Define geology. Present=past

• Geology is the study of the Earth, the materials of which it is made, the structure of those materials, and the processes acting upon them. It includes the study of organisms that have inhabited our planet. An important part of geology is the study of how Earth’s materials, structures, processes and organisms have changed over time.

Georgia’s geologic history covers at least 1 billion years. The state can be subdivided into five regions or provinces based on characteristic landforms, types and ages of rocks, and geologic structures. These provinces are known as the CoastalPlain, Piedmont, Blue Ridge, Valley and Ridge, and Appalachian Plateau.

THE HISTORY OF LIFE

• EARLY HISTORY OF EARTH• EVIDENCE• HOW OLD IS SOMETHING?• WHAT IS GEOLOGIC TIME?• FIRST CELLS• ENDOSYMBIONT THEORY

WHAT DO YOU THINK EARLY EARTH WAS LIKE?

• HOW OLD?• 4.5 BILLION YEARS• BIG BANG - GRAVITY CAUSES DUST PARTICLES TO

CONDENSE• METEORS FOR MILLIONS OF YEARS - HOW HOT WOULD

THE EARTH BE?• EARTH HAS TO COOL DOWN - STEAM ESCAPES AND RAIN

ALLOWS COLLECTION OF WATER - EARTH NOW HAS……• ATMOSPHERE OF AMMONIA, METHANE, WATER

VAPOR, CO2, AND NITROGEN• WHAT IS MISSING?

THE HISTORY OF LIFE

• EARLY HISTORY OF EARTH• EVIDENCE• HOW OLD IS SOMETHING?• WHAT IS GEOLOGIC TIME?• FIRST CELLS• ENDOSYMBIONT THEORY

Courtesy NASA/JPL-Caltechhttp://origins.jpl.nasa.gov/habitable-planets/invest16.html

WHAT EVIDENCE DO SCIENTISTS USE?

• FOSSILS!– TRACE– MOLD– CAST– AMBER– IMPRINT– PETRIFIED

• WHERE ARE FOSSILS USUALLY FOUND?• WHO STUDIES THESE?• HOW DO SCIENTISTS DETERMINE THE AGE OF SOMETHING

BILLIONS OF YEARS OLD?– RELATIVE DATING– RADIOMETRIC DATING

THE HISTORY OF LIFE

• EARLY HISTORY OF EARTH• EVIDENCE• HOW OLD IS SOMETHING?• WHAT IS GEOLOGIC TIME?• FIRST CELLS• ENDOSYMBIONT THEORY

GEOLOGICAL TIME

• TOO OLD FOR YEARS OR MONTHS• FOUR ERAS DEPENDING ON WHICH ORGANISMS LIVED• PRECAMBRIAN• PALEOZOIC• MESOZOIC• CENOZOIC

WHY DO WE HAVE DIFFERENT ERA’S?

PRECAMBRIAN• WHAT DO SCIENTISTS THINK WAS ALIVE WAY BACK

THEN??• BACTERIA• THIS ERA LASTED FOR BILLIONS OF YEARS UNTIL MORE

LIVING ORGANISMS EVOLVED

Precambrian EraThe oldest rocks in Georgia are found in the Piedmont and Blue Ridge provinces and are Proterozoic in age (1 to 1.3 billion years old). These rocks were originally deposited as sediment, which was compressed into sedimentary rocks and then altered by heat and pressure into a metamorphic rock called gneiss. Granite and other igneous rocks intruded and were also metamorphosed. The rocks were folded, faulted, uplifted, and then eroded. These metamorphic rocks, called the Grenville gneisses, form the "basement" upon which the younger rocks of the Appalachian mountain system have been deposited.Between 630 and 700 million years ago, the rifting (or splitting apart of the continent) began, which led to the opening of the Iapetus Ocean (or proto–Atlantic Ocean) along the eastern margin of North America. From the Late Proterozoic to the Early Cambrian, the Grenville mountains eroded, and streams transported sediments to the sea, which covered much of Georgia at that time. These sediments were compacted into sedimentary rocks and later metamorphosed to the gneiss, marble, metaconglomerate, phyllite, quartzite, schist, and slate found in the Blue Ridge and/or Piedmont regions of Georgia.Volcanic islands were present in this ancient sea, and eruptions produced igneous rocks, which were also later metamorphosed. Today these rocks are amphibolite, hornblende gneiss, and other metavolcanic rocks. Gold was deposited from mineral-rich hot waters moving through cracks in the volcanic rocks on the sea floor. This gold has been mined in the Dahlonega area since its discovery in 1828.

