Editorial: Cutting-Edge Analogue Modeling Techniques Applied to Study Earth Systems

Our understanding of Earth systems is built on field observations, geological and geophysical investigations and modeling. For over two hundred years, geologists are building analog models to test theories and understand the physics leading to field observations. Analog models do not aim to reproduce nature but rather to simplify the system so that parameters like geometry, kinematics, or dynamics can be isolated and investigated. Analog models allow to investigate complex three-dimensional problems at high-resolution. In addition to deciphering outcrop observations, analog models offer the opportunity to predict structures not accessible for direct observation. Analog models provide a full 4-D view of geological processes, allowing for investigating the time evolution of structures

Combining low-temperature thermochronology with 3-D probabilistic kinematic modeling including uncertainties in the Eastern Alps

To understand the exhumation history of the Alps and its foreland, it is important to accurately reconstruct its time-temperature evolution. This is often done employing thermokinematic models. However, one problem of many current approaches is that they rely on prescribed geometric structures at depth without considering their uncertainty. Therefore, the aim of this work is to compare low-temperature thermochronological data with a 3-D probabilistic kinematic model. To this end, we combine 3-D kinematic forward modeling with a systematic random sampling approach to automatically generate an ensemble of kinematic models in the range of assigned uncertainties. These can later be used to obtain a 3-D probabilistic exhumation map, from which exhumation values for the sample positions of thermochronological data can be interpolated, and compared to estimates made solely from thermochronology. In a next step, the uncertainties assigned to the kinematic model can be updated with the thermochronological data, to obtain an even more robust model. We apply this approach to the Bavarian Subalpine Molasse, which is particularly suited as a test case, as it connects the Alpine orogen with its foreland, and should shed light on the strain distributions during the latest stages of Alpine mountain building. Preliminary results using previously published data show that the estimated exhumation from the modeling can serve as a constraint to thermochronological interpretations, leading to an uncertainty reduction. In a next step, we will use our own (U-Th)/He measurements to obtain an integrated picture of foreland evolution and associated uncertainties over space and time

Dating the youngest deformation in the Alps with ESR thermochronometry

Low-temperature thermochronology is a useful tool to reconstruct tectonic deformation and landscape evolution within the first 2 km of the crust. It is a suitable tool to investigate deformation associated with cooling and exhumation of the lower crust in orogenic settings. Low temperature thermochronology is applied here to understand the Neogenic post-collisional extensional event that occurred in the Alps, because a gap in previous age dating exists between a thousand and a million years. Quartz is the most common mineral in the crust; occurring in magmatic as well as sedimentary and metamorphic rocks. The potential of quartz electron-spin resonance (ESR) as a radiation dosimeter has been well documented, and many studies applied the method to date sediments and heated rocks (e.g. tephra). In this study, we apply quartz ESR dating as an ultralow-temperature thermochronometer, characterized by a closure temperature of 30°-90°, and dating range of 103-107 years. We show the results of ESR thermochronometry on quartz applied to rocks from crustal-scale faults in the Central (Simplon Fault) and Eastern Alps (Brenner and Salzachtal Faults). Here, the lower crust has been tectonically exhumed, associated with exhumation of the Lepontine Dome and Tauern Window, respectively. Thermochronological data are available from this area, such as fission tracks or U-Th/He data on zircon and apatite. Results of the ESR measurements of 15 samples crossing the Brenner and Salzachtal faults (northern and western border of the Tauern Window) show that the ESR ages of quartz get younger (<1Ma) inside the western part of the Tauern Window, in accordance with fission track and (U-Th)/He ages. In general, younger ages (between 200 and 500 ka) are also obtain closer to the fault zone, localized near (e.g. Simplon Fault) or at the bottom of the valley (e.g. Brenner Fault), compared with the protolithic rocks (600-900 ka). We interpret the trend of the ESR ages as an exhumation of the isotherms due to both recent uplift of the footwall of the fault and for erosion of the valley, where the later overprints the former. These results promise to establish ESR as an ultra-low thermochronometer using quartz for the Quaternary landscape reconstruction of the Alpine chain

