The remains of the rocks were transported by the glacier at various distances, as a result of which a moraine formed. As part of this diverse mass, you can find clay particles, sand, the remains of gravel, as well as stones of various shapes and sizes, which are engraved in a certain way and have furrows on their surface.
Glacial deposits and landforms
Glaciers are directly involved in the formation of the terrain. They are formed in the climatic zones of the polar regions, at high altitude in the mountains. The movement of the glacier is caused by one of the qualities of ice, the ability to change location under a certain pressure. At the same time, ice plasticity, which increases in direct proportion to temperature, occupies an important place. As a rule, the movement takes place at a 30-meter depth.
During movement, the initial shape of the glacier can change, shears, cracks, folds of different shapes and sizes are formed. As for the speed of movement, on average they are small, reaching about 100 meters per year. As a result of the melting of glaciers , meltwater flows and entire glacial lakes are formed, which implies the formation of new, altered sediment composition and landscape changes.
Types of Glacial Deposits
About a third of the entire earth's surface has been covered by glaciers to date. Now this figure is 10%. Even a single glaciation can cause global change. All ice deposits can be divided into two large groups: sorted and unsorted.
Answering the question, as a result of which the moraine was formed, it is necessary to clarify what kind of glacial deposits it belongs to. It cannot be called completely unsorted, although it belongs to this group. Morena is poorly sorted debris directly picked up or deposited by a glacier.
Glacial residues sorted by water belong to another category. They are also subdivided into those that separated not far from the glacier, in direct contact with it, and into remnants that were washed beyond its limits by rivers or melted streams.
Glacier Contact Deposits
Sorted glacial deposits have a rather diverse structure, due to which one can observe the variability of relief forms. Of greatest interest are deposits at the contact with the glacier. Such a formation as kama terraces arose as a result of the accumulation of various rocks along the icy edges of the glacier, located mainly in the valleys of rivers and reservoirs. When the ice melted, these fragments separated along the sides of the valleys. Those that fell under icing led to landslides and landslides. And the educated hills were called kams.
Ozy is another glacial sorted sediment resembling undulating ridges consisting of large sandy rocks and gravel. Once upon a time they were at the bottom of tunnel drains and very rarely climbed to the surface.
Moraines: characterization according to E.V. Shantser
The main moraines incorporate particles of different sizes, from clay ones to boulder ones. Characteristic features are areal occurrence, strong rocks of clastic material and the absence of obvious layers. Among the composite material of this type of moraine, which is characterized by a high density, residues of rocks that are completely atypical for a given area can be found. Due to its strength, this material can be actively used in construction work.
The composition and color characteristics of the moraine are greatly influenced by the geological structure of the glacier itself. When it melts on the slopes of the valley, a certain number of layers of the longline type are formed, which can form whole moraine terraces. The oldest deposits and loose fragments are smoothed out or completely washed out by melt water, stormy rivers.
Morena in the composition of glacial formations
The glacial group of sediments is very diverse and includes:
- glacial moraines;
- fluvioglacial precipitation as a result of melting glaciers;
- limnoglacial remains of glacial reservoirs;
- solifluction deposits;
- marine glacial sediments.
What resulted in the formation of moraine? These glacial deposits are formations of poorly sorted debris and look like heaps of various blocks, stones mixed with sand and clay. At first glance, all this mass is located in a completely random manner, but this is not so. Upon closer and more detailed examination, it can be concluded that when the glacier melts, the inner layers of the moraine are transferred to its base. But sometimes strong ice flows are thoroughly washed by the moraine, as a result it represents a large number of large boulders.
Three types of moraine
Glacier moraines come in three types. The inner glacial moraine is formed as a result of the penetration of debris into the inner glacial layers. During the movement of glaciers in different terrain, they take with them rocks, boulders, sand and clay that come across on the way. The bottom moraine is formed by scraping and transferring rock debris, and then, depending on certain factors, the strength and speed of movement transfers this collected material in itself, at the base and in deeper layers of the glacier.
End moraines form, as a rule, on the outskirts of a glacier. These blocks filled with rocks are formed when the glacial margin for a long time was in one place, and the glacier at the same time brought here continuously new clastic material. This is possible if the glacier is restricted due to some protrusion or other obstacle. The ultimate moraine in its appearance resembles hills and ridges located parallel to each other. Such formations include not only hard rocks, but also loose layers of river or lake sediments, which the glacier picked up.
Morena: mechanical classification
In their composition, moraines are very diverse. The following types of glacial moraines are distinguished:
- rocky;
- sandy;
- sandy loam;
- loamy;
- clayey.
In its pure form, moraine is quite rare, usually in certain areas there is a mixed composition. In order to correctly diagnose and study glacial deposits, a single study of rocks and materials is not enough, it is necessary to understand their paragenetic relationship with other formations.
Distinctive properties of moraine
Multicomponent material is selected by the glacier during gliding, as a result of which a moraine has formed, which can either be transported (mobile) or deposited (genetic forms of ice formations separated from the glacier). Morena can exist as a separate form of glacial landscape. The main one consists of loose sediments, which are characteristic of plains, drumlins, and hilly moraine reliefs.
Water-glacial deposits are obtained during sedimentation in the upper layers of the glacier. This type of moraine is filled with rough rubble and large boulders. Final deposits are formed at the final point of movement of the glacier with the beginning of its melting. The moraine composition of minerals (quartz, mica, feldspar) is directly dependent on the rocks bent under the body of the glacier. It also affects the position of the moraine inside the ice mass, as well as the processes of transformation of residues during prolonged movement.
Glacial deposits are both continental and mountain. They differ in a number of parameters, in particular, the processes of relief formation and the forms, composition and types of deposits.