Transcript Geological Timescale

Active Learning Assignment
(Geotechnics and Applied Geology 2130606)
Enrollment Number
Name
140 150 106 091
RATHWA RANCHHOD
140 150 106 092
SALAT HEMANG
140 150 106 093
SAVALIYA NIKUNJ
140 150 106 094
SAVALIYA VIVEK
140 150 106 095
SAWAN MAHESHWARI
140 150 106 096
SHARMA TUSHARKUMAR
140 150 106 097
SHINGADIYA VIVEK
140 150 106 098
SHRIMALI MITAL
140 150 106 099
SIDI DILER
140 150 106 100
SOLANKI MAYANKKUMAR
140 150 106 121
ZALA MITTALBA
140 150 106 122
ZALA RAJVEERSINH
140 150 106 123
IRFAN AAQIB
Under Guidance of : P.V. MARVANIYA
“The geological time scale (GTS) is a system of
chronological measurement that relates stratigraphy
to time, and is used by geologists, paleontologists,
and other Earth scientists to describe the timing and
relationships between events that have occurred
throughout Earth's history.”
Aeon : An indefinite and very long period of time. [half
a billion years or more]
Era : A major division of time that is a subdivision of
an aeon and is itself subdivided into periods. [several
hundred million years]
Period: A unit of geological time during which a
system of rocks formed. [one hundred million years]
Epoch: A division of time that is a subdivision of a
period and is itself subdivided into ages,
corresponding to a series in chronostratigraphy.
[millions of years]
Event
Humans Develop
Age of mammals,
Extinction of Dinosaurs
and many other species
Age of Reptiles
Age of Amphibians
Age of Fishes
Age of Invertebrates
The entire interval of the existence of visible life
is called the Phanerozoic eon.
The great Precambrian expense of time is
divided into Proterozoic, Archen, and Hadean eons
in order of increasing age.
The names of eras in Phanerozoic (the eon of
visible life) are the Cenozoic (“recent life”),
Mesozoic (“Middle life”) and Paleozoic (“Ancient
life”).
The further subdivision of the eras into 12 “periods” is
based on identifiable but less profound changes in life
forms.
To observe a Holocene environment,
simply look around you! The Holocene is
the name given to the last 11,700 years* of
the Earth's history — the time since the end
of the last major glacial epoch, or "ice age."
Since then, there have been small-scale
climate shifts — notably the "Little Ice
Age" between about 1200 and 1700 A.D. —
but in general, the Holocene has been a
relatively warm period in between ice
ages.
This mammoth (right), found in
deposits in Russia, was one of the
largest land mammals of the
Pleistocene, the time period that
spanned from 2.6 million to 11,700
years ago.* Pleistocene biotas were
extremely close to modern ones —
many genera and even species of
Pleistocene conifers, mosses,
flowering plants, insects, mollusks,
birds, mammals, and others survive
to this day. Yet the Pleistocene was
also characterized by the presence of
distinctive large land mammals and
birds.
The Pliocene, 5.3 to 2.6 million years ago,* was a time of
global cooling after the warmer Miocene. The cooling
and drying of the global environment may have
contributed to the enormous spread of grasslands and
savannas during this time. The change in vegetation
undoubtedly was a major factor in the rise of longlegged grazers who came to live in these areas.
The Miocene Epoch, 23.03 to 5.3 million
years ago,* was a time of warmer global
climates than those in the preceding
Oligocene or the following Pliocene and
it's notable in that two major ecosystems
made their first appearances: kelp forests
and grasslands.
The overall pattern of biological change for
the Miocene is one of expanding open
vegetation systems (such as deserts,
tundra, and grasslands) at the expense of
diminishing closed vegetation (such as
forests). This led to a rediversification of
temperate ecosystems and many
morphological changes in animals.
The Oligocene Epoch, right smack in the middle of the Tertiary Period
(and end of the Paleocene), lasted from about 33.9 to 23 million years
ago.* Although it lasted a "short" 11 million years, a number of major
changes occurred during this time. These changes include the appearance
of the first elephants with trunks, early horses, and the appearance of
many grasses — plants that would produce extensive grasslands in the
following epoch, the Miocene.
The Eocene is the second of five epochs in the Tertiary Period — the
second of three epochs in the Paleocene — and lasted from about 55.8 to
33.9 million years ago.* The oldest known fossils of most of the modern
orders of mammals appear in a brief period during the early Eocene and
all were small, under 10 kg.