PALEOZOIC ERA540 MILLION YEARS AGO!!

• NOW THE EARTH IS GETTING LARGER LIFE! • FIRST PART OF PALEOZOIC IS CALLED CAMBRIAN

• PROTISTS!SEA PLANTS!SEA ANIMALS!LAND PLANTS!LAND ANIMALS!

• WHAT ENDED THE PALEOZOIC ERA?? MASS EXTINCTION!

Paleozoic EraFrom the Cambrian to the Pennsylvanian periods, the southeastern part of North America lay south of the equator in a relatively tropical climatic zone.

Cambrian Period, Ordovician Period, and Silurian PeriodDuring the Cambrian period (542 to 490 million years ago), sandstones, dolostones, and shales were deposited on beaches and in shallow seas covering the eastern edge of North America. During the Late Cambrian and Early Ordovician periods, carbonate rocks, or limestones, were deposited in the warm, shallow waters of this sea. During the Ordovician period (488 to 444 million years ago), Volcanic eruptions left ash which is now weathered to a clay called bentonite, are interbedded with Ordovician limestones in northwestern Georgia. A volcanic island arc and possibly a small continent collided with North America in the Middle to Late Ordovician period, resulting in the formation of the Appalachian Mountains.

Devonian PeriodDuring the Devonian period (416 to 359 million years ago), a mountain range, known as the Acadian highlands, was formed along North America's east coast. Erosion occurred as most of Georgia remained high and dry following this mountain-building event. Between the Middle Silurian and the Middle Devonian, no sedimentary rocks were deposited in Georgia, or those deposited were eroded away before the end of the Devonian.During the Late Devonian, a shallow sea flooded the northwestern part of Georgia and much of central North America depositing a layer of black shale.

Mississippian PeriodDuring the Mississippian period (359 to 318 million years ago), thick deposits of limestone and chert formed The third and final Paleozoic mountain-building event produced the folds and thrust faults in both the Valley and Ridge and the Appalachian Plateau. In addition, Piedmont and Blue Ridge rocks were thrust west-northwestward on top of the folded and faulted sedimentary rocks of the Valley and Ridge.

Pennsylvanian PeriodDuring the Pennsylvanian period (318 to 299 million years ago), most of Georgia was located within the core of a large Appalachian mountain range, which was 4 to 7 kilometers high and rivaled the Himalayan mountain system (in present-day Asia) in size. Along the western side of the Appalachian mountain range lay a vast swampy lowland covered by lush tropical forests that were inhabited by fern-like plants, huge insects, and amphibians. Rivers flowed westward, depositing sandstones, conglomerates, and mudstones as the mountains eroded. Extensive coal deposits formed in the swamps. Compression on rocks in the Piedmont and Blue Ridge areas were metamorphosed. In some places temperatures were so high that the rocks began to melt and huge bodies of granitic magma began to form deep within the core of the mountain range.

MESOZOIC ERA245 MILLION YEARS AGO!!

• DINOSAURS! REPTILES! SMALL MAMMALS APPEAR! BIRDS EVOLVE!• PLATE TECTONICS

• WHAT ENDED THE MESOZOIC ERA?MASS EXTINCTION! METERORITE?