The Memory of a Fault Gouge: An Example from the Simplon Fault Zone (Central Alps)

Faut gouge forms at the core of the fault as the result of a slip in the upper brittle crust. Therefore, the deformation mechanisms and conditions under which the fault gouge was formed can document the stages of fault movement in the crust. We carried out a microstructural analysis on a fault gouge from a hanging-wall branch fault of the Simplon Fault Zone, a major low-angle normal fault in the European Alps. We use thin-section analysis, together with backscattered electron imaging and X-ray diffractometry (XRD), to show that a multistage history from ductile to brittle deformation within the fault gouge. We argue that this multistage deformation history is the result of continuous exhumation history from high to low temperature, along the Simplon Fault Zone. Because of the predominance of pressure solution and veining, we associated a large part of the deformation in the fault gouge with viscous-frictional behaviour that occurred at the brittle-ductile transition. Phyllosilicates and graphite likely caused fault lubrication that we suggested played a role in localizing slip along this major low-angle normal fault

The Memory of a Fault Gouge: An Example from the Simplon Fault Zone (Central Alps)

A fault gouge forms at the core of the fault as the result of a slip in the upper brittle crust. Therefore, the deformation mechanisms and conditions under which the fault gouge was formed can document the stages of fault movement in the crust. We carried out a microstructural analysis on a fault gouge from a hanging-wall branch fault of the Simplon Fault Zone, a major low-angle normal fault in the Alps. We use thin-section analysis, together with backscattered electron imaging and X-ray diffractometry (XRD), to show that a multistage history from ductile to brittle deformation, together with a continuous exhumation history from high to low temperature, took place within the fault gouge. Because of the predominance of pressure solution and veining, we associated a large part of the deformation in the fault gouge with viscous-frictional behaviour that occurred at the brittle-ductile transition. Phyllosilicates and graphite likely caused fault lubrication that we suggested played a role in the formation of this major low-angle normal fault. © 2022 by the authors. Licensee MDPI, Basel, Switzerland

Foreland dynamics as a measure of mountain building processes

Forelands record the uplift and exhumation history of mountain belts. The alpine foreland basin is particularly exciting, as is shows late-orogenic exhumation, possibly as a reaction to mantle-driven, plate convergence, or climatic forcings. However, inferring the contribution of the individual drivers to exhumation from stratigraphic or thermochronological data is challenging. The reason for this are along strike variability basin of stratigraphy, different degree of exhumation, as well as structural style of the Subalpine Molasse (i.e., the fold-thrust belt at the southern fringe of the basin). Furthermore, the influence of fluid flow on the thermochronological ages is unknown. Exhumation estimates in the central part of the basin are mostly based on stratigraphic arguments. Thermochronological data is scarce and limited to local studies. As the Molasse has also been uplifted in the central part of the basin since the Miocene, it is probable that it also responds to deep-seated processes, but to a lesser extent than the western part of the basin. This may be a result of different slab dynamics along strike the orogen. To test this, we used detrital and in situ low-temperature thermochronological age dating to shed light on the surface expression of the underlying geodynamic process (Figure 1). Data shows that most ages in the central part of the basin are unreset, while resetting occurs in the southernmost tectonic slices of the Subalpine Molasse. Generally, Miocene shortening in the Subalpine Molasse progressively decreases from west to east. The pattern coincides with slab geometries at depth (Mock et al., 2020). A general trend of lesser erosion from west to east is also visible in the flat lying Molasse based on vitrinite reflectance data. This suggests that a geodynamic driver is required for explaining basin exhumation on basin scale. Locally, the pattern is more complex. Particularly in the Subalpine Molasse, exhumation may be associated with plate convergence. To test the influence of faulting on exhumation, we constrained the geometries of the fold-thrust belt. Using a new compilation of stratigraphy and structures along the entire Alpine deformation front (Ortner et al., 2023), we identified two key regions: the Bregenzerach south of the eastward termination of the Jura Mountains, and the Hausham Syncline southeast of Munich. The Bregenzerach region lies at the surface boundary between Eastern and Western Alps. Furthermore, previously published thermochronological data indicate thrust activity in the mid-Miocene. Structures at depth are reasonably well-constrained due to good outcrop conditions and seismic data. The Hausham Syncline represents the region where structures at depth are less well constrained, and additionally the frontal triangle zone of the Subalpine Molasse tapers out. Structural modeling shows that it is possible to quantify the uncertainty of structures at depth, paving towards thermo-kinematic modeling including structural uncertainty (Brisson et al., 2023; Frings et al., 2023). The extensive thermochronological dataset offers the opportunity to identify local particularities not in line with the general trends observed in the data. Using thermal springs as proxy for heat flow (Luijendijk et al., 2020), we show that fluid flow may at least locally influence the cooling pattern. This is important for translating cooling into exhumation, particularly in regions where less data is available and thus outliers may be overlooked

