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Task 2. Read the text. Translate it into Ukrainian. Talk about batholiths,
stocks, and laccoliths.

Massive Intrusive Bodies: Batholiths, Stocks, and Laccoliths
BATHOLITHS. By far the largest intrusive igneous bodies are batholiths.
Batholiths occur as mammoth linear structures several hundreds of kilometres long and
up to 100 kilometers wide, Batholiths are almost always made up of felsic and
intermediate rock types and are often referred to as “granite batholiths.” Large granite
batholiths consist of hundreds of plutons that intimately crowd against or penetrate one
another. These bulbous masses were emplaced over spans of millions of years. The
intrusive activity that created the Sierra Nevada batholith, for example, occurred nearly
continuously over a 130-million-year period that ended about 80 million years ago.
STOCKS. By definition, a plutonic body must have a surface exposure greater
than 100 square kilometers to be considered a batholith. Smaller plutons of this type are
termed stocks. However, many stocks appear to be portions of much larger intrusive
bodies that would be called batholiths if they were fully exposed.
LACCOLITHS. A 19th century study by G. K. Gilbert of the U.S. Geological
Survey in the Henry Mountains of Utah produced the first clear evidence that igneous
intrusions can lift the sedimentary strata they penetrate. Gilbert named the igneous
intrusions he observed laccoliths, which he envisioned as igneous rock forcibly injected
between sedimentary strata, so as to arch the beds above, while leaving those below
relatively flat. However, these central magma bodies are the source material for
branching offshoots that are true laccoliths, as Gilbert defined them.

Task 3. Describe each of the four basic intrusive features (dikes, sills,
laccoliths, and batholiths). What is the largest of all intrusive igneous bodies? Is it
tabular or massive? Concordant or discordant?

Individual work

Task 1. Read the text and translate it into Ukrainian (in written form).
Build up a list of key terms to the text.

Mineral Resources and Igneous Processes
Given the growth of the middle class in countries such as China, India, and
Brazil, the demand for metallic natural resources has increased exponentially in recent
years. Some of the most important accumulations of metals, such as gold, silver, copper,
mercury, lead, platinum, and nickel, are produced by igneous processes. These mineral
resources result from processes that concentrate desirable materials so that they can be
profitably extracted. Therefore, knowledge of how and where these important materials
are likely to be concentrated is very important.
The igneous processes that generate some of these metal deposits are quite
straightforward. For example, as a large basaltic magma body cools, the heavy minerals
that crystallize early tend to settle to the lower portion of the magma chamber. This type
of magmatic segregation serves to concentrate selected metals producing major deposits
of chromite (ore of chromium), magnetite, and platinum.
Magmatic segregation is also important in the late stages of the magmatic
process. This is particularly true of granitic magmas in which the residual melt can
become enriched in rare elements and some heavy metals. Further, because water and
other volatile substances do not crystallize along with the bulk of the magma body,
these fluids make up a high percentage of the melt during the final phase of
solidification.

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