Pliocene-Pleistocene sedimentary-tectonic development of the Mesaoria (Mesarya) Basin in an incipient, diachronous collisional setting: facies evidence from the north of Cyprus

AbstractThe Mesaoria (Mesarya) Basin exemplifies multi-stage basin development within a regional setting of diachronous continental collision. The Plio-Pleistocene represented a period of major sediment accumulation between two topographic highs, the Kyrenia Range in the north and the Troodos Massif in the south. During Pliocene time, open-marine marls and chalks of the Nicosia (Lefkoşa) Formation accumulated in a shelf setting. The Early Pleistocene period was characterized by a relative fall in sea level and a change to shallower-water bioclastic deposition of the Athalassa (Gürpınar) Formation. The northern margin of the basin was approximately delineated by the E–W neotectonic Ovgos (Dar Dere) fault zone. A carbonate ramp system formed directly to the south of this structural feature. During Early Pleistocene time, the basin evolved from an open-marine shelf to semi-enclosed lagoons with deltaic deposits, and finally to a non-marine aeolian setting, flanked by the rising Kyrenia Range to the north. Synthesis of geological evidence from the Mesaoria (Mesarya) Basin as a whole, including outcrop and borehole evidence from the south, adjacent to the Troodos Massif, indicates that the Pliocene – Early Pleistocene represented a relatively quiescent period. This intervened between Late Miocene – earliest Pleistocene southward thrusting–folding of the Kyrenia Range and Pleistocene intense surface uplift of both the Kyrenia Range and the Troodos Massif. The basin development reflects flexurally controlled collapse during Late Miocene – earliest Pliocene time related to southward thrusting, followed by strike-slip during westward tectonic escape of Anatolia, and finally regional uplift controlled by under-thrusting of continental crust from the south, as collision progressed.</jats:p

A new palaeogeographic model for the post-glacial marine and estuarine sediments of the Firth of the Forth, Scotland

This report provides an overview of the post-glacial sedimentary evolution of the Firth of the Forth during the late Quaternary. The superficial sediments of the Firth of the Forth vary in thickness from 10 m to nearly 150 m. An understanding the superficial sediments has uses for understanding geotechnical properties, for groundwater modelling and any potential geothermal energy sites. Therefore, this report aims to provide a preliminary understanding of the nature of the superficial sediments across the Firth of the Forth and wider controls of their deposition. The overall aim of this work is to understand the three-dimensional spatial distribution of superficial sediments across the Firth of Forth. The report is in two parts, firstly looking at the literature to develop a model for the post-glacial evolution of the Firth of the Forth and types of sediments that are expected. Secondly, using borehole records to look at the composition of the superficial sediments and assess the developed model. From the literature a palaeogeographic model for the Firth of the Forth was developed for the post-late glacial maximum (LGM) time. This model (testable hypothesis) describes eight major events and their topographic feature or sedimentary deposit. This model includes: 1) a post-glacial sea-level incursion; 2) collapse of the LGM ice sheet; 3) sea-level fall resulting in a local beach deposit; 4) fluvial/estuarine deposition; 5) Younger Dryas glaciation; 6) fluvial/estuarine deposition; 7) marine transgression; and 8) a marine regression. This model is based on data and interpretations from a combination of journal publications and BGS memoirs. The BGS held borehole records from across the entire Firth of the Forth are used to describe the composition and variability of the superficial sediments and test the literature-based model for the post-glacial evolution of the region. Although the borehole records are a relatively low resolution dataset they still provide the first information of the compositional make-up of the thickest sedimentary sequences across the Firth of the Forth. The data provided in geotechnical borehole records is an important stepping-stone toward further work, such as more detailed sedimentary interpretations from field work and new drilled core. Furthermore a useful outcome of further work would be a geotechnical classification of the highly variable superficial sediments across the Firth of Forth

Sedimentary response to the tectonic uplift of the Kyrenia Range, northern Cyprus, in its Eastern Mediterranean tectonic setting

