Geysers
Date: 2015-10-07; view: 416.
Geysers are 1 … springs that periodically discharge their water with 2 … violence. All geysers have a 3 … narrow pipe extending down from their vents into their reservoirs. A build-up and sudden release of steam bubbles probably relieves the 4 … on the heated water below ground so that it boils and 5 …upward. The period between 6 … varies from minutes to months in different geysers, depending upon the structure of the 7 …, its water supply, and its heat source.
Typical geyser structure shows 8 … system of fissures extending down to regions where 9 … water becomes 10 …and finally erupts.
Missed word:
A. – ground
B. – geyser
C. – explosive
D. – eruptions
E. – complex
F. – long
G. – thermal
H. – superheated
I. – surges
J. – pressure
Exercise 3. Read the following texts and match them with the corresponding titles below:
1. Hot Springs; 2. Caves; 3.Artesian Wells; 4.Springs
Text A. They are those where water is confined to a permeable aquifer by impervious beds, and where the catchment or intake area (and thus the water level in the aquifer) is higher than the well head. This allows the water to flow toward the surface under its own internal pressure.
Text B. They are sources of running water produced by the water table intersecting the ground surface. A few of the many ways they can be formed are shown in the diagrams above. Some springs are dry at seasons when the water table is depressed; others flow without interruption.
Text C. They are generally confined to areas of recent vulcanism where groundwater is heated at depth by contact with igneous magmas. Such springs arå well developed in Yellowstone National Park and North Island, New Zealand. Terrace deposits may be produced when hot spring water deposits dissolve mineral matter. Mammoth Springs of Yellowstone National Park are formed of calcium carbonate (travertine). Geysers, intermittent fountain-like hot springs, often build cones of siliceous geyserite.
Text D. They reflect the work of groundwater. Limestone is dissolved by circulating water in subsurface joints and fissures. The enlargement gradually produces a cave. Inside a cave, dripping water, rich in calcium bicarbonate and CO2, often produces precipitates that form stalagmites and stalactites.
Exercise 4. Look through the texts above once again and decide true or false are the following statements:
1. Intake area of Artesian wells is higher than the well head.
2. All springs at any season flow without interruption.
3. At depth the ground water is heated by contact with igneous magmas.
4. Limestone is dissoluble material.
Exercise 5. Read and translate the following sentence using the code below:
6-21-13-1-18-15-12-5-19 1-18-5 7-5-25-19-5-18-19 12-15-3-1-20-5-4
9-14 22-15-12-3-1-14-9-3 18-5-7-9-15-1419 20-8-1-20 5-13-9-20 6-21-13-5-19 21-19-21-1-11-11-25 9-14 20-8-5 6-15-18-13 15-6 19-20-5-1-13.
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