Mapping Earth Analogs from Photometric Variability: Spin-Orbit Tomography for Planets in Inclined Orbits

Aiming at obtaining detailed information of surface environment of Earth analogs, Kawahara & Fujii (2011) proposed an inversion technique of annual scattered light curves named the spin-orbit tomography (SOT), which enables one to sketch a two-dimensional albedo map from annual variation of the disk-integrated scattered light, and demonstrated the method with a planet in a face-on orbit. We extend it to be applicable to general geometric configurations, including low-obliquity planets like the Earth in inclined orbits. We simulate light curves of the Earth in an inclined orbit in three photometric bands (0.4-0.5um, 0.6-0.7um, and 0.8-0.9um) and show that the distribution of clouds, snow, and continents is retrieved with the aid of the SOT. We also demonstrate the SOT by applying it to an upright Earth, a tidally locked Earth, and Earth analogs with ancient continental configurations. The inversion is model independent in the sense that we do not assume specific albedo models when mapping the surface, and hence applicable in principle to any kind of inhomogeneity. This method can potentially serve as a unique tool to investigate the exohabitats/exoclimes of Earth analogs.Comment: 15 pages, 14 figures, 2 tables; published in The Astrophysical Journa

Multi-scale and uncertainty assessment of contractional thick-skinned structures in petroleum basins of the Andean back-arc

The study areas of this PhD thesis are located in the Peruvian and Argentinean Andean Back-Arc in South America. The thesis focuses on two major themes: firstly, on contractional thick-skinned tectonics (and related processes, regarding interplay and linkage of different structural styles); secondly, on multi-scale structural data integration and the quantification of uncertainty in kinematic restoration through forward modeling. Key scientific questions of this PhD thesis relate to the following: What controls the deformation styles in the Andean Back-Arc? How did the fractures in igneous rocks (hosted in thick-skinned structures) evolve in the greater tectonic context? How can uncertainty in kinematic restoration be quantified better? Data from numerous different sources was integrated and assessed. The data sources used herein, include 2D and 3D seismic data, well data, surface geology, satellite imagery, digital terrain data, earthquake focal mechanisms, drill core data and gravity-magnetics data. For the Santiago and Pachitea Basins (Peru), the analysis resulted in revised structural styles, improved structural architecture, new data on structural timing, new shortening amounts, new slip rates and an improved understanding of the interplay of different structural styles with particular emphasis on the impact of salt tectonics. For the Neuquén Basin (Argentina), a new evolutionary fracture model in oil producing igneous intrusions (sills), including improved reservoir characterization, was developed. For the Malargüe Anticline, also located in the Neuquén Basin, a novel workflow was developed, to quantify uncertainty quantification in kinematic restoration through forward modeling. In summary, highly variable tectonic response mechanisms are observed in the Andean Back-Arc. However, the impact of the mechanical stratigraphy appears to be more important and widespread than anticipated. Thick-skinned growth (with varying influence of salt tectonics) triggers thin-skinned thrusts. Alternating stress fields in the Back-Arc can explain complex fracture systems in brittle igneous rocks, where cooling fractures are overprinted by subsequent tectonic shearing motion. A newly developed forward modeling workflow allows for improved uncertainty quantification of thick-skinned contractional structures. This new workflow has various implications and should be tested by future researchers with various parameters simultaneously (e.g. through numerical modeling) and should be tested in other tectonic settings around the world, such as e.g. extensional or strike-slip settings

Potential Fossil Yield Classification (PFYC) Survey of Nevada Surficial Geology, and a Multi-Sensor, Remote Sensing, Change-Detection Study of Land-Use/Land-Cover Urbanization Impacting the Las Vegas Formation Located in Northwestern Las Vegas Valley

This thesis is a combination of two separate but related projects. The first project is a Potential Fossil Yield Classification (PYFC) survey. The PFYC is a Bureau of Land Management funded survey designed to synthesize paleontologic information into a geographic information system (GIS) as a distributable geodatabase. The database is designed to represent surficial geologic deposits contained in a polygon shapefile. Throughout the State of Nevada each polygon represents a mapped geologic unit at a scale of at least 1:250 k. Each mapped geologic unit is then assigned a “potential fossil yield classification”, a numerical ranking value of 1-5 based on the known fossils within a geologic unit. Fossil type and abundance are considered in the assignment of a PFYC value, 1 being the lowest, and 5 being the highest. The second project consists of a multi-temporal land-use/land-cover change detection analysis designed to measure effects of rapid urbanization within a geologic unit identified to have the highest fossil potential based on the results of the PFYC survey. The Las Vegas Formation (LVfm) is a Pleistocene groundwater discharge deposit that has been shown to contain significant vertebrate fossils, thus being assigned a PFYC value of 5. The proximity of the LVfm to the densely populated city of Las Vegas provides a unique opportunity quantify effects of urbanization to lands rich with fossil resources. This project is designed to utilize remotely sensed imagery and aerial light detection and ranging (LiDAR) point clouds to accurately quantify urbanization effect

