Earth's History study guide notes
Terms in this set (53)
The principle of uniformitarianism states that geologic processes that happened in the past can be explained by current geologic processes.
Fossils are a trace or remains of an organism that lived long ago, most commonly preserved in sedimentary rock. May be skeletons, or body parts, shells, burrows, or ancient coral reef.
Amber is formed when hardened tree sap is buried and preserved in sediment.
In La Brea Tar Pits in California asphalt pools have trapped and preserved many fossils over the past 40,000 years.
When something starts to break down and tear apart over time
Petrification happens when an organism's tissues are replaced by minerals.
Fossilized structure that formed in sedimentary rock by animal activity on or in a soft sediment.
The fossil record shows part of the history of life on Earth.
The composition of sedimentary rock shows the source of the sediment that makes up the rock.
Features on a sedimentary rock called ripple marks record the motion of wind or water waves over sediment.
Other features called mud cracks form when fine-grained sediments at the bottom of a shallow body of water are exposed to the air and dry out.
At one time the continents formed a single land mass called Pangea. Pangea broke apart about 200 million years ago.
Massive, irregularly shaped slab of solid rock, generally composed of both continental and oceanic lithosphere.
The climate of an area describes the weather conditions in the area over a long period of time.
Sea Floor sediments
Evidence about past climates can also be found deep beneath the ocean floor.
Ice cores give a history of Earth's climate over time.
Determining whether an object or event is older or younger than other objects or events.
The principle that states that younger rocks lie above older rocks if the layers have not been disturbed
Break in the geologic record that is made when rock layers are eroded or when sediment is not deposited for a long period of time.
An ordered arrangement of rock layers that is based on the relative ages of the rocks, with the oldest rocks at the bottom of the column.
When Earth's forces move rock layers up or down unevenly which causes the layers to be slanted.
Bending of rocks that can happen when rock layers are squeezed together
Break or crack in Earth's crust where rocks can move
Igneous rock that forms when magma is injected into rock and then cools and becomes hard
Magma or lava solidified
Magma pushes or intrudes into cracks in existing rocks. When the melted rock cools and solidifies, the resulting feature is called an igneous intrusion.
Material pushed or drawn through a die of the desired cross-section
Determining the actual ages of these time spans, and establishing the beginning and ending dates of geologic eons, eras, and periods.
Widely distributed fossil
The series of processes in which rock changes from one type to another
A solid material made up of minerals forming the surface on Earth
Forms when high temperature and pressure change the texture and mineral content of the rock
Composed of minerals formed from solutions or sediments from older rock
A solid inorganic substance of natural occurrence
Rising of regions of the crust to higher elevations
Sinking of regions of the crust to lower elevations
An area where a set of deep cracks form
Melted Rock ( Igneous and Metamorphic rock)
Melted Igneous rock and when magma reaches the surface it turns into lava
Solid substance having a natural geometrically regular form with symmetrically arranged plane faces
Weathering, Erosion, Deposition, Compaction, CementationG
Scientific study of the origin, history, and structure of Earth and the processes that shape it
Geologic Time scale
Divides Earth's history into intervals of time defined by major events or change on Earth
A event causing great and often sudden damage or suffering, a disaster
Largest unit of geologic time. Earth's 4.6-billion-year history is divided into 4 Eons: the Hadean, Archean, Proterzoic, and Phanerozoic
The Paleozoic, Mesozoic, and Cenozoic era's.
An Era subdivided into a number of periods
The periods of the Cenozoic, the present era, are further divided into Epochs
Precambrian time began with the formation of Earth about 4.6 billion years ago. Massive supercontinents formed and broke up at least twice during Precambrian time. Toward the end of the Precambrian time, much of Earth's land surfaces were located near the poles and covered in ice. Land on Earth was largely frozen and lifeless.
Began around 540 million years ago as the global supercontinent Pannotia was breaking up. The climate during the late Paleozoic varied as Pangea drifted toward and away from the South pole. At the start of the Paleozoic, all life was found in the ocean. Life diversified quickly and dramatically during the Cambrian Explosion, during which , most major groups of organisms first evolved.
Began about 250 million years ago after the Permian mass extinction. The climate during the Mesozoic era was likely warm. Periods of heavy volcanism added carbon dioxide to the atmosphere. Life during the Mesozoic was dominated by dinosaurs. The few mammals were very small. A mass extinction event about 65 million years ago marks the end of the era- and the dinosaurs.
Began about 65 million years ago with the Cretaceous mass extinction and continues to the present. Greenland split apart from North America and Europe, marking the final break up of Pangaea. Polar ice caps formed. the Cenozoic Era is divided into two periods: the Tertiary, and Quaternary.
Some early scientists used catastrophism to explain geologic changes on Earth. Catastrophism is the principal that states that all geologic change occurs suddenly.