The Pacific-North America plate boundary in central and southern California has a complex tectonic history, and constraints are poor for inception of an extensional fault system linked to the southern San Andreas fault, a major tectonic element of this plate boundary. Furthermore, decades of research has shown relationships between climate, tectonics, and surface processes in most orogens across the globe (e.g. Alps, Himalaya, Andes, Alaska Ranges), however the role climate plays in modulating erosion and mass fluxes from extensional mountains blocks to sedimentary basins over 104-5 yr timescales is debated. In the eastern California-Walker Lane shear zone, exposures of sedimentary basin fill allow inversion of erosion- and sediment-flux rates from a linked catchment-fan system within an extensional block. In this dissertation, I present two field and geo-thermochronology based studies that explore research topics related by common tectonic setting and geography within the Pacific-North America plate boundary. First I present new low-temperature thermochronology (apatite U-Th-Sm/He) and thermal history modeling to document the kinematic evolution of the Santa Rosa mountains, where the cooling history constrains initiation timing of the west Salton Detachment fault, and the southern San Andreas fault system. I document an age of ca. 8 Ma for exhumation initiation of the Santa Rosa block, from paleodepths of ~4.5–3 km, at vertical rates of ~0.15–0.36 mm/yr, accelerating to ~1.3 km/Ma since ca. 1.2 Ma during initiation of the San Jacinto fault zone. Second, I present a new data set of cosmogenic radionuclide-derived burial ages and paleodenudation rates (26Al/10Be) from the Pleasant Canyon complex in the Panamint Range, and show that denudation rate and sediment flux have varied by a factor of ~2x since the middle Pleistocene. I conclude high frequency variability is driven by climate change, and not tectonic perturbations, as supported by published constraints for exhumation timing. The middle Pleistocene transition from 40–100 ka periodicity may drive the observed changes, a tentative conclusion that makes testable predictions for stratigraphic records of past climate in other locations. Empirical evidence for climate-modulated erosion and sediment flux provides valuable constraints for numerical models of landscape evolution and sedimentary basin architecture. / Ph. D.

Cette étude porte sur l’analyse des séries jurassiques du Shaqra Group (Toarcian to Kimmeridgian) qui affleurent de manière continue en Arabie centrale le long d’un transect de plus de 1000 km de long. Ces séries se sont accumulées sur une vaste plate-forme épicontinentale peu profonde, en contexte tropical. Ces affleurements permettent ainsi d’observer la partie occidentale des séries renfermant des systèmes pétroliers prolifiques exploités en subsurface en Arabie Saoudite. L’analyse sédimentologique de nombreuses coupes et la réalisation de corrélations stratigraphiques de haute résolution sur un transect de 600 km au sud de Riyad, complété par des corrélations avec les données de forage plus à l’est (entre Riyadh et le Rimthan Arch), permettent de distinguer une organisation séquentielle à différents ordres de fréquence et de reconstituer l’évolution de la plate-forme au sein de ces séquences. La plate-forme jurassique évolue d’une plate-forme horizontale caractérisée par des systèmes mixtes à la transition continental-marin du Toarcien au Callovien moyen (formations Marrat et Dhruma) vers un système de type rampe - bassin intrashelf du Callovien au Kimméridgien inférieur (formations Tuwaiq et Hanifa) pour finir par une plate-forme aggradante carbonatée et silico-clastique (Fm. Jubaila) puis carbonatée et évaporitique en contexte aride (Fm. Arab) au Kimméridgien. Les cycles tectono-stratigraphiques de 2ème ordre du Jurassique inférieur et moyen sont limités à la base et au sommet par des discontinuités régionales. Ils occupent un dépôt-centre stationnaire et décrivent un onlap côtier de grande ampleur avec un maximum transgressif au Callovien moyen (Upper Tuwaiq Mb.). Durant le Jurassique supérieur, les dépôts de rampe carbonatée de la Formation Hanifa passent progressivement vers l’ouest à des dépôts plus profonds de bassin intrashelf relativement riches en matière organique (Khurais - Rimthan Arch). La séquence Jubaila – Arab-D montre des variations d’épaisseur qui indiquent une déformation de grande longueur d’onde de la plate-forme arabe à cette période. Les faciès récifaux du membre Arab D sont interprétés comme représentant le maximum d’inondation de ce