Global distribution of modern shallow marine shorelines. Implications for exploration and reservoir analogue studies

Acknowledgments Support for this work came from the SAFARI consortium which was funded by Bayern Gas, ConocoPhillips, Dana Petroleum, Dong Energy, Eni Norge, GDF Suez, Idemitsu, Lundin, Noreco, OMV, Repsol, Rocksource, RWE, Statoil, Suncor, Total, PDO, VNG and the Norwegian Petroleum Directorate (NPD). This manuscript has benefited from discussion with Bruce Ainsworth, Rachel Nanson and Christian Haug Eide. Boyan Vakarelov and Richard Davis Jr. are thanked for their constructive reviews and valuable comments that helped to improve the manuscript.Peer reviewedPostprin

Tetrapod ichnology in Italy: the state of the art Guest editorial

This year, 2020, marks the 150th anniversary of the seminal work by Giulio Curioni (1870), representing the first published scientific contribution on tetrapod footprints from Italy. We took this opportunity to discuss the current state of the art on tetrapod ichnology in our country, with a jubilee volume, titled “Tetrapod ichnology in Italy: the state of the art”. The volume involves the scholars who first pioneered this discipline in Italy in the seventies of the last century, along with all the authors who have worked on the topic in recent decades, and younger generations who have just started to enthusiastically contribute to vertebrate ichnology. After briefly introducing the idea at the base of the Special Volume, as well as some aspects of the discipline and the current methodologies involved in ichnological studies, we present each of the contributions to serve the Italian ichnological heritage.Fil: Romano, Marco. Università di Roma; ItaliaFil: Citton, Paolo. Universidad Nacional de Río Negro. Sede Alto Valle. Instituto de Investigaciones en Paleobiología y Geología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Digital fault mapping and spatial attribute analysis of basement-influenced oblique extension in Passive margin settings

Oblique extension and passive margin segmentation may be attributed to the influence of basement structures. Pre-existing fabrics exert a strong control on the overall rift geometry in extensional settings, and can lead to the development of complex fault patterns, obliquely extending segments, deformation partitioning and transfer zones. In offshore settings, the nature of basement structure cannot easily be determined from seismic data, and onshore studies are increasingly used to assess basement controls. A digital mapping methodology GAVA (Geospatial Acquisition Visualisation and Analysis) has been developed to integrate regional- to outcrop-scale data. Digital field mapping methods using DGPS, Laser-Rangefinder and field-GIS are used to map faults to a dm- to mscale accuracy by collecting spatial co-ordinates on a handheld computer whilst traversing along or across the exposed fault systems. Benefits of digital mapping include: more rapid data collection and analysis; all data geospatially located and stored in a digital database; GIS-based analysis and visualisation techniques; digital data format enables direct comparison with fault arrays interpreted from seismic data. The GAVA workflow has been used to investigate three case studies on the North Atlantic Passive Margin: 1) NW Scotland; 2) Lofoten, NW Norway; and 3) Davis Strait, West Greenland. Each case study combines regional onshore and offshore mapping, using remote sensing and seismic interpretation, with detailed outcrop mapping of onshore fault exposures. Fault attributes (e.g. fault orientation, kinematics, fault linkage, fault-rock, overprinting relationships) observed at individual localities were collected in a GIS database. Kinematic fault analysis was carried out using strain inversion techniques at various scales. Spatial analysis was carried out using ArcGIS to identify relationships between various structures, while 3-D models were constructed in order to visualise these relationships over several orders of magnitude. Results show that the complexity of rifted margins may be linked to changes in the obliquity of pre-existing structures relative to the regional extension vector. However, direct reactivation of structures need not always occur. The influence of pre-existing structures may also lead to localized variations in stress/strain orientations, which if analyzed in isolation can indicate extension non-parallel to regional stresses. Therefore, spatial analysis and studies across a range of scales is essential when analyzing such zones. Digital (GIS) mapping methods are an ideal may to carry out such studies, although further development of analysis and visualisation tools for geosciences is required in the field of GIS

The Volcanic Development and Petroleum System Evolution of the Faroe-Shetland Basin.

