Marine geology and geophysics

la presente publicación describe algunos aspectos relevantes desde los puntos de vista jurídico, técnico y científico para que el Ecuador sea parte del ordenamiento jurídico de los mares,  y luego de conocer todas las ventajas, se adhiera bajo las condiciones favorables para los intereses marítimos nacionales a esta convención, y así poder, bajo este marco extender la plataforma continental más allá de las 200 millas marinas en las cordilleras submarinas de Carnegie, Cocos y Colón adyacentes.
para Ecuador, país miembro de la Comisión del pacífico sudoeste, es un acto importante en la evolución del derecho internacional marítimo, pues la declaración de santiago de 1952 marcó un hito histórico en la extensión de los derechos soberanos de los estados, que en el año 1982, se proclamó mundialmente como Zona Económica Exclusiva (ZEE). Esta visión ha permitido avanzar en el desarrollo de nuestro país marítimo que posee una potencialidad en su suelo y subsuelo marino para extender su plataforma continental a partir de las islas Galápagos, considerando que su morfología submarina proviene de un paleo recorrido del punto caliente, elemento geológico contribuyente en la evolución y desarrollo de las islas Galápagos, las cuales son parte de la plataforma insular ecuatoriana y como tal, son elementos constitutivos por su continuidad geológica, es por tanto que las cordilleras de Cocos, Colón y Carnegie adyacentes tienen similares características geológicas a las islas y pueden a través del artículo 76 de la ConVEMAr extender su plataforma más allá de las 200 millas náuticas.
desde el punta de vista geológico la relación de origen del producto de una interacción del centro de divergencia sobre el punto caliente en diferentes periodos geológicos, provoca el mayor magnetismo en la Cordillera de Carnegie durante un lapso inicial de formación de hace 20 millones hasta hace 11 millones de años en el flanco Este, posterior a ello un salto hacia el norte del centro de divergencia sobre el punto caliente provocó la montura en el centro de esta cordillera en el flanco oeste y la actual ubicación del centro de divergencia sobre el punto caliente que presenta la configuración de la plataforma de Galápagos; es por tanto, este activo magnetismo diferente de corteza de las cuencas adyacentes de panamá y pacífico como la principal evidencia física de una continuidad y un derecho para que se extienda la plataforma más allá de las 200 mn.
desde el punto de vista técnico, sustentar los derechos históricos y circunstanciales especiales, que son la base del trazado de nuestro sistema de líneas de base, ha sido el fundamento para trazar nuestro espacio marítimo desde 1951 y que sirvieron para promulgar nuestros espacios marítimos en concordancia con la ConVEMAr. El aporte de ésta publicación permitirá conocer los derechos existentes en nuestro mar y con ello poder realizar una correcta administración de los recursos vivos y no vivos existentes en nuestros espacios marítimos.

In contrast to the use of marine seismic reflection techniques for reservoir-scale applications, where seismic inversion for quantitative sediment analysis is common, shallow-water, very-high-resolution seismic reflection data are seldom used for more than qualitative reflection interpretation. Here, a quantitative analysis of very-high-resolution marine seismic reflection profiles from a shallow- water (<50 m water depth) fjord in northern Norway is presented. Acquired using Sparker, Boomer, and Chirp sources, the failure plane of multiple local landslides correlates with a composite reflection that reverses polarity to the south. Using a genetic algorithm, a 1D post-stack acoustic impedance inversion of all three profiles is performed, calibrating against multi-sensor core logger (MSCL) data from cores. Using empirical relationships the resulting impedance profiles are related to remote sediment properties, including: P-wave velocity; density; mean grain size; and porosity. The composite reflector is consistently identified by all three data sources as a finer-grained (by one Phi), lower density (c. 0.2 g/cm3 less than background) thin bed, with an anomalous low velocity zone (at least 100 m/s lower than background) associated with the polarity reversal to the south. Such a velocity contrast is consistent with an accumulation of shallow free gas trapped within the finer- grain, less permeable layer. This study represents the first application of acoustic impedance inversion to very-high-resolution seismic reflection data and demonstrates the potential for directly relating seismic reflection data with sediment properties using a variety of commonly used shallow seismic profiling sources.

