Historical Geol.xlsx - Historical Geol Flashcards
Examines the origin and evolution of the Earth, its continents, oceans, atmosphere, and life
Historical Geol
Some key concepts in histotical geol
The Earth’s surface have changed over geologic time
The rocks record the changes that occurred over geologic time
Interdisciplinary approach = comprehensive geologic “story
Explain Neptunism; who theorized it
─ Rocks formed from crystallization of minerals in the ocean.
─ Earth originally consisted of water, then suspended materials settled to form the core and the continents.
─ Abraham Gottlob Werner
Explain Plutonism/Vulcanism; who theorized it
─ Rocks formed from intrusive magmatic activity, which were then eroded and deposited on the seabed, re-formed as sedimentary rocks by heat & pressure, then raised again.
─ First proposed by Abbe Anton Moro (1750) and later used by James Hutton
Explain Catastrophism; who popularized it
─ Landscape shaped by sudden, short-lived, worldwide violent catastrophes. Each epoch ended with these events based on extinction and succession in the fossil record.
─ Popularized by Georges Cuvier; anchored from Neptunism
Explain Uniformitarianism or Gradualism; who conied it
─ Assumes that the natural laws and processes operating in the present time have operated in the past.
─ Geologic change occurring slowly over long time periods
─ Coined by William Whewell, proposed by James Hutton (1785; anchored from Plutonism), refined by John Playfair, and popularized by Charles Lyell.
Explain Neocatstrophism; who where behind it
─ Sudden extinctions by high-magnitude, low-frequency events (disastrous but seldom catastrophes) like asteroid impacts.
─ “Steady-state” Uniformitarianism can’t explain episodic particularities in the fossil or rock record
─ First by Schindewolf (1963), then Alvarez (1980s)
Explain Actualism; who where behind it
─ Modern belief that most geological processes are gradual yet there are periods of abrupt change.
─ Same process but different intensity and duration
─ Georges Louid Leclerc, Comte de Buffon
Explain relative dating
─ Comparison of strata to determine an ordered sequence of events in geologic history
─ “Which is older” and not “How old”
─ Stratigraphic Principles
Explain absolute dating
─ Gives accurate numerical ages of geologic materials to determine their ages.
─ “How old” and not “Which is older”
─ Experimental methods
Explain The principle of Superposition
In an undisturbed sequence of strata, each bed is older than the bed above it and younger than the bed below it.
Explain The principle of Original Horizontality
Each stratum must have been originally deposited in a horizontal manner.
Explain The principle of Lateral Continuity
Each stratum is deposited continuously in all directions unless (1) hindered by an obstacle, (2) the supply has run out, or (3) has reached at the basin’s edge.
Principle of Cross-cutting Relationships
Geological objects that cuts or displaces another is younger.
Who were the people behind Principle of Cross-cutting Relationships
Developed by Steno, formulated by Hutton, elaborated by Lyell. 14
Lyell’s Principle of Inclusions
Any geologic feature (rocks, minerals, fragments) included within another is older than the enclosing medium.
Smith’s Principle of
Fossil Succession
Fossils succeed one another vertically in a definite and determinable manner which can be identified over wide distances.
Buried erosional or non-depositional surface separating two rock units of different ages indicating a “halt” in the deposition of sediments.
Represents time with no deposition, hence “missing rock” in the record.
Unconformity
is the missing time.
Hiatu
Separates strata of two different dip angles. Records a period of strata deformation followed by stable depositional conditions
Angular Unconformity
Separates igneous/metamorphic rocks and sedimentary strata.
Records either a period of exposure of magmatic rocks followed by sediment deposition, or by magmatic rocks intruding into sedimentary strata.
Nonconformity
Separates parallel sedimentary strata.
Records period of erosion and/or non-deposition of sedimentary rocks atop older sedimentary strata. Common in tectonically-stable area and in basins.
Disconformity
Separates parallel sedimentary strata but with no obvious erosional surface between them; needs fossil evidence to validate.
Paraconformity
are short paraconformities (short interruption with little or no erosion).
