampers
reconstruction of depositional settings. The bathymetry of the Middle and Late Triassic Hallstatt
Basins is a case in point. Since the 1960’s, two contrasting models have been applied. The
deep-basin model assumes uniform subsidence between carbonate platforms and basins such
that water depth is about equal to the difference in thickness between basins and platforms,
i.e. 800 m or more. In the shallow-basin model, water depth is 200 m or less because the basin
floor is assumed to have risen relative to the platforms, probably driven by salt-tectonics.
The shallow-basin model is supported by well-preserved transitions between outer platform
and marginal basin sediments. Middle-Triassic examples draw additional support from the fact
that the thickness variation of the overlying Raibl Formation (Carnian) that levels the platformbasin
relief, is much less than predicted by the deep-basin model. Support for the deep-basin
model is provided by the analogy with the well-preserved Middle-Triassic platforms of the
Dolomites in the Southern Alps and the Permian Capitan platform in the USA, both exhibiting
800-meter high slopes and minimal differential movement between platform and basin.
Recently, steep and over 600 m high clinoforms of Dachstein Limestone have been discovered
at the Gosaukamm in the NCA. This shows that parts of the Hallstatt Basins were deep but
does not exclude the possibility of a rise of the basin floor relative to the platforms. Slope
bedding in the Dolomites and at Gosaukamm is mainly planar and close to the angle of repose
of non-cohesive material. This geometry indicates that the platforms exported mainly sand and
rubble with very little mud – in stark contrast to the mud-rich modern platforms of the Bahamas
and the Caribbean. The steep slopes might serve as recorders of water stratification in the
Hallstatt Basins using chemistry of marine carbonate cements and biota.
24-9 14:30 Ortner, Hugo
THRUSTING AND SEDIMENTATION: A MODEL FROM THE NORTHERN CALCAREOUS
ALPS (NCA)
ORTNER, Hugo, Geology and Paleontology, University of Innsbruck, Innrain 52,
Innsbruck 6020 Austria, hugo.ortner@uibk.ac.at
A ramp-flat model can be used to describe thrusting and coeval sedimentation in a deep
marine environment: As the frontal part of a nappe climbs up a ramp, water depth above the
area of structural thickening decreases. Isolated carbonate platforms or shortlived carbonate
buildups develop on the evolving structure, shedding biogenic detritus into the surrounding
areas. Further growth will uplift the nappe above the ramp and upper footwall flat above sea
level. The nappe covers the upper footwall flat and ends deposition there. The synorogenic
sedimentary successions of the western NCA can be compared to specific positions in such
a model:
Upper Footwall sedimentation: On the upper footwall flat below the thrusted units,
conformable onset of synorogenic sedimentation records distant onset of contraction related to
orogeny, and deposition of shallow water biogenic detritus shows the approaching nappe. The
youngest sediments below the thrust record the local maximum age of thrusting. This situation
is comparable to Aptian-Albian synorogenic sedimentation of the Tannheim and Losenstein
Fms. on top of the Allgäu thrust sheet, which are overlain by the Lechtal thrust sheet, and to
Albian-Cenomanian synorogenic sedimentation of the Lech Fm. on top of the southern Lechtal
thrust sheet, which is overlain by the Inntal thrust sheet. The uppermost Lech Fm. locally
contains shallow water detritus (“Urgonian”) transported by gravity flows and thereby records
the destruction of carbonate buildups at the flanks of the approaching Inntal thrust sheet.
SESSION NO. 24
Thrust-sheet-top sedimentation: On top of the thrust unit, unconformable transgression of
terrestric sediments on deeply eroded older rocks records exhumation. Growth geometries in
thrust-sheet-top deposits record internal shortening of the thrust sheet after emplacement. The
Branderfleck Fm. on top of the northern Lechtal nappe and of the Gosau Group on top of the
Inntal nappe are found in this structural position. Undisturbed synorogenic sedimentation will
continue beyond the areas of active structural growth.
A problem remains subsidence during shortening of the NCA. In the Cretaceous, the NCA
were a foreland fold-and-thrust belt with respect to the closure of the Meliata ocean, but also in
the hanging wall of the ?retreating Penninic subduction that caused subsidence.
24-10 14:45 Niemeyer, Adelbert
NEW OBSERVATIONS ON GEOMORPHOLOGY AND LOESS SEDIMENTS IN THE
BAVARIAN MOLASSE BASIN – THE TERTIARY HILLS BETWEEN LANDSHUT AND
REGENSBURG
HOFFMANN, Markus1 , NIEMEYER, Adelbert2 , and FRIEDRICH, Anke M. 1 , (1) Department
of Earth and Environmental Sciences, University of Munich, Luisenstr. 37, Munich,
80333, Germany, (2) Erlus AG, Hauptstraße 106, Neufahrn / NB, 84088, Germany,
Adelbert.Niemeyer@erlus.com
For more than 50 years numerous geologists have worked on the observation and
interpretation of the youngest part of Tertiary Hills in the Bavarian Molasse basin. This part
is mostly covered with Pleistocene loess and loess loam. A widely accepted standard model
explaining the shape of the landscape represents the results of this work. This landscape
is dominated by NW-SE striking asymmetric hills and valleys. The model, based on climatic
processes and particular on the aeolian loess deposition, can explain these hills. But an
alternative mechanism to produce these structures is also possible, namely active faulting.
