Lower Aptian ammonite and carbon isotope stratigraphy in the eastern Prebetic Domain (Betic Cordillera, southeastern Spain)

Major global palaeobiologic and palaeoenvironmental changes occurred during the Early Aptian. Precise dating and timing of the different events is crucial to determine possible cause-effect relationships between them. In this regard, the combination of biostratigraphic and chemostratigraphic data can provide a very useful tool for time control. So far attempts to correlate the Lower Aptian carbon isotope record and the ammonite zonation yielded contradictory conclusions. In this paper, we present the results of an integrated analysis of the ammonite stratigraphic distribution and highresolution carbon isotope profiles from Lower Aptian sections of the eastern Prebetic Domain (Betic Cordillera, southeastern Spain). We recognized, in ascending order, the Deshayesites oglanlensis, Deshayesites forbesi, Deshayesites deshayesi, and Dufrenoyia furcata Zones. This succession is the same as that recently identified in the eastern Iberian Chain, and it closely correlates with both standard Mediterranean and Boreal zonations. The carbon isotope record displays the trends globally recognized for the Early Aptian, with two long positive shifts separated by a pronounced negative excursion. Calibration of this isotopic record with the ammonite zonation shows that the age of OAE 1a, which corresponds to the negative excursion and subsequent positive shift, is constrained to the middle/upper part of the Deshayesites forbesi Zone

The Cretaceous-Tertiary transition at Beloc, Haiti: micropaleontologic record and blostratigraphic Implications

The section studied is located immediately south of the village of Beloc, in the Southern Peninsula of Haiti. Rock sequences of that locality have the distinctive stratigrapbic characteristic of yielding a series that spans the transition from the Cretaceous to the Tertiary (K/T boundary), which is distinguished by a conspicuous marker bed composed of spherulites. The micropaleontologic data based on foraminifers indicate the presence of several important biozones charateristies of the boundary zone, namely the uppermost part of ihe Abathomphalus mayaroensis Zone, part ? of the Guembelitria cretacea Zone, and the Parvularugoglobigerina eugublna Zone, respectively. The calcareous nannoplanktons also yield transitional taxa that concur with the foramihiferal data, as they are indicative of the Micula prinsii Zone (uppermost Maastrichtian), as well as the lower part of NP1 or basal Danian. The absolute frequency of the different groups greatly diminish at the level that is assigned to the lowest Danian, which is coincident with the biotic crisis of the K/T boundary event. The dramatic decrease is particularly evident in the nannofos.sils, which are reduced by 7/7 00 to 1/400 of the assemblages recorded toward the end of the Maastrichtian. The relatively high frequency ofThoracosphaera spp.(up to 8 percent total), the predominance of heterohelicids, and the remarkable abundance of juvenile globotruncanids (about 50 percent) in the Cretaceous materials seem to also indicate a very unstable planktonic ecosystem toward the end of the Maastrichtia

Impact glass spherules in the Chicxulub K-Pg event bed at Beloc, Haiti: Alteration patterns

International audienceWe have investigated six impact glass spherules from the K-Pg event bed at Beloc, Haiti, using optical and electron microscopy, electron microprobe and in situ laser ablation-mass spectrometry (LA-ICP-MS; 37 trace elements, spot size 90-35m), in order to understand geochemical changes during alteration. The mm-sized glass spherules are partly or totally altered to smectite, but original textural features are preserved. The average trace-element composition of glass matches that one of the upper continental crust. Hints for a meteoritic component are lacking (Ni/Cr<1.3; Pt below detection limit). Compared to this fresh glass, smectites are strongly depleted in trace elements, except for Li, Sc, V, Ni, Ga, Ge, and Ba. The chondrite-normalized REE distribution patterns are flat with subchondritic abundances, related to their very low degree of crystallinity. We observe a positive Eu and a strong negative Ce anomaly; the latter is explained by formation of an organic Ce4+-complex, soluble under reducing conditions. Zr/Hf of glasses and smectites is chondritic to superchondritic (35-40), whereas Nb/Ta in smectite is subchondritic (5-12) compared to Nb/Ta in the glass (similar to 14-18). The low Nb/Ta is due to the low Nb concentrations in the smectite. Using in situ techniques with high spatial resolution, we have documented for the first time the significant changes in diagnostic elemental ratios during alteration of glass spherules. This has to be taken into account in the interpretation of geochemical data of not only impact materials but also volcanic glass, especially if bulk rock methods are used