Diastems
Unconformity that truncates the younger strata as they deposit atop older layers. Occurs when young sediments are deposited against older strata or exposed rock,
Buttress Unconformity
Disconformity or nonconformity with no distinct surface or contact but consists of materials derived from the underlying rock.
Blended Unconformity
Technique of placing geologic information distributed over widely-separated outcrops to create an accurate chronological profile of an entire geologic period or locality.
May be based on lithology, fossils, ages, magnetic polarity, unconformity, etc.
Steno’s Correlation
unstable parent nucleus emits two protons and two neutrons.
Alpha decay,
electron is emitted from a neutron in the nucleus.
Beta decay
a proton captures an electron and is thereby converted to a neutron.
Electron capture
is time it takes for 1/2 of the original unstable parent element to decay into the new stable daughter element
Half Life
C 14 Half Life
5730 years
H 3 Half Life
12.35 years
Pu 239 Half Life
24 065 years
Ra 222 Half Life
3.8 days
Bi 212 Half Life
60.55 minutes
Sr 85 Half Life
64.84 days
Sr 89 Half Life
50.5 days
Sr 90 Half Life
29.12 years
U 235 Half Life
703 my
U 238 Half Life
4.4 by
Uses 14C to date organic matter.
Radiocarbon Dating
14C has a half-life of 5,730 years, so it is used to date any material of up to
60,000 years old
Uses radioisotope 40K with a half-life of 1.3 billion years.; This is used to calibrate the Geomagnetic Polarity Time Scale
40K - 40Ar Dating
Dates materials to the last time they were heated. As radiation is absorbed, electrons within the minerals are freed producing light in the process.
Thermoluminescence
Dating method using the patterns of tree rings (growth rings) and is used to date the time these rings have formed
Dendrochronology
Maximum Age for Dendrochronology
11k years
Segment of the Earth’s history represented and recorded in the strata.
Geologic Time
is divided based on the relative age relationships in vertical stratigraphic position and fossils content (used to recognize in global scale)
Relative Time (Chronostratic)
is divided based on radiometric dating methods on rock types, yielding numerical ages.
Absolute Time (Chronometric)
observed rock beds with shell fossils located above sea level and viewed as once-living; implied transgression & regression
Xenophanes and Colophon
reasoned that land and sea positions changed over long time periods
Aristotle
wrote the concept of stratification, and recognized fossils as “petrifications of the bodies of plants and animals”
Avicenna
postulated that Earth is 6,000 years old
Bishop James Ussher
established stratigraphic principles in his book “De solido intra solidum naturaliter content dissertationis prodromus
Niels Stensen
postulated Earth is 75,000 years old based from hot iron balls cooled down and related to a similar-sized Earth
Georges Louis de Buffon
believed a 100 million years old based on the uniform decay of thermal structure as observed to present surface gradient
William Thomson, Lord Kelvin
believed a 100 million years as age based on the salt contents of the ocean and the erosion rate of sodic & potassic rocks to raise the ocean salinity to present levels; first to apply radioactivity method
John Joly
postulated 1.6 – 3.0 billion years based on the Uranium (U-Pb decay); formulated the modern geologic time scale
Arthur Holms
System of chronological dating used as a representation of time and events based on the rock record.
Geologic Time Scale
the International Chronostratigraphic Chartwas created by
the International Commission on Stratigraphy (ICS) of the International Union of Geological Sciences (IUGS)
used the terms “montes primarii” for rocks formed before the Deluge, and “monticulos secundarios” for rocks from the debris
Thomas Burnet
rocks formed before the Deluge
montes primarii
rocks from the debris.
monticulos secundarios
According to the plutonists, the primary rocks are ____ and ____ while the secondary rocks are ____
Igni and Meta; Seds
pioneered the systematic rock divisions using stratigraphy and fossils. Local names were given and rocks are correlated across continents; Chronostratic
William Smith, and Georges Cuvier and Alexandre Brogniart
formulated the modern GTS using radioactive dating, enhanced by the discovery of isotope and mass spectrometry; Chronometric
Arthur Holms
In 2023, the Anthropocene Working Group of SQS proposed to designate the Anthropocene as a new geological epoch, based on radionuclides such as Plutonium as physical markers with ________________as reference for the globally-synchronous event marking the end of Holocene.
