Trace elements in the pelagic coelenterate, Velella lata

Twelve elements (Cu, Ni, Mn, Ti, Si, Cr, Sr, V, Ba, Ag, Pb, and Mo), not previously reported from the genus Velella, were found in the ash of V. lata; zirconium was also searched for but was not found. Cu, Ni, Mn, Ti, Mg, Ca, and Al were determined quantitatively. The concentration of trace elements in the whole animal and in five different tissues of V. lata was determined in specimens ranging from 14.4 to 84.6 mm in length. The Mg:Ca ratio in Velella is lower than that in sea water but. higher than that in Scyphozoa. Presumably this is due to concentration of magnesium in the chlorophyll of commensal zooxanthellae

Silicified Mississippian Paleosol Microstructures: Evidence for Ancient Microbial-Soil Associations

Silica-replaced microfeatures in a well-developed, Upper Mississippian paleosol from north-central Arizona, were examined by scanning electron microscopy using back-scattered electron imagery. Preserved microfeatures include hollow and solid tubiform filaments and mycelium-like stringers which radiate from problematic (biogenic?) soil structures. Preservation of these features suggest that microstructures in the soil zone are not uniformly destroyed during post-diagenetic silica replacement and that biological soil symbionts may have occurred as early as the Upper Mississippian (~280 Mya)

Hannibal's trek across the alps: Geomorphological Analysis of sites of geoarchaeological interest

International audienceA ~2200 year-old question related to Hannibal's invasion route across the Alps into Italia, has been argued by classicists without recovery of material evidence. A comparison of topographical descriptions in the ancient literature with environmental parameters in the Alps, attempted here for the first time, provides a database against which various pathways can be assessed. Identification of sites using geological, geomorphological, astronomical, chemical and petrological methods leads to the exclusion of certain transit points and targeting of others where geoarchaeological excavation might yield important evidence related to the military culture of ancient Carthage

Asian dust-storm activity dominated by Chinese dynasty changes since 2000 BP

The Asian monsoon (AM) played an important role in the dynastic history of China, yet it remains unknown whether AM-mediated shifts in Chinese societies affect earth surface processes to the point of exceeding natural variability. Here, we present a dust storm intensity record dating back to the first unified dynasty of China (the Qin Dynasty, 221–207 B.C.E.). Marked increases in dust storm activity coincided with unified dynasties with large populations during strong AM periods. By contrast, reduced dust storm activity corresponded to decreased population sizes and periods of civil unrest, which was co-eval with a weakened AM. The strengthened AM may have facilitated the development of Chinese civilizations, destabilizing the topsoil and thereby increasing the dust storm frequency. Beginning at least 2000 years ago, human activities might have started to overtake natural climatic variability as the dominant controls of dust storm activity in eastern China

Habitability of the Phoenix landing site

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95488/1/jgre2706.pd

Nanoscale Observations Support the Importance of Chemical Processes in Rock Decay and Rock Coating Development in Cold Climates

Conventional scholarship long held that rock fracturing from physical processes dominates over chemical rock decay processes in cold climates. The paradigm of the supremacy of cold-climate shattering was questioned by Rapp’s discovery (1960) that the flux of dissolved solids leaving a Kärkevagge, Swedish Lapland, watershed exceeded physical denudation processes. Many others since have gone on to document the importance of chemical rock decay in all cold climate landscapes, using a wide variety of analytical approaches. This burgeoning scholarship, however, has only generated a few nanoscale studies. Thus, this paper’s purpose rests in an exploration of the potential for nanoscale research to better understand chemical processes operating on rock surfaces in cold climates. Samples from several Antarctica locations, Greenland, the Tibetan Plateau, and high altitude tropical and mid-latitude mountains all illustrate ubiquitous evidence of chemical decay at the nanoscale, even though the surficial appearance of each landscape is dominated by “bare fresh rock.” With the growing abundance of focused ion beam (FIB) instruments facilitating sample preparation, the hope is that that future rock decay researchers studying cold climates will add nanoscale microscopy to their bag of tools