Geologic Time

A presentation by

the Group 5

/andrea

• Fossils

– Types of Fossils

–Classification of Organisms

• Principles in Relative Dating

• Dendrochronology

• Geologic Time Scale

FOSSILS Fossils are the preserved

remains or traces of animals,

plants, and other organisms

from the remote past.

The study of fossils across

geological time is one of the

most important functions of the

science of paleontology.

TYPES OF FOSSILS

1. Bones- the hard connective tissue forming the substance of the skeleton of most vertebrates.

2. Imprints- produced when

pressure is exerted to the surface

leaving a mark.

3. Burrow- A hole or tunnel dug in

the ground by a small animal, such

as a rabbit or mole, for habitation

or refuge.

4. Coprolites- Fossilized excrement.

5. Gastrolith- A small stone found in the stomach of some reptiles, fish, and birds that aids in digestion by helping grind ingested food material.

6. Molds- Any of various fungi that often cause disintegration of organic matter.

7. Amber- a pale yellow, sometimes

reddish or brownish, fossil resin of

vegetable origin, translucent, brittle, and

capable of gaining a negative electrical

charge by friction

8. Petrified Wood- stoned of frozen

wood.

• Archaeobacteria

• Eubacteria

• Protista

• Fungi

• Plantae

• Animalia

CLASSIFICATION OF ORGANISMS

“Ancient” bacteria.

Archaeobacteria are, like bacteria, prokaryotes and therefore have no cell nucleus or any other organelles within their cells.

ARCHAEOBACTERIA

“True” Bacteria. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals.

EUBACTERIA

They are a diverse group of eukaryotic microorganisms.

PROTISTA

adopted from the Latin fungus, meaning "mushroom.”

referring to the macroscopic structures and morphology of some mushrooms and molds

FUNGI

include familiar organisms such as trees, herbs, bushes, grasses, vines, ferns, mosses, and green algae

PLANTAE

including the type of coelom, symmetry, body plan, and presence of segmentation.

ANIMALIA

• Uniformitarianism

• Superposition

• Horizontality

• Continuity

• Cross – cutting Relations

• Inclusions

• Baked Contacts

PRINCIPLES OF RELATIVE DATING

The processes that happened in the past is still happening in the present

“The present is the key to the past.”

UNIFORMITARIANISM

The rock layers below are relatively older than the layers above.

SUPERPOSITION

The rock layers are deposited in a horizontal manner.

HORIZONTALITY

The rock layers are deposited in continuous sheets

CONTINUITY

Faults are always younger than the rock layers that they cut.

CROSS CUTTING RELATIONS

Fragments found in an igneous layer.

INCLUSIONS

When an igneous intrusion “bakes” surrounding rock, the rock that has been baked must be older than the intrusion.

BAKED CONTACTS

analyzes tree rings to determine the geologic age of features.

DENDROCHRONOLOGY

The largest time unit on the geologic time scale, next in order of magnitude above era

EON

ERA

• A major division on the geologic calendar

• Still divided into shorter units called periods

The basic unit of the geologic calendar that is the subdivision of an era

Can still be divided into smaller units called epochs.

PERIOD

EPOCH

• A unit of the geologic calendar that is a subdivision of a period.

HADEAN EON ( part of the eon, not the epoch.. I

ran out of space)

hadean eon

• It started at Earth's formation about 4.6

Ga and ended roughly 3.8 billion years ago.

• The name "Hadean" derives from Hades,

Greek for "Underworld", referring to the conditions on Earth at the time.

• The magma ocean formed (ultramafic)

• There is no sign of life.

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During this time, the Earth's crust cooled enough that rocks and continental plates began to form

Archean rocks are often heavily metamorphized deep-water sediments

ARCHEAN EON

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The transition to an oxygenated atmosphere during the Mesoproterozoic.

Several glaciations, including the hypothesized Snowball Earth during the Cryogenian period in the late Neoproterozoic.

The Ediacaran Period (635 to 542 Ma) which is characterized by the evolution of abundant soft-bodied multicellular organisms.

PROTEROZOIC EON

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starts shortly after the breakup of a supercontinent called Pannotia and at the end of a global ice age

Toward the end of the era, the continents gathered together into a supercontinent called Pangaea, which included most of the Earth's land area.

PALEOZOIC ERA

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Cambrian continents are thought to have resulted from the breakup of a Neoproterozoic supercontinent called Pannotia

The waters of the Cambrian period appear to have been widespread and shallow.

CAMBRIAN PERIOD

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started at a major extinction event called the Cambrian-Ordovician extinction events.

Invertebrates diversify into many new types. Early corals, articulate brachiopods, bivalves, nautiloids, trilobites, ostracods, bryozoa, many types of echinoderms, branched graptolites, and other taxa all common. Conodonts appear. First green plants and fungi on land.

ORDOVICIAN PERIOD

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During the Silurian, Gondwana continued a slow southward drift to high southern latitudes.

First Vascular plants , first millipedes and arthropleurids on land. First jawed fishes populate the seas. Brachiopods, and crinoids all abundant.

SILURIAN PERIOD

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the first fish evolved legs and started to walk on land as tetrapods.

The first seed-bearing plants spread across dry land, forming huge forests. In the oceans, primitive sharks became more numerous than in the Silurian and the late Ordovician. The first ammonite mollusks appeared, and trilobites, the mollusc-like brachiopods.