The aim of this study is to assess the global occurrence of large submarine canyons to provide context and
guidance for discussions regarding canyon occurrence, distribution, geological and oceanographic significance
and conservation. Based on an analysis of the ETOPO1 data set, this study has compiled the first inventory of
5849 separate large submarine canyons in the world ocean. Active continental margins contain 15% more
canyons (2586, equal to 44.2% of all canyons) than passive margins (2244, equal to 38.4%) and the canyons are
steeper, shorter, more dendritic and more closely spaced on active than on passive continental margins. This
study confirms observations of earlier workers that a relationship exists between canyon slope and canyon
spacing (increased canyon slope correlates with closer canyon spacing). The greatest canyon spacing occurs in
the Arctic and the Antarctic whereas canyons are more closely spaced in the Mediterranean than in other
areas.
River-associated, shelf-incising canyons are more numerous on active continental margins (n=119) than on
passive margins (n=34). They are most common on the western margins of South and North America where
they comprise 11.7% and 8.6% of canyons respectively, but are absent from the margins of Australia and
Antarctica. Geographic areas having relatively high rates of sediment export to continental margins, from
either glacial or fluvial sources operating over geologic timescales, have greater numbers of shelf-incising
canyons than geographic areas having relatively low rates of sediment export to continental margins. This
observation is consistent with the origins of some canyons being related to erosive turbidity flows derived
from fluvial and shelf sediment sources.
Other workers have shown that benthic ecosystems in shelf-incising canyons contain greater diversity and
biomass than non-incising canyons, and that ecosystems located above 1500 m water depth are more
vulnerable to destructive fishing practices (bottom trawling) and ocean acidification caused by anthropogenic
climate change. The present study provides the means to assess the relative significance of canyons located in
different geographic regions. On this basis, the importance of conservation for submarine canyon ecosystems
is greater for Australia, islands and northeast Asia than for other regions.

Small, low cost Autonomous underwater vehicles (AUVs) provide ideal platforms for shallow water survey, as they are capable of unmanned navigation and can be programmed to acquire data at constant depth, or constant altitude above the seabed. AUVs can be deployed under most sea states and are unaffected by vessel motions that often degrade sonar and magnetometer data quality. The integration of sonar and magnetometer sensors on AUV’s is challenging, however, due to limited payload and strong magnetic fields produced by the vehicle motor.
In this study, a Marine Magnetics Explorer Overhauser magnetometer was mated to a portable AUV (OceanServer Iver2) creating the first practical AUV- deployed magnetic survey system. To eliminate magnetic interference from the AUV, the magnetometer was tethered to the AUV with a 5 m tow cable, as determined by static and dynamic instrument testing. The results of the magnetic tests are presented, along with field data from a shallow water test area in Lake Ontario near Toronto, Canada. AUV-acquired magnetic survey data were compared directly with a conventional boat-towed magnetic survey of the same area. The AUV magnetic data were of superior quality despite being collected in rough weather conditions that would have made conventional survey impossible. The resulting high-resolution total magnetic intensity and analytic signal maps clearly identify several buried and surface ferrometallic targets that were verified in 500-kHz side- scan sonar imaging and visual inspection by divers.

Наред с интензивното развитие на дистанционните методи и дигиталната фотограметрия, приложението на безпилотните летателни системи (БЛС) предоставя отлични възможности за прецизни измервания на Българската черноморска крайбрежна зона (БЧКЗ), чието интегрално картографиране включва и подводния брегови склон в качеството му на неделима част от БЧКЗ. Разнообразието от абразионен, акумулативен и техногенен бряг предоставя възможност за тестване на набор от подходи за заснемане на БЧКЗ с различни типове БЛС, което от своя страна улеснява избора на най-подходяща методика в съответствие с типа бряг и неговите пространствени характеристики. С настоящата статия се цели да се демонстрира методика за заснемане с БЛС и генериране на дигитални модели на релефа, съчетани с растерни ортомозайки с разделителна способност под 5 cm на базата на изображения от БЛС, които са основополагащи за изследване на силно изменчиви форми на бреговия и дънния релеф. Подробно са описани методиката на заснемане, процедурите по обработка на получените данни и генерирането на интегрален теренен модел на сушата и подводната част от бреговата зона. На примера на два представителни района от БЧКЗ са дадени анализ и интерпретация на геоморфоложката пространствена структура.