Mesozoic Era and Cenozoic Era

Triassic Period and Jurassic PeriodMesozoic fault-bounded rift basins, which contain Late Triassic and Early Jurassic sedimentary rocks, are found in the subsurface of Georgia. They are buried beneath the younger sedimentary rocks of the Coastal Plain, as well as beneath continental shelf sediments. These formed as the Atlantic Ocean began to open and as Africa began to rift or split away from North America. The Mesozoic basins are filled with a variety of nonmarine sedimentary rocks ranging from red sandstones and siltstones to fine-grained shales and coarse-grained conglomerates deposited in river and lake environments. Following the deposition of the Triassic-Jurassic sedimentary rocks of the buried Mesozoic rift basins, approximately 100 million years of erosion occurred before the Late Cretaceous rocks of the Coastal Plain were deposited. The youngest rocks in Georgia are found in the Coastal Plain Province. These rocks range in age from Late Cretaceous to Holocene (97 million years old to the present). Cretaceous sedimentary rocks overlap Piedmont metamorphic and igneous rocks at the fall line, which follows a series of waterfalls marking the upstream extent of navigable waters in the state.

CENOZOIC ERA66 MILLION YEARS AGO!

• MAMMALS FLOURISH• PRIMATES ABOUT 30 MILLION YEARS AGO

• MODERN HUMAN SPECIES – ABOUT 200,000 YEARS AGO

Cretaceous Period and Paleogene PeriodDuring the Cretaceous period (145 to 65.5 million years ago), the climate was much warmer than it is today, and tropical conditions existed in Georgia. No glaciers existed at the poles, and as a result, sea level was much higher than it is at present. The Atlantic Ocean covered southeastern Georgia inland as far as present-day Macon, Columbus, and Augusta, and left marine sediments containing mollusk shells, sharks' teeth, bits of turtle shell, and the occasional dinosaur bone. Dinosaurs roamed Georgia during the Cretaceous and sometimes floated out to sea after they died. From the Late Cretaceous period to the Middle Eocene epoch of the Paleogene period (about 40 to 100 million years ago), large quantities of kaolinite, a white alumino-silicate clay resembling chalk, were deposited in middle Georgia. (Kaolin is mined for use in the manufacture of glossy paper, plastic, rubber, paints, ceramics, and other products. Georgia is the world's leading producer of kaolin.) This clay derives from the weathering of feldspar, a mineral found in Piedmont rocks. The clay was transported by streams and deposited in deltas, estuaries, and coastal marshes.Marine deposits associated with kaolin, including abundant limestone, indicate that the Coastal Plain was flooded by a warm, shallow sea. A dramatic event occurred about 35 million years ago during the Eocene era, when an asteroid or comet struck the Chesapeake Bay region of Virginia. The impact shattered and melted the rocks at the point of impact, forming a crater 90 kilometers in diameter and ejecting droplets of molten rock, which flew through the air for hundreds of kilometers. The molten rock cooled to form coin-sized, translucent, green glassy stones known as tektites, some of which landed in the sea covering east-central Georgia.The climate cooled dramatically near the end of the Eocene, and during the remainder of the Cenozoic era, glaciers began to grow and the worldwide sea level dropped. The seas receded from Georgia, and sediments derived from the erosion of the Appalachian Mountains and the Piedmont built eastward. Sediments were deposited at a thickness of more than 5,000 meters, or 5 kilometers, in the Coastal Plain area and thickened toward the southeast.Neogene PeriodGlaciers periodically covered much of northern North America during the Pleistocene epoch (1.8 million years ago to the present), although Georgia remained ice-free. The seas alternately flooded and retreated from the land along the coast as the glaciers advanced and receded. During peak glacial episodes, sea level was about 100 to 120 meters lower than at present, and the coast was out near the edge of the continental shelf. Between glaciations, sea level stood as much as 50 meters above present levels. Sea-level high stands are marked by beach ridges. Beaches were dominated by white quartz sand, but during times of rising sea level or higher wave energy, concentrations of black sands, rich in such heavy minerals as ilmenite, zircon, rutile, epidote, sillimanite, staurolite, magnetite, tourmaline, and kyanite, formed on the beaches. Some of these heavy mineral sands are present in Pleistocene beach ridges near the Okefenokee Swamp and contain valuable economic deposits of titanium.During the Pleistocene, Georgia was inhabited by mammals not seen today, including mastodons, mammoths, elephants, camels, bison, tapirs, and giant ground sloths up to 6 meters tall. The climate was arid at times during the Pleistocene. About 20,000 years ago, rivers dried up and strong winds from the west blew the river sand into large dunes. Pleistocene sand-dune fields remain along the east side of several rivers, including the Flint, Ohoopee, and Canoochee.