DEVONIAN PERIOD

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The rock beds that define the Mississippian are well identified.

Large primitive trees, first land vertebrates, and amphibious sea-scorpions live amid coal-forming coastal swamps. Lobe-finned rhizodonts are dominant big fresh-water predators. In the oceans, early sharks are common and quite diverse; echinoderms abundant.

CARBONIFEROUS PERIOD -

MISSISSIPIAN

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The Pennsylvanian is named after the state of Pennsylvania, where rocks from this epoch are widespread.

Amphibians common and diverse. First reptiles and coal forests. Highest-ever atmospheric oxygen levels. Goniatites, brachiopods, bryozoa, bivalves, and corals plentiful in the seas and oceans.

CARBONIFEROUS PERIOD -

PENNYSYLVANIAN

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The Permian period was named after the kingdom of Permia, Russia by Scottish geologist Roderick Murchison in 1841.

Landmasses unite into supercontinent Pangaea. In the mid-Permian, coal-age flora are replaced by cone-bearing gymnosperms and by the first true mosses. Permian-Triassic extinction event occurs 251 mya: 95% of life on Earth becomes extinct.

PERMIAN PERIOD

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Mesozoic means 'middle animals’. It is often called the 'Age of the Reptiles.’

The Mesozoic was a time of tectonic, climatic and evolutionary activity. The continents gradually shifted from a state of connectedness into their present configuration. The climate was exceptionally warm throughout the period.

MESOZOIC ERA

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Both the start and end of the Triassic are marked by major extinction events.

Corals of the hexacorallia group made their first appearance.

Archosaurs dominant on land as dinosaurs. Cynodonts become smaller and more mammal-like, while first mammals and crocodilia appear. Dicrodium flora common on land.

TRIASSIC PERIOD

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The Jurassic constitutes the middle period of the Mesozoic era, also known as the "Age of Reptiles"

The start of the period is marked by the major Triassic–Jurassic extinction event.

Gymnosperms and ferns common. Many types of dinosaurs. Mammals common but small. First birds and lizards.

JURRASIC PERIOD

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The Cretaceous was a period with a relatively warm climate and high eustatic sea level.

The oceans and seas were populated with now extinct sea reptiles, ammonites and rudists. At the same time, new groups of mammals and birds as well as flowering plants appeared.

Flowering plants proliferate. Many new types of dinosaurs evolve on land.

CRETACEOUS PERIOD

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meaning "new life"

The most recent of the three classic geological eras and covers the period from 65.5 million years ago to the present. It is marked by the Cretaceous–Tertiary extinction event at the end of the Cretaceous that saw the demise of the last non-avian dinosaurs and the end of the Mesozoic Era.

CENOZOIC ERA

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The Tertiary is a an out-of-date term for a geologic period 65 million to 1.8 million years ago.

The Tertiary covered the time span between the superseded Secondary period and an out-of-date definition of the Quaternary period.

TERTIARY PERIOD

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most notable as being the time in which it is theorized that mammals evolved from relatively small, simple forms into a plethora of diverse animals in the wake of the mass extinction that ended the preceding Cretaceous Period.

PALEOGENE PERIOD

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Climate tropical. Modern plants appear; Mammals diversify into a number of primitive lineages following the extinction of the dinosaurs. First large mammals.

PALEOCENE EPOCH

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Moderate, cooling climate. Archaic mammals flourish and continue to develop during the epoch. First grasses. Reglaciation of Antarctica and formation of its ice cap and the Icehouse Earth climate that would follow it to this day, from the settlement and decay of seafloor algae drawing in massive amounts of atmospheric Carbon Dioxide.

EOCENE EPOCH

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Warm but cooling climate, moving towards Icehouse; Rapid evolution and diversification of fauna, especially mammals. Major evolution and dispersal of modern types of flowering plants.

OLIGOCENE EPOCH

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The Neogene covers roughly 23 million years.

During the Neogene, mammals and birds evolved considerably.

Some continental motion took place. Climates cooled somewhat over the duration of the Neogene culminating in continental glaciations in the Quaternary period that follows.

NEOGENE PERIOD

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Moderate Icehouse climate, puncuated by ice ages.

Modern mammal and bird families became recognizable. Horses and mastodons diverse. Grasses become ubiquitous. First apes appear.

MIOCENE EPOCH

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Intensification of present Icehouse conditions, Present ice age begins roughly 2.58 MYA; cool and dry climate. Australopithecines, many of the existing genera of mammals, and recent mollusks appear. Homo habilis appears.

PLIOCENE EPOCH

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The Quaternary Period is the geologic time period after the Neogene Period 1.805 +/- 0.005 million years ago to the present.

The Quaternary includes two geologic epochs: the Pleistocene and the Holocene Epoch.

QUARTERNARY PERIOD

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Flourishing and then extinction of many large mammals .

Evolution of anatomically modern humans.

Dawn of human stone-age cultures.

Lake Toba supervolcano erupts 75,000 years before present, causing a volcanic winter and pushes humanity to the brink of extinction.

PLEISTOCENE EPOCH

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The last glacial period ends and rise of human civilization. Quaternary Ice Age recedes.

Cultures continue to grow in complexity and technical advancement through the Iron Age.

Mount Tambora erupts in 1815, causing the Year Without a Summer in Europe and North America from a volcanic winter.

HOLOCENE EPOCH

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/andrea