Grammar focus

Infinitive

Task 1. Translate the sentences into Ukrainian paying special attention to the underlined infinitives.

1. Volatiles tend to be most abundant near the tops of magma reservoirs.

2. When magma rises (or the rocks confining the magma fail) a reduction in pressure occurs and the dissolved gases begin to separate from the melt, forming tiny bubbles.

3. At temperatures of 1000 °C and low near-surface pressures, these gases can quickly expand to occupy hundreds of times their original volumes.

4. Because of the high viscosity of silica-rich magma, a significant portion of the volatiles remain dissolved until the magma reaches a shallow depth, where tiny bubbles begin to form and grow.

5. To summarize, the viscosity of magma plus the quantity of dissolved gases and the ease with which they can escape largely determine the nature of a volcanic eruption.

6. To explore this idea, a pioneering investigation into the crystallization of magma was carried out by N. L. Bowen in the first quarter of the 20th century.

7. Data of this type led them to examine the possibility that magma might change (evolve) and thus become the parent to a variety of igneous rocks.

8. It is typically only the magma in the upper part of a magma chamber that has a sufficiently high gas content to trigger a steam-and-ash explosion.

9. The movement of silica-rich, rhyolitic lava may be too slow to perceive.

10. Andesitic and rhyolitic magmas tend to generate relatively short prominent flows, a few hundred meters to a few kilometres long.

Task 2. Translate the sentences into Ukrainian paying special attention to the underlined infinitive complexes. How do we call the underlined complexes?

1. As magma moves up the fractures, a further drop in confining pressure causes more gas bubbles to form and grow.

2. Hot basaltic magmas contain a smaller gaseous component and permit these gases to escape with relative ease.

3. On Sunday, May 18, 1980, the largest volcanic eruption to occur in North America in historic times transformed a picturesque volcano into a decapitated remnant.

Discussion

Task 1. Read and memorize the following words:

intrusive - інтрузивний, плутонічний	coarse-grained - крупнозернистий, грубозернистий
setting- спосіб будови	composition - суміш, сплав
mount - накопичення	constituent – складова частина, елемент
strip away – знімати, здирати	exposure - вихід пластів
contain - містити	trace amount of smth. – невелика кількість, залишки, сліди (чогось)
extrusive – екструзивний (тойб що виступає)	fine-grained - дрібнозернистий
visible - видимий	observe - спостерігатись

Task 2. Read the text. Translate it into Ukrainian. Talk about igneous processes and igneous compositions, provide only general information.