A brief history of Pachoras from the 5th to the 7th centuries

The development of Pachoras, an important town in mid-5th century AD Nobadia, was broken violently by a flood at the beginning of the second half of the 6th century. The settlement and enclosure were devastated and abandoned until the close of the 6th century when the Cathedral of Aetios was built on a 5-m-high dune, engulfing the interior of the enclosure.

Putative Martian Microbes Formed Plentiful Ooids on Mars.

NASA’s Mars Rover Curiosity discovered plentiful indigenous spherical ooids at High Dune and Namib Dune in Bagnold dune field, Gale Crater, Mars. The spherical Martian ooids contain nuclei and range from around 0.15 mm to 0.5 mm in diameter. Colors of the spherical Martian ooids are various, including white, yellow translucent, green, gray, and yellow. The spherical Martian ooids should have been formed by microbes, because ooids of Earth have recently been found to be formed by microbes and microbial borings are found in ooids of Earth and of Mars. There is no evidence that proves ooids are formed by agitated water.

EFFECT OF FUTURE STORM CLUSTERING ON BEACH/DUNE EVOLUTION AND COASTAL FLOODING

Future storm impacts on dune evolution due to changing storm frequency were simulated in XBeach at an exemplary dune system, Formby Point, UK. Probabilistic approaches were used to establish the future storm clusters from 2015 to 2065 in three scenarios, using measured data in Liverpool Bay. Cross-shore profile simulations were carried out in two series: Recovery and Cluster. Recovery used the same initial profile assuming that the profile is fully recovered when the subsequent storm event occurs. Cluster used the modified profile from the previous storm event. Within a single event, the maximum erosion and accretion of the profile occurred under the Recovery conditions due to the presence of a pronounced nearshore ridge-runnel pattern that evolved during severe storm events. Only a few storm events impacted on the upper dune area resulting in a bed level change, which under the Cluster approach was more noticeable when compared with the Recovery approach. The inter-tidal area experienced erosion while the sub-tidal area showed accretion in both the Recovery and the Cluster approaches, and the agreement of bed level change was considerably higher than that in the upper dune area. Vulnerability of the upper dune area increases in the Cluster approach as the initial storm events flatten the nearshore ridge-runnel pattern, and then the severe storm events directly impact on the dune front. High dune elevation at Formby Point prevents lowering of the dune crest due to the storm cluster erosion and therefore it can still withstand against flooding. Spatial modelling of the dune system is required to gain more insights of erosion and flood prone areas along this coast.

WAVE OVERWASH OF VEGETATED DUNES

Sand dunes play a significant role during coastal storms by absorbing the impacts of storm surge and high waves. Therefore, rapid profile changes and destruction of sand dunes, which may be caused by wave-induced overwash, lead to an increased flood risk landward of dunes. The effects of vegetation on dune erosion and overwash during storm events, however, have never been studied. This study is based on a laboratory experiment investigating the effects of woody plants on dune erosion and overwash of high and low dunes. During the five tests conducted foredune scarping was observed for the three high dune tests but did not occur for the two low dune tests. A narrow vegetation placed on the steep backdune of the high dune did not reduce wave overtopping and sand overwash. However, the wide vegetation figuration, which covered the backdune and foredune, reduced foredune scarping, prevented wave overtopping initially and reduced sand overwash after the initiation of wave overtopping for the high dune. It also slowed down the erosion process of the low dune significantly by retarding wave uprush and reducing wave overtopping and overwash.

Evidence of High Sea Level during Isotope Stage 5c in Queensland, Australia

Thirty-nine species of scleractinian corals have been recovered from under a high dune on the western (mainland) side of North Stradbroke Island, eastern Australia. The corals are associated with thin intertidal sediments and their good condition implies burial in situ and preservation in a saturated zone. Most likely this occurred as the coast prograded and a large dune advanced into the littoral zone, burying intertidal sediments and coral. The species assemblage indicates a sheltered environment but one open to the ocean without wide fluctuations in salinity. Three species yielded a mean 230Th/234U age of 105,000 yr B.P. which is significantly younger than the nearest Pleistocene corals at Evans Head, New South Wales. The corals provide evidence of a sea stand near present sea level during isotope Stage 5c, which is considerably higher than previously suggested for this period. Their good condition implies that the overlying parabolic dune is of comparable age and formed during that high stand of sea level. Also, the isotope age provides a maximum period for the development of giant podzols in the podzol chronosequences on coastal dunes in southern Queensland.