Lecture 11: Early Paleozoic Geology

This flashcard set details the early Paleozoic era, focusing on significant geological and biological events. It includes information on the formation of early continents, the development of major life forms, and the environmental changes that shaped this dynamic period in Earth's history.

Sequence Stratigraphy

The study of rock layers (sequences) and their relationships to sea transgression and regression.

Tippecanoe Sequence

A series of rock layers formed during the late Ordovician to early Silurian periods; represents a time when seas covered parts of North America, creating layers of sediment like sand, mud, and carbonates that eventually became rock.

Sequence

The process of sea level rise and sea level fall producing a certain type of deposit.

Supratidal sabhka evaporites

Salt and mineral deposits that form in coastal areas above the high tide line, where seawater occasionally floods, fills pores, and then evaporates leaving salt.

Taconic Orogeny

1st Paleozoic mountain building event; uplift, erosion, intrusion of batholiths along the eastern margin of North America.

Tapeats Sandstone

A Cambrian sedimentary rock formation, known for its coarse, light-colored sandstone layers.

Sauk Sequence

A series of rock layers that formed during the early Cambrian period; represents a time when shallow seas covered parts of North America, leaving behind layers of sediment that turned into rock like sandstone and shale.

Queenston Clastic Wedge

A wedge of rust-red terrestrial clastics became increasingly coarser and thicker toward mountainous source area as streams along the mountains deposited this material; due to erosion of the rising Taconic Mountains.

Regression

Sea level falls; coarser deposits found at the bottom and finer are on top.

Restricted-basin evaporites

Sea water enters a physically restricted basin at a rate slower than it evaporates; as a result, brines at the bottom start to form evaporites, leaving behind salts and other dissolved substances.

Reverse fault

When one side of the fault moves up compared to the other side, due to compressive forces pushing the crust together; steep slope

Sandstone

Type of rock made from tiny grains of sand that have been compacted and cemented together.

Oolites

Abiotic round carbonate concretions; evidence of epeiric seas.

Photic zone

Depth of water which light reaches; good for photosynthesis.

Precambrian Vishnu Schist and Granite

Types of very old rocks found in the Grand Canyon area.

Pannotia

3rd supercontinent that formed during the Neoproterozoic Era; broke up during the early Paleozoic.

Muav Limestone

A Cambrian rock formation, characterized by its light-colored, fine-grained limestone.

Limestone

A type of rock made mostly from calcium carbonate; it forms mainly from the remains of sea creatures like coral and shells that get compressed over time.

Laurentia

An ancient landmass that roughly makes up North America and parts of Greenland; it was part of early supercontinents like Rodinia and Pangaea.

Isostatic equilibrium

When the Earth's crust balances out with the underlying mantle so that the crust stays at a stable level. If weight is added or removed, the crust adjusts to maintain balance.

Iapetus Ocean

The opening of the Proto-Atlantic ocean, separating Laurentia from Pannotia and creating a passive margin.

Frenchman Mountain

A prominent geological feature in southern Nevada, known for its striking red and white sedimentary rock layers that date back to the Permian period.

Flat-pebble conglomerates

First evidence of epeiric seas (shallow sea); fine grained dolomitic and lime-mud sediments (carbonate material) show signs of having been ripped up and remobilized during storms.

Epeiric seas

Shallow seas

Dolostone/Dolomite

Limestone that was later hydrologically altered by some magnesium substitution for calcium.

Caledonian Orogeny

A mountain-building event caused by the collision of ancient continents in the Late Silurian to Early Devonian period; led to the formation of the Caledonian Mountains in northern Europe and eastern North America.

Bright Angel Shale

A Cambrian sedimentary rock formation, characterized by its gray and greenish-gray shale and siltstone layers.

Basin

Natural rock formations where the rock creates a depression.

Arches

Natural rock formations where the rock has been raised.

Cambrian Explosion

The rapid appearance of diverse animal species during the early-middle Cambrian period.

Great Unconformity

A significant gap in the rock record where much older rocks are overlain by much younger sedimentary layers.

Passive Margin

The edge of a continent where no significant tectonic activity occurs.

Isostatic Rebound

The rising of the Earth's crust back to its original position after the removal of weight.

Stromatolites

Layered structures formed by cyanobacteria in shallow water, often found in fossil form.

Shale

Fine-grained sedimentary rock formed from compacted clay and silt, characterized by its ability to split into thin layers.

Carbonates

Sedimentary rocks formed from carbonate minerals, such as limestone and dolostone.

Evaporites

Chemical sediments formed by the evaporation of water, leaving behind salts and minerals.

Ophiolites

Distinctive rock assemblages representing remnants of oceanic plates added to continental margins.

Convergent Plate Boundaries

Areas where lithospheric plates move towards each other, leading to geological processes like subduction and mountain formation.

Thrust Fault

A type of fault where rocks are pushed up and over each other due to compressional forces, often associated with convergent plate boundaries.

Granite

A type of intrusive igneous rock commonly found at convergent plate boundaries, formed from the cooling and solidification of magma beneath the Earth's surface.

Orogeny

The process of mountain building through tectonic plate interactions, involving folding, faulting, and volcanic activity.

Sedimentary Rocks

Rocks formed from the accumulation and lithification of sediments, such as sandstones, shales, and conglomerates, often found in basins due to erosion of nearby mountains.

Transgression

The advance of the sea over land due to factors like rising sea levels or sinking land, leading to the deposition of marine sediments over terrestrial ones.

Quartz Sandstones

Sedimentary rocks composed primarily of quartz grains, common in regions like the Appalachian Basin and indicative of erosion from nearby mountainous areas.

Iron-Rich Deposits

Sedimentary rocks containing high concentrations of iron minerals, often formed in tropical environments with intense weathering and later used as ore in industries like steel production.

Ophiolites

Slices of oceanic crust and upper mantle that have been uplifted onto land, providing insights into the formation of oceanic crust at mid-ocean ridges.

Cordillera

The system of mountain ranges in western North America, including the Rockies, Sierra Nevada, and Coast Ranges, which began to form during the Paleozoic due to tectonic activity and volcanic processes.