Where are and how basalt columns were formed?
Column separateness (in popular speech - basalt columns, columns) - the phenomenon not unique as often write, but rare. The author found out these nature sanctuaries only in 24 countries (50 exposures) though they also have to be everywhere where basalts are opened with erosive processes. Their structure also not always truly basalt - there are also other rocks (diorites, dacites, liparita). But is closer than
to a body …, to basalt. And you what thought? In geology such educations are called as a geological body (for example, the intrusion - a geological body …). In sense, not warm, but volume!
At first - pictures of Russia.
1. Cape Column, island of Kunashir . The cape in the east of the island of Kunashir. Is in It is southern - the Kuril city district of the Sakhalin region of Russia. It is formed by volcanic breeds of a volcano of Mendeleyev. The cape represents the steep rocks up to 40 m high pressing in Nemuro Strait several ledges. Gradually rocks collapse, forming at feet blockages of stone “bars“.
2. Kamchatka Krai .
A) Extrusive dome Gigilen, volcano Ichinsky Volcano .
Ichinsky Volcano - stratovulkan in the central part of the peninsula of Kamchatka. The top of a volcano is the highest point of the Central Range. The volcano is located on its western slope, in upper courses of the rivers Fast Hayryuzova, Ich, Fast Kozyrevskaya, is the only active volcano of ridge and now shows weak fumarolny activity.
B) Coast of a bay of Olga . A bay Olga of Kronotsky Biosphere Reserve for mammals - the popular summer resort, whales hurry to acquire fat and to gambol in the protected reserved water area since the beginning of May.
3. North Caucasus. Elbrus, Kabardino - Balkaria, Terskol - the village in the Elbrus region of Kabardino - Balkaria, is included into the rural settlement Elbrus).
4. Krasnoyarsk Krai .
A) Taimyr Peninsula . National natural biospheric park “Taimyr“.
B) The exposure “Red Stones“ is in vicinities of Talnakh on Taimyr, in the valley of a stream Coal (~ in 40 km from Norilsk). The gorge is located in a massif Harayelakh. It is formed by two anonymous tops. It received the name for characteristic bright is reddish - the brown color connected with features of aeration of basalt lavas.
Looked round? Now answer to a question: how they were formed ?
A) The most striking example of structures are cellular lava covers. In basalts are known to five - six-sided columns (from 3 to 7 sides). It is quite possible that at the initial stages of origin of these structures also the convective mechanism of Benar as differently it is still difficult to explain simultaneity of a zalozheniye of all cracks was involved here. And after a zalozheniye of the correct network of cracks they developed deep into as basalt columns contracted under the cooling effect of the filtering water.
B) Formation of basalt columns happens in the course of hardening of large volumes of the cooling-down liquid lava which is exposed at this time to differentiation of substance in it owing to convection during cooling of a lava. Differentiation of substance begins in even absolutely liquid lava as a result of emergence and further mutual coordination of thermal convection streams in almost motionless cooling-down lava which formed the whole lava lakes after a volcanic eruption. So spontaneously arisen convection streams for some time (before hardening of a lava) will mutually be coordinated in the form of the convection cells adjoining with each other - almost correct vertical hexagons.
C) This six-sided form of cross section of a column is explained by the concept “minimum of superficial energy“, on simple - the border, the better is shorter. It can be observed not only on pools etc., and mainly in grains of metals (under a microscope) at their slow hardening from a liquid state. The border of grain “tries“ to become shorter, at the same time the volume of grain does not want to decrease, and in the place of a convergence of three grains (columns, in our case) borders will be shorter only if the corner between them is equal the 120th hail. Therefore, also we receive the correct hexagon.
D) Scientists from Toronto institute revealed a secret of mysterious six-sided columns. They visited the Giant`s Causeway and in a number of places with the similar phenomenon where they measured geometrical characteristics of polygons. According to the statement of physicists, the sizes of the columns reaching from several centimeters to several meters in the diameter depend, first of all, on the speed of eruption and cooling of a lava. Further, using results of field supervision, experiments and the mathematical theory, the Canadian physicists established that a key to the solution of difficulty is the fact that columns are formed by the same method both when cooling a lava, and when hardening starch.
To understand how columns of that or other size are formed, scientists reproduced the phenomenon in laboratory. With this purpose also used mix of water and corn starch which when heating and drying forms the cracks and longish columns absolutely similar to basalt columns. Varying the mode of heating and drying of starch, scientists received dependence with which sights of this sort are formed. According to the received results, the lava cools down more slowly, the columns is largely as a result turn out.
Authors of research claim that the coefficient found by them connecting the speed of cooling and drying permits to predict also the size of cells and in other similar actions, like drying of dirt, cracking of paint or cracking of a permafrost layer.