The Cretaceous is usually noted for being the last portion of the "Age of
Dinosaurs“. Lasted from 145.5 to 65.5 million years ago.
Also during this time, we find the first fossils of many insect groups, modern
mammal and bird groups, and the first flowering plants. Cretaceous saw the
first appearance of many life forms that would go on to play key roles in the
coming Cenozoic world.
Great plant-eating dinosaurs roaming the earth, feeding on lush ferns and
palm-like cycads and bennettitaleans … smaller but vicious carnivores
stalking the great herbivores … oceans full of fish, squid, and coiled
ammonites, plus great ichthyosaurs and long-necked plesiosaurs …
vertebrates taking to the air, like the pterosaurs and the first birds. This was
the Jurassic Period, 199.6 to 145.5 million years ago* — a 54-million-year
chunk of the Mesozoic Era.
In many ways, the Triassic, lasting from 251.0 million
years ago to 199.6 million years ago,* was a time of
transition. It was at this time that the world-continent of
Pangea existed, altering global climate and ocean
circulation. The Triassic also follows the largest
extinction event in the history of life, and so is a time
when the survivors of that event spread and recolonized.
The organisms of the Triassic can be considered to
belong to one of three groups: holdovers from the
Permo-Triassic extinction, new groups which flourished
briefly, and new groups which went on to dominate the
Mesozoic world. The holdovers included the lycophytes,
glossopteris, and dicynodonts. While those that went on
to dominate the Mesozoic world include modern
conifers, cycadeoids, and the dinosaurs.
The Permian period lasted from 299 to 251 million years ago* and was the
last period of the Paleozoic Era. The distinction between the Paleozoic and
the Mesozoic is made at the end of the Permian in recognition of the
largest mass extinction recorded in the history of life on Earth.
On land, a relatively smaller extinction of diapsids and synapsids cleared the way
for other forms to dominate, and led to what has been called the "Age of
Dinosaurs."
The Carboniferous Period lasted from about 359.2 to 299 million years ago* during
the late Paleozoic Era. The term "Carboniferous" comes from England, in reference
to the rich deposits of coal that occur there. These deposits of coal occur throughout
northern Europe, Asia, and Midwestern and eastern North America.
Biologically, we see one of the greatest evolutionary innovations of the Carboniferous:
the amniote egg, which allowed for the further exploitation of the land by certain tetra
pods. It gave the ancestors of birds, mammals, and reptiles the ability to lay their eggs
on land without fear of desiccation.
•Stratigraphy Laws are basic principles that
all geologists use in deciphering the spatial
and temporal relationships of rock layers.
These laws were developed in the 17th and
19th centuries based upon the work of Neils
Steno, James Hutton and William Smith,
among others.
1. Original Horizontality : All sedimentary rocks are originally
deposited horizontally. Sedimentary rocks that are no longer
horizontal have been tilted from their original position.
“Strata either perpendicular to the horizontal or
inclined to the horizon were at one time parallel to the
horizon” - Steno, 1669
2. Lateral Continuity : sedimentary rocks are laterally continuous
over large areas. A useful way for Wisconsinites to consider this law is
to think of snowfalls. As snow falls, it is not limited to the intersection
of Main and Division streets, nor UWSP campus, but falls over a larger
area such as Central Wisconsin. Sediments also "rain" down in a similar
fashion such that sedimentary layers are laterally continuous over an
area similar to, or greater than, Central Wisconsin.
"Material forming any stratum were continuous
over the surface of the Earth unless some other solid
bodies stood in the way." Steno, 1669
3. Superposition : "...at the time when any given stratum
was being formed, all the matter resting upon it was
fluid, and, therefore, at the time when the lower stratum
was being formed, none of the upper strata existed."
Steno, 1669.
4. Cross-Cutting Relations :
"If a body or
discontinuity cuts across a stratum, it must have formed
after that stratum." Steno, 1669.
5. Law of Inclusions :
This law states that
rock fragments (in another rock) must be older than the
rock containing the fragments.
6.Law of Faunal Succession :
This law was
developed by William "Strata" Smith who recognized
that fossil groups were succeeded by other fossil
groups through time. This allowed geologists to
develop a fossil stratigraphy and provided a means to
correlate rocks throughout the world.
Questions, Comments or Remarks?