Search

A new species of Spirobranchus (Annelida: Serpulidae) is described based on specimens collected at the coastal Shonan area of Sagami Bay and the adjacent areas of Honshu, Japan. Spirobranchus akitsushima sp. nov. forms large aggregations in the intertidal rocky zone of warm-temperate Japanese shores. This species was referred to as Pomatoleios kraussii (Baird, 1864) until the monotypic genus Pomatoleios was synonymized with Spirobranchus. This new species is formally described based on morphologically distinct Japanese specimens with supporting DNA sequence data. The calcareous opercular endplate of Spirobranchus akitsushima sp. nov. lacks a distinct talon, but some specimens have a slight rounded swelling on the endplate underside, while in other species of the S. kraussii complex a talon is present, usually extended, and with bulges. We examined sub-fossil tube aggregations of the new species and suggest that such aggregation stranded ashore is a good indicator of vertical land movements (uplift and subsidence) resulting from past events, such as earthquakes, in Honshu, Japan. [ABSTRACT FROM AUTHOR]

Beachrocks are well known as significant proxies for paleoenvironmental analysis as they indicate the coastal evolution. The combination of geomorphological and archaeological sea level indicators has a significant contribution to the coastal paleogeographic reconstruction. In this study, we studied a beachrock from the Diolkos area (West Corinth canal, Greece) and remnants of Diolkos slipway to reconstruct the coastal evolution before Diolkos construction until today. We conducted detailed mapping of Diolkos beachrock using DGPS-GNSS, as well as mineralogical analysis and OSL dating of beachrock samples. The results showed that a beachrock slab was preserved before the construction of Diolkos below it, followed by its submergence by a co-seismic event after Diolkos abandonment during 146 B.C. Consequently, a new beachrock was developed on top of the submerged Diolkos around 120 ± 14 A.D. The RSL was stable until 1596 ± 57 A.D. when the beachrock developed even closer to the present-day coastline. After 1596 A.D., it was uplifted by 12 cm until it reached today's condition. [ABSTRACT FROM AUTHOR]

Beachrocks are well known as significant proxies for paleoenvironmental analysis as they indicate the coastal evolution. The combination of geomorphological and archaeological sea level indicators has a significant contribution to the coastal paleogeographic reconstruction. In this study, we studied a beachrock from the Diolkos area (West Corinth canal, Greece) and remnants of Diolkos slipway to reconstruct the coastal evolution before Diolkos construction until today. We conducted detailed mapping of Diolkos beachrock using DGPS-GNSS, as well as mineralogical analysis and OSL dating of beachrock samples. The results showed that a beachrock slab was preserved before the construction of Diolkos below it, followed by its submergence by a co-seismic event after Diolkos abandonment during 146 B.C. Consequently, a new beachrock was developed on top of the submerged Diolkos around 120 ± 14 A.D. The RSL was stable until 1596 ± 57 A.D. when the beachrock developed even closer to the present-day coastline. After 1596 A.D., it was uplifted by 12 cm until it reached today’s condition.

Abstract: The vertical range of past sea level indicated by tidal flat deposits is equal to the sum of the sediment thickness and tidal range. Defining position of the dated sample in tidal flat deposits can increase the accuracy of former sea level determinations. The salt-water peaty layer often contains mixtures of autochthonous and allochthonous organic carbon and the tidal flat deposits may contain biological remains transported from shallow marine sources. These allochthonous remains have older ages than those of the layers containing the dated materials. Most published 14C data on the East China Sea Shelf are inadequate to define a precise postglacial sea level rise curve. Good results in determining both precise former sea levels and reliable 14C ages can be provided by selecting large plant roots and wood fragments from peaty layers, and selecting less worn foraminifera tests and mollusk shells of dominant species in modern equivalent environments (such as foraminifera Ammonia beccarii vars. or mollusk Corbicula fluminea) from the peaty layer, its close overlying deposits and the base of tidal flat deposits without a basal peaty layer. The stepwise model for postglacial sea level rise on the East China Sea Shelf (Liu, 2001; Liu et al., 2004) was mostly determined by freshwater peat, shallow marine and subtidal samples, which cannot provide precise water levels. The reliability of many 14C ages used is also questionable due to unknown proportions of allochthonous material. Thus the stepwise model is unsupported by available data. A rough sea level curve in last 13,000yr on the East China Sea Shelf is herein proposed. It seems simple but is effective based on valid data. [Copyright &y& Elsevier]