The large volume of intrusive igneous material associated with volcanic rift margins introduces significant uncertainty to both hydrocarbon exploration and subsequent prospectivity. Understanding the habit, emplacement and distribution of such material in the context of rift evolution is essential to understanding the evolution of volcanic rift margins. The recent availability of high-quality 3D seismic data from the rift basins of the NE Atlantic Margin has enhanced our understanding of the 3D geometry and emplacement mechanisms of sill intrusions. Although how these intrusions fit within the wider margin context is often overlooked. The West of Shetland area provides an insight into the process of volcanic rift interaction in a petroleum prospective area. Using multi-client 2D and 3D seismic data this study places reservoir scale observations of sill morphology, distribution and sill-fault interactions within a wider basin context. The study demonstrates that the style and volume of sill intrusion is heavily influenced by the large scale basin structure, the position along the volcanic margin and small scale structural heterogeneities. Given the variations in sill size and frequency there are also implications for the bulk intrusive magma distribution across the margin. Predicting hydrocarbon prospectivity in frontier, or under-explored basins, is inherently uncertain. In order to reduce this uncertainty, sensitivity analysis is performed on key modeling input parameters to define a best practice workflow for undertaking basin modeling in the Faroe-Shetland Basin and similar passive continental margin settings. As the emplacement of igneous intrusions into sedimentary successions has been shown to locally elevate heat flow, the sill complex is incorporated into the regional 2D modeling to investigate the effect sill emplacement has on hydrocarbon prospectivity. The results highlight the importance of determining the timing of emplacement and the volume of igneous material when assessing the potential impact on maturation and generation of hydrocarbons. The modelling suggests that through an appraisal of sensitivity in areas of poor, limited or even absent data, such as frontier basins we can derive a more constrained basin modeling approach that reduces exploration uncertainty

ROLE OF INHERITANCES IN SHAPING THE ZAGROS THRUST AND FOLD BELT

The claim that a place has a unique geology is made often, and never incorrectly. The Zagros fold and thrust belt represents an exceptional example where different structural and stratigraphic inheritances co-exist along the same mountain range, playing a key role in determining the lateral variability of the thrust and fold belt. To the south-east, the Zagros mountains are limited by the Makran subduction zone. The subduction is pinned laterally by the continental collision of Arabia and Asia in the Straits of Hormuz area, where the Zagros and Oman chains meet. This zone of transition forms a major structural reentrant where the Zagros deformation front and the main Zagros thrusts converge. This boundary represents the eastern limit of the Hormuz salt basin, characterized by a minimum of two kilometers thick salt unit deposited during the Neoproterozoic-Cambrian times. The Hormuz salt province aerially extends for over 500 km toward the north-west along the Fars Province, where spectacular diapirism developed previously to the Zagros contractive event. Besides, the presence of an effective basal decollement resulted in a wide detached thrust and fold belt shaping the structural salient of the Fars arc. The northwestern-ward thinning and finally pinchout of the Hormuz salt is progressively taken over by the presence of the Mountain Front Flexure, a major structure of the Zagros orogenic system underlain by the deeply rooted and seismically active Mountain Front Fault system. These coupled structural features divide the belt from its foreland and their trace is sinuous, forming a sequence of salients and recesses, formally named, Dezful embayment, Lurestan arc and Kirkuk embayment. In this work we combine the interpretation of on-shore and off-shore seismic reflection profiles, field data, earthquake data, geomorphic analysis, and, remote sensing interpretations, to build a series of geological maps, 3D geological reconstructions, geological and balanced cross-sections, and, sequential restorations in the eastern Fars province and the Lurestan region. We provide new evidence from different structures of the Zagros fold-and-thrust belt, to stress the role of inheritances related with the previous rift architecture and the presence of the lateral facies change to the Hormuz salt sequence, as an important lateral variations of the mechanical properties of the multilayer, and a dramatic change in the structural style related with the pre-contractional Hormuz salt diapirism. In the Fars province we propose new interpretations for several on-shore and off-shore pre-contractional salt structures. Our evolutional models show how the deformation of inherited salt structures predates thrust wedging and leads to squeezing, roof arching, crestal extension and finally extrusion. Further shortening result on secondary welding as evidenced by the collapse of the extrusion summit dome and reverse faulting nucleated at the secondary welds. Regional cross sections across the eastern Hormuz salt pinch-out aim to understand the switch in structural style from a salt-detached thin- to thick-skinned thrusting. In the Lurestan region we introduce a new interpretation of an hyperextended margin architecture segmented by inherited N-S and NE-SW striking faults, in an alternance of more proximal or distal rift domains. The integration of our results with previous knowledge indicates that the Mountain Front Fault system developed in the necking domain of the Jurassic rift system, ahead of an array of inverted Jurassic extensional faults, in a structural fashion which resembles that of a crustal-scale footwall shortcut. Within this structural context, the sinusoidal shape of the Mountain Front Flexure in the Lurestan area arises from the re-use of the original segmentation of the inverted Jurassic rift system