40ar/39ar Dating of alunite from the Pueblo Viejo Gold-Silver District, Dominican Republic

New 40Ar/39Ar ages for alunite from the Moore and Monte Negro deposits in the Pueblo Viejo district, as well as from a newly discovered alunite-bearing zone on Loma la Cuaba west of the known deposits, are reported here. The ages range from about 80 to 40 Ma, with closely adjacent samples exhibiting very different ages. Interpretation of these results in the context of estimated closure temperatures for alunite and the geologic and tectonic evolution of Hispaniola does not lead to a simple conclusion about the age of mineralization. The simplest interpretation, that mineralization was caused by a buried Late Cretaceous (~80 Ma) intrusion, is complicated by lack of intrusions of this age in the area and absence of alteration in overlying limestone. The alternative interpretation, that mineralization was formed during Early Cretaceous (~110 Ma) magmatism and that the 40Ar/39Ar ages were completely reset by Late Cretaceous thrusting, is complicated by a lack of information on the timing and thermal effects of thrusting in central Hispaniola. Alunite studies have yielded similar unclear results in other pre-Cenozoic ore systems, notably those of the Lachlan fold belt in Australia

Analysis of adaptive responses of Pinus pinaster to changing environmental conditions in the Mediterranean region

Recent climate evolution studies highlight the progressive temperature increase and prevalence of seasonal drought, with specially incidence in the Mediterranean region. Although conifers are very important species regarding forest conservation, sustainability and productivity, given the large forest surface they cover in Spain and their active role in preventing soil erosion and desertification, we know little about the molecular mechanisms which control adaptation in this ancient taxonomic group

Intracellular gene transfer in action: Dual transcription and multiple silencings of nuclear and mitochondrial cox2 genes in legumes

The respiratory gene cox2, normally present in the mitochondrion, was previously shown to have been functionally transferred to the nucleus during flowering plant evolution, possibly during the diversification of legumes. To search for novel intermediate stages in the process of intracellular gene transfer and to assess the evolutionary timing and frequency of cox2 transfer, activation, and inactivation, we examined nuclear and mitochondrial (mt) cox2 presence and expression in over 25 legume genera and mt cox2 presence in 392 genera. Transfer and activation of cox2 appear to have occurred during recent legume evolution, more recently than previously inferred. Many intermediate stages of the gene transfer process are represented by cox2 genes in the studied legumes. Nine legumes contain intact copies of both nuclear and mt cox2, although transcripts could not be detected for some of these genes. Both cox2 genes are transcribed in seven legumes that are phylogenetically interspersed with species displaying only nuclear or mt cox2 expression. Inactivation of cox2 in each genome has taken place multiple times and in a variety of ways, including loss of detectable transcripts or transcript editing and partial to complete gene loss. Phylogenetic evidence shows about the same number (3–5) of separate inactivations of nuclear and mt cox2, suggesting that there is no selective advantage for a mt vs. nuclear location of cox2 in plants. The current distribution of cox2 presence and expression between the nucleus and mitochondrion in the studied legumes is probably the result of chance mutations silencing either cox2 gene.

Caracterização geocronológica (U-Pb), geoquímica e isotópica (Sr, Nd, Hf) do complexo Rio Capivari no terreno Embu

