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Northern Morocco (northern + morocco)
Selected AbstractsThe microstratigraphic record of abrupt climate changes in cave sediments of the Western MediterraneanGEOARCHAEOLOGY: AN INTERNATIONAL JOURNAL, Issue 5 2001Marie-Agnès Courty The purpose of this paper is to illustrate how calcareous sediments from Pleistocene and Holocene rockshelters and open caves of the Western Mediterranean can provide a stratigraphic record of abrupt climate change. The method proposed here is based on microstratigraphic examination of sedimentary sequences using microscopic techniques. The most important processes for characterizing the sensitivity of each cave to climate variables are: (1) the modes and rate of carbonate sediment production, (2) the nature and intensity of the pedogenic processes responsible for the synchronous alteration of carbonate materials (either those derived from the cave walls or those deposited on the ground surface), and (3) the supply of allogenic sediments, particularly by eolian activity. The cave sediment sequences presented record the marked coolings known as Dansgaard-Oeschger stadials and Heinrich events that occurred during the Pleistocene and the Holocene, as demonstrated by the high resolution records from ice and deep sea cores. At Abric Romanì in northeastern Spain, a series of sharp climatic deteriorations of increasing severity is shown to have occurred synchronously with the transition from the Middle to the Upper Paleolithic, with a period of seasonal frost and strong winds at ca. 37,000 yr B.P., tentatively correlated with Heinrich event 4. At Pigeon Cave, Taforalt (northern Morocco), the transition from the Aterian to Ibero-Maurusian/Epipalaeolithic cultures is dated to around 24,000,20,000 yr B.P. and is punctuated by a series of short cold pulses with evidence for seasonal freezing, soil erosion, and minimal evapotranspiration. In El Miron cave in north-central Spain, the exceptional nature of the Younger Dryas cooling produced a marked destabilization of the cave walls and roof. At El Miron, the stratigraphic evidence for sediment removal due to the rapid percolation of snow melt under a degraded soil cover allows us to reconstruct the nature of the negative excursion at ca. 8200 yr B.P. This example also illustrates how climate-controlled pedogenic processes can create a stratigraphic signature which has often been confused with a sedimentary hiatus. We conclude that cave sediments provide a valuable record of Pleistocene and Holocene climate changes. In appropriate contexts, these sequences allow us to examine the ecological stress generated by these unique global events at a local and regional level and improve our understanding of the complex anthropological processes that occurred at the same time. © 2001 John Wiley & Sons, Inc. [source] Thermal structure of the Alboran Domain in the Rif (northern Morocco) and the Western Betics (southern Spain).JOURNAL OF METAMORPHIC GEOLOGY, Issue 4 2006Constraints from Raman spectroscopy of carbonaceous material Abstract In the Rif (northern Morocco) and the Western Betics (southern Spain), the Alboran Domain forms a complex stack of metamorphic nappes including mantle peridotites (Beni Bousera and Ronda). We present in this paper new temperature data obtained in the Alboran Domain based on Raman spectroscopy of carbonaceous material (RSCM thermometry). In the lower metamorphic nappes of the Alboran Domain (lower Sebtides,Alpujárrides) temperature ranges from > 640 °C at the base of the metapelitic sequence to 500 °C at the top. The relationships between field isotherms and nappe structure show that peak temperatures were reached during strong ductile thinning of these nappes whereas they partly postdate this main episode in the Rif. In the upper nappes of the Alboran Domain (Ghomarides,Maláguides), generally supposed to be only weakly metamorphosed, temperatures range from ,500 °C at their base down to < 330 °C at the top. This temperature gradient is consistent with progressive Cenozoic resetting of K,Ar and 40Ar,39Ar ages. These nappes were thus affected by a significant thermal metamorphism, and the available age data in the underlying Sebtides,Alpujárrides show that this metamorphism is related to the metamorphic evolution of the whole Alboran Domain during the Late Oligocene,Early Miocene. Such thermal structure and metamorphic evolution can be explained by generalized extension in the whole Alboran Domain crustal sequence. At a larger scale, the present thermal structure of the Alboran Domain is roughly spatially consistent around the Beni Bousera peridotites in the Rif, but much more affected by late brittle tectonics around the Ronda peridotites in the Western Betics. Therefore, on the basis of the observed thermal structure, the metamorphic evolution of the Alboran Domain can be interpreted as the result of the ascent of hot mantle units contemporaneous with thinning of the whole lithosphere during an Oligo-Miocene extensional event. The resulting structure has however been dismembered by late brittle tectonics in the Western Betics. [source] Traumatic myiasis in dogs caused by Wohlfahrtia magnifica and its importance in the epidemiology of wohlfahrtiosis of livestockMEDICAL AND VETERINARY ENTOMOLOGY, Issue 2009R. FARKAS Abstract In the province of Al Hoceima, northern Morocco, and on two farms in Hungary, dogs were inspected for the presence of traumatic myiasis. Nine and four infested dogs were found in Morocco and Hungary, respectively. All the larvae and adults reared from them in the laboratory were identified as Wohlfahrtia magnifica (Schiner) (Diptera: Sarcophagidae). To our knowledge, these are the first cases of wohlfahrtiosis in dogs to be reported in these countries. All infested animals lived close to livestock, where wohlfahrtiosis was endemic. Infested body sites included limbs (six cases), external genitalia (two), ears (three), nose (one) and neck (one). Developing larvae caused severe welfare problems and tissue destruction in most cases. Although the number of cases reported here is small, wohlfahrtiosis in dogs may be very important from an epidemiological perspective because farm and stray dogs can act as both reservoirs and carriers of this parasitic fly species. Therefore, education of dog owners concerning the risk factors in endemic regions is recommended in order to reduce the prevalence of wohlfahrtiosis in dogs and thereby in livestock. Both owners and veterinarians should pay regular attention to any wounds and to the natural orifices of dogs, especially during the fly seasons. [source] Differences in pollinator faunas may generate geographic differences in floral morphology and integration in Narcissus papyraceus (Amaryllidaceae)OIKOS, Issue 11 2007Rocío Pérez-Barrales Pollinators may generate selective pressures that affect covariation patterns of multiple traits as well as the mean values of single floral morphological traits. Berg predicted that flowers pollinated by animals whose morphology closely matches the flower's shape will be phenotypically more integrated (tighter correlation of flower traits) than will flowers pollinated by animals not closely fitting the floral morphology. We tested this hypothesis by comparing, in the Strait of Gibraltar region (south Spain, northern Morocco), populations of Narcissus papyraceus that have geographical differences in pollinator faunas. Long-tongued, nectar-feeding moths dominate the pollinator faunas of those populations close to the Strait of Gibraltar, whereas short-tongued, pollen-feeding syrphid flies dominate in peripheral populations farther from the Strait. Populations pollinated by moths and flies differed in the mean values of several floral traits, consistent with the evolution of regional pollination ecotypes. Populations pollinated by moths showed stronger intercorrelation (floral integration) than populations pollinated by hoverflies. Moth-pollinated populations also showed less variation in flower traits than vegetative traits, and this difference was stronger than in fly-pollinated populations. Thus, the pattern of differences in the phenotypic architecture of the Narcissus flowers is consistent with the hypothesis that populations have responded to different selective pressures generated by different pollinators. These data also supported most of the specific predictions of Berg's hypotheses about integration and modularity. [source] | |||||||||||||