Crawford Lake in S. Canada
why did the IUGS downvoted the Anthropocene epoch proposition
> epoch division too large
temporal scale
epochs start after worldwide extinction
societal rather than geological; designate as event rather than epoch
timing
Hadean Eon duration
4.6 – 4.0 Ga
Archean Eon duration
4.0 – 2.5 Ga
Proterozoic Eon duration
2.5 Ga – 538 Ma
Phanerozoic Eon duration
538 Ma – present
Describe Geochronology
- measures age of materials and gives temporal distribution (fancy talk of saying time divisions)
- uses radioisotopes, paleomags, etc. to get age
- Time Units
Describe Chronostratigraphy
- Studies rock strata ages by relating to each other ( like which formed first)
- sequence and order or rocks during deposition
- Rock Units
Describe Time units
- Divides by Late, Middle , and Early
- How Old?
Describe Rock units
- Divides by Upper, Middle, and Lower
- Which is Older
Geochronologic vs Chronostratigraphic Units
Eon - Era - Period - Epoch - Age
Eonothem - Erathem - System - Series - Stage
2nd largest time unit; composes the Eon
Era/Erathem
There are 10 defined eras
Eoarchean, Paleoarchean, Mesoarchean, Neoarchean, Paleoproterozoic, Meso-Proterozoic, Neoproterozoic, Paleozoic, Mesozoic, and Cenozoic Eras
3rd largest unit; composes the Era
Period / System
Oldest and most recent period/system
Siderian (Proterozoic); Quaternary (Cenoic)
sub-periods for Carboniferous
Mississippian and Pennsylvanian Periods
2nd smallest geochronologic unit
Epoch/Series
Oldest and most recent epoch/series
Terreniuvian Epoch (Cambrian Period); Holocene Epoch (Quaternary Period)
Smallest hierarchical unit; composes the Epoch
Age/Stage
Oldest and most recent Age/Stage
Fortunian Age (Terreneuvian Epoch); Meghalayan Age (Holocene Epoch)
Non-hierarchical formal unit of unspecified rank
Used to correlate with Magnetostratigraphi, Lithostratigraphic or Biostratigraphic Units
Chron / Chronozone
Reference points in the stratigraphic section defining the lower boundary of a Stage, marked by gold spike.
Global Boundary Stratotype Section and Point (GSSP)
Considerations for the GSSP designatio
> defines the stage’s lower boundary
lower boundary defined by prinmary marker
thick enough outcrop and cant be affected by tectonic, sedmentary, and metamorphic processes
- Chronological reference point and criterion in geologic record to define boundaries between chronostratigraphic units in a stata.
- Primarily used for rocks older than Ediacaran that lacks a good fossil record
Global Standard Stratigraphic Age (GSSA)
Observable diameter is
93 billion light years
age of the universe
13.78
main contents of the universe based on Lambda CDM model
Baryonic (ordinary matter) - 4.9%
Dark Matter - 26.8
Dark Energy - 68.3
Calculated the circumference of the Earth, instigating a curved shape of the Earth’s surface rather than a flat surface.
Eratosthenes
Earth was the center of the universe while the stars, planets, and other heavenly bodies revolved around it
Geocentric Model
who made the geocentric model
Ptolemy (150 CE) in his Almagest
Earth and planets revolved around the Sun.