O Complexo Rio Capivari (CRC) é constituído por ortognaisses migmatíticos de composições graníticas a tonalíticas e anfibolitos subordinados (magmas toleíticos) em lascas tectônicas no Terreno Embu. As composições dos gnaisses do CRC são predominantemente cálcio-alcalinas a álcali-cálcicas. Idades U-Pb em núcleos de zircão com zoneamento oscilatório indicam cristalização magmática dos protólitos em três períodos principais 2.4, 2.2-2.1 e 2.0 Ga. Idades metamórficas foram reconhecidas em bordas de zircão totalmente escuras nas imagens de catodoluminescência e variam entre 620-590 Ma. A suíte sideriana (2.4 Ga) apresenta caráter juvenil, como evidenciado pelos valores positivos de \'\'épsilon\'\'IND.Nd\' (+3.8) e \'\'épsilon\'\'IND.Hf\' (+0.3 a +4.8) e pela ausência de núcleos de zircão herdado, comumente encontrados em rochas que sofreram retrabalhamento crustal. A suíte de idades riacianas (2.2-2.1 Ga) apresenta idades modelos TDM arqueanas (2.6-3.3 Ga), valores negativos de \'\'épsilon\'\'IND.Nd\' (-12.0 a -4.0) e negativos a levemente positivos de \'\'épsilon\'\'IND.Hf\' (-7.8 a +0.5). Portanto, tais rochas derivam de retrabalhamento de reservatórios crustais antigos. A suíte de idade orosiriana (2.0 Ga) apresenta fontes mais antigas e retrabalhadas com valores altamente negativos de \'\'épsilon\'\'IND.Nd\' (-10.4) e \'\'épsilon\'\'IND.Hf\' (-1.2 a -13.6), sugerindo prolongada residência crustal com idades modelo \'T IND.DM\' e \'T IND.Hf\' >3.3 Ga. As assinaturas de elementos traços em rocha total e a química de zircão sugerem fontes máficas para o gnaisse sideriano. Reservatórios de crosta média, mas de profundidades variáveis, parecem ser a principal fonte dos gnaisses riacianos e orosirianos. Análises em diagramas tectônicos discriminantes baseados em elementos traços de rocha total com elevadas razões \'La/Yb IND.(N)\' (>10), Nb/Yb (>2) e Th/Yb (>1), somados aos valores de \'Y IND.2\'\'O IND.3\' (<3000 ppm), U/Yb (>0.5) e Nb/Yb (0.01-0.10) da química de zircão, sugerem que ambas as suítes de idades foram geradas em ambientes de arco magmático continental, mas com um gap de 200-300 Ma entre o gnaisse sideriano e os gnaisses riacianos sem dados ou informações geológicas. Perfis multielementos (elementos traços) comparativos entre representação de amostras típicas de arco continental associado à subducção de crosta oceânica (margem andina) e amostras de arcos de ilha (Ilhas Mariana) confirmam afinidade com ambiente de arco continental para o CRC, associado à subducção de placa oceânica, principalmente para o gnaisse sideriano. Apesar de pouco representativo, devido ao número de amostras (n=1), uma acresção juvenil em 2.4 Ga colabora para uma dinâmica contínua da evolução da crosta continental. O papel desempenhado pelo CRC na evolução geral do Terreno Embu permanece enigmático. Os dados isotópicos de \'\'épsilon\'\'IND.Nd(590)\' e \'ANTPOT.87 Sr\'/\'ANTPOT.88 Sr IND.(i)\' do CRC (-27.3 a -19.7 e 0.704 a 0.722, respectivamente) indicam evolução temporal não compatível com o requerido para as fontes dos granitos ediacaranos do Terreno Embu, que exigem a participação de reservatórios mais primitivos (\'\'épsilon\'\'IND.Nd(590)\' -13 a -7) e empobrecidos em Rb (\'ANTPOT.87 Sr\'/\'ANTPOT.88 Sr IND.(i)\' \'\'QUASE IGUAL A\' 0,710).

Magnetostratigraphy and biostratigraphy of ODP Leg 105 sites and DSDP Hole 12-112

During Ocean Drilling Program (ODP) Leg 105, three sites (Sites 645 through 647) were drilled in Baffin Bay and the Labrador Sea to examine the tectonic evolution and the climatic and oceanic histories of this region. Biostratigraphic and magnetostratigraphic results vary at each site, while stratigraphic resolution depends on the limited abundance of marker species and the completeness of the paleomagnetic record. Because of the paucity of planktonic microfossils and the poor paleomagnetic record signatures, stratigraphic determinations at Site 645 often rely on defining minimum temporal constraints on specific samples or stratigraphic intervals. The completed stratigraphy indicates that the sedimentary sequence recovered at Site 645 is early Miocene to Holocene in age. The magnetostratigraphy and biostratigraphies are better defined at Sites 646 and 647 in the Labrador Sea. Site 646 generally contains a well-developed magnetostratigraphy and calcareous microfossil biostratigraphy. This biostratigraphy is based on calcareous nannofossils and planktonic foraminifers typical of the North Atlantic Ocean. Siliceous microfossils are also present at Site 646, but they are restricted to upper Pliocene through Holocene sediments. The stratigraphic sequence recovered at Site 646 is late Miocene to Holocene in age. Based primarily on the calcareous nannofossil stratigraphy, the sequence recovered at Site 647 consists of lower Eocene to lower Oligocene, lower Miocene, upper Miocene, and upper Pliocene through Holocene sediments. Three hiatuses are present in this sequence: the older hiatus separates lower Oligocene sediments from lower Miocene sediments, another hiatus separates lower Miocene sediments from upper Miocene sediments, and the youngest one separates upper Miocene from upper Pliocene sediments. A magnetostratigraphy is defined for the interval from the Gauss/Matuyama boundary through the Brunhes (Clement et al., this volume). Both planktonic foraminifers and siliceous microfossils have restricted occurrences. Planktonic foraminifers occur in Pliocene and younger sediments, and siliceous microfossils are present in lower Miocene and lower Oligocene sediments. The near-continuous Eocene through lower Oligocene sequence recovered at Site 647 allows the calcareous nannofossils and diatom stratigraphies at this site to act as a Paleogene stratigraphic framework. This framework can be compared with the stratigraphy previously completed for DSDP Site 112.

