Erosion, & Types of Weathering Chapter 10
Erosion A process where water, wind, or gravity transports soil (sediment) from its source
The process by which rocks are broken down into smaller pieces • There are 2 main types, chemical & Physical Weathering
Mechanical Weathering • The break down of rock into smaller pieces due to physical means • Frost wedging (water freezing in rock cracks) • Abrasion (other rocks or sediment rubbing against rock.)
Chemical Weathering • Rocks break as a result of a chemical change • Acid rain • Chemical decomposition • Gases in the air (oxidation)
Deposition • Is the process where material lays to rest • Sediment is deposited in bodies of water and on land
Chapter 6 The Rock Record ? ? ?
Sedimentary Rock Layers • This is a normal record of rock. Layers are undisturbed. The Geologic Column is a model of what rock layers should look like.
Uniformitarianism • A principle or rule that states that events that happened in the past can be explained by current earth (geologic) processes • Earth Processes like erosion, weathering, and deposition remain uniformed and do not change.
Catastrophism • A principle that states that geologic changes happen suddenly. (natural disasters) • They believed the Earth was only a few thousand years old. • Catastrophic events formed the Earth, created volcanoes, mountains, oceans, etc.
Relative Dating • Determines which comes first. Determining if rock layers are older or younger • Compare them to undisturbed rock around the world
Principle of Superposition • A principle or rule that states that younger rocks lie above older rocks in un-disturbed sequences • As you move from top of rock layers to the bottom the rock layers get older
Uplift • movement within the Earth that moves rocks to the surface
Unconformities • Is a disturbance in the layer of a rock. • Represents thousands, to millions of years in missing time in the layers of a rock • Can be created through: • Erosion and weathering (p159, figure 4) • Faulting- (earthquakes) • Folding (anticlines, synclines, and monoclines) • Tilting • intrusion
Rock Intrusion • A layer of molten rock (hardened magma) from the Earth’s interior that squeezes into existing rock and then cools. • Melts surrounding layers • Interrupts the rock time scale.
Types of Unconformities • Disconformity – part of a parallel rock layer is missing. (Layers may be eroded away and deposited elsewhere) • Nonconformity- horizontal sedimentary rock layers lay on the eroded surface of intrusive igneous rocks or metamorphic rocks • Angular unconformity- rocks are tilted or folded due to earthquakes or uplift (p 160)
Erosion Weathering Uplift Deforestation Mechanical weathering Chemical weathering Relative dating Uniformitarianism Superposition Intrusion Catastrophism Un-conformity Strip Mining Frost Wedging Abrasion Terms