Heliocentric Model
Who were behind the Heliocentric Model
Nicholas Copernicus (1543), supported by Galileo and Kepler
Universe is expanding but maintains a constant average density
Steady State Theory
Who proposed the Steady State Theory
Sir James Jean in 1928
Universe is continuously expanding from an initial state of high density and temperature (the Singularity
Big Bang Model
Who proposed the Big Bang theory
Georges Lemaitre, 1927
the big bang theory are supported by which concepts
Supported by the Red Shift (Doppler Effect), the CMB, the Hubble-Lemaitre Law.
explain the Hubble Lemaitre Law
the observation in physical cosmology that galaxies are moving away from Earth at speeds proportional to their distance. In other words, the farther they are, the faster they are moving away from Earth
predates the explosion; the point of infinite density, temperature, and curvature where all known physical laws collapse (become meaningless)
Cosmological Singularity
Evidences of the Big Bang
- Red Shift and Doppler Effect
- Hubble – Lemaitre Law
- Cosmic Microwave Background
- Abundance of lighter elements
is the alteration of a wave’s frequency relative to its distance from the observer. Distant galaxies emit light at the red spectrum, indicating very far distance. Conversely, near objects emit light in the blue spectrum.
Doppler Effect
Accurate method of calculating the distance of an object from a certain perspective relative to background.
Parallax
relates a body’s position as observed from Earth at specific time, and compares that body’s location in space as then observed again from Earth after 6 months
Stellar Parallax
Arno Penzias and Robert Wilson, 1965
Cosmic Microwave Background
Sequence of Events during the Big Bang
- Plank
- Grand Unification
- Electroweak Epoch
- Inflationary Epoch
- Early Thermalization
- Electroweak Breaking
- Quark Epoch
- Hadron Epoch
- Lepton Epoch
- Photon Epoch
Nucelosynthesis - Matter Domination
- Recombination &
Photon Decoupling - Dark Ages
- Reionization Epoch &
Earliest Galaxies - Population II & I Stars
- Dark Energy Era
as expansion continues, universe becomes larger, colder, more dilute. All structures decompose to sub-atomic particles & photons.
Heat Death
expansion accelerates and so extreme that spacetime is pulled apart and unable to exist.
Big Rip
expansion stops then reverses and all matter accelerates towards the common center.
BIg Crunch
collapse of quantum fields results to annihilation of all current particles (and anti-particles) and form new forces and particles
Vacuum Instability
Expansion of Singularity; 4 forces still combined
Plank Epoch
Grand
Unification
Epoch
Gravity
separates;
physical
characteristics
meaningless
Inflation
Epoch
Cosmic inflation
& supercooling;
Quark-Gluon
Plasma forms
Hadrons
forms,
including
Baryons
Quark
Epoch
Hadrons
destroyed
emitting
light
Hadron
Epoch
Lepton
Epoch
Leptons
dominated,
then were
destroyed
Photons dominated,
interacting with other
baryons.
Nuclear fusion (from
2 mins to 20 mins)
Photon
Epoch
Only photons were
source of light; CMB
shifted into infrared,
and universe is
devoid of visible light
Dark
Ages
force separated first after the Big Bang
Gravity
Who where behind the solar nebular model
Accepted theory by Immanuel Kant (1755); modified by Pierre Laplace (1795)
growth at the expense of smaller planetesimals
Runaway Accretion
growth of largest planetesimals
Oligarch Arccretion
embryos merge with other; Mercury & Mars, water on Earth
Merger State
where a core is formed then enveloped by accreted gas.
Nucleated Instability Model
Duration of the Hadean Eon
4.567 Ga to 4.0 Ga.
explain the Iron Catastrophe
Iron and Nickel melted and sank to form the core, created the magnetosphere, while buoyant oxygen-seeking rocks rose and formed the primitive crust
in this model of explaning the formation of Earth’s layers, immiscible liquid NiFe globules in a silicate magma sank and separated
Rain Out Model
Moon was part of the Earth (from Pacific Ocean) and later separated.
Fission Theory
Moon & Earth condensed individually and separately from solar nebula
Condensation Theory
Explain the Giant Impact Hypothesis
Theia collided with proto earth
flown fragments coalesced to form the moon
Photochemical Dissociation
(UV rays dissociate H2O into H2 & O2
stars become brighter as they age. The Sun has become 30% brighter; poses problem with ocean formation.
Faint Young Sun Paradox
Period of intense bombardment of meteorites,
comets, asteroids, and other rock fragments
Marks the boundary of Hadean and Archean.
Late Heavy Bombardment (4.1 Ga – 3.8 Ga)
postulates that Jovian planets underwent orbital migration and scattered objects from the asteroid belt and/or Kuiper Belt, into eccentrical orbits into the terrestrial planets.