(Table 1) Organic carbon and radiogenic isotopes analysis of DSDP Hole 22-218 sediments

Modern erosion of the Himalaya, the world's largest mountain range, transfers huge dissolved and particulate loads to the ocean. It plays an important role in the long-term global carbon cycle, mostly through enhanced organic carbon burial in the Bengal Fan. To understand the role of past Himalayan erosion, the influence of changing climate and tectonic on erosion must be determined. Here we use a 12 Myr sedimentary record from the distal Bengal Fan (Deep Sea Drilling Project Site 218) to reconstruct the Mio-Pliocene history of Himalayan erosion. We use carbon stable isotopes (d13C) of bulk organic matter as paleo-environmental proxy and stratigraphic tool. Multi-isotopic - Sr, Nd and Os - data are used as proxies for the source of the sediments deposited in the Bengal Fan over time. d13C values of bulk organic matter shift dramatically towards less depleted values, revealing the widespread Late Miocene (ca. 7.4 Ma) expansion of C4 plants in the basin. Sr, Nd and Os isotopic compositions indicate a rather stable erosion pattern in the Himalaya range during the past 12 Myr. This supports the existence of a strong connection between the southern Tibetan plateau and the Bengal Fan. The tectonic evolution of the Himalaya range and Southern Tibet seems to have been unable to produce large re-organisation of the drainage system. Moreover, our data do not suggest a rapid change of the altitude of the southern Tibetan plateau during the past 12 Myr. Variations in Sr and Nd isotopic compositions around the late Miocene expansion of C4 plants are suggestive of a relative increase in the erosion of High Himalaya Crystalline rock (i.e. a simultaneous reduction of both Transhimalayan batholiths and Lesser Himalaya relative contributions). This could be related to an increase in aridity as suggested by the ecological and sedimentological changes at that time. A reversed trend in Sr and Nd isotopic compositions is observed at the Plio-Pleistocene transition that is likely related to higher precipitation and the development of glaciers in the Himalaya. These almost synchronous moderate changes in erosion pattern and climate changes during the late Miocene and at the Plio-Pleistocene transition support the notion of a dominant control of climate on Himalayan erosion during this time period. However, stable erosion regime during the Pleistocene is suggestive of a limited influence of the glacier development on Himalayan erosion.

Geology and landslide geomorphology of the Burpee Hills, Skagit County, Washington, USA