What do we mine out of the ground?

• Minerals, rocks (ex. limestone, granite)• Salt, clay, phosphates, sand, soil, bauxite (Al

ore), copper • Coal, oil, natural gas, U• Renewable or nonrenewable?

How do we know where to mine?

• Exploratory Wells Aerial photos • Satellite images• Radiation monitoring• Magnetometer• Seismic surveys (use explosives, detect shock waves)• Chemical analysis of rock and water

Depending on where the resource is…

Surface mining

Indiana

Illinois

•Most mining in U.S.

•“Overburden” is stripped away

•Wastes are “spoils”

Strip Mining

“Since the mid-1970s, strip-miners in Montana, as well as in other states, are required by law to remove overburden in an orderly manner, to refill the pits after mining the coal, restoring the overburden as nearly as possible to its original condition, and to replant it with the original types of vegetation. "The art and science of mine reclamation are now so highly developed," say geologists David Alt and Donald Hyndman, "that the recently worked sites are visible only to a knowing and practiced eye."1 Some of the lignite mined here at Colstrip is used to generate electricity at the plant in the upper center. The rest is shipped to coal-fired generators in other parts of the country, via 100-car "unit" trains.”

Mountain top removal

Mountaintop removal mining is a form of surface mining that involves the topographical alteration and/or removal of a summit, summit ridge, or significant portion of a mountain, hill, or ridge in order to obtain a desired geologic material.

Subsurface mining

• Kentucky coal mine: longwall mining

What’s good about subsurface mining? What’s bad about it?

Methods•Longwall mining - A set of longwall mining equipment consists of a coal shearer mounted on conveyor operating underneath a series of self-advancing hydraulic roof supports Longwall miners extract "panels" - rectangular blocks of coal. As a longwall miner retreats back along a panel, the roof behind the supports is allowed to collapse in a planned and controlled manner.•Room-and-pillar mining or continuous mining - Room and pillar mining is commonly done in flat or gently dipping bedded ores. Pillars are left in place in a regular pattern while the rooms are mined out. In many room and pillar mines, the pillars are taken out, starting at the farthest point from the mine haulage exit, retreating, and letting the roof come down upon the floor. Room and pillar methods are well adapted to mechanization, and are used in deposits such as coal, potash, phosphate, salt, oil shale, and bedded uranium ores.•Blast mining – An older practice of coal mining that uses explosives such as dynamite to break up the coal seam, after which the coal is gathered and loaded onto shuttle cars or conveyors for removal to a central loading area. •Shortwall mining– A coal mining method that accounts for less than 1% of deep coal production, shortwall involves the use of a continuous mining machine with moveable roof supports, similar to longwall.

Atmospheric scientists study weather processes; the global dynamics of climate; solar radiation and its effects; and the role of atmospheric chemistry in ozone depletion, climate change, and pollution.

Economic geologists explore for and develop metallic and nonmetallic resources; they study mineral deposits and find environmentally safe ways to dispose of waste materials from mining activities.

Engineering geologists apply geological data, techniques, and principles to the study of rock and soil surficial materials and ground water; they investigate geologic factors that affect structures such as bridges, buildings, airports, and dams.

Environmental geologists study the interaction between the geosphere, hydrosphere, atmosphere, biosphere, and human activities. They work to solve problems associated with pollution, waste management, urbanization, and natural hazards, such as flooding and erosion.

Geochemists use physical and inorganic chemistry to investigate the nature and distribution of major and trace elements in ground water and Earth materials; they use organic chemistry to study the composition of fossil fuel (coal, oil, and gas) deposits.

Geochronologists use the rates of decay of certain radioactive elements in rocks to determine their age and the time sequence of events in the history of the Earth.

Geologists study the materials, processes, products, physical nature, and history of the Earth.

Geomorphologists study Earth's landforms and landscapes in relation to the geologic and climatic processes and human activities, which form them.

Geophysicists apply the principles of physics to studies of the Earth's interior and investigate Earth's magnetic, electric, and gravitational fields.