cycle qui se termine par le développement de systèmes carbonatés – évaporitiques à la fin du Jurassique. / They serve as westernmost reference for adjacent prolific reservoirs and source-rock bearing intrashelf basins. Several hierarchical sequences (second to fourth order) have been recognized in outcrops sections (600 km long south of Riyadh) and correlated with gamma-ray logs of subsurface wells (550 km long from Riyadh to Rimthan Arch). The Jurassic platform evolved from very-flat continental-to-nearshore mixed carbonate-siliciclastic platform (Marrat-Dhruma; Toarcian to Middle Callovian) to differentiated ramp with deep intrashelf basins (Tuwaiq-Hanifa; Callovian to Early Kimmeridgian) to a lowstand followed by flat aggraded platform (Jubaila-Arab-D; Kimmeridgian). Tectonic related siliciclastic influx took place in arid condition during the Kimmeridgian (Jubaila Fm.). The Jurassic platform ends with the mixed carbonate-evaporite systems of the Arab Fm. A first second-order tectono-eustatic cycle (Marrat to Tuwaiq) is bounded at the base and top by regional unconformities. It has a stationary depocenter, and show long-term coastal onlap and marine transgression that reached its maximum extent during the upper Tuwaiq (Middle Callovian). The Hanifa Fm. consists of four 3rd-order sequences aggraded flat-toped platform (outcrops to Khurais) marked at the base by argillaceous limestone and top by pure high-energy carbonates with localized reef buildups. The Jubaila Arab-D is two 3rd-order sequences begin with low-stand deposits followed by long-term transgression. These formed flat successions with lateral thickness variations controlled by differential subsidence increased in the Arabian Basin. The transgression is marked by storm-influenced inner-platform with sandstone quartz, grainstones and restricted lime-mudstone. The Maximum marine transgression is placed in the Arab-D with reef buildups in the westernmost inner-platform. During highstand, the reefs are gently prograding out into Rimthan Arch leaving behind restricted lagoon and sabkhah/salina anhydrite.

Le Jurassique supérieur est une période qui présentait une paléogéographie et des conditions climatiques globales favorables au développement des systèmes sédimentaires dominés par les tempêtes. L’objectif de ce travail est de comprendre les facteurs contrôlant la dynamique de ces systèmes, ainsi que la relation entre les variations de fréquences et d’intensité des tempêtes et les changements climatiques. Trois coupes ont été choisies pour cette étude : les Pas (passage Oxfordien – Kimméridgien) et la coupe du Rocher d’Yves (Kimméridgien supérieur), près de La Rochelle ; la coupe du Cap de la Crèche (Kimméridgien supérieur – début du Tithonien), dans le Boulonnais. Ces coupes sont analysées pour la sédimentologie, les palynofaciès et les nannofossiles calcaires. Pour chacune d’elles, un modèle de faciès détaillé est établi, permettant de proposer une interprétation séquentielle et cyclostratigraphique précise. L’interprétation cyclostratigraphique permet d’interpréter les dépôts de tempêtes en terme de variations de fréquence des tempêtes. L’interprétation séquentielle permet de s’affranchir des variations du niveau marin relatif pour interpréter les dépôts de tempêtes en terme de variations d’intensité des tempêtes. Les points communs et les différences entre ces deux systèmes sont discutés, tant du point de vue de la dynamique sédimentaire que de l’enregistrement et de la préservation des dépôts de tempêtes. Enfin, la relation entre les variations de fréquence et d’intensité des tempêtes et les changements climatiques est discutée. Les faciès sédimentaires de La Rochelle et du Boulonnais présentent une organisation spatiale relativement similaire. La production carbonatée des systèmes présente des similitudes et des différences. Elle semble capable de réagir très rapidement aux variations du niveau marin relatif, augmentant avec l’élévation du niveau marin relatif. Les deux systèmes ont également une évolution similaire dans le temps. Les dépôts de tempêtes des deux sites montrent des morphologies similaires, liées aux conditions de dépôt et de préservation. Il a été possible de mettre en relation les variations d’intensité, de fréquences, et les changements du climat. Ainsi, les variations d’intensité des tempêtes semblent évoluer en parallèle des variations de fréquence, les valeurs d’intensité les plus élevées correspondant aux valeurs de fréquences les plus élevées. De plus, ces augmentations de fréquence et d’intensité ont lieu en même temps que l’augmentation des