Assessing the size of a former ocean of which only remnants are found in mountain belts is challenging but crucial to understanding subduction and exhumation processes. Here we present new constraints on the opening and width of the Piemont–Liguria (PL) Ocean, known as the Alpine Tethys together with the Valais Basin. We use a regional … Read more…
Porphyry copper (Cu) systems occur along magmatic belts derived in subduction zones. Our current under- standing of their formation is restricted to observations from the overriding plate, resulting in a knowledge gap in terms of processes occurring in convergence zones through time. An association between key tectonic processes and the timing and location of porphyry … Read more…
The driving mechanisms of Earth’s climate system at a multi-Myr timescale have received considerable attention since the 1980’s as they are deemed to control large-amplitude climatic variations that result in severe biogeochemical disruptions, major sea-level variations, and the evolution of Earth’s land- and seascapes through geological time. The commonly accepted mechanism for these changes derives … Read more…
Behnam Sadeghi from EarthByte Group has published a new paper in journal “Ore Geology Reviews”, based on his PhD thesis. In this research, to explore the VMS Cu deposits throughout Sweden a novel multifractal model of concentration-distance from centroids (C-DC) has been developed and applied to the till data provided by the Geological Survey of … Read more…
The existence of mantle plumes was first proposed in the 1970s to explain intra-plate, hotspot volcanism, yet owing to difficulties in resolving mantle upwellings with geophysical images and discrepancies in interpretations of geochemical and geochronological data, the origin, dynamics and composition of plumes and their links to plate tectonics are still contested. In a recently … Read more…
Dr. Behnam Sadeghi from EarthByte Group has published this paper recently in the journal “Geochemistry-Chemie der Erde” (Special Issue of “Mineral exploration: a journey from fieldwork, to laboratory work, computational modelling and mineral processing”). This research is part of a research project with the University of Neyshabur, which has been done in SE Iran. Abstract … Read more…
Behnam Sadeghi has published this paper in the Iranian Journal of Earth Sciences. In this research, he has developed an algorithm to down-scale the maps, to reduce the simulation time and the required memory, but to keep the same geostatistical performance and accuracy. This model strongly helps with huge and time-consuming simulations. Abstract In geochemical … Read more…
Carbonate accumulation rates (CAR) in the South Atlantic through time, with the average CCD for the South Atlantic shown in black, which the CCD in the Walvis Ridge/Rio Grande Rise area is shown in magenta. Deep-sea carbonate deposition is a complex process that is encapsulated in the carbonate compensation depth (CCD)—a facies boundary separating calcareous … Read more…
Weighting of BLEG data with drainage and catchment properties to enhance Au anomalies Dr. Behnam Sadeghi with Profs. Huseyin Yilmaz and Franco Pirajno, has published this paper in journal “Geochemistry/Chemie der Erde”, based on bulk leachable extractable gold (BLEG) data in Western Turkey, considering several other relevant parameters such catchments’ areas, slopes and curvatures plus … Read more…
Category-based fractal modelling: A novel model to integrate the geology into the data for more effective processing and interpretation Dr. Behnam Sadeghi and his PhD supervisor, Prof. David Cohen, has published another paper in Journal of Geochemical Exploration. This paper is based on his PhD thesis. In this research, they have proposed two novel fractal … Read more…
Long-lived, widespread intraplate volcanism without age progression is one of the most controversial features of plate tectonics. Previously proposed edge-driven convection, asthenospheric shear, and lithospheric detachment fail to explain the ~5000-km-wide intraplate volcanic province from eastern Australia to Zealandia. We model the subducted slab volume over 100 million years and find that slab flux drives … Read more…
The relationships between plate motions and basal mantle structure remain poorly understood, with some models implying that the basal mantle structure has remained stable over time, while others suggest that it could be shaped by the aggregation and dispersal of supercontinents. Here we investigate the evolution of mantle flow driven by end‐member plate tectonic models … Read more…
Modeling the Dynamic Landscape Evolution of a Volcanic Coastal Environment Under Future Climate Trajectories Kyle Manley, T. Salles and R. D. Müller As anthropogenic forcing continues to rapidly modify worldwide climate, impacts on landscape changes will grow. Olivine weathering is a natural process that sequesters carbon out of the atmosphere, but is now being proposed … Read more…
Abstract: Polymetallic nodules found on the abyssal plains of the oceans represent one of the slowest known geological processes, and are a source of critical and rare metals for frontier technologies. A quantitative assessment of their occurrence worldwide has been hampered by a research focus on the northeastern Pacific Ocean and the lack of a … Read more…
Abstract: Subduction is a fundamental mechanism of material exchange between the planetary interior and the surface. Despite its significance, our current understanding of fluctuating subducting plate area and slab volume flux has been limited to a range of proxy estimates. Here we present a new detailed quantification of subduction zone parameters from the Late Triassic … Read more…
