Fort Augustus lies within the Great Glen at the south-western end of Loch Ness (Merritt et
al., 2013, fig.17). The settlement straddles the Caledonian Canal, which follows the valley of
the River Oich south-westwards towards Loch Oich and, eventually, Fort William. The
landforms and deposits in the vicinity of Fort Augustus include drift limits, kame-and-kettle
topography and raised lake shorelines. They provide important information for interpreting
events that occurred during late-glacial times, in particular, evidence for re-depression of the
Earth's crust by the build-up of ice in the western Highlands during the Loch Lomond Stadial
(LLS) (Firth, 1986, 1989), and for catastrophic drainage of the former ice-dammed lake in
Glen Spean and Glen Roy, some 30 km to the south-west, towards the end of the Stadial
(Sissons, 1979a, 1981). Three sites are described here; Borlum (NH 384 084), the ‘north
shore’ of Loch Ness (NH 386 105) and Auchteraw (NH 364 082) (Fig. 1). A summary of
each site is given below together with some new information obtained from a recent
geological survey of the district (BGS, 2012). All modern BGS mapping around Fort
Augustus is available digitally or as paper maps at the 1:10,000 scale.
This Sheet Description describes the Quaternary and solid geology of the Umm Azzimul 1:100 000 scale geological map. The Umm Azzimul district covers approximately 2700 km2 in the far southeast of the UAE along the border with Saudi Arabia and Oman. This district spans the transition from the extensive sand sea of the Ramlat ar Rabbad in the northwest to the distal alluvial fan sediments and Miocene limestone outcrops along the border with Oman around Al Manadir and Umm Azzimul, and includes the eastern extension of the Liwa megabarchan field.
The oldest rocks in the area are the Miocene Dam Formation limestones and dolomites that form flat or very gently sloping limestone pavements within the interdunes in the far southeast of the district. In the northeast, these are partially overlain by the fluvial sands and gravels of the Hili Formation. These fluvial gravels represent the very distal end of a large alluvial fan system that extends out from the Hajar Mountains. The lithological composition of these gravels reflects their source area in the Hamrat Duru region of Oman, rather than the ophiolite source seen further north. These alluvial fans peter out in a series of continental sabkhas underlain by both fluvial and aeolian sands.
The major part of the Umm Azzimul district consists of aeolian dunes of various morphologies. The dune morphology changes systematically in a south and south-easterly direction across the district, reflecting the migration of the dunes driven by the prevailing wind. In the northwest, the extensive Ramlat ar Rabbad sand sea is comprised of large barchan dunes that get progressively smaller to the south and east. Across the central part of the district, these morph into more discrete megabarchan dunes and dune ridges separated by flat interdune sabkhas. Much of the south-western part of the sheet is occupied by large crescentic megabarchan dunes up to 130 m high that extend west into the Liwa area, whilst in the east, the elongate linear dune ridges, punctuated by numerous star dunes and occasional megabarchans are more common. The star dunes become more frequent close to the Oman border. These dune ridges and star dunes can rise up to 100 m above the surrounding interdunes. Most of the district is sparely populated, with no major urban areas and few roads. The south of the region is also host to the relatively small Qusawira and Mender oilfields.
ABSTRACT The Gaick is an enigmatic glaciated landscape in the Central Grampians, Scotland, dominated by an expansive dissected plateau. Previous studies have postulated widely differing interpretations of the glacial landforms and current understanding of the glacial events in this area is partly restricted by the absence of detailed glacial geomorphological mapping. To address this issue, we present a comprehensive 1: 46,000-scale glacial geomorphological map, covering an area of ∼520 km2. A combination of detailed field mapping and interpretation of aerial photographs and Digital Surface Models (DSMs) has revealed a variety of glacial, periglacial and fluvial landforms, including an abundance of moraines and meltwater channels within valleys. We also identify a glacial sediment-landform assemblage, dissected glaciogenic material, that has not previously been reported in the Scottish Highlands. The geomorphological map provides the necessary foundation for elucidating the extent, dynamics and timing of former glaciation in the area.
The far north-east of Scotland encompasses a wide range of landscapes, from the rolling hills of Moray and the coastal flagstone cliffs of Caithness, to the blanket peat bogs of the Flow Country and the ancient rugged mountains of eastern Sutherland. These landscapes have all formed during a long and complex geological history, from rocks that were buckled and warped by continental collisions that occurred many hundreds of millions of years ago, to the sculpting of the hills and valleys by glaciers just a few thousand years ago. Since Neolithic times, the inhabitants of the region have made use of its geological resources and also changed its appearance irrevocably. This book describes the whole of that geological and human history, laying bare the events that have shaped the landscape of this remote but intriguing corner of Scotland.
This Sheet Description describes the Quaternary and solid geology of the Abu Dhabi 1:100 000 scale geological map. The Abu Dhabi district covers 3620 km2 along the Arabian Gulf coast including the northern part of Saadiyat island, Abu Dhabi, part of the Mussafah district and many of the islands to the west. These include Futaisi, Bu Kesheishah, Halat al Bharaini, Al Dabiya, Bu Qumah, Bu Shara, Al Qanatir and Al Rafiq. The sheet also includes a significant part of the coastal plain southwest of Abu Dhabi between Shunayyin in the east to Borquat al Rashid in the west, and south to Maharqah, across which the main E11 coastal highway runs. In the southeast of the district, an area of higher ground is formed of Miocene rocks draped by a variable sequence of cemented and unconsolidated dune sand. The region hosts several major oilfields including the Rumaitha, Shanayel, Al Dabb’iya, Umm al Dalkh, Al Mutarib and Umm al Lulu fields.
The region is dominated by a series of offshore islands, part of a chain of barrier islands that extend from north of Abu Dhabi to Marawah Island, west of the present area. These islands, along with the sea-ward margin of the coastal plain are mostly comprised of a thin sequence of intensively studied Holocene marine carbonates termed the Abu Dhabi Formation. These sediments represent a transgressive-regressive sequence, and form the classic carbonate-evaporitic ‘sabkhas’ for which the region is justly famous. The Abu Dhabi Formation includes a range of marine and supratidal facies including coastal spits, bars and beach ridges, lagoonal muds, algal mats and ooidal tidal deltas deposited over the last 10 000 years. The southern limit of the Holocene transgression is marked by a beach ridge running parallel to the coast and clearly visible on satellite imagery.
The barrier islands commonly have a core of well-cemented Pleistocene carbonate dune sand (Ghayathi Formation) around which the carbonate spits, bars and ridges of the Abu Dhabi Formation were accreted. The islands have been largely deflated down to the local water-table leading to the development of extensive sabkhas. Consequently, the islands are generally flat but punctuated by small Ghayathi Formation mesas and zeugen, forming mushroom-shaped outcrops rising up to 6 m above sea-level, locally capped with marine limestones of the Late Pleistocene Fuwayrit Formation. Offshore to the north of the island, below low water, is the Great Pearl Bank, an area of reefs and coralgal sands named after the former pearling industry in the region.
South of the Holocene beach ridge, much of the onshore area is an extensive, very gently sloping coastal plain, dominated by a deflated planation surface developed on either unconsolidated quartzose aeolian sand or well cemented carbonate grainstones of the Ghayathi Formation. The deflation surface is commonly marked by secondary gypsum forming a sabkha. The Ghayathi Formation palaeodunes are locally well exposed, forming spectacular wind-sculpted mesas and zeugen both on the islands and within the lagoons, but also onshore draping the Miocene rocks in the southeast of the district.
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