Glaciokarst is a geological term that refers to a specific type of karst landscape that been influenced significantly by past glacial activity. [1]
Karst landscapes consist of distinctive surface and subsurface landforms. These landforms are a result from dissolution of soluble rocks like limestone, gypsum or dolomite by water. [2] In the case of Glaciokarst, the karst landscape has been shaped by the action of glaciers due to glacial erosion, deposition or other processes that directly impact the soluble rocks in the area. [3] This unique blend of processes results in a landscape that not only documents the deep history of glaciation but also exemplifies the resilience and adaptability of the Earth's geological systems.Examples of glaciokarst landscapes are found in the Western Alps or the Eastern Alps such has Tennengebirge, Dachstein Mountains and even the Altai Mountains. [4]
Glaciokarst landscapes form through a interactions between ice and certain types of rock , like limestone, gypsum, or dolomite, that are able to dissolve in water. [5] When vast glaciers move over the land, they shape it by carving valleys and other glacial features. As these glaciers melt, the water formed contains a mild acid that can dissolve these specific rocks, creating gaps and hidden spaces underground. [5] Over time, the combination of glacial sculpting and rock dissolution produces distinct landforms such as sinkholes and caves within the regions affected by glaciers. [5] This creates a unique landscape showcasing the combined effects of glacier movement and the gradual erosion of rock, offering a fascinating array of features for exploration and study. [5]
An example of a formation of a glaciokarst is the glaciokarst of the Velež Mountain. This landscape showcase a karst terrain significantly affected by glacial processes during the Pleistocene period. [3] This landscape includes valley glaciers and a plateau glacier, primarily located on the northern slopes. The northern slopes exhibit features shaped by glacial erosion, presenting cirques, pavements, and roches moutonnées covered with small-scale karst features. [3] While in the lower regions of the Velež Mountain, formed significant moraine ridges, lateral moraines, breach-lobe moraines, and smaller recessional moraines, varying in composition and heights. [3] The absence of valley discharge and the presence of indicators of glacial erosion hint at a pattern of vertical drainage of sub-glacial waters into the karst landscape. [3] The outwash fans that filled some hollow areas displayed a change in the kind of dirt they carried, going from rough near the ice's edge to finer stuff as they moved away. This change shows how much glaciers shaped the mountain's land and water pathways. [3]
Glaciokarst landscapes have an array of unique features resulting from the fusion of glacial and karstic processes. Typical features found in glaciokarst landscapes may include glacially carved valleys, sinkholes formed by the dissolution of bedrock, and ice-contact features. [6] [7] Glaciokarsts encompass various classifications based on multiple criteria. [8] These classifications include distinctions regarding the presence of meltwater, the types of karstic rocks involved, proximity to the Equator, the relationship between glaciers and karst formations, the geographical location of the glaciokarsts, and the rate of glaciation. [6] [9] Glaciokarsts are predominantly composed of limestone but can also form on marble, dolomite, and gypsum. [2] Structurally, they are categorized into Alpine or continental types, and geosyncline or tabular types. [6] They can exist in marine or terrestrial environments, each with varying levels of precipitation and ice cover impacting the karst formations. [1] The interaction between the processes of glaciation and karstification can create intriguing geological formations and landscapes.
A glacier is a persistent body of dense ice that is constantly moving under its own weight. A glacier forms where the accumulation of snow exceeds its ablation over many years, often centuries. It acquires distinguishing features, such as crevasses and seracs, as it slowly flows and deforms under stresses induced by its weight. As it moves, it abrades rock and debris from its substrate to create landforms such as cirques, moraines, or fjords. Although a glacier may flow into a body of water, it forms only on land and is distinct from the much thinner sea ice and lake ice that form on the surface of bodies of water.
A moraine is any accumulation of unconsolidated debris, sometimes referred to as glacial till, that occurs in both currently and formerly glaciated regions, and that has been previously carried along by a glacier or ice sheet. It may consist of partly rounded particles ranging in size from boulders down to gravel and sand, in a groundmass of finely-divided clayey material sometimes called glacial flour. Lateral moraines are those formed at the side of the ice flow, and terminal moraines were formed at the foot, marking the maximum advance of the glacier. Other types of moraine include ground moraines and medial moraines.
Till or glacial till is unsorted glacial sediment.
Geomorphology is the scientific study of the origin and evolution of topographic and bathymetric features generated by physical, chemical or biological processes operating at or near Earth's surface. Geomorphologists seek to understand why landscapes look the way they do, to understand landform and terrain history and dynamics and to predict changes through a combination of field observations, physical experiments and numerical modeling. Geomorphologists work within disciplines such as physical geography, geology, geodesy, engineering geology, archaeology, climatology, and geotechnical engineering. This broad base of interests contributes to many research styles and interests within the field.
Glaciology is the scientific study of glaciers, or more generally ice and natural phenomena that involve ice.
A landform is a natural or anthropogenic land feature on the solid surface of the Earth or other planetary body. Landforms together make up a given terrain, and their arrangement in the landscape is known as topography. Landforms include hills, mountains, canyons, and valleys, as well as shoreline features such as bays, peninsulas, and seas, including submerged features such as mid-ocean ridges, volcanoes, and the great ocean basins.