Landforms within the Skagit Valley record a complex history of land evolution from Late Pleistocene to the present. Late Pleistocene glacial deposits and subsequent incision by the Skagit River formed the Burpee Hills terrace. The Burpee Hills comprises an approximately 205-m-thick sequence of sediments, including glacio-lacustrine silts and clays, overlain by sandy advance outwash and capped by coarse till, creating a sediment-mantled landscape where mass wasting occurs in the form of debris flows and deep-seated landslides (Heller, 1980; Skagit County, 2014). Landslide probability and location are necessary metrics for informing citizens and policy makers of the frequency of natural hazards. Remote geomorphometric analysis of the site area using airborne LiDAR combined with field investigation provide the information to determine relative ages of landslide deposits, to classify geologic units involved, and to interpret the recent hillslope evolution. Thirty-two percent of the 28-km2 Burpee Hills landform has been mapped as landslide deposits. Eighty-five percent of the south-facing slope is mapped as landslide deposits. The mapped landslides occur predominantly within the advance outwash deposits (Qgav), this glacial unit has a slope angle ranging from 27 to 36 degrees. Quantifying surface roughness as a function of standard deviation of slope provides a relative age of landslide deposits, laying the groundwork for frequency analysis of landslides on the slopes of the Burpee Hills. The south-facing slopes are predominately affected by deep-seated landslides as a result of Skagit River erosion patterns within the floodplain. The slopes eroded at the toe by the Skagit River have the highest roughness coefficients, suggesting that areas with more frequent disturbance at the toe are more prone to sliding or remobilization. Future work including radiocarbon dating and hydrologic-cycle investigations will provide a more accurate timeline of the Burpee Hills hillslope evolution, and better information for emergency management and planners in the future.

Optimization of wireless power transfer via magnetic resonance in different media

A wide range of non-destructive testing (NDT) methods for the monitoring the health of concrete structure has been studied for several years. The recent rapid evolution of wireless sensor network (WSN) technologies has resulted in the development of sensing elements that can be embedded in concrete, to monitor the health of infrastructure, collect and report valuable related data. The monitoring system can potentially decrease the high installation time and reduce maintenance cost associated with wired monitoring systems. The monitoring sensors need to operate for a long period of time, but sensors batteries have a finite life span. Hence, novel wireless powering methods must be devised. The optimization of wireless power transfer via Strongly Coupled Magnetic Resonance (SCMR) to sensors embedded in concrete is studied here. First, we analytically derive the optimal geometric parameters for transmission of power in the air. This specifically leads to the identification of the local and global optimization parameters and conditions, it was validated through electromagnetic simulations. Second, the optimum conditions were employed in the model for propagation of energy through plain and reinforced concrete at different humidity conditions, and frequencies with extended Debye's model. This analysis leads to the conclusion that SCMR can be used to efficiently power sensors in plain and reinforced concrete at different humidity levels and depth, also validated through electromagnetic simulations. The optimization of wireless power transmission via SMCR to Wearable and Implantable Medical Device (WIMD) are also explored. The optimum conditions from the analytics were used in the model for propagation of energy through different human tissues. This analysis shows that SCMR can be used to efficiently transfer power to sensors in human tissue without overheating through electromagnetic simulations, as excessive power might result in overheating of the tissue. Standard SCMR is sensitive to misalignment; both 2-loops and 3-loops SCMR with misalignment-insensitive performances are presented. The power transfer efficiencies above 50% was achieved over the complete misalignment range of 0°-90° and dramatically better than typical SCMR with efficiencies less than 10% in extreme misalignment topologies.

Argon, uranium, thorium and lead composition and ages of ODP Leg 180 sites

During Ocean Drilling Program (ODP) Leg 180, 11 sites were drilled in the vicinity of the Moresby Seamount to study processes associated with the transition from continental rifting to seafloor spreading in the Woodlark Basin. This paper presents thermochronologic (40Ar/39Ar, 238U/206Pb, and fission track) results from igneous rocks recovered during ODP Leg 180 that help constrain the latest Cretaceous to present-day tectonic development of the Woodlark Basin. Igneous rocks recovered (primarily from Sites 1109, 1114, 1117, and 1118) consist of predominantly diabase and metadiabase, with minor basalt and gabbro. Zircon ion microprobe analyses gave a 238U/206Pb age of 66.4 ± 1.5 Ma, interpreted to date crystallization of the diabase. 40Ar/39Ar plagioclase apparent ages vary considerably according to the degree to which the diabase was altered subsequent to crystallization. The least altered sample (from Site 1109) yielded a plagioclase isochron age of 58.9 ± 5.8 Ma, interpreted to represent cooling following intrusion. The most altered sample (from Site 1117) yielded an isochron age of 31.0 ± 0.9 Ma, interpreted to represent a maximum age for the timing of subsequent hydrothermal alteration. The diabase has not been thermally affected by Miocene-Pliocene rift-related events, supporting our inference that these rocks have remained at shallow and cool levels in the crust (i.e., upper plate) since they were partially reset as a result of middle Oligocene hydrothermal alteration. These results suggest that crustal extension in the vicinity of the Moresby Seamount, immediately west of the active seafloor spreading tip, is being accommodated by normal faulting within latest Cretaceous to early Paleocene oceanic crust. Felsic clasts provide additional evidence for middle Miocene and Pliocene magmatic events in the region. Two rhyolitic clasts (from Sites 1110 and 1111) gave zircon 238U/206Pb ages of 15.7 ± 0.4 Ma and provide evidence for Miocene volcanism in the region. 40Ar/39Ar total fusion ages on single grains of K-feldspar from these clasts yielded younger apparent ages of 12.5 ± 0.2 and 14.4 ± 0.6 Ma due to variable sericitization of K-feldspar phenocrysts. 238U/206Pb zircon, 40Ar/39Ar K-feldspar and biotite total fusion, and apatite fission track analysis of a microgranite clast (from Site 1108) provide evidence for the existence of a rapidly cooled 3.0 to 1.8 Ma granitic protolith. The clast may have been transported longitudinally from the west (e.g., from the D'Entrecasteaux Islands). Alternatively, it may have been derived from a more proximal, but presently unknown, source in the vicinity of the Moresby Seamount.

