Loch Lomond Stadial and Flandrian shorelines in the inner Moray Firth area,Scotland

Morphological mapping and stratigraphical investigations have identified surface and buried relict marine features in the inner Moray Firth area. The features consist of a buried gravel layer formed during the Loch Lomond Stadial, a buried beach of early Flandrian age, and surface beaches and estuarine flats of mid-late Flandrian age. Analysis of the altitudes of morphological features has identified two buried and five (possibly six) surface glacio-isostatically tilted raised shorelines. The steepest shoreline is associated with the buried gravel layer and slopes down towards N20°E at a gradient of 0.20m/km. Younger shorelines have lower gradients between 0.16–0.03m/km. The shoreline sequence combined with published data defines relative sea-level movements in the area during the last 11000 years. The inner Moray Firth shorelines are correlated with similar features in other areas of Scotland which include the Main Lateglacial, Main Buried and Main Postglacial Shorelines.     

Implications of new Quaternary uplift models for correlation between the Middle and Upper Thames terrace sequences, UK

Modelling of uplift histories in the Upper and Middle Thames valleys has revealed an important difference, in the form of additional early post-Anglian uplift in the Middle Thames, attributed to an Anglian (~ 440 ka) glacio-isostatic effect. Terraces in the Upper Thames around Oxford seem unaffected by glacio-isostasy and their heights show regional uplift of ~ 35–40 m since the Anglian. The result of the glacio-isostasy is that Anglian terraces are significantly higher above the valley floor in the Middle Thames (up to 55 m) than in the Upper Thames. Recognition of this displacement of Middle Thames terraces has solved long-standing problems of correlation between this area and the Upper Thames: the pre-Anglian (Cromerian Complex) age of the Sugworth Channel deposits, indicated by biostratigraphy, is no longer a difficulty, whereas the Hanborough Terrace is now thought to be of Anglian age, albeit incorporating pre-Anglian faunal remains and perhaps with a significant early post-Anglian component. These findings have implications for the understanding of the effects of Middle Pleistocene glacio-isostasy and of landscape evolution on the periphery of glaciated regions.     

Glacio-isostasy and Glacial Ice Load at Law Dome, Wilkes Land, East Antarctica

The Holocene sea-level high stand or “marine limit” in Wilkes Land, East Antarctica, reached 30 m above present sea level at a few dispersed sites. The most detailed marine limit data have been recorded for the Windmill Islands and Budd Coast at the margin of the Law Dome ice cap, a dome of the East Antarctic Ice Sheet (EAIS). Relative sea-level lowering of 30 m and the associated emergence of the Windmill Islands have occurred since 6900 ¹⁴C (corr.) yr B.P. Numerical modeling of the Earth's rheology is used to determine the glacio-isostatic component of the observed relative sea-level lowering. Glaciological evidence suggests that most of EAIS thickening occurred around its margin, with expansion onto the continental shelf. Consequently, a regional ice history for the last glacial maximum (LGM) was applied in the glacio-isostatic modeling to test whether the observed relative sea-level lowering was primarily produced by regional ice-sheet changes. The results of the modeling indicate that the postglacial (13,000 to 8000 ¹⁴C yr B.P) removal of an ice load of between 770 and 1000 m from around the margin of the Law Dome and adjacent EAIS have produced the observed relative sea-level lowering. Such an additional ice load would have been associated with a 40- to 65-km expansion of the Law Dome to near the continental shelf break, together with a few hundred meters of ice thickening on the adjoining coastal slope of the EAIS up to 2000 m elevation. Whereas the observed changes in relative sea level are shown to be strongly influenced by regional ice sheet changes, the glacio-isostatic response at the Windmill Islands results from a combination of regional and, to a lesser extent, Antarctic-wide effects. The correspondence between the Holocene relative sea-level lowering interpreted at the margin of the Law Dome and the lowering interpreted along the remainder of the Wilkes Land and Oates Land coasts (105°–160° E) suggests that a similar ice load of up to 1000 m existed along the EAIS margin between Wilkes Land and Oates Land.     

Strandflat development and Quaternary shorelines on Tiree and Coll,Scottish Hebrides

The islands of Tiree and Coll in the Scottish Inner Hebrides are dominated by staircases of glaciated rock-platform surfaces in Lewisian gneiss that are interpreted here as areas of strandflat. The rock platform surfaces exhibit differential glacio-isostatic uplift from east to west and are considered to indicate at least four separate periods of strandflat formation during prolonged intervals of Quaternary cold climate. It is suggested that many of the well-known areas of high rock platform located farther east in the Scottish Inner Hebrides represent eroded remnants of the strandflat surfaces described here. The existence of the Tiree and Coll strandflat surfaces in conjunction with their formation during periods of Quaternary glaciation implies that they were produced during periods when mainland Scotland was ice-covered yet when the western margin of the ice sheet was normally located east of these islands. A prominent Late-glacial raised shoreline also occurs on both islands and declines in altitude to the west, from 22 m in northeastern Coll to 9 m in western Tiree. It is believed that this shoreline, whose regional gradient is 0.39 m km^?1, may represent part of the Main Wester Ross Shoreline that was formed in the Northwest Highlands of Scotland during a period of glacial advance that interrupted the decay of the last (Late Devensian) ice sheet. The general similarity in altitude between the Late-glacial shoreline features and rock platform surfaces implies that during each period of Quaternary strandflat formation, relative sea-level returned to the same approximate position. This would appear to indicate that the glacio-isostatic and glacio-eustatic components affecting the positions of relative sea level in Scotland have remained in approximate equilibrium throughout the duration of the Quaternary.     

Empirical estimation of isostatic uplift using the lake-tilting method at lake Fegen and lake S?ven, southwestern Sweden

A nonuniform glacio-isostatic uplift results in differential uplift for different parts of a lake. If the lake outlet is situated in the area with the greatest rate of uplift, then the lake will be continuously transgressed. Ancient lake levels can be estimated by dating transgressed peat at different depths in such a lake. Two lakes in southwestern Sweden have been investigated by this method and the course of glacio-isostatic uplift has been determined empirically. The uplift can be expressed by an exponential function through the following formula

地壳均衡与海平面变化

提要:在全球海面变化的近期研究中，无论是均衡模式、还是重力模式，写考虑到冰川均衡作用和水力均衡作用。本文认为，绝对均衡表示地壳均街的最终结果，相对均衡表示地壳均衡中一系列中间过程。这两种均衡之间的差别，往往被人们所忽视。
    定量计算的结果表明，冰盖的吸引不仅使周围的海面升高，而且使内核在外核中产生定向运动。由于参加相对均衡的大陆壳数量不同、宕石圈的强度不同，陆壳与陆充、陆克与洋壳之间将产生不同幅度的垂直运动。这为解释全球海面变化不一致性提供了另一个新思路。
        

地壳形变与海平面变化

本文根据冰川和海平面变化资料，探讨地壳形变对冰川消长和海平面升降的响应，并由此得出可以解释相应的地球物理现象的有益结果。这些结果对地壳形变的测量和地震预报有重要意义。