In this study, we present new observations from field mapping, DEM analyses, resistivity
tomography profiles and coring to underline this hypothesis. Observations are:
(a) Individual Tertiary hills extend over a length scale from 0.5 to > 6 km, dominantly striking
NW-SE and show steep slopes (6 to 24°) on their WSW flanks. The thickest loess deposits
of up to 20 m are adjacent to these windward SW slopes. The NE slope is usually flatter and
wider with only a thin loess cover of up to 4 m. The described hills are separated by narrow
valleys (50 to 150 m wide). On the valley floor pediment wedges and fluvial deposits are often
lacking. (b) Small rivers in some of the valleys exhibit sharp left-stepping bends with most
prominent examples near the village of Neufahrn/NB. (c) Several linear, NW-SE striking, 2 to
9 m high morphologic steps with a length of 0.5 to >10 km are observed 10 km south of the
Danube river. (d) Further a Quarry log close to the Danube river flood plain near Schafhöfen
reveal disturbed layers of Pleistocene fluvial sediments containing offset sand lenses and soft
sediment deformation features.
These observations can challenge the classic interpretation of aeolian deposition as the
dominant process forming the Tertiary hills. Instead we suggest that tectonic activity during the
Quaternary may have contributed to the geomorphology of this region.
24-11 15:20 Sarnthein, Michael
PEAK GLACIAL C-14 VENTILATION AGES SUGGEST MAJOR DRAW-DOWN OF CARBON
INTO THE ABYSSAL OCEAN
SARNTHEIN, Michael1 , SCHNEIDER, Birgit1 , and GROOTES, Pieter M. 2 , (1) Institut
für Geowissenschaften, Universität Kiel, Olshausenstr. 40, Kiel, D 24098, Germany,
ms@gpi.uni-kiel.de, (2) Leibniz Laboratory, Universität Kiel, Kiel, D 24098, Germany
Ice core records of the past 800,000 years have clearly demonstrated glacial-interglacial
atmospheric CO variations on the order of 100 ppm. During the last deglaciation, an estimate
2
of about 700 GtC is required to effect the rise in atmospheric CO together with land carbon
2
uptake, when the terrestrial biosphere was recovering from glacial conditions. The origin of
this carbon is usually attributed to oceanic carbon release, although the detailed mechanisms
remained elusive, since an adequately old and carbon rich deep ocean reservoir seemed
unlikely. Here we present evidence for changes in the deep-ocean carbon reservoir from a
new ocean-wide, though still fragmentary 14C data set showing that during the Last Glacial
Maximum (LGM) and parts of Heinrich stadial 1 (HS-1) the maximum 14C age difference
between ocean deep waters and the atmosphere exceeded the modern values by ~1000 to
1500 14C yr, in the extreme by up to 4500 yr. In the modern ocean the apparent 14C ventilation
age of water masses below 2000 m water depth appears directly linked to the concentr ation
of dissolved inorganic carbon (DIC) in seawater, with an aging by ~400 yrs corresponding to a
rise of ~60 µmol/kg DIC. This link is summarizing various independent effects of carbon supply,
the ’solubility pump’ that includes the gradual aging of deep waters and the ’biological pump’
that integrates plankton productivity, the local flux of organic carbon, and calcium carbonate
dissolution. Applying the modern 14C-DIC relationship to the prolonged apparent residence time
of LGM deep waters suggests that the deep ocean then was indeed able to absorb and store
about 750 Gt DIC in addition to the modern carbon inventory.
24-12 15:50 von Rad, Ulrich
ANNUAL TO MILLENNIAL MONSOONAL VARIABILITY DURING THE PAST 75,000 YEARS
RECORDED IN ARABIAN SEA SEDIMENTS: A REVIEW
VON RAD, Ulrich, Bundesanstalt f. Geowissenschaften und Rohstoffe (retired), Stilleweg 2,
Hannover, 30655, Germany, u.vonrad@web.de and LÜCKGE, Andreas, Bundesanstalt f.
Geowissenschaften und Rohstoffe, Stilleweg 2, Hannover, 30655, Germany
The Arabian Sea is a key area for addressing questions about the annual to millennial
variability of the Indian monsoon. During the Late Holocene laminated (varved) sediments
were deposited in the oxygen minimum zone (OMZ) off Pakistan which can be correlated in
all our cores and allow ultra-high-resolution paleoclimate studies. Varve counting, checked
by AMS-14C dating, detailed lithofacies analysis, X-ray fluorescence scanning, flux rates from
sediment traps, and the lamina-by-lamina-analysis of a five-year record (1993-1998) support
our interpretation of the annual character of the varves.
We used a high-resolution laminated sediment record from the OMZ off Pakistan to
investigate the Late Holocene climatic change in great detail. Independant proxies ( varve
thickness, inorganic geochemical composition, alkenone-derived sea surface temperatures
and oxygen isotopes of planktic foraminifera) reflect the monsoon-driven ”moisture history“
in the northeastern Arabian Sea during the past 5000 years. Maximum precipitation during
the enhanced NE monsoon around 3100-3200 y BP was followed by an onset of a gradual
aridification around 3000 yrs BP which continued until about 2000 to 2200 y BP.
Millennial changes of monsoonal intensity are also recorded in the Late Pleistocene
sediments: Short-term “warm” interstadials (“Dansgard-Oeschger events”) alternate with cool
stadials (“Heinrich events”) that can be correlated (by the Toba ashfall) with the same events in
the ice cores from Greenland, and with many high-resolution climate records from subtropical
northern hemisphere areas. Apparently, these synchronous teleconnections between the
subtropical Indian Ocean and the high-latitude North Atlantic Ocean. are forced by the highfrequency
varability of the atmospheric monsoon circulation.
Munich, Germany A35
Tuesday