Stratigraphic Architecture of Deep Sea Depositional Systems in the Southern Tyrrhenian Sea: Some Examples in the Ischia and Stromboli Volcanic Islands (Southern Italy)

The stratigraphic architecture of deep sea depositional systems has been discussed in detail. Some examples in Ischia and Stromboli volcanic islands (Southern Tyrrhenian sea, Italy) are here shown and discussed. The submarine slope and base of slope depositional systems represent a major component of marine and lacustrine basin fills, constituting primary targets for hydrocarbon exploration and development. The slope systems are characterized by seven seismic facies building blocks, including the turbiditic channel fills, the turbidite lobes, the sheet turbidites, the slide, slump and debris flow sheets, lobes and tongues, the fine-grained turbidite fills and sheets, the contourite drifts and finally, the hemipelagic drapes and fills. Sparker profiles offshore Ischia are presented. New seismo-stratigraphic evidence on buried volcanic structures and overlying Quaternary deposits of the eastern offshore of the Ischia Island are here discussed to highlight the implications on marine geophysics and volcanology. Regional seismic sections in the Ischia offshore across buried volcanic structures and debris avalanche and debris flow deposits are here presented and discussed. Deep sea depositional systems in the Ischia Island are well developed in correspondence to the Southern Ischia canyon system. The canyon system engraves a narrow continental shelf from Punta Imperatore to Punta San Pancrazio, being limited southwestwards from the relict volcanic edifice of the Ischia bank. While the eastern boundary of the canyon system is controlled by extensional tectonics, being limited from a NE-SW trending (counter-Apenninic) normal fault, its western boundary is controlled by volcanism, due to the growth of the Ischia volcanic bank. Submarine gravitational instabilities also acted in relationships to the canyon system, allowing for the individuation of large scale creeping at the sea bottom and hummocky deposits already interpreted as debris avalanche deposits. High resolution seismic data (Subbottom Chirp) coupled to high resolution Multibeam bathymetry collected in the frame of the Stromboli geophysical experiment aimed at recording seismic active data and tomography of the Stromboli Island are here presented. A new detailed swath bathymetry of Stromboli Island is here shown and discussed to reconstruct an up-to-date morpho-bathymetry and marine geology of the area, compared to volcanologic setting of the Aeolian volcanic complex. The Stromboli DEM gives information about the submerged structure of the volcano, particularly about the volcano-tectonic and gravitational processes involving the submarine flanks of the edifice. Several seismic units have been identified around the volcanic edifice and interpreted as volcanic acoustic basement pertaining to the volcano and overlying slide chaotic bodies emplaced during its complex volcano-tectonic evolution. They are related to the eruptive activity of Stromboli, mainly poliphasic and to regional geological processes involving the geology of the Aeolian Arc.

