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This paper aims to verify how wave energy and longshore sediment transport rates could have influenced the evolution of the Rio Grande do Sul Holocene barriers in the last 5000 y, assuming that wave climate conditions did not change much during the Middle and Late Holocene. Calculations of wave energy based on visual observations and longshore sediment transport show that both wave energy and sediment transport decrease as the coastline becomes concave (embayed) and increase as the coastline becomes convex (projected). These variations alongshore create a positive and negative imbalance, respectively, in the sediment budget. The long-term operation of these processes has produced progradational barriers in embayments and retrogradational barriers along projections. In the transition zones between embayed to convex coastlines, neither depositional nor erosional processes predominate, creating a sediment balance and producing aggradational barriers. [ABSTRACT FROM AUTHOR]

This paper examines the behaviour of wind flow within a trough blowout on the Manawatu coastline, lower west coast, North Island, New Zealand. The trough blowout is 40 metres long, 20 metres wide and 7-8 metres deep. Virtually any wind flow approaching the blowout from a seaward, alongshore or slightly offshore direction in an arc of at least 200 degrees to the entrance orientation will be directed into the blowout. This happens for a number of reasons including (i) the relatively deep trough topography is an area of intense localised low pressure and winds are "sucked" into the blowout; (ii) topographic steering by the blowout erosional walls; (iii) local flow separation over the blowout wall crests and within the blowout during alongshore and offshore winds, and (iv) re-direction/deflection of low to moderate obliquity approach flows to seawards and over the foredune. This research indicates that winds from a wide range of approach directions will influence blowout flow, sand transport, erosion and deposition patterns, and evolution. It cannot be assumed that only "onshore" winds will transport sediment up a blowout. The implications for routine determination of sand transport by remote sensing in blowouts are significant. [ABSTRACT FROM AUTHOR]

A Holocene sea level curve for Singapore is presented. Radiocarbon dating of a variety of shell, wood, peat and coral material is utilised to derive the curve. Most of the dated material comes from a low energy, 'quietwater' estuarine environment. at Sungei Nipah, and the remainder from the tops of relict Porites coral bommies at Pulau Semakau. Determination of the curve takes into consideration the environmental factors and conditions that determined the elevation range of thematerial dated. The tentative results indicate that the Holocene Post-Glacial Marine Transgression reached present mean sea level around 6,500 to 7,000 years BP, rose to nearly 3 m above present, and began to fall to present MSL around 3000 or less years ago, A comparison ofthe proposed sea-level curve with the curve for Peninsular Malaysia indicates that the highest mid-Holocene sea level may have been closer to +3 m rather than +5 m. [ABSTRACT FROM AUTHOR]