The development of folds in bedded chert and related rocks in the Malaguide Complex, southern Spain

Folds and folding mechanism in a chert sequence and related rocks of the Maláguide Complex (the uppermost tectonic unit of the Betic Zone) have been investigated. The geometric study shows that folds that developed in the chert sequence are usually angular in shape and asymmetric. Chevron and conjugate folds are common.Folding in bedded chert is explained in terms of a suggested model:

1. (1) Development of folds by kink and conjugate kinking.

2. (2) As the shortening increases, the interlimb angles decrease; in the kink folds this is caused by a reduction of the angle between the layers within the kink and the kink boundaries. There seems to be a relationship between this angle and the asymmetrical thinning-out in the limbs of many folds: the smaller is the angle between the kink boundary and the layers within the kink band, the larger is the reduction of the thickness in these layers.

Single limestone layers embedded in slate deform very probably by a buckling mechanism, implying tangential longitudinal strain and an additional flattening.     

Crystal bending in metamorphic calcite,and its relations to associated twinning

This paper deals with the incidence and geometry of lattice bending in calcite of naturally strained marble and possible relations in time to associated {01¯12} twinning, as revealed by microscopic examination with a universal stage. Microscopic technique and graphic treatment of data with a view to identifying the relation in time of bending to twinning, and possible glide mechanisms involved in the bending process are reviewed as a basis for present and subsequent investigation of this general topic.In most instances development of surviving thin e twins postdates bending of the host crystal (such twins everywhere are rationally oriented). Rarely (in contrast with experimental experience) some thin twins are slightly irrational (L_e lamellae) and apparently developed in the final stages of bending. Thick twins (a few tens of microns wide) on the other hand rather commonly predate or are synchronous with bending.The geometry of bending (external rotation) — especially for rotation less than 25° —commonly is compatible with models (based on experimental experience) of simple translation in the strained domains. The commonest translation system so identified is on {10¯11}, with sense of shear, where recognizable, either negative or positive. Translation on {02¯21} is relatively rare. Unexpectedly there is rather strong but not conclusive evidence of translation on {0001} parallel to an a axis. This mechanism, hitherto never identified with certainty, is now here documented unequivocally in a crystal of calcite experimentally strained at 300° C, 5 kb.     

Reconnaissance geochronology of basement rocks from the Amazonas and Maranhão Basins in Brazil

Rb/Sr whole rock as well as K/Ar whole rock and mineral age determinations have been carried out on drill core samples obtained from the crystalline basement underlying the Amazonas and Maranhão Basins in Brazil. The data confirm the existence of an ancient basement under the Upper and Middle Amazonas Basin. The primary age of the granitic rocks is estimated at about 1560 Ma which correlates with recent age data obtained on granitic rocks on both sides of the Amazonas syneclise. In some areas the K/Ar ages show a decrease probably due to the effect of the Nickerie thermal episode described previously in the Guayana Shield.In the basement of the interconnected Lower Amazonas and Maranhão Basins Late Precambrian (Caririan) metamorphism and igneous activity seems to have been pervasive. The data allow the continuation of the Brazilian age province known in northeastern Brazil under the Maranhão Basin, linking this province to the Brasilia-Paraguay orogenic belt of similar age.     

Location,location, location: changes in the diversity of animal resources exploited by Tardiglacial humans in northern Spain

Prey diversity of Homo sapiens in north Iberia exhibited shifts associated with climate warming after the Last Glacial Maximum, as deduced from animal remains obtained from Upper Palaeolithic caves in Asturias (northern Spain). Significant association of prey diversity and river proximity was found during adverse climate conditions, indicating opportunistic predation. A high increase of prey diversity was found when small animals (including fish) were taken into account in archaeological records, highlighting the importance of this type of prey in Palaeolithic diets. Copyright © 2009 John Wiley & Sons, Ltd.     