The impact of the Bohemian Spur on the cooling and exhumation pattern of the Eastern Alpine wedge

Fold and thrust belt dynamics and architecture may largely be impacted by the geometry of the overridden basement. The Bohemian Spur, the subcrop extension of the Bohemian massif, guided thrust propagation leading to the arcuate shape of the orogen and a narrowing of the Molasse Basin at the transition to the between the W-E trending Eastern Alps and the SW-NE trending Western Carpathians. Thermochronological studies in the Eastern Alps were mainly focused on the core of the collisional orogen, where deformation has been most prominent. Further to the east, some FT work is concentrated along fault zones but thermochronometers with lower closure temperatures have hardly been applied to higher elements of the nappe pile. Due to the scarcity of the dataset and preferential application of fission track dating uppermost crustal cooling below ca. 80 °C remains undetected. In this study we present new apatite (U-Th)/He and apatite fission track data from clastic units of the Rhenodanubian Flysch zone and the Northern Calcareous Alps. We find reset ages, that monitor a so far un(der)appreciated phase of prominent Late Oligocene to Miocene cooling. Thermal modeling of age data from the flysch samples reveals rapid Early Miocene cooling at rates of up to 40 °C/Ma between ca. 20 and 15 Ma. We propose a buttressing effect of the underlying tectonically structured eastern rim of the Bohemian Spur to be the driving mechanism for this phase of intensified exhumation. Our tectonic model (Fig. 1a) invokes contractional reactivation of pre-existing normal faults inherited from Penninic continental rifting. This positive inversion led to the shortening of the Jurassic half-graben infill and its extrusion as a major fold. Thermochronological data and thermal modeling of data from samples in the Lunz nappe of the Northern Calcareous Alps nappe pile indicate less punctuated cooling and exhumation. Modeling defines an increase of cooling rates at the latest at ca. 27 to 25 Ma, i.e., earlier than in the Flysch samples. Cooling occurred at a much lower rate of 3 to 6 °C/Ma and was synchronous with northward movement of the deformation front. In our tectonic model (Fig. 1b), we propose a staircase pattern that influences wedge dynamics: The topographically segmented downgoing plate leads to less localized and more distributed deformation invoking a broader area of uplift than the spatially focused uplift of the Flysch samples. Wedge propagation is initially inhibited or retarded by the relief of the basement. The ongoing northward movement of the propagating wedge is compensated through deep duplexing of the autochthonous foreland sequence. When calling upon deep-seated processes to explain the exhumation pattern the buttressing effect needs to be taken into account. Early Miocene drainage pattern reorganization in the Molasse Basin is proposed to be a consequence of uplift induced by the subcrop promontory

Rückkopplung zwischen Klima und Tektonik?

