Iowa DOT's
policy is to be
sensitive to the environment
and foster and enhance
environmental stewardship.
IOWA DEPARTMENT OF TRANSPORTATION
Presents
Rocks and Roads
Unit 1: Geology of Iowa
F. Unit 1 Glossary
|
TERM |
DEFINITION |
| aquifer | A layer of rock that can hold groundwater in sufficient quantity to serve wells. |
| bedrock | The first layer of solid rock found either at or below the land surface. |
| Cenozoic Era | A span of geologic time covering approximately 65 million years. Also called the “Age of Mammals.” |
| channel | Where a natural body of surface water flows or may flow. |
| chemical deposition | The process by which elements bond together and settle out of water, forming sediments. |
| course | The path followed by water, or the channel it flows through. |
| cyclical | Repeating sequences of like deposits. |
| Des Moines Lobe | The most recent glacial deposit in central Iowa. |
| deposit | Earth sediments that accumulated through any natural process such as, water, wind, volcanoes and glaciers. |
| deposition | The process by which sediments accumulate to form a deposit. |
| dolomite | The term used to describe rocks composed of the mineral dolomite, deposited underwater. |
| environment | A geographically restricted area where sediments accumulate. |
| erosion | The process by which the materials of the earth’s crust are worn away and at the same time carried to a new location. This process can be accomplished by wind, water or ice. |
| equator | The line of latitude that divides the northern and southern hemispheres of the earth. |
| evaporate | To convert into vapor or fumes; to expel moisture from. |
| fossil | The remains, or traces of an animal or plant that has been preserved from a previous geologic time period. |
| flood plains | The nearly level lowlands next to rivers. |
| glacial drift | The general term applied to glacial deposits; interchangeable with glacial till. |
| glacial till | The general term applied to glacial deposits; interchangeable with glacial drift. |
| granite | A term applied to quartz-bearing rocks formed deep below the earth’s surface. |
| gravel | A natural accumulation of rounded rock pieces that are the products of erosion of an original parent material. |
| igneous rock | Rock formed from the crystallization of liquid magma. |
| kame | Low mound or knob, deposited by a glacial stream. |
| kettle | Bowl-shaped depression, often containing a lake, formed by the melting of a large block of ice that was left behind by a retreating glacier. |
| landscape | The distinct associations of landforms, as modified by geologic forces that can be seen in a single view. |
| limestone | A sedimentary rock consisting of the mineral calcium carbonate that was created by precipitation or from the accumulation of the skeletons of sea animals. |
| lithify | The process of converting sediments to solid rock, generally through cementation and/or compaction. |
| lobe | A rounded, tongue-like projection of glacial drift (i.e. Des Moines Lobe). |
| loess | A wind-carried deposit consisting of very small sediments. |
| magma | A body of molten liquid rock found within the earth, including any dissolved gases and crystals. |
| meander | One of a series of curves, bends or turns in a stream channel. |
| Mesozoic Era | A span of geologic time covering from 225 to 65 million years ago. Also called the “Age of Reptiles.” |
| metamorphic rock | Rock formed underground by the alteration of pre-existing rock through pressure, heat, and/or chemically active liquids. |
| molten | Melted liquid rock. |
| moraine | A ridge of material deposited by a glacier. |
| oxbow lake | A crescent-shaped body of water, located by the side of a stream in the abandoned channel of a meander that cut itself off. |
| Paleozoic Era | A span of geologic time covering from 570 to 225 million years ago. Also called the “Age of Invertebrates.” |
| physical deposition | The accumulation of sediments in an area over a long time forming a deposit. |
| precipitate | The settling out of water of dissolved sediments and chemicals. |
| quartzite | A metamorphic rock formed from exposing a sandstone to high pressures and/or temperatures. |
| sandstone | A
rock consisting mostly of sand-sized quartz sediments (i.e., from
a beach) that have been cemented together.
|
| sediments | Materials that form as a direct result of the weathering of rocks. Often they are transported to accumulate in another location, forming a deposit. |
| sedimentary rock | There
are two types. The first is a rock formed from the weathered products
of pre-existing rocks that have been transported, deposited and lithified.
The second is a rock that has precipitated out of water from dissolved
organic or inorganic materials. |
| shale | A very fine-grained,
layered sedimentary rock composed of mud-sized clay sediments. |
| terrain |
A region of the earth’s surface considered as a physical structure.
|
TO: G. Activities