Lower Aptian ammonite biostratigraphy in the Maestrat Basin (Eastern Iberian Chain, Eastern Spain). A Tethyan transgressive record enhanced by synrift subsidence

The present paper analyses the stratigraphic distribution of ammonites collected in the Lower Aptian sediments of the Maestrat Basin (E Spain). The faunal successions obtained from the systematic sampling of ten selected sections located in several sub basins led us to identify four biostratigraphic units (from base to top: Deshayesites oglanlensis, Deshayesites forbesi, Deshayesites deshayesi and Dufrenoyia furcata Zones) that are directly correlatable with the current Mediterranean standard zonation. This study further provides essential biochronologic information to accurately date the different lithostratigraphic units included in the interval studied. Thus, the upper part of the Xert Formation can be tentatively attributed to the lowermost Aptian (D. oglanlensis Zone). The Forcall Formation, which has yielded most of the ammonites, practically extends within most of the Lower Aptian. Its lower and middle parts (Cap de Vinyet and Barra de Morella Members) correspond to the upper part of the D. oglanlensis Zone and the lower part of the D. forbesi Zone, respectively. The base of the Morella la Vella Member (upper part of the Forcall Formation) includes the local record of Oceanic Anoxic Event 1a (OAE 1a) and correlates with the Roloboceras hambrovi horizon (middle/upper part of the D. forbesi Zone). The boundary between the Forcall Formation and the Villarroya de los Pinares Formation is diachronous and varies depending on the sub-basins. The base of the Villarroya de los Pinares Formation can be dated as the middle-upper part of the D. furcata Zone in the Galve, Perelló and Salzedella sub-basins

Lower Aptian ammonite and carbon isotope stratigraphy in the eastern Prebetic Domain (Betic Cordillera, southeastern Spain)

Major global palaeobiologic and palaeoenvironmental changes occurred during the Early Aptian. Precise dating and timing of the different events is crucial to determine possible cause-effect relationships between them. In this regard, the combination of biostratigraphic and chemostratigraphic data can provide a very useful tool for time control. So far attempts to correlate the Lower Aptian carbon isotope record and the ammonite zonation yielded contradictory conclusions. In this paper, we present the results of an integrated analysis of the ammonite stratigraphic distribution and highresolution carbon isotope profiles from Lower Aptian sections of the eastern Prebetic Domain (Betic Cordillera, southeastern Spain). We recognized, in ascending order, the Deshayesites oglanlensis, Deshayesites forbesi, Deshayesites deshayesi, and Dufrenoyia furcata Zones. This succession is the same as that recently identified in the eastern Iberian Chain, and it closely correlates with both standard Mediterranean and Boreal zonations. The carbon isotope record displays the trends globally recognized for the Early Aptian, with two long positive shifts separated by a pronounced negative excursion. Calibration of this isotopic record with the ammonite zonation shows that the age of OAE 1a, which corresponds to the negative excursion and subsequent positive shift, is constrained to the middle/upper part of the Deshayesites forbesi Zone

Unlocking the Potential: The Role of Universities in Pursuing Regeneration and Promoting Sustainable Communities

The election of New Labour in 1997 gave fresh impetus to the regeneration and community engagement agendas, and these are clearly central pillars in the Government's drive for sustainable communities. As major institutions in many towns and cities, universities can potentially play a major role in the development of our urban areas and make a significant contribution to the creation of sustainable communities. This paper examines the contribution of universities to urban regeneration and to local communities in England. Whilst there have been numerous case studies assessing the impact of specific universities on local and regional economies and wider research on the impact of universities on the national economy, there has generally been little attention given to their contribution to wider regeneration aims. Rather than adopting a case study approach, the research has focused on a nationwide survey generating quantitative and qualitative data to assess how universities perceive their role within this wider context, the extent to which they have become involved in such initiatives and possible barriers to such involvement. The research indicates that whilst many universities in England have been involved in regeneration and community initiatives, there is potential for more substantial and influential involvement, which could have significant benefits for the country's deprived areas and communities.