Coupling between Climate and Tectonics? 1 Low temperature thermochronology and structural geology applied to the pro-wedge of the European Alps 1 1 Thermochronological approach to the late stage evolution of the Molasse basin and the Interaction between climate and tectonics 9 1.1 General Introduction and Summary 9 1.2 Allgemeine Einführung und Zusammenfassung 12 1.3 The Molasse Basin 15 1.3.1 Geographic setting 15 1.3.2 Pre-Tertiary Basin Evolution 15 1.3.3 Tertiary Basin Evolution 17 1.3.4 Tectonic Setting 22 1.4 Methods 23 1.4.1 Principles of Thermochronology 23 The concept of closure temperature 23 1.4.2 Fission track formation and fading 26 1.4.3 Fission track age determination 29 1.4.4 (U-Th-Sm)/He dating 31 2 Resolving the latest uplift and erosion history of the Northern Alpine Foreland Basin with low temperature thermochronology 35 2.1 Introduction 35 2.2 Regional geologic context 37 Tertiary basin evolution 38 2.3 The Subalpine Molasse 39 General overview of the discussed cross sections 41 2.4 Fission Track and (U-Th-Sm)/He Principles and Methods 42 2.5 Sampling Strategy 43 2.6 Thermal Modelling of the data 45 2.7 Results 46 2.7.1 AFT age distribution 46 Entlebuch horizontal section 46 Entlebuch vertical section 55 Rigi horizontal section 56 Rigi vertical section 58 2.7.2 Comparison of EDM and LA-ICP-MS AFT results 59 2.7.3 (U-Th-Sm)/He age distribution 61 Entlebuch horizontal section 61 Entlebuch drill hole section 61 Rigi horizontal section 62 Rigi vertical section 63 2.7.4 Comparison of apatite (U-Th-Sm)/He and AFT results 63 2.7.5 Modelled burial and exhumation histories 64 2.8 Discussion 69 2.8.1 Thermochronology age pattern across thrusts 70 2.8.2 Heat flow across active thrusts 72 2.8.3 Tectonics in the Subalpine Molasse 72 2.8.4 The link to the inner Alps 73 2.8.5 The link to the Jura Mountains and critical taper theory 75 2.9 Conclusions 76 2.10 Acknowledgements 77 3 Supplementary information to “Resolving the latest uplift and erosion history of the Northern Alpine Foreland Basin with low temperature thermochronology” 78 3.1 Density and magnetic separation techniques applied 78 3.2 Apatite fission track dating and its application 78 3.2.1 Theoretical background 78 3.2.2 Application of the fission track method 79 3.3 Assumption of Ns = 0.5 89 3.4 EDM sampling strategy and age dating procedure 90 3.5 Differences between LA-ICP-MS and EDM data 90 3.6 Apatite (U -Th-Sm)/He dating and its application 92 3.6.1 Theoretical background 92 3.6.2 Application of the (U-Th-Sm)/He method 94 3.7 Excluding single (U-Th-Sm)/He ages 94 3.8 The weighted mean (U-Th-Sm)/He age 95 3.9 Modelling the data 97 3.10 Heat and fluid flow in the NAFB 97 3.11 Glacial erosion in the NAFB 99 3.12 Calculation of shortening based on thermochronology 100 4 Critical taper analysis of the Central Alps reveals variations in detachment strength. 103 4.1 Introduction 103 4.2 Geological framework 105 4.3 Critical taper analysis 111 4.4 The Central Alpine critical wedge 113 4.5 Correlation of wedge mechanics and observed geology 119 4.6 Summary and conclusions 121 4.7 Acknowledgements 122 5 Have the Central Alps been in tectonic steady state since 10 Ma? Results from low temperature thermochronology and critical wedge considerations 123 5.1 Introduction 123 5.2 Geological framework 125 5.3 Tectonic slices in the Subalpine Molasse 126 5.4 Thermochronological Methods 128 5.5 New thermochronological data 129 5.6 Thermal history 135 5.7 Interpretation of the cooling signals 137 5.8 Lateral correlation of tectonic events 137 5.9 Post 10 Ma shortening in the Central Alps 139 5.10 Restoration of Late Miocene wedge geometry 141 5.11 Discussion: Are the Central Alps in tectonic steady state since 10 Ma? 146 5.12 Conclusions 149 5.13 Acknowledgements 149 6 Conclusions 150 7 References 152Continental collision results in