Tectonics of Central and Eastern California, Late Cretaceous to Modern

The Late Cretaceous to Modern tectonic evolution of central and eastern California has been studied for many decades, with published work generally focusing on specific geographic areas and time periods. The resulting literature leaves the reader, whether graduate student, faculty member, or layperson, wondering what a coherently integrated tectonic evolution might look like, or if it would be at all possible to undertake such a task. This question is the common thread weaving together the four studies presented in this work. Each of the individual chapters is targeted at a specific location and time period which I have identified as a critical yet missing link in piecing together a coherent regional tectonic story. In the first chapter, we re-discover a set of major west down normal faults running along the western slope of the southern Sierra, the western Sierra fault system (WSFS). We show that one of these faults was offset by roughly a kilometer in Eocene time, and that this activity directly resulted in the incision of much of the relief present in modern Kings Canyon. The second chapter is a basement landscape and thermochronometric study of the hanging wall of the WSFS. New data from this study area provide a significant westward expansion of basement thermochronometric data from the southern Sierra Nevada batholith. Thermal modeling results of these data provide critical new constraints on the early exhumation of the Sierra Nevada batholith, and in the context of the results from Chapter I, allow us to piece together a coherent chronology of tectonic forcings and landscape evolution for the southern Sierra Nevada. In the third chapter, I present a study of the surface rupture of the 1999 Hector Mine earthquake, a dextral strike slip event on a fault in the Eastern California Shear Zone (ECSZ). New constraints on the active tectonics in ECSZ will help future studies better resolve the enigmatic mismatch between geologic slip rates and geodetically determined regional rates. Chapter IV is a magnetostratigraphic pilot study of the Paleocene Goler Formation. This study provides strong evidence that continued investigation will yield new constraints on the depositional age of the only fossil-bearing Paleocene terrestrial deposit on the west coast of North America. Each of these studies aims to provide important new data at critical missing links in the tectonic evolution of central and eastern California.

Optimization of Wireless Power Transfer via Magnetic Resonance in Different Media

A wide range of non-destructive testing (NDT) methods for the monitoring the health of concrete structure has been studied for several years. The recent rapid evolution of wireless sensor network (WSN) technologies has resulted in the development of sensing elements that can be embedded in concrete, to monitor the health of infrastructure, collect and report valuable related data. The monitoring system can potentially decrease the high installation time and reduce maintenance cost associated with wired monitoring systems. The monitoring sensors need to operate for a long period of time, but sensors batteries have a finite life span. Hence, novel wireless powering methods must be devised. The optimization of wireless power transfer via Strongly Coupled Magnetic Resonance (SCMR) to sensors embedded in concrete is studied here. First, we analytically derive the optimal geometric parameters for transmission of power in the air. This specifically leads to the identification of the local and global optimization parameters and conditions, it was validated through electromagnetic simulations. Second, the optimum conditions were employed in the model for propagation of energy through plain and reinforced concrete at different humidity conditions, and frequencies with extended Debye's model. This analysis leads to the conclusion that SCMR can be used to efficiently power sensors in plain and reinforced concrete at different humidity levels and depth, also validated through electromagnetic simulations. The optimization of wireless power transmission via SMCR to Wearable and Implantable Medical Device (WIMD) are also explored. The optimum conditions from the analytics were used in the model for propagation of energy through different human tissues. This analysis shows that SCMR can be used to efficiently transfer power to sensors in human tissue without overheating through electromagnetic simulations, as excessive power might result in overheating of the tissue. Standard SCMR is sensitive to misalignment; both 2-loops and 3-loops SCMR with misalignment-insensitive performances are presented. The power transfer efficiencies above 50% was achieved over the complete misalignment range of 0°-90° and dramatically better than typical SCMR with efficiencies less than 10% in extreme misalignment topologies.

Subsidence history, thermal maturity, and structural inversion of the Greater Caucasus-Kura-Adjara-Trialeti basin system of central-eastern Georgia

