Pollen analysis, particle size analysis, end-member modelling and x-ray fluorescence measurements from sediment cores off Cape Ghir, Morocco

Understanding past human-climate-environment interactions is essential for assessing the vulnerability of landscapes and ecosystems to future climate change. This is particularly important in southern Morocco where the current vegetation is impacted by pastoralism, and the region is highly sensitive to climate variability. Here, we present a 2000-year record of vegetation, sedimentation rate, XRF chemical element intensities, and particle size from two decadal-resolved, marine sediment cores, raised from offshore Cape Ghir, southern Morocco. The results show that between 650 and 850 AD the sedimentation rate increased dramatically from 100 cm/1000 years to 300 cm/1000 years, and the Fe/Ca and pollen flux doubled, together indicating higher inputs of terrestrial sediment. Particle size measurements and end-member modelling suggest increased fluvial transport of the sediment. Beginning at 650 AD pollen levels from Cichorioideae species show a sharp rise from 10% to 20%. Pollen from Atemisia and Plantago, also increase from this time. Deciduous oak pollen percentages show a decline, whereas those of evergreen oak barely change. The abrupt increase in terrestrial/fluvial input from 650 to 850 AD occurs, within the age uncertainty, of the arrival of Islam (Islamisation) in Morocco at around 700 AD. Historical evidence suggests Islamisation led to population increase and development of southern Morocco, including expanded pastoralism, deforestation and agriculture. Livestock pressure may have changed the vegetation structure, accounting for the increase in pollen from Cichorioideae, Plantago, and Artemisia, which include many weedy species. Goats in particular may have played a dominant role as agents of erosion, and intense browsing may have led to the decline in deciduous oak; evergreen oak is more likely to survive as it re-sprouts more vigorously after browsing. From 850 AD to present sedimentation rates, Fe/Ca ratios and fluvial discharge remain stable, whereas pollen results suggest continued degradation. Pollen results from the past 150 years suggest expanded cultivation of olives and the native argan tree, and the introduction of Australian eucalyptus trees. The rapidly increasing population in southern Morocco is causing continued pressure to expand pastoralism and agriculture. The history of land degradation presented here suggests that the vegetation in southern Morocco may have been degraded for a longer period than previously thought and may be particularly sensitive to further land use changes. These results should be included in land management strategies for southern Morocco.

20 movies of x-ray tomograms of different Alpinia fossils

The fossil floras described by Dieter MAI and Harald WALTHER are invaluable for understanding the past plant diversity in Europe, and provide important information on the occurrence of taxa in the fossil record that is critical for evolutionary studies. Among the taxa they recognized were seeds assigned to the extant genus Alpinia ROXB. (Zingiberaceae, Zingiberales). We reinvestigated 28 specimens that were assigned to Alpinia arnensis (CHANDLER) MAI, Alpinia cf. arnensis, and Alpinia bivascularis MAI from the Ypresian (lower Eocene) of the UK, upper Eocene of Germany, and lower Miocene of Germany using non-destructive synchrotron-based X-ray tomography to reveal internal anatomy. None of the samples studied show an anatomy consistent with extant Alpinia or even Zingiberales. The fossils lack the globose shape, often striate external surface, seed coat structure, operculum, and micropylar collar seen in all Alpinia, and lack the chalazal chamber seen in many Alpinia species. Two specimens from the lower Miocene of Germany showed the structure of fruits of Caricoidea CHANDLER (Cyperaceae) with a single-layered exocarp, thick mesocarp, and sclerified endocarp. The other specimens are recognized as Carpolithes albolutum nom. nov. (incertae sedis) from the Ypresian of the UK, C. phoenixnordensis sp. nov. (incertae sedis) from the upper Eocene of Germany, C. bivascularis comb. nov. (incertae sedis) from the lower Miocene of Germany as well as indeterminate tegmens from the lower Miocene of Germany. This reinvestigation demonstrates that there is, as yet, no confirmed fossil record for the extant genus Alpinia. Furthermore, at least four different taxa are recognized from what had been two extinct species, enhancing our understanding of these important European Cenozoic carpofloras.

Minerals, geochemistry and x-ray power characteristics at DSDP Sites 54-424, 60-458 and 60-459

Secondary minerals filling veins and vesicles in volcanic basement at Deep Sea Drilling Project Sites 458 and 459 indicate that there were two stages of alteration at each site: an early oxidative, probably hydrothermal, stage and a later, low-temperature, less oxidative stage, probably contemporaneous with faulting in the tectonically active Mariana forearc region. The initial stage is most evident in Hole 459B, where low-Al, high Fe smectites and iron hydroxides formed in vesicles in pillow basalts and low-Al palygorskite formed in fractures. Iron hydroxides and celadonite formed in massive basalts next to quartz-oligoclase micrographic intergrowths. Palygorskite was found in only one sample near the top of basement in Hole 458, but it too is associated with iron hydroxides. Palygorskite has previously been reported only in marine sediments in DSDP and other occurrences. It evidently formed here as a precipitate from fluids in which Si, Mg, Fe, and even some Al were concentrated. Experimental data suggest that the solutions probably had high pH and somewhat elevated temperatures. The compositions of associated smectites resemble those in hydrothermal sediments and in basalts at the Galapagos mounds geothermal field. The second stage of alteration was large-scale replacement of basalt by dioctahedral, trioctahedral, or mixed-layer clays and phillipsite along zones of intense fracturing, especially near the bottom of Holes 458 and 459B. The basalts are commonly slickensided, and there are recemented microfault offsets in overlying sediments. Native copper occurs in one core of Hole 458, but associated smectites are dominantly dioctahedral, unlike Hole 459B, where they are mainly trioctahedral, indicating nonoxidative alteration. The alteration in both holes is more intense than at most DSDP ocean crust sites and may have been augmented by water derived from subducting ocean crust beneath the fore-arc region.

Appendix A. Microfocus X-ray Computed Tomography cross-sectional images of Joergensenium arcticum Ikenoue, Dumitrica and Bjørklund n. sp.

Radiolarians in the Arctic Ocean have been studied lately in both plankton and sediment trap samples in the Chukchi Sea area. These studies have shed light on new radiolarian taxa, especially within the order Entactinaria, including two new species of Joergensenium, Joergensenium arcticum from the western Arctic Ocean, so far restricted to the Pacific Winter Water in the Chukchi Sea, and Joergensenium clevei hitherto found in the northern part of the Norwegian Sea south of the Fram Strait. The taxonomic position of the order Entactinaria is discussed and the genus Joergensenium has been emended. We have also observed in detail the internal structure of J. arcticum using Microfocus X-ray Computed Tomography and have utilized three-dimensional imaging for the first time in a species description.