telescoping of Earth’s crust and the consequent formation of orogens with a complex internal structure, a characteristic mechanical configuration and resulting complex kinematics. Orogenic fronts mark the foremost position of active deformation, thus forming the linkage between the orogen and its foreland basin and therefore registering the spatiotemporal history of the two. Resolving this history contributes to our understanding of the kinematic history of orogens and consequently enables an assessment of the contribution of the driving forces behind mountain building; the results of which provide insights on the interactions between climate and tectonics, a topic which has been and continues to be heavily debated (Molnar and England, 1990; Willett, 1999; e.g. Beaumont et al., 2001; Whipple and Meade, 2006; Whipple, 2009). A suitable study area to investigate these interactions between climate and tectonics are the Central European Alps, due to the unparalleled amount of geological and structural data and the well studied present day kinematics. Additionally, countless studies document the uplift and erosion history (e.g. Ratschbacher et al., 1989; Pfiffner et al., 1990; Lammerer and Weger, 1998; Frisch et al., 2000; Bistacchi et al., 2001; Malusa and Vezzoli, 2006; Genser et al., 2007; Kuhlemann, 2007; Champagnac et al., 2009; Vernon et al., 2009a; Norton et al., 2010b; Glotzbach et al., 2011b). Like the inner Alps, the foreland basin has been the focus of numerous studies, and so both basin stratigraphy and tectonic setting are well resolved (e.g. Ganss and Schmidt-Thomé, 1953; Trümpy, 1980; Homewood et al., 1986; Pfiffner, 1986; Müller et al., 1988; Schlunegger et al., 1997a; Sinclair, 1997b; a; Sissingh, 1997; Kuhlemann and Kempf, 2002; Pfiffner et al., 2002; Berge and Veal, 2005; Berger et al., 2005a; Berger et al., 2005b). Accordingly, the Central Alps can serve as a natural laboratory for resolving the complex system of coupled processes that are responsible for deformation and surface response. The potential of similar coupling processes are reported from other orogens all over the world, for example the Olympic Mountains (e.g. Montgomery and Brandon, 2002), Taiwan (e.g. Fuller et al., 2006)and the Himalayas (e.g. Whipple, 2009) and may therefore be discussed in a similar way. In this thesis I focus on the North Alpine pro-wedge and scrutinize the potential driving forces of tectonic activity. The key questions I try to answer are: • Is it possible to constrain further the timing and amount of deformation (i.e. shortening) in the foreland fold and thrust belt of the European Alps, in particular in Late Neogene times? • What does this timing and magnitude of deformation tell us about the kinematics of late stage exhumation and the relation between the Alps and their foreland? • Can we evaluate the influence of climate (or climate changes) on timing and magnitude of deformation within the foreland fold and thrust belt? To address these questions, I combine low temperature thermochronology (in particular apatite fission track and apatite (U-Th-Sm)/He dating) with critical taper analysis and try to extrapolate the present day kinematic situation into the past; thus providing an instrument to understand wedge dynamics through time. The following sub-chapters give a general overview over the working area and the applied thermochronological methods. Chapter 2 demonstrates the application of low temperature thermochronology to the foreland basin of the Central Alps and reveals that the Subalpine Molasse in Switzerland was tectonically active in Neogene times. It is shown that this tectonic activity is coeval with tectonic activity in internal parts of the orogen, as well as with the more external Jura Mountains. This chapter was submitted to Tectonics. Chapter 3 is supplementary information