Regional Seas integrative studies,as a basis for an ecosystem-based approach to management: The case of the Bay of Biscay

Marine legislation world-wide has, as a recent final objective, the maintenance of a good environmental or ecological status for marine waters, habitats and resources. The concept of environmental status takes into account the structure, function and processes of marine ecosystems, bringing together physical, chemical, physiographic, geographic and climatic factors: subsequently, integrating such conditions, with anthropogenic impacts and activities undertaken in the area concerned. Such an approach is intended to permit an assessment of the environmental status at the ecosystem level, i.e. ‘ecosystem-based approach’, or ‘ecosystem-based management’.Such legislation emphasises the need for the development of methodologies, to assess environmental status. As such the knowledge acquired within Regional Seas, discussed at International Symposia and, finally, published as Special Issues, can serve as the basis for a regional ecosystem-based approach to management and the integrative assessment of marine systems. Hence, the Bay of Biscay is used in this contribution, as an example, to show past and present research, together with perspectives for the future. It is concluded that collaboration between institutions (marine research institutes, universities) and countries (France, Spain, Portugal, the United Kingdom and Ireland) could result in an interesting ‘case-study’, for the further implementation of the European Marine Strategy Framework Directive, at the level of this particular Regional Sea. In this way, the experience gained in the implementation of the Water Framework Directive within the ecoregion, together with the information collated in the eleven International Symposia of Oceanography of the Bay of Biscay, celebrated until now, can be very useful, for an ecosystem-based management approach for this Regional Sea.     

Concurrent imaging of chlorophyll fluorescence,Chlorophyll a content and green fluorescent proteins‐like proteins of symbiotic cnidarians

Research on photosynthetic cnidarians has been mainly focused on the symbiosis established between the cnidarian host and its dinoflagellates endosymbionts from genus Symbiodinium. Despite the potential of imaging techniques for assessing the spatial distribution of key parameters of cnidarian photobiology, such as photochemical activity, chlorophyll a content or green fluorescent proteins (GFPs), to our best knowledge, no study has ever attempted to simultaneous map these three features. In this study, we developed a modified imaging pulse amplitude fluorometer by applying excitation light of different wavelengths and selectively detecting short spectral bands through bandpass filters. The imaging system was used to sequentially excite and quantify chlorophyll variable fluorescence (maximum quantum yield of photosystem II, F_v/F_m), Chl a content (normalized difference vegetation index) and relative content of GFPs. The spatial distribution of these photophysiological parameters was mapped both horizontally, across the surface of the soft corals Sarcophyton cf. glaucum and Sinularia flexibilis and the zoanthid Protopalythoa sp., and vertically, throughout a vertical section of S. cf. glaucum. Results showed bleached areas within each individual coral colony and registered photophysiological changes with S. cf. glaucum tissue depth. Analysis of Protopalythoa sp. polyps’ expansion revealed differential surface patterns of NDVI and GFP concentration, and a negative relation between these latter parameters within each polyp. This novel non‐invasive approach allowed a high‐resolution characterization of the spatial relationship between these key parameters through the analysis of image information on a pixel‐by‐pixel basis, which has great potential for investigating the physiological state of symbiotic associations.     

Assessing the benthic quality status of the Bohai Bay (China) with proposed modifications of M-AMBI

Multivariate AZTI's Marine Biotic Index (M-AMBI) was designed to indicate the ecological status of European coastal areas. Based upon samples collected from 2009 to 2012 in the Bohai Bay, we have tested the response of variations of M-AMBI, using biomass (M-BAMBI) in the calculations, with different transformations of the raw data. The results showed that the ecological quality of most areas in the study indicated by M-AMBI was from moderate to bad status with the worse status in the coastal areas, especially around the estuaries, harbors and outfalls, and better status in the offshore areas except the area close to oil platforms or disposal sites. Despite large variations in nature of the input data, all variations of M-AMBI gave similar spatial and temporal distribution patterns of the ecological status within the bay, and showed high correlation between them. The agreement of new ecological status obtained from all M-AMBI variations, which were calculated according to linear regression, was almost perfect. The benthic quality, assessed using different input data, could be related to human pressures in the bay, such as water discharges, land reclamation, dredged sediment and drilling cuts disposal sites. It seems that M-BAMBI were more effective than M-NABMI (M-AMBI calculated using abundance data) in indicating human pressures of the Bay. Finally, indices calculated with more severe transformations, such as presence/absence data, could not indicate the higher density of human pressures in the coastal areas of the north part of our study area, but those calculated using mild transformation (i.e., square root) did.     

Contribution of SHRIMP U–Pb zircon geochronology to unravelling the evolution of Brazilian Neoproterozoic fold belts

The South-American continent is constituted of three major geologic–geotectonic entities: the homonym platform (consolidated at the end of the Cambrian), the Andean chain (essentially Meso-Cenozoic) and the Patagonian terrains, affected by tectonism and magmatism through almost all of the Phanerozoic. The platform is constituted by a series of cratonic nuclei (pre-Tonian, fragments of the Rodinia fission) surrounded by a complex fabric of Neoproterozoic structural provinces.