Along with the intensive development of remote sensing and digital photogrammetry, the application of Unmanned Aerial Systems (UAS) provides excellent opportunities for high-precision surveys of the Bulgarian Black Sea coastal zone (BBSCZ). The integrity of these photomapping studies requires inclusion of the submarine coastal slope, as it represents an indivisible part of the BBSCZ. The combination of erosional/abrasional, depositional and technogenic types of coast allows for testing various surveying approaches using different types of drones, thus facilitating the selection of the most suitable methodology depending on the particular location and its spatial properties. The aim of the present article is to demonstrate a methodology for the extraction of digital surface models and raster orthomosaics with ground resolution finer than 5 cm from drone imagery data. These geospatial products represent a fundamental prerequisite for studying highly erratic coastal land- and bedforms. The photomapping and subsequent data processing workflow for the extraction of an integral digital terrain model, covering both the terrestrial and underwater sectors of the coastal zone, are thoroughly described herein. The interpretative analysis of the spatial geomorphic pattern is exemplified for two representative case study sites within the BBSCZ.

Crustal rheology controls the style of rifting and ultimately the architecture of rifted margins. Here we review the formation of three magma-poor margin pairs, Iberia-Newfoundland, the central segment of the South Atlantic Rift, and the South China Sea by integrating observational data into a numerical forward modelling framework. We utilise a 2D version of the finite element code SLIM3D, which includes nonlinear temperature-and stress-dependent elasto-visco-plastic rheology and is able to reproduce a wide range of rift-related deformation processes such as flexure, lower crustal flow, and faulting. Extension in cold, strong, or thin crust is accommodated by brittle faults and ductile shear zones that facilitate narrow rifts with asymmetric fault geometries. Hot, weak, or thick continental crust is dominated by ductile deformation and often extends symmetrically into a wide rift system. This simple recipe provides the standard framework to understand initial rift geometry, however, it is insufficient to account for the dynamics of intermediate and late rift stages that shape the final margin architecture. Asymmetric conjugate margins where one side is wide and the other narrow can be formed via both wide and narrow rift styles, which we reproduce with weak and strong crustal rheologies, respectively. Exemplified by the Iberia-New-foundland conjugates and the Central South Atlantic, we define three characteristic rift phases: an initial phase of simultaneous faulting, an intermediate phase of rift migration that involves sequential fault activity, and finally, the breakup phase. Crustal rheology plays an overarching role in governing the dynamics of these asymmetric margins: we illustrate that weak rheologies generally prolong the phase of simultaneous faulting, while rift migration is enabled by initial fault asymmetry as well as relatively weak crust. Formation of the predominantly symmetric and wide margins of the South China Sea was controlled by extraordinarily weak crust that extended the phase of simultaneous faulting until breakup. The weak crustal rheology of this region relates to the South China Sea's pre-rift history where plate convergence lead to crustal thickening and magmatic additions in a back-arc regime shortly before the onset of rifting.