Landforms are categorized by characteristic physical attributes such as their creating process, shape, elevation, slope, orientation, rock exposure, and soil type.
A cirque is an amphitheatre-like valley formed by glacial erosion. Alternative names for this landform are corrie and cwm. A cirque may also be a similarly shaped landform arising from fluvial erosion.
Glacial landforms are landforms created by the action of glaciers. Most of today's glacial landforms were created by the movement of large ice sheets during the Quaternary glaciations. Some areas, like Fennoscandia and the southern Andes, have extensive occurrences of glacial landforms; other areas, such as the Sahara, display rare and very old fossil glacial landforms.
Orjen is a transboundary Dinaric Mediterranean limestone mountain range, located between southernmost Bosnia and Herzegovina and southwestern Montenegro.
A terminal moraine, also called an end moraine, is a type of moraine that forms at the terminal (edge) of a glacier, marking its maximum advance. At this point, debris that has accumulated by plucking and abrasion, has been pushed by the front edge of the ice, is driven no further and instead is deposited in an unsorted pile of sediment. Because the glacier acts very much like a conveyor belt, the longer it stays in one place, the greater the amount of material that will be deposited. The moraine is left as the marking point of the terminal extent of the ice.
In glaciology, a roche moutonnée is a rock formation created by the passing of a glacier. The passage of glacial ice over underlying bedrock often results in asymmetric erosional forms as a result of abrasion on the "stoss" (upstream) side of the rock and plucking on the "lee" (downstream) side. Some geologists limit the term to features on scales of a metre to several hundred metres and refer to larger features as crag and tail.
Plucking, also referred to as quarrying, is a glacial phenomenon that is responsible for the weathering and erosion of pieces of bedrock, especially large "joint blocks". This occurs in a type of glacier called a "valley glacier". As a glacier moves down a valley, friction causes the basal ice of the glacier to melt and infiltrate joints (cracks) in the bedrock. The freezing and thawing action of the ice enlarges, widens, or causes further cracks in the bedrock as it changes volume across the ice/water phase transition, gradually loosening the rock between the joints. This produces large pieces of rock called joint blocks. Eventually these joint blocks come loose and become trapped in the glacier.
The Lyngen Alps are a mountain range in northeastern Troms og Finnmark county in Norway, east of the city of Tromsø. The mountain range runs through the municipalities of Lyngen, Balsfjord, and Storfjord. The mountains follow the western shore of the Lyngen fjord in a north-south direction. The length of the range is at least 90 kilometres (56 mi) and the width is 15–20 kilometres (9.3–12.4 mi). The mountains dominate the Lyngen Peninsula, which is bordered by the Lyngen fjord to the east, and the Ullsfjorden to the west.
U-shaped valleys, also called trough valleys or glacial troughs, are formed by the process of glaciation. They are characteristic of mountain glaciation in particular. They have a characteristic U shape in cross-section, with steep, straight sides and a flat or rounded bottom. Glaciated valleys are formed when a glacier travels across and down a slope, carving the valley by the action of scouring. When the ice recedes or thaws, the valley remains, often littered with small boulders that were transported within the ice, called glacial till or glacial erratic.
A karst window, also known as a karst fenster, is a geomorphic feature found in karst landscapes where an underground river is visible from the surface within a sinkhole. In this feature, a spring emerges, then the discharge abruptly disappears into a sinkhole. The word fenster is German for 'window', as these features are windows into the karst landscape.
The glacial series refers to a particular sequence of landforms in Central Europe that were formed during the Pleistocene glaciation beneath the ice sheets, along their margins and on their forelands during each glacial advance.
Old and Young Drift are geographic names given to the morainic landscapes that were formed in Central Europe; the Old Drift during the older ice ages and the Young Drift during the latest glaciations – the Weichselian in North Germany and the Würm in the Alps. Their landforms are quite different. Areas of Old Drift have been heavily flattened and transformed as a result of geomorphic processes such as denudation and erosion, whilst areas of Young Drift have largely retained their original shape. Whilst the majority of Old Drift moraines were formed during the Saale glaciation about 130,000 to 140,000 years ago, the Young Drift moraines in Central Europe are only about 15,000 to 20,000 years old. The terms Old and Young Drift are used for all elements of the glacial series even though the meltwater deposits and landforms are not strictly moraines.
The geology of Estonia is the study of rocks, minerals, water, landforms and geologic history in Estonia. The crust is part of the East European Craton and formed beginning in the Paleoproterozoic nearly two billion years ago. Shallow marine environments predominated in Estonia, producing extensive natural resources from organic matter such as oil shale and phosphorite. The Mesozoic and much of the Cenozoic are not well-preserved in the rock record, although the glaciations during the Pleistocene buried deep valleys in sediment, rechanneled streams and left a landscape of extensive lakes and peat bogs.
The Edaga Arbi Glacials are a Palaeozoic geological formation in Tigray and in Eritrea. The matrix is composed of grey, black and purple clays, that contains rock fragments up to 6 metres across. Pollen dating yields a Late Carboniferous to Early Permian age.
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