to Chapter 2, showing methodological details. Chapter 4 focuses on the Alps as an orogenic wedge and shows that critical taper theory is applicable for the Central Alps. Detailed analysis of surface and detachment slopes reveals variations in effective coefficient of friction of the basal detachment between the foreland and the more internal parts of the orogen. Exceedingly weak detachments are found also within pelitic horizons, which cannot be solely attributed to elevated pore pressures. Chapter 5 combines the two approaches (low temperature thermochronology and critical wedge analysis) in order to constrain Alpine wedge dynamics through time. Additional thermochronological data from a profile crossing the Subalpine Molasse east of the Jura Mountains show that the Neogene tectonic activity is a regional feature. Shortening rates in the west and the east of the Central Alps have been similar since at least the Late Miocene. I combine the thermochronological data from the Subalpine Molasse with data from the External Crystalline Massifs and restore the Late Miocene wedge geometry of the Central Alps. It becomes obvious that the taper of the Central Alps has not changed significantly since 10 Ma. Accordingly, the Central Alps have been in steady state since then. Consequently, this study shows the tectonic contribution to the Late Miocene- to-present orogenic evolution. This thesis shows that we have no evidence that Miocene to Pliocene climatic events influenced the wedge stability and kinematics on the northern flank of the Central Alps, and therefore primarily plate boundary or mantle-induced processes controlled the tectonics of the Neogene-to-Recent foreland thrusting. Chapter 6 summarizes the results of the individual chapters.Die Kollision zweier Kontinente führt zur Bildung von Gebirgen mit einer komplexen internen Struktur, einem individuellen mechanischen Bau und daraus resultierender komplexer Kinematik. Orogenfronten bilden den äußersten Rand aktiver Verkürzung und gleichzeitig die Verbindung zwischen dem Gebirge und seinem Vorland. Sie archivieren deswegen deren raumzeitliche Entwicklung. Erkenntnisse über die Entwicklung von Orogenfronten tragen maßgeblich zum Verständnis der Kinematik von Gebirgen bei und erlauben Rückschlüsse auf die Kräfte, die für Gebirgsbildung verantwortlich sind. Deswegen bieten sich Orogenfronten auch für die Untersuchung von potentiellen Wechselwirkungen zwischen Klima und Tektonik an – eine Fragestellung, über die bereits seit über 20 Jahren heftig diskutiert wird (Molnar and England, 1990; Willett, 1999; e.g. Beaumont et al., 2001; Whipple and Meade, 2006; Whipple, 2009). Die europäischen Zentralalpen sind ein geeignetes Untersuchungsgebiet, um unterschiedlich gesteuerte Prozesse zu verstehen, da es aus diesem Raum eine beispiellose Menge an geologischen und strukturellen Daten vorhanden ist und die Kinematik bereits detailliert beschrieben wurde. Zusätzlich dokumentieren zahllose Studien die Hebungs- und Abtragungsgeschichte der Zentralalpen (z.B. Ratschbacher et al., 1989; Pfiffner et al., 1990; Lammerer and Weger, 1998; Frisch et al., 2000; Bistacchi et al., 2001; Malusa and Vezzoli, 2006; Genser et al., 2007; Kuhlemann, 2007; Champagnac et al., 2009; Vernon et al., 2009a; Norton et al., 2010b; Glotzbach et al., 2011b). Wie die Alpen selbst, so ist auch das Vorland im Detail untersucht worden und die Stratigraphie des Beckens sowie der derzeitige tektonische Aufbau sind gut bekannt (z.B. Ganss and Schmidt-Thomé, 1953; Trümpy, 1980; Homewood et al., 1986; Pfiffner, 1986; Müller et al., 1988; Schlunegger et al., 1997a; Sinclair, 1997b; a; Sissingh, 1997; Kuhlemann and Kempf, 2002; Pfiffner et al., 2002; Berge and Veal, 2005; Berger et al., 2005a; Berger et al., 2005b).Die europäischen Zentralalpen sind also ein „natürliches Versuchslabor“, das