Salt water intrusions of marine origin are a major cause of contamination for coastal fresh water aquifers. They are generated mainly by the uncontrolled exploitation of fresh water in pumping stations from coastal areas. In Romania, such marine intrusions have occurred in the southern part of Black Sea's coastline, in the area of Vama Veche and Costineşti resorts, contaminating the main aquifers which are hosted within Sarmatian (late Middle Miocene) lumachelic and oolitic limestones. Fresh water exploitation management requires the identification, mapping and monitoring of marine intrusions. These are achievable by means of an adequate application of geoelectrical methods, because sea water intrusions lead to major variations of the aquifers resistivity. Apparent resistivity surveys such as electrical profiling and vertical electrical sounding (VES) are able to delineate the areal extent of these intrusions and to identify the approximate depth of the fresh water/salt water interface. Assuming the subsurface geology consists of horizontal and homogeneous layers, the VES apparent resistivity data can be interpreted in terms of layer thicknesses and true resistivities, i.e. a one-dimensional (1-D) geoelectrical model with a stepwise variation of true resistivity with depth. The optimal model is obtained by repeated forward modeling trials or through the inversion of measured apparent resistivities.
This paper presents an algorithm and a set of software applications for the forward modeling of VES apparent resistivity curves, by using digital linear filtering. The codes were elaborated in MATLAB programming environment and allow the calculation of the theoretical VES response for horizontally-layered geological media with virtually unlimited number of layers, including layers with a quasi-continuous resistivity variation. The latter option can be used to simulate particular hydrogeological situations regarding the sea water intrusions in fresh water aquifers, which often show a mixing/transition zone of variable salinity and resistivity. The interpretation of VES curves recorded in Vama Veche area by using the elaborated software indicates that the sea water intrusion occurs at more than 50 m depth. This agrees with water wells tests which confirm the presence of salt water at 40–60 m depth in that area.

The Andaman-Nicobar Accretionary Ridge forms the eastern boundary of the Bay of Bengal and is presently being constructed by accretion and underplating of sediments offscraped from the obliquely colliding Bengal Fan. Net accretion is relatively low (~28%) with the rest subducted mostly into the upper mantle. Although subduction initiated along the margin at ~95 Ma, large-scale subduction accretion likely accelerated during the Early Miocene by which time wedge top basins had formed. Prior to that time sediment offscraped against the ophiolitic backstop was probably derived from the adjacent magmatic arc of Burma during the Eocene, as well as some erosion of continental sources, probably from the Sibumasu Block, which forms the western edge of Sundaland. The scale of this accretion was small and potentially interrupted by times of tectonic erosion during the Palaeogene. The influence of continental erosion increased into the Oligocene, potentially accompanied by modest flux from the Indus-Yarlung Suture via the Irrawaddy River. Drainage capture in eastern Tibet in the Early Miocene and opening of the Andaman Sea, probably in the Late Miocene, has removed these source areas to the Andaman Trench.

Marine geohazard research has developed during recent decades, as human activities intensified towards deeper waters. Some recent disastrous events (e.g., the 2004 Indian Ocean and 2011 Japan tsunamis) highlighted geohazards socioeconomic impacts. Marine geohazards encompass an extensive list of features, processes, and events related to Marine Geology. In the scientific literature there are few systematic reviews concerning all of them. Using the search string
‘geohazard*’, this bibliometric-based review explored the scientific databases Web of Science and Scopus to analyze the evolution of peer-reviewed scientific publications and discuss trends and future challenges. The results revealed qualitative and quantitative aspects of 183 publications and indicated 12 categories of hazards, the categories more studied and the scientific advances. Interdisciplinary surveys focusing on the mapping and dating of past events, and the determination of triggers, frequencies, and current perspectives of occurrence (risk) are still scarce. Throughout the upcoming decade, the expansion and improvement of seafloor observatories’ networks, early
warning systems, and mitigation plans are the main challenges. Hazardous marine geological events may occur at any time and the scientific community, marine industry, and governmental agencies
must cooperate to better understand and monitor the processes involved in order to mitigate the resulting unpredictable damages.

The aim of the research work is to prepare geomorphological map for land use planning with the help of remotely sensed data of Ishwardi Upazila in Pabna district northwestern part of Bangladesh. About 246.9 sp. km area was mapped from satellite images (spot and Landsat TM) in the scale 1:50000 with the increase of population, this area is expanding rapidly without sustainable planning. Everywhere new structures are being constructed ignoring the existing urbanization regulation, commerce, trade, administration and other municipal facilities. Unplanned urbanization and town development without considering morphogeological and engineering information creates the geo environmental problem that hinders sustainable development of an area. Keeping this view in mind morphogeological mapping is carried out in the study area to provide geo-scientific information for future development.

The mapped area is underlain by part of the Padma River flood plain and the old Ganges flood plain (i.e., Barind Tract) and shows a distinct boundary between these two major land-forms. The deposits are divided into seven map units: five on the flood plain of Atrai River and two over the Pleistocene Barind Tract, Active channel deposit, abandoned channel deposit, Natural Levee Deposits, Floodplain deposits.