This study aims at defining the tectonic evolution of a portion of the Caucasian region, in Georgia, which experienced a complex pattern of deformation events throughout Mesozoic and Cenozoic times. An integrated approach was applied to unravel the thermo-tectonic history of three inverted sedimentary basins from burial to exhumation. Additionally, this dissertation provides examples of structural inversion of sedimentary basins in response to far-field transmission of compressional stresses away from collision zones, contributing to elucidate the dynamics of stress partitioning during continental collisions. The Adjara-Trialeti fold-and-thrust belt in south-western Georgia results from the structural inversion of a Middle Eocene continental back-arc rift basin opened as a consequence of the Northern Neotethys slab rollback. This study quantitatively defines the subsidence and exhumation history of the Adjara-Trialeti basin, constraining its Middle Miocene inception of structural inversion. The western Kura Basin is a flexural foreland basin trapped between the Lesser Caucasus to the south and the Greater Caucasus to the north. This study constrains successive and competing episodes of flexural subsidence during Oligocene-Miocene times, followed by partial inversion through thick- and thin-skinned tectonics in response to continued convergence between the adjacent, oppositely verging orogenic belts. The Greater Caucasus results from the structural inversion of a Jurassic continental back-arc basin, but the timing of its growth is still debated. An across-strike transect in its southern central domain was studied, indicating that this sector of the Greater Caucasus experienced two phases of structural inversion during Late Cretaceous-Paleocene and Late Miocene times. Overall, the dataset presented in this dissertation points to a complex and episodic history of incremental deformation, characterised by successive phases of extensional and compressional tectonics which developed in response to sequential terrane accretion at the southwestern margin of Eurasia since Late Cretaceous times, eventually determining the current configuration of the Arabia-Eurasia collision zone.

Quantifying rates of landscape evolution and tectonic processes by thermochronology and numerical modeling of crustal heat transport using PECUBE

PECUBE is a three-dimensional thermal-kinematic code capable of solving the heat production-diffusion-advection equation under a temporally varying surface boundary condition. It was initially developed to assess the effects of time-varying surface topography (relief) on low-temperature thermochronological datasets. Thermochronometric ages are predicted by tracking the time-temperature histories of rock-particles ending up at the surface and by combining these with various age-prediction models. In the decade since its inception, the PECUBE code has been under continuous development as its use became wider and addressed different tectonic-geomorphic problems. This paper describes several major recent improvements in the code, including its integration with an inverse-modeling package based on the Neighborhood Algorithm, the incorporation of fault-controlled kinematics, several different ways to address topographic and drainage change through time, the ability to predict subsurface (tunnel or borehole) data, prediction of detrital thermochronology data and a method to compare these with observations, and the coupling with landscape-evolution (or surface-process) models. Each new development is described together with one or several applications, so that the reader and potential user can clearly assess and make use of the capabilities of PECUBE. We end with describing some developments that are currently underway or should take place in the foreseeable future. (C) 2012 Elsevier B.V. All rights reserved.

Mesozoic to recent evolution of the Andean forearc of northern Chile (22-24 s)

The Andean forearc of northern Chile comprises four morphotectonic units, which include from east to west: 1) The Cordillera de la Costa: composed of Jurassic granites and andesites, thought to represent a volcanic arc, the Mejillones terrane, an accreted allochthonous terrane, and the Lower Cretaceous Coloso basin, which formed through forearc extension along the suture between the Mejillones terrane and the Jurassic arc. Palaeomagnetic studies of the above units have identified approximately 29+/-11 degrees of clockwise rotation. Rotation is due to extension (caused by subduction roll back and slab pull), at an angle to the direction of absolute motion of the South American Plate. 2) The Central Depression: a large arid basin containing isolated fault-bounded blocks of pre-Mesozoic metamorphosed igneous rocks, Triassic sediments and volcanics, and Jurassic carbonates, deposited in a. back-arc basin setting. The isolated blocks formed through extension along previous thrust faults, these originated through compression of the back-arc basin due to accretion of the Jurassic volcanic arc. 3) The Precordillera.: composed of Permian-Triassic rift-related sediments and volcanics, Jurassic continental sediments synchronous with back-arc basin sedimentation, and Cretaceous and Oligo-Miocene continental sediments deposited in foreland basins. Palaeomagnetism has identified clockwise rotation in rocks ranging in age from Jurassic-Miocene. Rotation in the Precordillera. affected larger structural blocks than in the Cordillera de la Costa. 4) The Salar Depression: a. series of arid continental basins developed on continental crust. These basins nay have originated in the Triassic, when rifting of the South American craton is thought to have taken place. In conclusion, palaeomagnetic and geological evidence is consistent with the view that the north Chilean forearc was largely under an extensional stress regime. However, the presence of extensive compressional structures in Palaeocene and older rocks in the forearc together with the currently active foreland thrust belt of Argentina. indicate that throughout the evolution of the Andean Orogen, a delicate balance between compressional and extensional tectonic regimes has existed.