What Geologic Process Changes Pieces Of Rocks, Minerals, And Other Material Into Sedimentary Rock

Figure 1. The different colors and textures seen in this rock are caused by the presence of unlike minerals.

Introduction

At that place are 3 types of rocks: igneous, sedimentary and metamorphic. Each of these types is part of the stone bike. Through changes in conditions one stone type tin get another rock type. Or information technology can become a different stone of the same type.

What Are Rocks?

A stone is a naturally formed, non-living earth material. Rocks are made of collections of mineral grains that are held together in a firm, solid mass (figure ane).

How is a stone unlike from a mineral? Rocks are made of minerals. The mineral grains in a rock may be and then tiny that you tin can just run across them with a microscope, or they may be as big as your fingernail or fifty-fifty your finger (figure i).

Figure 2. A pegmatite from South Dakota with crystals of lepidolite, tourmaline, and quartz (1 cm scale on the upper left).

Effigy 2. A pegmatite from South Dakota with crystals of lepidolite, tourmaline, and quartz (1 cm scale on the upper left).

Rocks are identified primarily by the minerals they contain and by their texture. Each type of rock has a distinctive prepare of minerals. A rock may be made of grains of all i mineral type, such as quartzite. Much more unremarkably, rocks are made of a mixture of different minerals. Texture is a description of the size, shape, and system of mineral grains. Are the 2 samples in figure 2 the same rock type? Do they accept the same minerals? The same texture?

Figure 3. Rock samples.

Effigy iii. Rock samples.

Sample	Minerals	Texture	Formation	Rock type
Sample ane	plagioclase, quartz, hornblende, pyroxene	Crystals, visible to naked eye	Magma cooled slowly	Diorite
Sample 2	plagioclase, hornblende, pyroxene	Crystals are tiny or microscopic	Magma erupted and cooled quickly	Andesite

As seen in tabular array one, these two rocks have the same chemical composition and contain mostly the same minerals, but they do not have the same texture. Sample ane has visible mineral grains, but Sample 2 has very tiny or invisible grains. The 2 different textures indicate different histories. Sample 1 is a diorite, a rock that cooled slowly from magma (molten rock) underground. Sample ii is an andesite, a rock that cooled chop-chop from a very similar magma that erupted onto Earth's surface.

Three Main Categories of Rocks

Rocks are classified into three major groups according to how they form. Rocks can exist studied in hand samples that can exist moved from their original location. Rocks tin can also exist studied in outcrop, exposed rock formations that are attached to the basis, at the location where they are constitute.

Igneous Rocks

Igneous rocks form from cooling magma. Magma that erupts onto Earth'due south surface is lava, as seen in figure four. The chemical composition of the magma and the rate at which it cools determine what rock forms equally the minerals absurd and crystallize.

Figure 4. This flowing lava is molten rock that will harden into an igneous rock.

Figure four. This flowing lava is molten rock that volition harden into an igneous rock.

Sedimentary Rocks

Sedimentary rocks course by the compaction and cementing together of sediments, broken pieces of rock-like gravel, sand, silt, or clay (figure v). Those sediments can exist formed from the weathering and erosion of preexisting rocks. Sedimentary rocks also include chemical precipitates, the solid materials left behind after a liquid evaporates.

Figure 5. This sedimentary rock is made of sand that is cemented together to form a sandstone.

Figure v. This sedimentary rock is made of sand that is cemented together to form a sandstone.

Metamorphic Rocks

Metamorphic rocks form when the minerals in an existing rock are changed by heat or pressure within the Earth. See figure vi for an example of a metamorphic rock.

Figure 6. Quartzite is a metamorphic rock formed when quartz sandstone is exposed to heat and pressure within the Earth.

Figure 6. Quartzite is a metamorphic rock formed when quartz sandstone is exposed to rut and pressure within the Earth.

A unproblematic explanation of the 3 stone types and how to identify them can be seen in this video:

This video discusses how to identify igneous rocks:

This video discusses how to place a metamorphic rocks:

This Science Made Fun video discusses the conditions under which the three main stone types form:

The Stone Cycle

Figure 7. James Hutton is considered the Father of Geology.

Rocks modify equally a result of natural processes that are taking place all the time. Most changes happen very slowly; many take place beneath the World's surface, and then we may not even observe the changes. Although we may non see the changes, the physical and chemic properties of rocks are constantly changing in a natural, never-ending cycle chosen the rock cycle.

The concept of the rock bicycle was starting time developed by James Hutton, an eighteenth century scientist often called the "Male parent of Geology" (shown in figure seven). Hutton recognized that geologic processes accept "no [sign] of a outset, and no prospect of an end." The processes involved in the rock cycle oft take identify over millions of years. So on the scale of a man lifetime, rocks appear to exist "rock solid" and unchanging, but in the longer term, alter is always taking place.

In the rock cycle, illustrated in figure 8, the 3 chief rock types—igneous, sedimentary, and metamorphic—are shown. Arrows connecting the three rock types evidence the processes that change one rock blazon into another. The wheel has no start and no cease. Rocks deep within the Earth are right at present becoming other types of rocks. Rocks at the surface are lying in place earlier they are next exposed to a process that volition change them.

Figure 8. The Rock Cycle.

Figure viii. The Stone Bicycle.

Processes of the Rock Cycle

Several processes tin can plough one blazon of rock into another type of rock. The fundamental processes of the rock cycle are crystallization, erosion and sedimentation, and metamorphism.

Crystallization

Magma cools either underground or on the surface and hardens into an igneous rock. As the magma cools, different crystals course at unlike temperatures, undergoing crystallization. For example, the mineral olivine crystallizes out of magma at much higher temperatures than quartz. The rate of cooling determines how much time the crystals will have to course. Slow cooling produces larger crystals.

Erosion and Sedimentation

Weathering wears rocks at the World's surface downwardly into smaller pieces. The pocket-sized fragments are called sediments. Running h2o, ice, and gravity all send these sediments from one place to another by erosion. During sedimentation, the sediments are laid downwards or deposited. In order to form a sedimentary rock, the accumulated sediment must become compacted and cemented together.

Metamorphism

When a rock is exposed to extreme heat and force per unit area within the Earth merely does not melt, the stone becomes metamorphosed. Metamorphism may change the mineral composition and the texture of the stone. For that reason, a metamorphic rock may have a new mineral composition and/or texture.

Lesson Summary

Rocks are collections of minerals of diverse sizes and types.
The iii chief rock types are igneous, sedimentary, and metamorphic.
Crystallization, erosion and sedimentation, and metamorphism transform one rock type into another or change sediments into rock.
The stone cycle describes the transformations of 1 type of rock to another.

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