The land use map has also been prepared with the help of morphological maps using spot panchromatic satellite image, soil map and field data, and these are designated as elements 1,2,3,4,5.

The Western Continental Margin of India (WCMI) has evolved as a result of two stage rifting and breakup events, the first one between India and Madagascar during the mid Cretaceous, and the second event between India and Seychelles during the late Cretaceous. Detailed seismic studies by earlier workers in the offshore margin confirm that it is a poly-rift margin with significant volcanic emplacements, and on the basis of these datasets; the western margin was classified as volcanic. In the present study, constrained potential field modeling of four profiles across the western offshore region revealed that the eastern basin comprising of Laxmi and Laccadive basins as well as the adjoining Laxmi and the Laccadive ridges are underlain by the extended continental crust and has been punctured by several magmatic intrusions. The models further suggest that the Continent-Ocean Boundary (COB) lies to the west of Laccadive and Laxmi ridges, and also in the southern part of Laccadive basin. In this paper, we presented highresolution seismic images at the margin that have revealed the presence of deeper sedimentary strata below the K/T flood-basalts and provided detailed interpretation of few sections belonging to a 3D seismic block in the deepwater Kerala-Konkan offshore. The sections reveal numerous features such as the sag basin, fractures, faults and folding below the basaltic top. Further, significant sedimentary wedges terminating against the volcanic highs are inferred to be the Mesozoic sub-basalt plays. The interpreted crustal transects, the inferred combination of tectono-magmatic processes and the probable occurrence of sub-basalt sediments at the margin are analyzed and encapsulated to provide a basis for assessing deepwater petroleum prospectivity of the entire western margin offshore.

Computational underwater image analysis is developing
into a mature field of research, with an increasing number
of companies, academic groups and researchers showing interest
in it. While on the one hand, the basic question is addressed by
many groups, how algorithms can be applied to automatically
detect and classify objects of interest (OOI) in underwater image
footage, on the other hand the questions for efficiency and
performance, i.e. the time a computer (or a compute cluster)
needs to perform this task, has received much attention yet.
In this paper we will show, how nowadays methods for high
performance computing like parallelization and GPU computing
via CUDA (Compute Unified Device Architecture) can be used to
achieve both, image enhancement and segmentation in less than
0:2 sec per image (4224 x 2376 pixel) on average, which paves
the way to real time online applications.

In this study, a buckler crab, Cryptopodia angulata, reported for the first time from Majali, Karwar, West coast of India. This species occurs rarely in the Indian coastal waters and this is the first report from Karwar coast. External characters have been photographed and examined.

The Cauvery–Palar basin is a major peri-cratonic rift basin located along the Eastern Continental Margin of India (ECMI) that had formed during the rift-drift events associated with the breakup of eastern Gondwanaland (mainly India–Sri Lanka–East Antarctica). In the present study, we carry out an integrated analysis of the potential field data across the basin to understand the crustal structure and the associated rift tectonics. The composite-magnetic anomaly map of the basin clearly shows the onshore-to-offshore structural continuity, and presence of several high-low trends related to either intrusive rocks or the faults. The Curie depth estimated from the spectral analysis of offshore magnetic anomaly data gave rise to 23 km in the offshore Cauvery–Palar basin. The 2D gravity and magnetic crustal models indicate several crustal blocks separated by major structures or faults, and the rift-related volcanic intrusive rocks that characterize the basin. The crustal models further reveal that the crust below southeast Indian shield margin is ∼36 km thick and thins down to as much as 13–16 km in the Ocean Continent Transition (OCT) region and increases to around 19–21 km towards deep oceanic areas of the basin. The faulted Moho geometry with maximum stretching in the Cauvery basin indicates shearing or low angle rifting at the time of breakup between India–Sri Lanka and the East Antarctica. However, the additional stretching observed in the Cauvery basin region could be ascribed to the subsequent rifting of Sri Lanka from India. The abnormal thinning of crust at the OCT is interpreted as the probable zone of emplaced Proto-Oceanic Crust (POC) rocks during the breakup. The derived crustal structure along with other geophysical data further reiterates sheared nature of the southern part of the ECMI.

