Re-situating fieldwork and re-narrating disciplinary history in global mega-geomorphology

In 1985, more than thirty geomorphologists, planetary scientists, and remote sensing specialists gathered at a conference center in Oracle, Arizona, to discuss an emerging area of research that they called “mega-geomorphology.” Building on a conference of the same name held in London in 1981, they argued that new techniques of remote sensing and insights emerging from the study of extraterrestrial planets had created opportunities for geomorphology to broaden its spatial and temporal scope. This new approach was, however, neither unproblematic nor uncontested. In the discussions around mega-geomorphology that took place in the mid-1980s, the perceived conflict between the use of remote-sensing techniques to observe phenomena on vast spatial scales, on one hand, and the disciplinary centrality of fieldwork and field experience to geomorphology, on the other, was a recurrent theme. In response, mega-geomorphologists attempted to re-situate fieldwork and re-narrate disciplinary histories in such a way as to make remote sensing and planetary science not only compatible with geomorphological traditions but also means of revitalizing them. Only partially successful, these attempts reveal that the process of adopting a planetary perspective in geomorphology, as in other earth sciences, was neither straightforward nor inevitable. They also show how the field and fieldwork could remain central to geomorphology while also being extensively revised in light of new technical possibilities and theoretical frameworks.     

Elicitation of strikes of predatory insects by projected images and light spots

Résumé Les larves de Libellules lancent leur masque sur l'image projetée de proies vivantes, sur un point lumineux mobile engendré sur un oscilloscope et sur deux points statiques qui s'illuminent successivement. Les méthodes permettent de varier systématiquement les caractères du «stimulus déclencheur» et de mesurer le temps de réaction et la durée de la projection du masque.     

Water in granulites: implications for the nature and evolution of the lower continental crust

The lower continental crust is one of the most important sphere-layers in the deep earth, and is the direct place where the crust-mantle interactions occur. Granulites are the dominated rocks in the lower crust, and have critical implications for the knowledge of the composition, nature and evolution of the deep crust; fluids are important mediums influencing many geochemical, geophysical and geodynamical characteristics of the lower crust, and may also play a fundamental role in the petrogenesis of granulites and the formation of the lower crusts. In this paper, we review recent advances involved with the deep continental crust, granulites and fluids, and some long-standing debates. Combined with the Fourier-transform infrared spectroscopy (FTIR) analysis performed on the mineral assemblages (cpx, opx, plag and grt) in lower crustal granulite xenoliths and terrains (exposed section) from east China, it is suggested that structural water, dominated by OH, in these nominally anhydrous phases may constitute the most important water reservoir in the deep crust. This structual water may help to understand many lower crustal geological processes and phenomena (e.g. seismic activities and electrical conductive anomalies), and influences from these water must be taken into consideration.     

Hydrogen isotope compositions of mantle-derived amphibole megacrysts from Qilin, Guangdong and its tectonic significance

Hydrogen isotope compositions of mantle-derived amphibole megacrysts from Qilin, Guangdong Province have been obtained by ion micro-probe. δD and H contents are constant both among different samples and within single sample, demonstrating that their formation condition is very stable. High δD values suggest the presence of a component recycled from crust which is possibly related to the subduction of Pacific Plate beneath Eurasian Plate in Mesozoic.