Sediment (A) may someday become a clastic rock (B) if compacted and cemented together.
Click on image for full size
(A) courtesy of Bruce Molnia, Terra and (B) courtesy of Martin Miller, University of Oregon

Step 4: Turning a Pile of Sediment into Solid Rock!

Sediment is not a sedimentary rock unless the little grains become stuck together. The material that holds sediment together into a rock is called cement. Cement is mineral that forms when seawater or groundwater travels through the empty spaces between sediment. If the water contains the chemicals that are needed, mineral crystals will form in-between the sediment. The mineral holds the sediment together. Minerals like calcite, quartz, and sometimes hematite form the cement in sedimentary rocks.

A pile of sediment becomes a sedimentary rock more quickly when it is buried deep underground. This makes the sediment grains become squished closely together. However, the whole process can take tens to hundreds of thousands of years.

Last modified August 25, 2003 by Lisa Gardiner.

You might also be interested in:

Traveling Nitrogen Classroom Activity Kit

Check out our online store - minerals, fossils, books, activities, jewelry, and household items!...more

What Is a Mineral?

Minerals are the building blocks of rocks. They are non-living, solid, and, like all matter, are made of atoms of elements. There are many different types of minerals and each type is made of particular...more

Calcite

Calcite is typically found in the sedimentary rock called limestone. Calcite is also in marble, a metamorphic rock, which forms when limestone is put under strong heat and pressure. Calcite crystals have...more

Quartz

Quartz is one of the most common mineral in Earth’s crust! Silica (Si) and Oxygen (O) are the only elements within pure quartz. If a cooling magma has silica leftover after feldspars form, quartz is likely...more

Hematite

A piece of hematite may look like just a dark gray blob. That might seem difficult to identify but with a streak test you can easily identify it! Just rub the mineral against a white streak plate and...more

Step 3: Sediments Settling Down!

When water or wind loses energy and slows down, sediment can no longer be carried in it. The particles fall through the water or air and form a blanket of sediment on the bottom of a river, a lake, ocean,...more

Step 2: Sediments on the Move!

If you sneeze into a pile of dust, the little particles fly everywhere. But if you sneeze into a pile of rocks, they will stay put. It takes more force than a sneeze to move those rocks. Winds and water...more

Organic Sedimentary Rocks

The sediment in an organic sedimentary rock is made of fossils! The hard parts of animals, such as bones and shells, can become cemented together over time to make rock. Usually the bones and shells are...more

Windows to the Universe, a project of the National Earth Science Teachers Association, is sponsored in part is sponsored in part through grants from federal agencies (NASA and NOAA), and partnerships with affiliated organizations, including the American Geophysical Union, the Howard Hughes Medical Institute, the Earth System Information Partnership, the American Meteorological Society, the National Center for Science Education, and TERC. The American Geophysical Union and the American Geosciences Institute are Windows to the Universe Founding Partners. NESTA welcomes new Institutional Affiliates in support of our ongoing programs, as well as collaborations on new projects. Contact NESTA for more information. NASA ESIP NCSE HHMI AGU AGI AMS NOAA