Holocene relative sea-level changes on the margin of a glacio-isostatically uplifted area: an example from northern Caithness, Scotland

Abstract

Evidence is presented for Holocene relative sea-level changes on the margin of a glacio-isostatically uplifted area: the lower Wick River valley, northern Caithness, Scotland. Lithostratigraphic, biostratigraphic and chronostratigraphic analyses of intercalated clastic and organic sediments disclose evidence for a rapid rise of relative sea level from at least as low as -3.6 m to +1.5 m O.D. during the mid-Holocene, culminating between c. 6900 and c. 5900 BP. This is correlated with the Main Postglacial Transgression, identified widely in eastern Scotland. Following a subsequent regression, the sediments record two further marine transgressions beginning at c. 4400 and c. 1200 BP. The presence of late-Holocene estuarine deposits as the highest Holocene marine sediments is a situation only recorded to date at one other site in mainland Scotland. The coastal sediment sequence also indicates evidence for a palaeotsunami that occurred at between c. 7300 and c. 7000 BP and was associated with the Second Storegga Slide, one of the world's largest submarine sediment slides, located on the continental slope west of Norway.

Archaeology of the continental shelf: Marine resources, submerged landscapes and underwater archaeology

“…Or it may reflect time lags in the development of the technology and social organisation necessary to build and maintain seaworthy boats capable of dealing with Atlantic maritime conditions and strong tidal current, without which coastal occupation in Norway would have been scarcely possible. In Scotland the earliest sites are similarly present only after about 10 ka, and similar considerations apply, although here the relationship between sea level change and isostatic uplift is also locally variable and stretches of coastline with evidence of earlier archaeological sites may exist that have yet to be explored (Dawson and Smith, 1997;Smith et al, 2006;Wickham-Jones and Dawson, 2006;Karen Hardy, personal communication, 2007).…”

Tsunami Deposits

“…(ATWATER, 1992;CLAGUE et al, 1999;DAWSON et al, 1988;BONDEVIK, 1996;BONDEVIK et al, 1997a,b;BRYANT and PRICE, 1997;DAWSON and SMITH, 1997;HUTCHINSON et al, 1997). The majority of published stratigraphic descriptions of palaeotsunami deposits stem from these areas and clearly illustrate the contrasting patterns of tsunami deposition between areas subject to earthquake-induced coseismic subsidence (Pacific West Coast) and aseismic coastal areas (Scotland and Norway) where tsunami deposition accompanied submarine landslide-generated waves.…”

Mid-Holocene environmental changes in the Bay of Skaill, Mainland Orkney, Scotland: an integrated geomorphological, sedimentological and stratigraphical study

“…Trends of Holocene relative sea-levels (RSL) in Orkney are poorly known (de la Vega Leinert, 1998). However, the evidence that exists is not inconsistent with data obtained from the Wick River valley, northeast Scotland (Dawson and Smith, 1997), some 45 km south of Mainland Orkney. There, apart from minor stillstands, RSL has been continuously rising from approximately −4 m OD at ca.…”