Description: In my thesis, I studied marine and lacustrine sediment cores from different depositional provinces along the south-central Chilean margin with the overall objective to identify their records of paleoclimate and paleotectonics. First of all, I investigated sedimentary sequences that were recovered within the margin-parallel trench system (cp. Figure 1.2) and hence constitute long-term recorders [...] of the sediment transport between the continent and the abyssal zone of the lower plate.

Description: A set of 59 seismological stations was deployed in the Central Andes region at 21°S (Chile-Bolivia) along a profile ~600 km long and were operated between 2002 and 2004. The teleseismic tomographic images (from P- and S- waves) show low-velocity anomalies that are interpreted as the effects of melting or fluids at both flanks of the Altiplano plateau. Beneath the Central Volcanic Zone (CVZ) a low-velocity anomaly is interpreted to be caused by fluids that are the origin of the volcanic material from the CVZ. A low-velocity anomaly in the upper crust is interpreted as the Altiplano Low-Velocity Zone that appears to extend as far to the east as the Eastern Cordillera. A high-velocity body between 100 km and 150 km depth is interpreted as being part of the old cold lithosphere that detached from the base of the crust. The Brazilian Shield is thought to be responsible for the strong high-velocity anomaly on the eastern side of the Central Andes. In addition, another set of 19 stations was deployed in the southern Argentine Puna along a profile ~200 km long and were run over the same period of time (2002-2004). The intention was to study the crustal thickness at 25.5°S, where delamination of the lithosphere was proposed to explain the higher elevation of the Puna plateau. Beneath the plateau a negative velocity anomaly is observed and interpreted here as being the location of fluid transfer between the deeper and shallower portions of the crust, that emanate from the Benioff zone at depths of ~200 km. This anomaly clearly divides in two branches: one to the west towards the volcanic arc (CVZ) and the other to the east where the back-arc volcanoes are located. On their way to lower depths, the fluid paths are probably influenced by the presence of nearby isotherms. The bifurcation of the ascending path could be related to the presence of the lithosphere-asthenosphere boundary (LAB) at ~100-130 km. Based on our observations, the type and form of the anomaly, it is possible to propose the presence of a return-flow type model for fluid ascent in contraposition to the assumed corner-flow model usually proposed for the Andes. The fluids that cause the seismic anomalies beneath the Puna plateau are generated at deeper levels in the asthenosphere and ascend parallel to the oceanic slab in the manner of a return-flow. In the crust and beneath the Salar de Antofalla (SA), a high-velocity block with seismic activity is interpreted as part of the old and cold Palaeozoic magmatic arc (Faja Eruptiva de la Puna Occidental). The presence of this block is may be responsible for the distribution of volcanic activity localized at both sides of this anomaly. Eastern of the SA, it is possible to recognize a zone with low-velocities beneath the Galan volcano. A sharp limit imposed by high velocities, probably related to metamorphic rocks from the Paleozoic basement (Tacuil and Luracatao ranges) can be detected on the east of the profile. A high-velocity block with seismic activity is located in the crust beneath the Salar de Antofalla (SA) and interpreted as part of the old and cold Palaeozoic magmatic arc (Faja Eruptiva de la Puna Occidental). This block might be responsible for the distribution of volcanic activity localized at both sides of this anomaly. Beneath the Galan volcano and east of the SA, a zone with low-velocities can be recognized. A sharp limit towards high-velocities can be observed on the east of the profile, probably related to metamorphic rocks from the Palaeozoic basement (Tacuil and Luracatao ranges).

Description: This thesis summarizes the results of the WSM project’s second phase (1996‐2008). In particular it presents the major achievements that have been accomplished with the WSM 2008 database release that has been compiled under the guidance of the author. Furthermore, the thesis briefly presents three of the author’s numerical models that aim at quantification the temporal changes of the crustal stress field.