The Kyrenia Range forms part of an approximately east-west lineament extending from northern Cyprus to southern Turkey. During Plio-Pleistocene the northern Cyprus segment of the lineament uplifted to ca. 1000 m above modern sea level. Plio- Pleistocene sediments document the uplift of the Kyrenia Range. A combination of sedimentology and a range of dating techniques including uranium series, optical stimulated luminescence (OSL), strontium isotopes and magnetostratigraphy are used to help understand the geological processes controlling uplift. Shallowing from a deepmarine basin to a shallow-marine, cool-water carbonate ramp represents the earliest uplift of the Kyrenia Range. The base of the carbonate ramp is made up of thick-bedded, benthic foraminiferal-rich grainstones, which are discontinuously overlain by calcareous red algal-rich rudstones. Erosively overlying this sequence is a coral- and molluscrich conglomerate, representing a short-lived relative sea-level fall. The upper part of the carbonate ramp sequence is composed of cross-bedded grainstone representing a shoreface environment. Interbedded with the upper grainstone facies are occasional fluvial conglomerates. The shallowing-upward marine environment represents the earliest emergence of the Kyrenia Range. After a major break in deposition, six marine and non-marine terraces (K0 to K5) reflect the sedimentary response to the main phase of tectonic uplift of the Kyrenia Range. The K0 terrace, the oldest and highest terrace, is composed of megabreccia and is interpreted as representing a major phase of rapid tectonic uplift. The K2-K5 terraces form a series marine to non-marine terraces on the northern flank of the range and also non-marine terraces on the southern flank of the range. The terraces on the northern flank each begin with a major marine transgression followed by a regressive sedimentary sequence. Marine environments range from nearshore open-marine below the storm-wave base, to shoreface, foreshore (beachrock), and backshore lagoonal environments. The non-marine environments range from aeolian dune to fluvial drainage systems. The fluvial systems are characterised by channelised debris-flow deposits interbedded with mudstones and palaeosols. The non-marine deposits on the southern flank of the range comprise a series of fluvial drainage systems. The fluvial systems on the southern flank of the range comprise a mixture of planar-bedded and channelised conglomerates, mudstones and aeolianites. Portable luminescence data are used to correlate quantitatively the K4 and K5 terraces on both the northern and southern flanks of the range. Each of the K4 and K5 terraces produce a unique luminescence signal, which is used as the basis for correlating the lower terraces. The unique luminescence signals of the K4 and K5 terraces are likely to be caused by varying sedimentary histories of the quartz and feldspar grains within the two terraces. The shallow-marine environments surrounding the Kyrenia Range prior to major uplift were dated using strontium isotopes and palaeomagnetism. The results of this dating suggest that marine environments persisted throughout the Early Pleistocene. U-series and OSL dating were used to date the K4 and K5 terraces on the northern flank of the range. The U-series results indicate that the marine deposits of the K4 terrace formed during several Middle Pleistocene interglacial stages. The OSL dating shows that the aeolian dunes of the K5 terrace formed during a Late Pleistocene glacial stage. The formation of the K2-K5 terraces was controlled by the interaction between tectonic uplift, climatic change and global eustatic sea-level change. The basal marine deposit of each terrace formed during an interglacial stage. Major fluvial deposition also occurs during the interglacial period as a result of a wetter climate. The inter-glacialglacial transition resulted in major fluvial erosion as a result of falling global sea-level. Aeolian carbonate deposition was dominant during the glacial stage, which represent arid climatic conditions. The only exception to this is the K4 terrace, which represents three glacial stages. The K1-K3 terraces can be correlated with the global sea-level curve suggesting approximate ages for each terrace, and ca. 600 ka for the entire K1- K5 terrace sequence. The Kyrenia Range underwent rapid uplift during the late Early Pleistocene at >1.2 mm/yr, followed by continuous but slower uplift during the Middle to Late Pleistocene. These results indicate that the uplift occurred in tandem with the Troodos Massif in southern Cyprus. The driving mechanism of the uplift of the Kyrenia Range is likely to be related to the collision of the Eratosthenes Seamount with the Cyprus trench to the south of the island. The seamount-trench collision resulted in compressional tectonics around Cyprus within the large-scale tectonic setting resulting from the early stages of convergence of the African and Eurasian plates

Data acquisition by digitizing 2-D fracture networks and topographic lineaments in geographic information systems: further development and applications

Understanding the impact of fracture networks on rock mass properties is an essential part of a wide range of applications in geosciences from understanding permeability of groundwater aquifers and hydrocarbon reservoirs to erodibility properties and slope stability of rock masses for geotechnical engineering. However, gathering high-quality, oriented-fracture datasets in the field can be difficult and time-consuming, for example, due to constraints on field work time or access (e.g. cliffs). Therefore, a method for obtaining accurate, quantitative fracture data from photographs is a significant benefit. In this paper we describe a method for generating a series of digital fracture traces in a geographic information system (GIS) environment, in which spatial analysis of a fracture network can be carried out. The method is not meant to replace the gathering of data in the field but to be used in conjunction with it, and it is well suited when field work time is limited or when the section cannot be accessed directly. The basis of the method is the generation of the vector dataset (shapefile) of a fracture network from a georeferenced photograph of an outcrop in a GIS environment. From that shapefile, key parameters such as fracture density and orientation can be calculated. Furthermore, in the GIS environment more complex spatial calculations and graphical plots can be carried out such as heat maps of fracture density. Advantages and limitations compared to other fracture network capture methods are discussed

