JNCC Offshore Natura Survey : Anton Dohrn Seamount and East Rockall Bank areas of search : 2009/03-JNCC Cruise Report

This cruise report summarises operations and initial observations onboard the M/V Franklin during cruise 2009/03-JNCC on behalf of the Joint Nature Conservation Committee (JNCC). The cruise took place between the 1st and 29th of July 2009 and surveyed two Areas of Search (AoS) for offshore Special Areas of Conservation (SACs): Anton Dohrn Seamount located 155km west of the St Kilda archipelago, and East Rockall Bank located 260km west of the St Kilda archipelago (Figure 1). The main aims of the survey were to acquire acoustic and photographic “ground-truthing” data to enable geological, geomorphological and biological characterisation of the Anton Dohrn Seamount and East Rockall Bank AoS. Specifically, the data acquired will lead to the production of broadscale habitat maps, the identification and description of Annex I reef habitats with particular attention to the occurrence of bedrock, stony and biogenic reef, to identify and record any anthropogenic impacts in the areas of search and finally to evaluate data acquisition methods, techniques and equipment. The work programme was highly successful with 215 line kilometres of multibeam echosounder and 10 photographic “ground-truthing” sites acquired in the Anton Dohrn Seamount AoS, and 692 line kilometres of multibeam echosounder and 168 line kilometres of sidescan sonar data and 17 photographic “ground-truthing” sites acquired in the East Rockall Bank AoS. No physical sea-bed samples were acquired during this cruise. The data revealed the flanks and area immediately adjacent to Anton Dohrn Seamount to comprise predominantly gravel-rich sediment with bedrock outcropping on the steeper sections of the Seamount flanks. East Rockall Bank comprised predominantly gravelly muddy sand on the eastern flank of the Bank with gravel- and sand-rich sediments dominating the crest of the Bank. Interestingly, the parasitic cones surveyed within the Anton Dohrn area of search comprised predominantly corals, including large gorgonian species, small bamboo coral, the soft coral Anthomastus sp. and the antipatharian Leiopathes sp. Significant bedrock reef was encountered during the course of this cruise along an escarpment located on the eastern flank of Rockall Bank roughly coincident with the 500m bathymetric contour. This laterally extensive feature primarily comprises volcanic bedrock with possible sedimentary bedrock cropping out at sea bed colonised by large stylsaterid hydrocorals and sponges. Preliminary observations and interpretation of the data acquired during the course of this cruise suggest that several sites may fit the definition of Annex I reef under the EC Habitats Directive. If they fulfil the criteria for Annex I reef, they will be assessed against site selection criteria as possible areas for consideration as SACs

Geological evolution and hydrocarbon potential of the Hatton Basin (UK sector), north-east Atlantic Ocean

The deep-water Hatton Basin (flanked by the Hatton and Rockall Highs) is located 600km west of Scotland (NE Atlantic Ocean) on the western margin of the Eurasian continental plate. Prior to Atlantic opening the area was adjacent to SE Greenland. The basin straddles the UK/Irish median line. Water depths increase southwards from 1000m to over 1300m. The basin has never been licensed for hydrocarbon exploration and is currently the subject of ownership negotiations related to the UN Convention on Law of the Sea. Consequently it is under-explored. The deepest borehole penetration is by DSDP borehole 116 which reached TD at 854m below sea bed in the Late Eocene. The Pre-Cambrian metamorphic basement only crops out on Rockall Bank where high-grade gneiss and granulite have been sampled and dated at c. 1900 to 1700 Ma. This is a different terrane from that which underlies most of Scotland. Palaeozoic rocks have not been proved in the area but may provide some of the pre-rift basin infill. The Hatton Basin probably opened during the Cretaceous. Recent (2007) seismic data suggest the presence of tilted fault blocks on the basin margins. Mid Cretaceous (Albian) sandstones and mudstones have been proved at shallow depth on the Hatton High. The area was massively affected by Late Paleocene to earliest Eocene volcanism which emplaced several large central igneous complexes and caused widespread lavas which degrade the seismic data from the deeper geology. Atlantic rifting commenced west of the Hatton High at about 56 Ma. During the Cenozoic the basin was affected by differential subsidence and several unconformity-forming compressional events. Numerous potential hydrocarbon trap styles have been identified including syn-rift tilted fault blocks, folds, truncations, prograding fans, pinch-outs, scarp fans and traps related to sill intrusions. Reservoir intervals are likely to be present in the Cretaceous, Paleocene and Eocene. The overlying Oligocene to Recent sediments are mudstones and oozes and may provide a seal. The main risks for an accumulation are the presence of a source rock and the shallow occurrence of some of the potential traps

Event-based sub-basalt depth imaging applied to marine seismic data from north of Shetland, UK

Seismic wave propagation in media with high-velocity layers (basalts) can be described as an interference of various events commonly referred to as wave types or modes. Proposed here is the event-based processing sequence that enhances and migrates a chosen set of locally coherent arrivals such as PP reflections and mode conversions. While many other events exist, it attenuates most of these other events (e.g. multiples) during pre-processing. The key element is the event separation or mode filtering by means of the Generalized Discrete Radon Transform. This filter is performed by measuring the local Radon-attributes expressed in terms of the wavefront curvature and dip of individual events. Application of these attributes in conjunction with event-based prestack depth imaging methodology onto acquiring conventional 3 km towed streamer data along a 2D profile in the north of Shetland (UK) enables us to accurately delineate volcanic units and imaging beneath high-velocity layers. The main objective is to map the radially-dipping structure of the Erlend pluton and to investigate the potential existence of hydrocarbon bearing Cretaceous layers underneath volcanic units. This case study demonstrates how to produce detailed subsurface images within the region of interest by applying the closely tied processes of prestack event enhancement and separation, well-driven time processing for velocity model building, and final event-based prestack depth imaging. Results show enhanced structural detail and good continuity of principal volcanic units and deeper reflections, suggesting a faulted 0.6-0.9-km-thick succession of Cretaceous rocks in the proximity of well 209/09-1. Our velocity model complements existing low-resolution geophysical models inferred from gravity and wide-angle seismic data

Preliminary geological results of sea-bed sampling in the Hebrides-Rockall area from the RRS James Clark Ross in 2001

In 2001 the British Geological Survey (BGS) was awarded survey time on the NERC vessel RRS James Clark Ross, normally operated by the British Antarctic Survey. Originally a cruise length of up to four weeks duration had been anticipated. However, owing to problems encountered during a refit on the Tyne, the ship was eventually only available for two weeks. The RRS James Clark Ross sailed from Leith on 6th August 2001 and reached the first site the following day. A report on the operational procedures, and performance of the equipment, was given by Skinner (2001). The cruise was funded through the BGS Science Budget

United Kingdom Minerals Yearbook 2007 : statistical data to 2006

The United Kingdom Minerals Yearbook brings together data on minerals production, consumption and trade, and includes an authoritative commentary on current developments in the minerals industry. It is of interest to all those interested in Britain's mineral industry and its contribution to the national economy, and forms part of the long-term mining and quarrying record of the U