sich in besonderem Maße für die Untersuchung der mutmaßlichen Kopplung von klimatischen und tektonischen Prozessen eignet, welche für Deformation sowie die daraus resultierenden Reaktionen des Gebirgskörpers verantwortlich sein könnte. In dieser Doktorarbeit wird der Pro-Keil der nördlichen Alpen betrachtet und Kräfte, die für die Gebirgsbildung verantwortlich sein können, eingegrenzt. Die Schlüsselfragen sind: • Kann man den Zeitpunkt und die Magnitude der Deformation (Verkürzung) im Vorlandüberschiebungsgürtel der Europäischen Alpen genauer bestimmen, insbesondere die Verkürzung vom Neogen bis heute? • Was sagt das Ergebnis dieser Bestimmung bezüglich der Gebirgskinematik während der späten Exhumierungsgeschichte aus und was können wir für Rückschlüsse bezüglich der Verbindung zwischen Alpen und Vorland ziehen? • Was ist der Einfluss des Klimas (bzw. von Klimaschwankungen) auf den Deformationszeitraum und -magnitude? Um diese Fragen zu beantworten wird Niedrigtemperatur—Thermochronologie (genauer Apatit Spaltspur und (U-Th-Sm)/He Datierung) mit der Theorie der kritischen Keilform kombiniert und die heutige kinematische Situation in die Vergangenheit extrapoliert. Dabei werden Verfahren entwickelt, mit denen es gelingt, Gebirgsbildung und deren Entwicklung über die Zeit besser zu verstehen. Die vorgestellte Methodik ist für alle ähnlich strukturierten Gebirge anwendbar, in denen ebenso potentielle Interaktionen zwischen Oberflächenprozessen und Tektonik beschrieben wurden, wie z.B. den Olympic Mountains (USA) (z.B. Montgomery and Brandon, 2002), Taiwan Fold and Thrust Belt (z.B. Fuller et al., 2006) oder im Himalaya (z.B. Whipple, 2009). Die Doktorarbeit ist wie folgt gegliedert: Kapitel 2 beschreibt die Anwendung von Niedrigtemperatur-Thermochronologie auf das Vorland der Zentralalpen und zeigt dass, entgegen vorheriger Theorien, die Subalpine Molasse auch im Neogen aktiv deformiert wurde. Es wird aufgezeigt, dass diese Deformation zeitgleich mit Deformation im gebirgsinneren und im externen Jura Überschiebungsgürtel stattfand. Dieses Kapitel wurde bei Tectonics zur Veröffentlichung eingereicht. Kapitel 3behandelt methodische Details, die als zusätzliche Informationen für Kapitel 2 dienen. Kapitel 4 betrachtet die Alpen als kritischen Keil und stellt dar, dass die Theorie des kritischen Keils auf das Untersuchungsgebiet anwendbar ist. Eine detaillierte Analyse des basalen Abscherhorizonts und des Oberflächenwinkels zeigt variable Reibungskoeffizienten entlang des Décollements. Extrem niedrige Reibungskoeffizienten können nicht nur in salz-, sondern auch in tonreichen Einheiten nachgewiesen werden. Es kann gezeigt werden, dass dies nicht ausschließlich auf überhöhte Porendrücke zurückzuführen ist. Dieses Kapitel wurde bei G³ zur Veröffentlichung eingereicht. Kapitel 5 kombiniert die beiden Ansätze (Thermochronologie und Theorie des kritischen Keils). Zusätzliche thermochronologische Daten von einem Profil über die Subalpine Molasse zeigen dass die tektonische Aktivität, die im Schweizer Teil des Beckens entdeckt wurde, kein lokales Phänomen ist. Die Verkürzungsraten im Westen und im Osten der Zentralalpen sind seit mindestens dem späten Miozän vergleichbar. Die gesamten thermochronologischen Daten aus dem Vorland werden mit Daten aus den Externen Massiven verglichen. Es zeigt sich, dass der Orogenkeil sich seit etwa 10 Millionen Jahren nicht verändert hat und sich die Zentralalpen im kinematischen Gleichgewicht befinden. Diese Doktorarbeit zeigt dementsprechend den tektonischen Anteil an der Gebirgsbildung. Diese Doktorarbeit zeigt dass keine offensichtliche Korrelation zwischen klimatischen Ereignissen und tektonischer Aktivität besteht. Deswegen werden Plattentektonik oder Mantelprozesse als treibende Kraft der Überschiebungsaktivität postuliert. Kapitel 6 fasst die Ergebnisse zusammen