Nice Model
could have introduced amino acids to early ear
Accretion of Bio-Elements (ABEL) bombardment
2nd oldest eon; 32.6% of geologic time
Archean Eon
The Archean eon began with ____ and ended with ____
LHP; Huronian Glaciation
Oldest Archean microcontinents
Trans Hudson Belt
intrusive rocks with typical granitic composition (quartz and feldspar) but containing only a small portion of potassium feldspar. Tonalite, trondhjemite, and granodiorite often occur together in geological records, indicating similar petrogenetic processes; major components of Archean Cratons
Tonalite–trondhjemite–granodiorite (TTG)
process of outward growth of continents as plates collide with island arcs and other plates.
Continental Accretion
supercontinent; oldest continent. but
less size than Australia
Vaalbara
supercontinent in 2.7 Ga.
Comprised of later Laurentia & Baltica, the
western Australia (Yilgarn Craton, which
contained the 4.4 Ga zircon crystals), and
the Kalahari.
Kenorland
The shield that evolved from kenorland
Baltic/Fennoscandian Shield
Orogeny precursur to Kenorland
Algoman / Kenoran Orogeny
Layered sedimentary formation created by
Cyanobacteria using sand & rocks to form
mineral microbial mats.
Stromatolites
Oldest undisputed stromatolites
3.0 Ga found in the
Barberton Greenstone Belt, S. Africa
Archaean Atmosphere
No Oxygen , mostly CO2 and Methane
water layer between oxygenated and anoxic layers
Redoxcline
chemical sedimentary rocks characterized by alternating layers of iron-rich minerals and chert that are generally interstratified with bimodal submarine volcanic rocks and/or sedimentary sequences in Archean greenstone belts.
Algoma-type banded iron formations (BIF)
are thickly bedded Proterozoic BIFs composed of chert and
hematite (due to oxidation by oxygen). Most significant, esp. as source of Iron.
Superior-type BIF
oldest known glaciation at 2.9 Ga(Mesoarchean) corresponding to the diamictites of the Pongola Supergroup
Pongola Glaciation
3 ice ages at the end of Archean at 2.5 Ga. This coincides with the Great
Oxygenation Event. Oxygen reacted with CO2 and methane,
reducing greenhouse effect lowering the temperature
resulting to the death of anaerobic organisms
Huronian / Makganyene Glaciation
3rd eon and last eon of the Precambrian; 42.65% of GT (longest eon).
Proterozoic Eon
The Proterozoic eon began with ____ and ended with ____
Started with the Great Oxygenation Event and the Huronian Glaciation ice ages and ended with the appearance of complex hard-shelled organisms (Cambrian Explosion).
Establishment of Earth’s magnetic field
3.5 Ga
Age of Orogeny
Proterozoic Eon
Age of Orogeny
Nuna/columbia
Rodinia
Pannotia
period of peak free atmospheric oxygen; and its duration
Great Oxygenation Event
Began in Siderian Period
and ended in Rhyacian Period
Single-celled eukaryotes appeared after
Great Oxygenation Event
is the evolutionary radiation of
animals at 575 Ma.
Avalon Explosion
Current eon in GT from 539 Ma, denoting the most evolution of multicellular life
Phanerozoic Eon
eras of Phanerozoic Eon and duration
•Paleozoic Era is the first era from 539 Ma – 251 Ma
• Mesozoic Era is the middle era from 251 Ma – 66 Ma
• Cenozoic Era is the current era from 66 Ma
• 6 continents in Paleozoic
Baltica, Gondwana, Laurentia, Kazakhstania, China,
and Siberia.