Over the last decades, human impact on the coastal and marine environment has reached unprecedented levels. In order to mitigate this impact, it is necessary to facilitate the integrated management of the marine environment and to optimize maritime spatial planning, so an improvement of our knowledge of the seabed and dynamics of the processes in the coastal zone is needed. The specific transitional character between the land and the sea suggests a complex analysis of the land-based processes affecting the marine area. Integration of data from swath bathymetry and airborne LiDAR scanning allow us to create a general digital model of the terrain and seafloor relief with a cell size of 3 m for the area between Sozopol and Tsarevo and to understand the coastal morphology in details. Combining the terrain model with sonar mosaics , orthophoto images and seabed sediment data (both grab sampling and video observations), a complete map of the coastal zone was produced. By applying globally accepted schemes for clastic sediment rock classification, the seabed sediment varieties were defined in detail by their physical characteristics and verified by geological sampling. The results can be used for high accuracy bathymetric maps for navigation, habitat characterization, maritime spatial planning, integrated management of the coastal zone, etc.

The oceanic lithosphere in the Bay of Bengal (BOB) formed 80–120 Ma following the breakup of eastern Gondwanaland. Since its formation, it has been affected by the emplacement of two long N-S trending linear aseismic ridges (85oE and Ninetyeast) and by the loading of ca. 20-km of sediments of the Bengal Fan. Here, we present the results of a combined spatial and spectral domain analysis of residual geoid, bathymetry and gravity data constrained by seismic reflection and refraction data. Self-consistent geoid and gravity modeling defined by temperature-dependent mantle densities along a N-S transect in the BOB region revealed that the depth to the Lithosphere-Asthenosphere boundary (LAB) deepens steeply from 77 km in the south to 127 km in north, with the greater thickness being anomalously thick compared to the lithosphere of similar-age beneath the Pacific Ocean. The Geoid-Topography Ratio (GTR) analysis of the 85°E and Ninetyeast ridges indicate that they are compensated at shallow depths. Effective elastic thickness (Te) estimates obtained through admittance/ coherence analysis as well as the flexural modeling along these ridges led to the conclusions: i) 85°E Ridge was emplaced in off-ridge environment (Te = 10–15 km); ii) the higher Te values of ∼25 km over the Afanasy Nikitin Seamount (ANS) reflect the secondary emplacement of the seamount peaks in off-ridge environment, iii) that the emplacement of the Ninetyeast Ridge north of 2°N occurred in an off-ridge environment as indicated by higher Te values (25-30 km). Furthermore, the admittance analysis of geoid and bathymetry revealed that the admittance signatures at wavelengths >800 km are compensated by processes related to upper mantle convection.

T hisresearchcomparedtheinterpretationresultsoftheVerticalElectricalSoundingdataacquiredusingtheconventional SchlumbergerandmodifiedSchlumbergerarrayswithaviewtoassessingtheeffectivenessofthemodifiedSchlumbergerarrays ofverticalelectricalsoundingasanalternativetotheconventionalSchlumbergerarrayatsiteswithspaceconstraintduring groundwaterexploration.Atotalofthirty-seven(37)soundinglocationswereoccupiedandonehundred(100)soundingdata forbothconventionalSchlumbergerandmodifiedSchlumbergerarrayswerecollectedacrossdifferentrockunitswithinIbadan metropolis,south-westernNigeria,withelectrodespacing(ݐ䰝е/2)rangingfrom1to75m.Thefielddatawereinterpreted qualitativelybycurvematchingandcomputeriterativemethods.Also,statisticalanalysisofsubsurfaceunitsandthecoefficient ofcorrelation“ݑŢofthestatisticalplotsofthefielddatashowstherelationshipbetweenthedifferentarrays.Therawdataplotof thedifferentarraysshowssignificantsimilaritieswhilestatisticalanalysisofthegeo-electricparametersobtainedfromthedifferent arraysacrossvariedlithologicunitsshowthatstrongrelationshipsexistbetweenthedifferentfieldmethods.Thecoefficientof correlationݑŷithvaluesrangingfrom0.7to0.99impliesthatagoodsimilarityexistsbetweenthedifferentfieldmethodsemployed inthisstudy.Hence,modifiedSchlumbergerarrayscanbesaidtobeagoodalternativetotheconventionalSchlumbergerarrayfor groundwaterexplorationespeciallyinurbansettingswherespaceconstraintisamajorchallenge

