Regents Earth Science Test Preparation Practice

    Scheme For Igneous Rock Identification

    Base your answers to questions 1 on the passage and cross section below and on your knowledge of Earth science. The cross section represents one theory of the movement of rock materials in Earth’s dynamic interior. Some mantle plumes that are slowly rising from the boundary between Earth’s outer core and stiffer mantle are indicated.

    Hot Spots and Mantle Plumes Research of mantle hot spots indicates that mantle plumes form in a variety of sizes and shapes. These mantle plumes range in diameter from several hundred kilometers to 1000 kilometers. Some plumes rise as blobs rather than in a continuous streak; however, most plumes are long, slender columns of hot rock slowly rising in Earth’s stiffer mantle. One theory is that most plumes form at the boundary between the outer core and the stiffer mantle. They may reach Earth’s surface in the center of plates or at plate boundaries, producing volcanoes or large domes.

    dynamic-earth, plate-tectonics, standard-1-math-and-science-inquery, geocentric-model-heliocentric-model, standard-6-interconnectedness, systems-thinking, standard-6-interconnectedness, models fig: esci62015-exam_g34.png

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    Base your answers to questions 8 on the passage and data table below, on the graph in image provided, and on your knowledge of Earth science. The data table shows the average percentages of sodium and calcium, and the average densities of samples from each of the six varieties of plagioclase feldspar. The graph in image provided shows the range of sodium and calcium percentages for each of the six varieties of plagioclase feldspar.

    Plagioclase Feldspars

    The plagioclase feldspars are a family of six silicate minerals that are difficult to tell apart. They have the same crystal structure, cleavage, and hardness, and can be similar in color; however, they do differ slightly in chemical composition and density. The general chemical composition for plagioclase is (Na,Ca)AlSi3O8. The percentages of sodium (Na) and calcium (Ca) vary relative to each other, causing the differences in density. The mineral albite is sodium-rich, with little or no calcium, while anorthite is calcium-rich, with little or no sodium. The plagioclase feldspars with higher sodium content are more likely to be found in felsic igneous rocks, while the plagioclase feldspars with higher calcium content are more likely to be found in mafic igneous rocks.

    rocks-and-minerals, properties-identification-and-use-of-minerals, standard-1-math-and-science-inquery, eccentricity-rate-gradient-standard-error, standard-6-interconnectedness, models fig: esci62017-exampwr_g42.png

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    Base your answers to questions 9 on the passage below and on your knowledge of Earth science.

    Dimension Stone: Granite

    Dimension stone is any rock mined and cut for specific purposes, such as kitchen countertops, monuments, and the curbing along city streets. Examples of rock mined for use as dimension stone include limestone, marble, sandstone, and slate. The most important dimension stone is granite; however, not all dimension stone sold as granite is actually granite. Two examples of such rock sold as “granite” are syenite and anorthosite. Syenite is a crystalline, light-colored rock composed primarily of potassium feldspar, plagioclase feldspar, biotite, and amphibole, while anorthosite is composed almost entirely of plagioclase feldspar. Like actual granite, both syenite and anorthosite have large, interlocking crystals.

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    Base your answers to questions 10 on the geologic cross section shown below and on your knowledge of Earth science.

    reference-tables, scheme-for-metamorphic-rock-identification, rocks-and-minerals, formation-classification-and-application-of-rocks, standard-1-math-and-science-inquery, changing-length-of-a-shadow-based-on-the-motion-of-the-sun, standard-6-interconnectedness, models fig: esci12016-examw_g45.png

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    Base your answers to questions 11 on the diagram in image provided and on your knowledge of Earth science. The diagram represents several common rock-forming minerals and some of the igneous rocks in which they commonly occur. The minerals are divided into two groups, A and B. Dashed lines connect the diagram of diorite to the three minerals that are commonly part of diorite’s composition.

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    Base your answers to questions 12 on the passage, diagram of an ophiolite drill-core sample, and map below and on your knowledge of Earth science. The dot on the map represents the location where the ophiolite drill-core sample was taken.

    Ophiolites

    In some places, segments of oceanic crust, sediment, upper mantle, and rock have been heaved up by tectonic movements onto the edges of continents, where they often become part of mountains. These displaced oceanic lithosphere segments are called ophiolites. They provide an opportunity to study the composition of oceanic lithosphere and are a key feature in recognizing past tectonic plate convergence along subduction zones. Drill-core samples of ophiolites typically have the layering pattern shown in the drill-core sample below.

    reference-tables, scheme-for-igneous-rock-identification, rocks-and-minerals, formation-classification-and-application-of-rocks, standard-6-interconnectedness, models fig: esci12014-examw_g36.png

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    Base your answers to questions 13 on the passage below and on your knowledge of Earth science.

    The Mica Family

    The familiar term “mica” is not the name of a specific mineral, but rather the name for a family of more than 30 minerals that share the same properties. All members of the mica family have high melting points and are similar in density, luster, hardness, streak, type of breakage, and crystal shape. As a result, telling the micas apart can be difficult. However, some common members of the family can be identified by color. For example, biotite is black to dark brown while muscovite can be light shades of several colors, or even colorless. When less common members of the mica family have any of these colors, or have similar colors, chemical tests are needed to tell them apart.

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    Base your answers to questions 14 on the diagram below and on your knowledge of Earth science. The diagram represents a portion of the scheme for igneous rock identification. Line AB represents the percentages of the minerals in igneous rock 1 and line CD represents the percentages of the minerals in igneous rock 2.

    reference-tables, scheme-for-igneous-rock-identification, rocks-and-minerals, formation-classification-and-application-of-rocks, standard-1-math-and-science-inquery, changing-length-of-a-shadow-based-on-the-motion-of-the-sun fig: esci82017-examw_g62.png

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    Base your answers to questions 15 on the data table below and on your knowledge of Earth science. The data table shows the range of temperatures at which different minerals crystallize as molten magma cools and solidifi es.

    rocks-and-minerals, formation-of-minerals, standard-1-math-and-science-inquery, eccentricity-rate-gradient-standard-error, standard-6-interconnectedness, models fig: esci82022-exam_g49.png

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