Abstract: There are a significant number of image processing methods that have been developed during the past decades for detecting anomalous areas, such as hydrothermal alteration zones, using satellite images. Among these methods, dimensionality reduction or transformation techniques are known to be a robust type of methods, which are helpful, as they reduce the extent … Read more…
Abstract: Anomalous topographic swells and Cenozoic volcanism in east Africa have been associated with mantle plumes. Several models involving one or more fixed plumes beneath the northeastward migrating African plate have been suggested to explain the space-time distribution of magmatism in east Africa. We devise paleogeographically constrained global models of mantle convection and, based on … Read more…
Abstract: The complex and computationally expensive nature of landscape evolution models poses significant challenges to the inference and optimization of unknown model parameters. Bayesian inference provides a methodology for estimation and uncertainty quantification of unknown model parameters. In our previous work, we developed parallel tempering Bayeslands as a framework for parameter estimation and uncertainty quantification … Read more…
Abstract: Traditional approaches to develop 3D geological models employ a mix of quantitative and qualitative scientific techniques, which do not fully provide quantification of uncertainty in the constructed models and fail to optimally weight geological field observations against constraints from geophysical data. Here, using the Bayesian Obsidian software package, we develop a methodology to fuse … Read more…
Abstract: Reconstructions of past seafloor age make it possible to quantify how plate tectonic forces, surface heat flow, ocean basin volume and global sea-level have varied through geological time. However, past ocean basins that have now been subducted cannot be uniquely reconstructed, and a significant challenge is how to explore a wide range of possible … Read more…
Behnam Sadeghi has recently published a research paper in “Ore Geology Reviews”. This paper is based on one of the methods Behnam has developed in his PhD thesis. It is about a quite novel fractal model, named Concentration-Concentration (C-C), applied to geochemical anomaly classification. Also, in this paper Behnam has proposed a Bayesian framework, using … Read more…
Behnam Sadeghi has recently published a research paper about urban geochemistry in Cyprus, based on soil data, and using fractal models and statistical analysis. A part of this paper is from his PhD thesis. This is a collaborative project with the Geological Survey of Cyprus and UNSW School of Biological, Earth and Environmental Sciences. ABSTRACT: This … Read more…
Abstract: We present an updated oceanic crustal age grid and a set of complementary grids including spreading rate, asymmetry, direction and obliquity. Our dataset is based on a selected set of magnetic anomaly identifications and the plate tectonic model of Müller et al. (2019). We find the mean age of oceanic crust is 64.2 Myrs, … Read more…
Abstract: A major topic of debate in Earth and climate science surrounds the timing of closure of the Central American Seaway. While it is clear that the gateway was closed by ~2.8 Ma, recent studies based on geological and marine molecular evidence have suggested an earlier closing time of early to mid-Miocene. Here, we examine … Read more…
Abstract: Long-term variations in eustatic sea level in an ice-free world, which existed through most of the Mesozoic and early Cenozoic eras, are partly driven by changes in the volume of ocean basins. Previous studies have determined ocean basin volume changes from plate tectonic reconstructions since the Mesozoic; however, these studies have not considered a … Read more…
Abstract: Plate reconstructions since the breakup of Pangaea are mostly based on the preserved spreading history of ocean basins, within absolute reference frames that are constrained by a combination of age-progressive hotspot tracks and palaeomagnetic data. The evolution of destructive plate margins is difficult to constrain from surface observations as much of the evidence has … Read more…
A book chapter in: New Caledonia: Geology, Geodynamic Evolution and Mineral Resources. Geological Society, London, Memoirs, 51, 13–26, https://doi.org/10.1144/M51-2018-5 has finally been published. The book chapter, which gives a brief overview of the geodynamics of New Caledonia, was a collaboration between colleagues from New Caledonia, New Zealand, Australia and France. Abstract below: The SW Pacific … Read more…
Abstract: An International Ocean Discovery Program (IODP) workshop was held at Sydney University, Australia, from 13 to 16 June 2017 and was attended by 97 scientists from 12 countries. The aim of the workshop was to investigate future drilling opportunities in the eastern Indian Ocean, southwestern Pacific Ocean, and the Indian and Pacific sectors of the … Read more…
Abstract: The extraction of tectonic lineaments from digital satellite data is a fundamental application in remote sensing. The location of tectonic lineaments such as faults and dykes are of interest for a range of applications, particularly because of their association with hydrothermal mineralization. Although a wide range of applications have utilized computer vision techniques, a … Read more…
Abstract: Global sea level change can be inferred from sequence stratigraphic and continental flooding data. These methods reconstruct sea level from peri-cratonic and cratonic basins that are assumed to be tectonically stable and sometimes called reference districts, and from spatio-temporal correlations across basins. However, it has been understood that long-wavelength (typically hundreds of km) and low-amplitude … Read more…