Glacial geologists study the physical properties and movement of glaciers and ice sheets.

Hydrogeologists study the occurrence, movement, abundance, distribution, and quality of subsurface waters and related geologic aspects of surface waters.

Hydrologists are concerned with water from the moment of precipitation until it evaporates into the atmosphere or is discharged into the ocean; for example, they study river systems to predict the impacts of flooding.

Marine geologists investigate the ocean-floor and ocean-continent boundaries; they study ocean basins, continental shelves, and the coastal environments on continental borders.

Meteorologists study the atmosphere and atmospheric phenomena, including the weather.

Mineralogists study mineral formation, composition, and properties.

Oceanographers investigate the physical, chemical, biological, and geologic dynamics of oceans.

Paleoecologists study the function and distribution of ancient organisms and their relationships to their environment.

Paleontologists study fossils to understand past life forms and their changes through time and to reconstruct past environments.

Petroleum geologists are involved in exploration for and production of oil and natural gas resources.

Petrologists determine the origin and natural history of rocks by analyzing mineral composition and grain relationships.

Planetary geologists study planets and their moons in order to understand the evolution of the solar system.

Sedimentologists study the nature, origin, distribution, and alteration of sediments, such as sand, silt, and mud. Oil, gas, coal and many mineral deposits occur in such sediments.

Seismologists study earthquakes and analyze the behavior of earthquake waves to interpret the structure of the Earth.

Soil scientists study soils and their properties to determine how to sustain agricultural productivity and to detect and remediate contaiminated soils.

Stratigraphers investigate the time and space relationships of rocks, on a local, regional, and global scale throughout geologic time -- especially the fossil and mineral content of layered rocks.

Structural geologists analyze Earth's forces by studying deformation, fracturing, and folding of the Earth's crust.

Volcanologists investigate volcanoes and volcanic phenomena to understand these natural hazards and predict eruptions.

Igneous RocksIgneous rocks are crystalline solids which form directly from the cooling of magma. This is an exothermic process (it loses heat) and involves a phase change from the liquid to the solid state. The earth is made of igneous rock - at least at the surface where our planet is exposed to the coldness of space.

Sedimentary RocksIn most places on the surface, the igneous rocks which make up the majority of the crust are covered by a thin veneer of loose sediment, and the rock which is made as layers of this debris get compacted and cemented together. Sedimentary rocks are called secondary, because they are often the result of the accumulation of small pieces broken off of pre-existing rocks. There are three main types of sedimentary rocks:

Clastic: your basic sedimentary rock. Clastic sedimentary rocks are accumulations of clasts: little pieces of broken up rock which have piled up and been "lithified" by compaction and cementation.

Chemical: many of these form when standing water evaporates, leaving dissolved minerals behind. These are very common in arid lands, where seasonal "playa lakes" occur in closed depressions. Thick deposits of salt and gypsum can form due to repeated flooding and evaporation over long periods of time.

Organic: any accumulation of sedimentary debris caused by organic processes. Many animals use calcium for shells, bones, and teeth. These bits of calcium can pile up on the seafloor and accumulate into a thick enough layer to form an "organic" sedimentary rock.

Metamorphic RocksThe metamorphics get their name from "meta" (change) and "morph" (form). Any rock can become a metamorphic rock. All that is required is for the rock to be moved into an environment in which the minerals which make up the rock become unstable and out of equilibrium with the new environmental conditions. In most cases, this involves burial which leads to a rise in temperature and pressure

A rock is mineral matter of variable composition, consolidated or unconsolidated, assembled in masses or considerable quantities in nature, as by the action of heat or water

A mineral is any of a class of substances occurring in nature of definite chemical composition and usually of definite crystal structure. Hardness is the comparative ability of a substance to scratch or be scratched by another. Specific Gravity is a density ratio of a substance to water. Color is what the substance is. A Steak is the color left when a substance is rubbed on another substance. Cleavage shows breaking points of a substance. A luster is a shine. Crystal is symatry.

Road Building:

Gravel- crushed rockCement- ashes, sands, waterAsphalt- old rubber