Лаборатория по Археогеофизика
http://www.phys.uni-sofia.bg/bul/departments/ucsrt/agpl/index.html
Лабораторията е създадена през 2006 г. за внедряване на космически технологии (георадари) в търсенето и геофизическите проучвания на археологически терени у нас.
Лаборатория по Палеолуминесценция (Paleoluminescence lab.)
Лабораторията използва методи и апаратура разработени във Физическия факултет. Те са обект на 3 български изобретения и един канадски патент на екипа на лабораторията. Някой от устройствата разработени и използвани от лабораторията нямат аналози в чужбина, други са обект на многобройни опити за копиране или видоизменения от други лаборатории по света.

We calculated the sedimentary budget of the Northwest Sub-basin (NWSB), South China Sea for different geological times based on interpretations of four multichannel seismic profiles across the basin with constraints from International Ocean Discovery Program (IODP) Expeditions 367 and 368 drilling results. Sedimentation was generally dominated by regional tectonic events and climate change, but complicated by local tectonic events and geographic position, which resulted in a specific sedimentary budget in the NWSB compared with other marginal basins and the Southwest Sub-basin. The sedimentation rate was relatively low following the opening of the NWSB but increased gradually during the Middle Miocene, corresponding to the uplift of the Tibetan Plateau and the Asian monsoon. It reached its peak in the Late Miocene, corresponding to uplift of the Dongsha Island region that caused intensive bypass of eroded sediments from the Baiyun Sag into the abyssal basin, and reduced again during the Pliocene because of sediment storage on the wide northern continental shelf area compared to the abyssal basin during a period of high-stand sea level. Increase in sedimentation during the Pleistocene suggests that continental erosion and sediment transport to the abyssal basin were enhanced by an intensified Asian summer monsoon and glacial-interglacial climate fluctuations. Since the opening of the NWSB, the primary sediment provenance has been from southern China, with minor contributions from the Red River, Hainan Island, as well as local uplifts on the continental shelf. ARTICLE HISTORY

Multibeam bathymetry and sub-bottom profiler data acquired in 2011 from R/V Marcus Langseth in a broad grid over the Chukchi Sea margin reveal multiple glacigenic features on the top and slopes of the outer Chukchi Shelf/Rise and adjacent Borderland. Glacial lineations record a complex pattern of erosion likely formed by both local glaciation and far-traveled ice shelves/streams sourced from the Laurentide, and possibly East Siberian ice sheets. Multiple till units and stacked debris flows indicate recurrent glacial grounding events. Composite till wedges of several hundred meters thick extend the shelf edge by 10-20 km in places. Distribution of ice-marginal features on the Chukchi Rise suggests stepwise deglacial retreat towards the shelf, backing up the broad bathymetric trough at the eastern side of the Rise. Glacigenic features other than extensive iceberg scouring cannot be identified above 350-m depth, and no glacigenic bedforms are present on the current-swept shallow shelf. Despite the resulting uncertainty with the southern extent of the glaciation, the data suggest a widespread grounded-ice presence on the northern Chukchi Shelf, which makes it an important, previously underestimated component of the Arctic paleo-glacial system.