Homomorphic encryption and database query privacy

Homomorphic encryption is a particular type of encryption method that enables computing over encrypted data. This has a wide range of real world ramifications such as being able to blindly compute a search result sent to a remote server without revealing its content. In the first part of this thesis, we discuss how database search queries can be made secure using a homomorphic encryption scheme based on the ideas of Gahi et al. Gahi’s method is based on the integer-based fully homomorphic encryption scheme proposed by Dijk et al. We propose a new database search scheme called the Homomorphic Query Processing Scheme, which can be used with the ring-based fully homomorphic encryption scheme proposed by Braserski. In the second part of this thesis, we discuss the cybersecurity of the smart electric grid. Specifically, we use the Homomorphic Query Processing scheme to construct a keyword search technique in the smart grid. Our work is based on the Public Key Encryption with Keyword Search (PEKS) method introduced by Boneh et al. and a Multi-Key Homomorphic Encryption scheme proposed by L´opez-Alt et al. A summary of the results of this thesis (specifically the Homomorphic Query Processing Scheme) is published at the 14th Canadian Workshop on Information Theory (CWIT)

Quaternary domains : glacial drowned valley estuaries

This report provides a new interpretation of ‘Glacial Drowned Valley Estuaries’ as part of an ongoing upgrade of the BGS Quaternary Domains dataset. Glacial Drowned Valley Estuaries are major buried features found across the coastal area of GB. These features represent a fluvial landscape that has been dissected and deepened by multiple glaciations to form valleys that are in-part situated beneath modern sea-level. These buried glacial valleys have been and continue to be infilled with marine and estuarine sediment and are overlain by complex or fjord-type estuaries. They typically contain significant thicknesses of superficial sediment of up to 160 m and are often associated with major cities, ports, or industrial centres. Consequently, these features have important groundwater and engineering implications. This work uses a range of national-scale data sets to identify and map Glacial Drowned Valley Estuaries across GB. The identified Glacial Drowned Valley Estuaries are all in Scotland and occur north of the maximum known extent of Late Devensian glacial ice. The infill sequence predominantly comprises clay and silt with variable proportions of sand, gravel, and peat. The sediments are interpreted as glacial till, post-glacial marine and Holocene-aged estuarine sediments. The mapped extent of post-glacial marine sediment and key isostatically uplifted shorelines are used to define the boundary of the Glacial Drowned Valley Estuaries

Gneiss, fractures and saprolite: field geology for hydrogeology of the central Cauvery Catchment, south India

This report describes the geological observations and interpretations made following two reconnaissance field trips in October 2017 and April 2018 by Maarten Krabbendam and Romesh Palamakumbura, in the central Cauvery catchment in South India. The goal of the reconnaissance was to provide geological constraints to hydrogeological modelling to be undertaken as part of the UPSCAPE Project. The main geological constraints dealt with are fractures and the character of the regolith

New exposed section in the Ardersier Silts Formation : November 20th-21st, 2017

This report provides an overview of field observations from a two day visit to an exposed trench section through the Ardersier Silts Formation that crop out in the moraine that forms the Lateglacial cliffline, near the village of Ardersier in the Highlands Region of north-east Scotland. This section is within the SSSI site for the contorted silts of Ardersier, which are exposed in a nearby cliff face. The trench section exposed nearly 10 m of interbedded silts, sands and gravels and occasional clay veins. The trench section, which was continuous, was divided into upper, middle and lower portions for ease of description. The upper part of the section comprises a gravel and fine to medium-grained light brown to grey-coloured sand with lamination and occasional planar cross-bedding. This unconformably overlies a fine to medium-grained sand with planar cross bedding. The middle part of the section comprises a fine-grained sand with well-developed multiple beds of sand showing parallel lamination, planar-crossbedding and minor reverse faulting. In addition, relatively small (1–5 cm thick) sub-horizontal to sub-vertical clay veins cut through the entire sequence. The lower part of the section comprises a fine to medium-grained sand with massive clay veins and brecciation of the sand within the veins. The blocks of sand vary from centimetres to metres in size. The clay veins also vary in width from 2 cm to nearly 40 cm. Throughout the section are well-preserved fluid oxidising pathways. These both follow bedding and are displaced across bedding, by small-scale faulting and by fluid migration fronts. They form complex anastomosing networks of staining and occasional concentrations of silt and clay. Generally, the oxidising fluids appear to have migrated along the clay veins and diffused into the surrounding sand. Structural measurements from the largest and most prominent clay veins indicate that they are all of broadly similar dip and orientation. This may indicate that they all formed as a result of the same phase of fluid movement and glaciotectonic displacement that took place during the formation of the moraine. The upper portion of the newly exposed section, exhibits many of the features previously described from the sands exposed beneath the Baddock Till at the Hillhead Section, whereas the middle and lower parts resemble the sediments and structures that exposed within the Ardersier Silts Formation, beneath the Baddock Till, in the Jamieson’s Pit section. The well-exposed sedimentary structures within the sediments of the Ardersier Silts Formation are interpreted as a coastal shallow marine setting. The well-preserved hydrofracture network within the section demonstrates the diverse range of glacial deformation that occurred during deglaciation. It is likely that the hydrofracture network developed as consequence of ice-push and possibly glacial over-riding during the deglaciation of the Moray Firth ice-stream