températures, indiquant un lien entre le réchauffement du climat et l’augmentation de l’activité des tempêtes / The Late Jurassic was a period with paleogeography and global climatic conditions that favor the development of sedimentary systems dominated by storms. The purpose of this study is to better understand the controlling factors on the dynamic of these systems. Three sections are chosen. The Pas (Oxfordian – Kimmeridgian transition) and the Rocher d'Yves (Late Kimmeridgian) sections, near La Rochelle (Western France), correspond to a muddy, mixed carbonated – siliciclastic platform. The Cap de la Crèche section (Late Kimmeridgian – Early Tithonian) corresponds to a mixed carbonated – siliciclastic ramp, dominated by coarse material. Sedimentary, palynofacies, and calcareous nannofossil analyses are performed. For each section, a detailed facies model is proposed, allowing precise sequence- and cyclostratigraphic interpretations. The sequence and cyclostratigraphic frameworks allow the calculation of the storm frequency. Comparison between host facies and storm deposits allows the estimation of storm intensity. The similarities and differences between these two systems are discussed, for the sedimentary dynamic, and the record and preservation of the storm deposits. Finally, the relation between storm frequency and intensity and climate is discussed. La Rochelle and Boulonnais sedimentary facies have a similar spatial organization. Carbonate production of these systems presents similarities and differences. The carbonate production seems able to react very quickly to relative sea-level variations, increasing when sea-level is high. The two systems also have a similar evolution in time. The storm deposits of the two sites show similar morphologies, related to the conditions of deposition and preservation. It was possible to link the variations of storm intensity and frequency with the climate changes. The variations of storm intensity evolve in parallel of the variations of storm frequency, the highest values of intensity corresponding to the highest values of frequency. Moreover, this increase in frequency and intensity is consistent with increasing temperature, suggesting a link between the increasing storm activity and the climate warming

Η παρούσα διδακτορική διατριβή βασίζεται στην ανάλυση ενός ευρύ φάσματος δεδομένων θαλάσσιας σεισμικής ανάκλασης (μονο-κάναλα και πολυ-κάναλα) με στόχο την μελέτη της γεωτεκτονικής δομής, και των μηχανισμών που ελέγχουν τις ιζηματογενείς διεργασίες πλήρωσης της λεκάνης του Κορινθιακού κόλπου, του πλέον ενεργού τμήματος της ευρύτερης Κορινθιακής τάφρου, και ενός από τα ταχύτερα διανοιγώμενα τμήματα ηπειρωτικού φλοιού παγκοσμίως. Πιο συγκεκριμένα η διατριβή ασχολείται με: (1) την αναγνώριση και λεπτομερή χαρτογράφηση των υποθαλάσσιων ρηγμάτων του Κορινθιακού κόλπου και τη σύνδεσή τους με τις τεκτονικές και σεισμολογικές παρατηρήσεις στην ευρύτερη Κορινθιακή τάφρο, (2) τη διερεύνηση του βάθους του γεωλογικού υποβάθρου και της δομής του Κορινθιακού κόλπου, (3) τη μελέτη των ενεργών ιζηματογενών διεργασιών και της επίδρασης της ενεργού τεκτονικής στους μηχανισμούς διασποράς και απόθεσης ιζημάτων. Η διατριβή αποτελείται από εννέα (9) κεφάλαια. Στο πρώτο κεφάλαιο (1), επιχειρείται μια σύντομη βιβλιογραφική ανασκόπηση των έως σήμερα δημοσιευμένων εργασιών σχετικά με την τάφρο του Κορινθιακού. Ακολουθούν δύο σύντομα κεφάλαια, το κεφάλαιο 2 όπου προσδιορίζεται και περιγράφεται γεωγραφικά η περιοχή ερευνών και το κεφάλαιο 3 όπου αναπτύσσεται η μεθοδολογία της παρούσας μελέτης. Στο κεφάλαιο 4 παρουσιάζεται μια συνολική, ευρείας κλίμακας μελέτη των υποθαλάσσιων ρηγμάτων του Κορινθιακού κόλπου και παρουσιάζεται η χαρτογράφηση τους. Στο τέλος του κεφαλαίου ακολουθεί μια εκτενής συζήτηση γύρω από την σημασία των ευρημάτων της παρούσας έρευνας σε σχέση με τις υπάρχουσες δημοσιεύσεις. Στο κεφάλαιο 5, παρουσιάζονται τα συλλεγμένα δεδομένα της πολυ-κάναλης σεισμικής ανάκλασης που επέτρεψε την σεισμική απεικόνιση της τεκτονικής τάφρου έως και το βάθος του αλπικού υποβάθρου. Ακολουθεί το κεφάλαιο 6 όπου αναλύονται διεξοδικά οι κύριες ιζηματογενείς διεργασίες στο δυτικό Κορινθιακό κόλπο και συσχετίζονται με τη λεπτομερή τεκτονική χαρτογράφηση της περιοχής. Στο τέλος του κεφαλαίου 6, παρατίθεται επιπλέον η αξιολόγηση των βασικών μοντέλων ταξινόμησης των ιζηματογενών συστημάτων βαθιάς θάλασσας με βάση τα ευρήματα της διατριβής για το δυτικό Κορινθιακό κόλπο. Στο τέλος καθενός από τα κεφάλαια 4, 5 και 6 πραγματοποιείται σύνθεση των αποτελεσμάτων και αναπτύσσεται συζήτηση ως προς την σημασία των παρουσιαζόμενων