ALBERT

Description: Two case studies of the application of geoscientific maps for planning in semi-arid regions are presented, one for the Mediterranean province of Valencia and another for the island of Gran Canaria (Canaries). Both regions are very dynamic from the point of view of population growth and urban-touristic-industrial development, and they suffer from a serious degree of environmental degradation. The provincial/ island governments have undertaken programmes of geoscientific mapping and assessment to serve as a basis for the establishment of guidelines for future planning. Two map sets have been made (1:200,000 in Valencia and 1:50,000 in Gran Canaria), based on initial maps of homogeneous integrated units. These represent a series of hierarchical land subdivisions, progressively smaller and more detailed (morphodynamic environments, systems, units, elements), defined on the basis of morphostructure, climate, lithology, surficial deposits, landforms, topography, active processes, soils, vegetation and human influence. Each individual map unit is described by means of a form which includes 114 items, summarising its environmental features. Morphodynamic units have been evaluated in terms of qualities significant for planning, and a series of derivative maps has been developed (geologic hazards, soil capability, present degree of erosion, potential erodibility, quality for conservation). A final map shows the most advisable types of uses and the main limitations for human activities, mainly due to engineering geological factors. This is a synthesis document which can be used directly by planners.

Description: Middle Pleistocene strata of the Kidnappers Group consist of a conformable sequence of alternating fluvio-lacustrine and shallow marine sediments exposed along coastal cliffs near Cape Kidnappers, southern Hawkes Bay, New Zealand. Three major paleomagnetic polarity intervals are recognised and interpreted as Jaramillo Normal Subchron, upper Matuyama Reversed Chron and Brunhes Normal Chron. This and biostratigraphy indicates an age range of 0.97 to 0.54 Ma for the group, compared to 0.85 to 〈 0.33 Ma previously suggested by fission track ages of tuffs. The new age control and facies interpretations suggest that the upper part of the group represents oxygen isotope stages 22 to 15. The duration and magnitude of isotope stages is reflected in the relative thicknesses of lithological units. Glacial periods are recorded as alluvial aggradation in the form of braidplain conglomerates, while estuarine and subaerial sands and muds with temperate climate pollens represent interglacial periods. This contrasts with many coastal and shelf sequences where glacial periods are represented by unconformities. Chemical and paleomagnetic characterisation of silicic tuffs in the Kidnappers Group establishes correlation to other sections and cores in New Zealand, the Tasman Sea and the western Pacific Ocean, thus providing temporal correlation for a range of sedimentary environments.

Description: The structural setting of the Maltese Islands is governed by two rift systems of different ages and trends and the interference of both. Accompanying faults are exposed at many places along cliffs and belong to the most spectacular phenomena of rift faulting of the world. Malta is part of a wide shelf bridge that connects the Ragusa platform of southern Sicily and the Tripolitanian platform of northern Libya. The archipelago is underlain by a continental crust of African provenance. The older rift generation traversing the islands strikes about 50° to 70° to create a basin-and-range structure on western Malta, Comino and eastern Gozo. This micro-province is framed by two master faults at an average distance of 14 km. Crustal extension started during the Early Miocene, as observed by growth faulting and sedimentary dikes parallel to the future rift. A syndepositional uparching of about 200 m has preceded the physiographical rifting in post-Middle Miocene times. Discrete dip-slip faulting created an external wedge block, split by internal tilt blocks of antithetic character, both compensating an average 15% crustal spreading normal to the rift axis. Shoulder upwarping of approximately 120 m has evolved synchronously with the rifting. Structures of the first generation are crosscut by still active, second-generation rift faults, which on Malta strike about 120°, but on Gozo between 80° and 90°. These faults are associated with the Pantelleria rift, whose deep trough sets immediately south of the islands. Rifting was mainly originated during Late Miocene/Early Pliocene time to continue in parts up to the Present. A set of transform faults runs through the straits on both sides of Comino to form a complicated en echelon or Riedel shear structure on easternmost Gozo and westernmost Malta. Shoulder upwarping related to the Pantelleria rift has considerably tilted the block of Malta NNE-ward and caused the inundated river valleys of the natural harbour of Valletta. The superimposition of two rift structures of different trends has been caused principally by a rotation of the controlling stress regime about 10 m.y. ago. The active Afro—Eurasian collision front is located about 200 km north and northwest of the islands. A contemporary change of plate tectonic stresses is discussed to explain the intraplate rift pattern on Malta as foreland-specific reactions to plate tectonic processes.