In Middle Ordovician, this orogeny formed along the eastern Laurentia
(due to subduction of Iapetus Plate; 1st pulse of Appalachian Mts; deposition of
Catskill and Queenstone Delta). Dominant deposits are Oolitic carbonates
Taconic Orogeny
in Silurian, Baltica+Avalonia collided with Laurentia, forming Laurasia and closing
the northern Iapetus Ocean, and initiating the
Caledonian Orogeny
In Devonian, this orogeny initiated (3rd pulse of Appalachian Mts) as the
southern Iapetus narrowed between Laurasia and Gondwana. Other orogenies
include Antler (Cordillera) and Ellesmere (N. margin of Laurentia)
Acadian Orogeny
the passageway connecting Paleo-Tethys and Panthalassa.
Rheic Ocean
In Permian, complete assembly of Pangaea as Laurasia & Gondwana merged
(_____________). Enormous single ocean is called _________
Ouachita Orogeny; Panthalassa
When did pangea begin to split
Triassic
is a continental body of water which is very large in area and is either completely surrounded by dry land or connected to an ocean by a river, strait or “arm of the sea”.
Epeiric/Inland seas
The Cordilleran Mobile Belt was caused by
changing subduction angle of the Farallon Plate. This is
comprised of Nevadan Orogeny, Sevier Orogeny, and Laramide Orogeny
is a short interval of max temperature characterized by the highest global temperatures; release of methane hydrates
Paleocene-Eocene Thermal Maximum
First major transgression in North American craton;
Sauk Sequence
Widespread carbonate deposition overlying basal sandstone; record time of major reef building; its sea represented one of
the most complete flood in continent
Tippecanoe Sequence
Last complete sequence to cover North American craton; Caused by the Mid-Cretaceous superplume event.
Zuni Sequence
Sequences in the Paleozoic
Sauk, Tippecanoe, Kaskaskia, Absaroka, Zuni
sudden appearance of hard-shelled organisms and the rapid diversification of organism
Cambrian Explosion
Appearance of first jawless fishes (agnathans).
Paleozoic
First true coral reefs ; non vascular land plants
Ordivician
2nd largest mass extinction in terms of extinct genera
End-Ordovician Mass Extinction
First vascular land plant appeared in
Devonian; Cooksonia
Mass extinction caused by the closing of Iapetus Ocean and orogenic events
Frasnian-Fammenian
Important guide fossil for Pennsylvania-Permian
Fusulinids
Amphibians appeared in
Carboniferous
is the greatest mass extinction event ,Caused by deep-sea anoxia, increased CO2 levels, global warming, and widespread volcanism (Siberian Traps)
Permian-Triassic Mass Extinction
Age of Reptiles
Mesozoic
ancestors to modern fishes
Teleosts
Ancestors of birds
Archaeopteryx
extinction caused by major oceanic changes and Central Atlantic Magmatic
Province volcanism
• End-Triassic Mass Extinction
Non-avian dinosaurs went extinct. Caused by meteorite, Deccan Traps, and other factors.
Cretaceous – Paleogene Mass Extinction
Age of Mammals.
Cenozoic
was an important late Cenozoic paleozoogeographic biotic interchange event in which land and freshwater fauna migrated from North America to South America via Central America and vice versa, as the volcanic Isthmus of Panama rose up from the sea floor and bridged the formerly separated continents
Great American Biotic Interchange
Marks a break between endemic European fauna and mixed fauna with strong Asian
species; extinction of most European primates. Caused by global cooling and
oceanic overturn, meteorite impact in Late Eocene, and the major Antarctic
Glaciation
Eocene – Oligocene Extinction (Transition)
is the extinction of larger land mammals at
20,000 to 10,000 years ago caused by human hunting and overkill
Pleistocene Megafauna Extinction
Oldest known human hominin is
Sahelanthropus tchadensis
Members of Homo
include H. habilis (2.5 Ma), H. erectus (1.8 Ma), and
H. sapiens. Evolved species include H. neanderthalensis, Cro-Magnon,
H. floresiensis, H. luzonensis, H. denisova
Evolution of Primates
• Bipedalism in 10 Ma to 5.0 Ma
• Enlarged skull or brain case in 3.0 Ma to 2.0 Ma
• Stone tools at 2.6 Ma
• Wide geographical distribution at 2.0 Ma to 1.5 Ma
• Cultivation of fire at 1.5 Ma
• Art (cave paintings) at 35,000 years ago