The earthquake of 21 May 2014 (Mw 6.0) in the northern Bay of Bengal (BOB) highlights the importance of studies on intraplate earthquakes in the oceanic regime in understanding the state of stress of the oceanic lithosphere. The epicenter of the earthquake is located at a water depth of 2.5 km where the sediment thickness is nearly 12 km and it occurred at a depth of ~ 50km within the upper mantle. Its location on seismotectonic map of the region revealed that the epicenter is far away from the seismically active zone of the Burmese Arc in the east, and low-to-moderately active seismic region of the east coast of India in the west. The fault plane solution of this earthquake indicates that it is a strike-slip event with right-lateral sense of motion on a NW oriented nodal plane, and occurred on one of the NW-SE trending fracture zones that were earlier mapped in the BOB. Based on a compilation of long-term (1900-2011) intraplate earthquakes along with available focal mechanisms in BOB and the adjoining east coast of India, we conclude the following; i) the Precambrian structural trends, basin scale faults and minor lineaments at the east coast of India are favorably re-activated in their offshore extensions up to the shelf-slope areas of the margin, ii) earthquake occurrences in the BOB region can be correlated with the fracture zone trends in the central BOB and along the Ninetyeast ridge, or at the intersections of fracture zones with the subsurface trace of the 85o E ridge.  The 21 May 2014 earthquake is the result of re-activation of such a NW-SE trending fracture zone lying in the lithosphere of > 100 Ma in age. Further evaluation of this event in the light of global occurrence of oceanic intraplate earthquakes in the older lithosphere (> 80 Ma) suggests that such re-activation is possible in the high ambient stress state.

In the inaugural (July 1966) issue of the Newsletter of the Geological Society of Malaysia, the Society's founding president, Neville S. Haile, wrote an interesting note on the enactment by Malaysia's parliament of the Continental Shelf Act 1966. At that time, offshore oil exploration in Malaysia was just beginning and the geology of the continental shelf was virtually unknown. Fifty years have passed since, and we now have a much better understanding of the geology of the continental shelf, thanks to academic research and petroleum exploration. In parallel with the rapid advances in geoscientific understanding of continental margins and ocean basins and in the theory of plate tectonics, legal instruments have been put in place, internationally and nationally, to enable coastal States 3 to exercise jurisdiction over their maritime spaces, in particular the continental shelf, which may include the " extended " continental shelf beyond 200 nautical miles 4 (M) from the coastlines, for the purpose of exploration and exploitation of natural resources. This note is a brief progress update of the continental shelf in the Malaysian context after five decades of the enactment of the Continental Shelf Act 1966.. The bill lays claim to the sea-bed and subsoil off Western Malaysia (Malaya) beyond the 3-mile territorial limit and as far as the 200-meter isobaths. Supplementary legislation, the Petroleum Mining Enactment, regulates prospecting and exploration for oil. These acts empower the Federal Minister of Lands and Mines to issue licenses over the continental shelf for exploration, prospecting, and mining of natural resources. Resources within the 3-mile limit will be under the control of State Governments. It is known that a number of companies have applied for prospecting licenses for tin and oil on the continental shelf off the coasts of Malaya. Interest by oil companies has so far been confined to the east coast offshore area, whereas interest in tin is centered on the shelf off the west coast. The shelf off eastern Malaya is over 600 kilometers wide; it forms part of the Sunda shelf which joins Malaya, Sumatra, Borneo, and Java, and is one of the most extensive shelf seas of the world. It has an average depth of only about 70 meters. The delineation of the boundaries between the parts of the shelf owned by Malaysia, Thailand, Vietnam, and Indonesia may present some problems, and does not seem to have been attempted yet, but the parts of the shelf over which Malaysia claims sovereignty probably exceed the land area of Malaysia. The mineral potential of the continental shelf off Sabah and Sarawak (Eastern Malaysia) has long been recognized, and legislation laying claim to the shelf was enacted there as long ago as 1954. The Shell Group of Companies has been vigorously prospecting and drilling over the large areas of the Shelf off Sarawak, Brunei, and western Sabah, but so far has met with only minor successes. Many promising structures, however, remain to be drilled. Now that Malaysia has assumed sovereignty over such a huge area, it may be hoped that some attention will be given to the responsibilities of conduction scientific surveys, including marine geological surveys, over the shelf, and the adjoining marine South China Sea. So far, apart from oil company work, the results of which are mostly confidential, only one expedition, by the Geological Survey (Borneo Region) in 1963, in cooperation with the Shell Group and the British Navy, has been made. In spite of being done on a shoe-string budget and without sophisticated equipment, this produced significant results, indicating the wide scope for future work on the shelf off Malaysia's coasts.