Description: Menaquinones (vitamin K2) were the only isoprenoid quinones found in the Actinomycetes tested. Thermomonospora strains belonging to the species T. alba, T. curvata and T. fusca contained very complex mixtures of menaquinones with nine, ten and eleven isoprene units. Hexa- and octahydrogenated menaquinones with ten isoprene units constituted the major components in T. alba, whereas, octahydrogenated menaquinones with ten isoprene units predominated in T. curvata and T. fusca. Substantial amounts of hitherto undescribed hexa-, octa-, and decahydrogenated menaquinones with eleven isoprene units were also present in the three species. The representative of the taxon Thermomonospora (Actinobifida) chromogena examined differed in possessing major amounts of tetrahydrogenated menaquinones with only nine isoprene units; a pattern also found in Saccharomonospora viridis, Actinomadura flexuosa and Micromonospora halophytica subsp. halophytica. The chemotaxonomic data and supporting results of numerical taxonomic studies suggest that Actinobifida chromogena may have been wrongly classified in the genus Thermomonospora.

Description: We studied the distribution and abundance of marine birds in Bransfield Strait and southern Drake Passage during January and February 1985. We identified clusters of bird species, “communities” with similar distributions, and examined the extent to which the distributions of these seabird communities reflected the underlying physical oceanography of the region. Based on temperature, salinity and silicon data, we identified 11 water masses which resulted from varying degrees of mixing of water from the Pacific Basin, the Bellingshausen Sea, the Weddell Sea and terrestrial runoff. Seabird species assemblages were associated with contiguous clusters of water masses, suggesting a response by the birds to apparently subtle differences in their marine habitat.

Description: The major tectonic elements of the Azores triple junction have been mapped using long-range side-scan sonar. The data enable the Mid-Atlantic Ridge axis to be located with a precision of a few kilometres. Major faults and other tectonic and volcanic elements of the ridge maintain their regional trend of 010° to 020° past the triple junction area. There is no oblique spreading, and only minor transform offsets of the Mid-Atlantic Ridge occur here. The main effect of the triple junction or Azores hot spot is to diminish the amplitude of the median valley to 200 m or less. There is no axial high: a topographic high seen on several profiles is located to the east of the Mid-Atlantic Ridge spreading axis and does not appear to have any fundamental significance. The third arm of the triple junction includes the Azores srreading centre which appears to have developed as a series of en echelon rifted basins (the Terceira Rift) extending from Formigas Trough at 36.8°N, 24.5°W to a point near 39.3°N, 28.8°W. There are indications that recent activity in the spreading centre may be concentrated in a series of ridges which flank the older rifted basins. Until recently the northwest end of the Terceira Rift was connected to the Mid-Atlantic Ridge axis either directly at an RRR junction, or via a transform fault. The triple junction has probably moved south during the last 6 Ma to a positin on the Mid-Atlantic Ridge near 38.7°N. Initiation of the Azores spreading centre may have occurred during the 36 Ma B.P. rearrangement of poles, with an RFF triple junction north from the East Azores fracture zone to the North Azores fracture zone and transferring a wedge of European plate to the African plate. The tectonic elements revealed by this study are in good agreement with inferred earthquake mechanisms and with the RM2 plate tectonic model of Minster and Jordan, but east-west motion between North America and Africa does not seem to be compatible with the other motions at the triple junction unless it is of very recent (2〉3 Ma) origin.

Description: The Hg concentration in horned octopus was studied in relation to its biological cycle. The metal was measured in the muscle tissue of specimens of different size, sex and maturity. This species proved to be a strong accumulator of mercury, whose concentration was found to be correlated with length independently of the sex. The relationship with size was found also for the organic form. Consideration was given to the danger of frequent consumption of this cephalopod and to its use as a biomonitor of environmental mercury impact.

Description: The aims of this project were to improve understanding of the basic life.cycle biology, stock structure, trophic interactions and fisheries exploitation of northeast Atlantic squid, in particular the loliginids Loligo forbesi and Loligo vulgaris. Multivariate analysis of morphometric data and isozyme electrophoresis shows that L. forbesi populations from the coast of mainland Europe are fairly homogeneous, but that those from the Azores are a distinct stock. Loligo forbesi and L. vulgaris are annual species with a peak of breeding in the winter (December-May) throughout the geographical range, and one or more seasonal peaks of recruitment. Loligo are probably batch spawners. Males grow larger than females, mature about 1 month earlier and recruit earlier to the fishery. Sexual maturity occured at two distinct size classes, more obviously in males than females. Fish, including many cimmercially important species, and Crustacea, were the dominant prey of Loligo. The incidence of fish in the diet increases with squid size. Squid of all types are eaten by fish, seals, cetaceans and seabird, although quantitative estimates of consumption by these trophic levels were low. Catches of squid from northeast Atlantic waters increased over the period 1980-1990 but currently supply only a minor component of the European market for squid, the balance being made up by imports. The squid catch in the northern part of the range shows wide fluctuations in abundance by area and by season. The applicability of assessment methods for these stocks is limited by inadequate and inaccurate statistical information, and because nearly all of the catch arises by-catch from finfisheries.