Description: In order to analyze mineralogical-geochemical changes occurring in whole rock reservoir samples (Stuttgart Formation) from the Ketzin pilot CO2 storage site, Brandenburg/Germany as well as to investigate single fluid-mineral reactions laboratory experiments and geochemical modeling were performed. The whole rock core samples of the Stuttgart Formation were exposed to synthetic brine and pure CO2 at experimental P-T conditions and run durations of 5.5 MPa/40 °C/40 months for sandstone and 7.5 MPa/40 °C/6 months for siltstone, respectively. Mineralogical changes in both sets of experiments are generally minor making it difficult to differentiate the natural variability of the whole rock samples from CO2-induced alterations. Results of sandstone experiments suggest dissolution of analcime, anhydrite, the anorthite component of plagioclase, chlorite + biotite, hematite and K-feldspar. Dissolution of anhydrite, the anorthite component of plagioclase and K-feldspar is also observed in siltstone experiments. During equilibrium simulations best matching models were ranked based on a mathematical statistical dispersion relation. The best matching model comprises a mineral combination of the albite component of plagioclase, anhydrite, dolomite, hematite, and illite. The equilibrium modeling showed that it is difficult to match K+, Fe2+ and SO4 2- brine concentrations simultaneously. The best matching subsets of the equilibrium models were finally run including kinetic rate laws. These kinetic simulations reveal that experimentally determined brine data was well matched, but reactions involving K+ and Fe2+ were not completely covered. Generally larger mismatches for dissolved Al3+ and Si4+ in all the completed simulations are most likely related to the sampling strategy and respective inaccuracies in the measured concentrations of dissolved Al3+ and Si4+. The kinetic simulation suppressing mineral precipitation yields best matches with experimental observations. The modeling shows acceptably well matches with measured brine ion concentrations, and the modeling results identified primary minerals as well as key chemical processes. It was also shown that the modeling approach is not capable of completely covering complex natural systems. Experiments on mineral separates were conducted with 2 M NaCl brine and pure CO2 using siderite, illite and labradorite samples. Experimental P-T conditions were 20 (30) MPa and 80 °C; run durations were one (siderite), two (illite) and three weeks (labradorite), respectively. Based on the acquired set of mineralogical-geochemical data the distinct experiments show: (i) dissolution of ankerite and stable siderite, which is therefore interpreted to be a potential CO2 trapping phase, (ii) preferred dissolution of the Ca-smectite component out of the illite-smectite mixed-layer mineral and (iii) dissolution of labradorite, respectively. No mineral precipitates (e.g. carbonate phases) were detected in any of the conducted laboratory experiments, and only one single kinetic simulation predicts the formation of minute amounts of dolomite. Based on the data acquired during this dissertation the mineralogical-geochemical effects of CO2 are minor, and the (chemical) integrity of the Ketzin reservoir system is not significantly affected by injected CO2.

Description: This study focuses on tectonics at the Neogene and late Quaternary time scales in the Main Cordillera and coastal forearc of the south-central Andes. For both domains I document the existence of previously unrecognized active faults and present estimates of deformation rates and fault kinematics. Furthermore these data are correlated to address fundamental mountain building processes like strain partitioning and largescale segmentation.

Description: The ability of any satellite gravity mission concept to monitor mass transport processes in the Earth system is typically tested well ahead of its implementation by means of various simulation studies. Those studies often extend from the simulation of realistic orbits and instrumental data all the way down to the retrieval of global gravity field solution time-series. Basic requirement for all these simulations are realistic representations of the spatio-temporal mass variability in the different sub-systems of the Earth, as a source model for the orbit computations. For such simulations, a suitable source model is required to represent (i) high-frequency (i.e., subdaily to weekly) mass variability in the atmosphere and oceans, in order to realistically include the effects of temporal aliasing due to non-tidal high-frequency mass variability into the retrieved gravity fields. In parallel, (ii) low-frequency (i.e., monthly to interannual) variability needs to be modelled with realistic amplitudes, particularly at small spatial scales, in order to assess to what extent a new mission concept might provide further insight into physical processes currently not observable. The new source model documented here attempts to fulfil both requirements: Based on ECMWF’s recent atmospheric reanalysis ERA-Interim and corresponding simulations from numerical models of the other Earth system components, it offers spherical harmonic coefficients of the time-variable global gravity field due to mass variability in atmosphere, oceans, the terrestrial hydrosphere including the ice-sheets and glaciers, as well as the solid Earth. Simulated features range from sub-daily to multiyear periods with a spatial resolution of spherical harmonics degree and order 180 over a period of 12 years. In addition to the source model, a de-aliasing model for atmospheric and oceanic high-frequency variability with augmented systematic and random noise is required for a realistic simulation of the gravity field retrieval process, whose necessary error characteristics are discussed. The documentation of the updated ESA Earth System Model (updated ESM) for gravity mission simulation studies is organized as follows: The characteristics of the updated ESM along with some basic validation is presented in Volume 1. A detailed comparison to the original ESA ESM (Gruber et al., 2011) is provided in Volume 2, while Volume 3 contains the description of a strategy to derive realistic errors for the de-aliasing model of high-frequency mass variability in atmosphere and ocean.

Description: This publication is a result of the 13th TRACE conference (Tree Rings in Archaeology, Climatology and Ecology) organized by the Department of Earth and Environmental Sciences at the University of St Andrews on May 6th – 10th, 2014 in Aviemore, Scotland, UK. [...]After review, 18 short papers are published in this volume, giving an overview of the wide spectrum of different fields covered at TRACE.