ευρημάτων της έρευνας. Στο κεφάλαιο 7 επιχειρείται μία σύντομη περίληψη και ανακεφαλαίωση των βασικότερων συμπερασμάτων της διατριβής,. Στο κεφάλαιο 8 γίνεται παράθεση της χρησιμοποιημένης βιβλιογραφίας, ενώ το κεφάλαιο 9 αποτελεί μια σύντομη σύνοψη της διατριβής στην αγγλική γλώσσα. Τέλος, στο παράρτημα Ι παρατίθενται τα βασικά στοιχεία και χαρακτηριστικά του ερευνητικού πλόα του ωκεανογραφικού σκάφους R/V Maurice Ewing που πραγματοποιήθηκε στο Κορινθιακό κόλπο το καλοκαίρι του 2001, για την συλλογή πολυ-κάναλων δεδομένων σεισμικής ανάκλασης χρησιμοποιώντας ένα σύστημα που περιελάμβανε ένα συνδυασμό από τις μεγαλύτερες σεισμικές πηγές και συστοιχίες υδροφώνων σε παγκόσμιο επίπεδο. / The seismic reflection surveys over one of the most active and rapidly extending regions in the world, the Gulf of Corinth, have revealed that the gulf is a complex asymmetric graben whose geometry varies significantly along its length. A total of 104 offshore faults were recognized on the seismic sections and a detailed map of the offshore faults has been produced. The offshore fault map of the Gulf of Corinth, shows that a major fault system of nine distinct faults limits the basin to the south. The northern Gulf appears to be undergoing regional subsidence and is affected by an antithetic major fault system consisting of ten faults. All these major faults have been active during the Quaternary. Uplifted coastlines along their footwalls, growth fault patterns and thickening of sediment strata toward the fault planes indicate that some of these offshore faults on both sides of the graben are active up to present. Our data ground-truth recent models and provides actual observations of the distribution of variable deformation rates in the Gulf of Corinth. Furthermore they suggest that the offshore faults should be taken into consideration in explaining the high extension rates and the uplift scenarios of the northern Peloponnesos coast. The observed coastal uplift appears to be the result of the cumulative effect of deformation accommodated by more than one fault and therefore, average uplift rates deduced from raised fossil shorelines, should be treated with caution when used to infer individual fault slip rates. Multi-channel seismic reflection data, over the western part of the Gulf of Corinth, image the whole sediment package and the alpine basement. The thickness of the sediments in the west Gulf of Corinth ranges between 1000 ms and 1386 ms, increasing towards the east. The deep seismic sections image a great number of faults most of which sole against the basement reflection. The vast majority of intrabasinal faults do not cut throw the surface sediments. These faults terminate at the base of a 200 ms thick surface sediment layer and therefore they are very difficult to recognize in the high resolution single channel seismic sections. The multi channel seismic sections in the west Gulf of Corinth verify a polarity shift of the graben’s asymmetry to the north. A major south dipping fault running along the axis of the basin, displaces both the whole sediment pile and the alpine basement showing a total throw of 580 ms. Further north, along the north slope, a tectonic horst displaces the alpine basement. This evidence suggest that at least one south dipping major fault should be included in the models trying to explain the proposed high deformation rates deduced from GPS surveys. The compilation of the very high resolution seismic reflection profiles collected over the last two decades in the western Gulf of Corinth; provides insights to the sedimentary processes of the fastest spreading sector of the Corinth rift. At best these seismic profiles image the uppermost 400 meters of the sedimentary column, which, considering the minimum and maximum proposed sedimentation rates corresponds to the last 200 ka of the rifts evolution. Seismic profiles reveal a total of 29 north and south dipping faults. These faults produce seafloor escarpments, with heights ranging between 100 m and 400 m. Strata thickening towards the fault planes suggest syn-sedimentary fault activity while in some cases absence of specific correlative reflections from the hangingwall block, suggest finite displacement that exceeds 480 m. Average fault orientation suggests an E-W trending structural grain with some NW-SE faults. Faults located close to the Gulf’s margin constitute the major basin bounding structures that produce accommodation space for the synrift sedimentation. Along the south margin these faults exhibit a right stepping configuration, which is also reflected on the coastline’s shape. In-between successive bounding faults well developed transfer zones are formed. These relay ramps constitute extensive gently dipping slopes that control drainage through river course diversion. Offshore sedimentation in front of the relay ramps builds thick strike-elongated base of slope aprons. The base of slope apron consists of a succession of sand and mud turbidites. Well-developed U-shape channels run through the apron surface. These channels are considerably wide and deep (up to 650 m wide and 100 m deep) showing a more or less stabilized subaqueous drainage network. A basin axis parallel fault in the middle of the basin cuts through the surface sediments and separates basin deposits into a south and a north sector. A 10.7 km long, 210 - 910 m wide and 40 – 60 m deep trubidite channel is nested along the fault trace of this intrabasinal fault. This axial channel is intersected by the lateral channel network that drains the adjacent south slope, serving as the terminal conduit fro the subaqueous drainage network. This pattern produces a highly effective transport network that allows for the coarse grained sediments to reach the deepest part of the Gulf of Corinth. Hangingwall sediments along both the north and the south margin exhibit progressive strata thickening towards the faults that define the basin plain - slope contact. Tilted sediment layers occupying the hangingwalls show an increase of tilt angles with depth, suggesting listric geometry for these faults. Along the south margin this sediment tilt is even more evident and appears to exert a control on the gravitational sediment mass movement deposition. Along the north margin, a tectonic horst running along the shelf-edge produces a structural barrier that traps land-derived clastic sediments within the shelf zone. The north-dipping fault of this horst acts as the master fault for the Eratini sub-basin, a secondary half-graben structure that hosts a 262 ms thick sediment pile. This study demonstrates that the western Gulf of Corinth is a pre-dominantly tectonically controlled depositional system with unstable boundaries. Minor to meso-scale drainage systems enter the Gulf along the fault controlled basin margins, providing the basin with a significant clastic sediment load. The seismic facies analysis resulted in the identification of five different depositional systems along the base of slope and the basin plain. Base of slope fans, a base of slope delta-fed apron, a major turbidite channel running along the axis of the basin plain, typical basin plain deposits, moat graben deposits adjacent to a major fault and an area dominated by high energy shallow channels and chutes, constitute the sedimentation pattern of the Western Gulf of Corinth. The interplay between the river courses and active faulting controls sediment availability along the basin margins. Dependent on the availability of allocthonous sediments and the prevailing sedimentary processes on the seafloor, the southern basin margin has been separated into a series of constructional and destructional type depositional systems. Active tectonic deformation along the basin margins and within the basin floor provides the necessary metastable conditions and the high energy potential for coarse grained sediment transport to high water depths. Furthermore active faulting exerts the primary control on both sediment transport pathways and the respective facies distribution pattern. This active sedimentation pattern offers an excellent opportunity to test the applicability of deep water sediment deposition systems. Indeed, the classification models proposed by Reading & Richards, 1994 and Richards et al., 1998, were tested in the western Gulf of Corinth. The models were proven quite consistent to the observations although our data show that actual sediment deposition systems are much more complicated. Seismic reflection profiling is a vital tool in assessing basin-formation and structural architectures. The seismic reflection surveys in the Gulf of Corinth demonstrate the effectiveness and importance of the methods in answering vital questions concerning the structure of the submerged sector of the Corinth rift. Seismic facies analysis combined with the application of sediment depositional system analysis offer a highly efficient and rapid technique for the delineation, characterization and prediction of the established sedimentation processes and their deposits. The results of this study would refine the existing tectono-sedimentary facies prediction models, which are broadly utilized in the oil industry.