M1 L1: Fundamental Principles of Stratigraphy

what is stratigraphy concerned with

1. Composition 2. Origin 3. Age Relationships 4. Geographic Extent of Layered or Stratified Rocks

importance of stratigraphy

1. gives you techniques for working out earth history 2. integrates diverse materials into a coherent view of how the earth and its life forms evolved 3. lets you test ideas on how varying combinations of processes affect the planets through time 4. helps you to understand how many economic materials formed and got distributed in the way they did - and so will hopefully help you find more

percentage of the mantle as part of the earth

82% volume, 68% mass

how did the earth form?

>4.7 B years ago; gathering of planetesimals. an unsorted conglomeration of Si compounds, and Fe and Mg oxides and smaller amounts of natural chemical elements. Such accumulation likely heated up the initial Earth. >Gravity compression also leads to temperature rise; the heat did not flow out easily because rocks are relatively poor conductors of heat. As a result, heat accumulated in the Earth's interior, probably averaging 1000°C. >The spontaneous disintegration of radioactive elements (e.g., U, Th, K) further caused heating of the Earth's interior in the course of billions of years.

what are the 10 principles of stratigraphy

>>by James Hutton 1. law of uniformitarianism >>by Nicolaus Steno 2. Law of superposition 3. law of original horizontality 4. law of lateral continuity >>by James Hutton 5. principle of cross-cutting relationships 6. law of included fragments/inclusions 7. law of unconformities >>by William "strata" Smith 8. Principle of fauna and flora succession 9. Correlation of rock units >>by Johannes Walther 10. Walther's law

Huttons laws

>PRINCIPLE OF CROSS-CUTTING RELATIONSHIPS >LAW OF INCLUSIONS / INCLUDED FRAGMENTS >LAW OF UNCONFORMITIES

Smiths laws

>PRINCIPLE OF FAUNAL AND FLORAL SUCCESSION >CORRELATION OF ROCK UNITS

explain the formation of the solar system

>the Universe originated from a cosmic explosion (origin unknown) that hurled matter in all directions 13.7 Billion years ago

how did the solar system form?

>the solar system originated from a single rotating cloud of gas and dust, starting 4.6 billion years ago >contracted due to gravity

consists of tilted or folded sedimentary rocks that are overlain by younger, more flat-lying strata. It indicates a long period of rock deformation and erosion.

ANGULAR UNCONFORMITY

The method of relating rock units from one locality to another

CORRELATION

principle used when relating rock units from one locality to another >thru recognize the rock type or rock sequence at two locations >use fossils

CORRELATION OF ROCK UNITS

Illustrated the concept of uniformity of natural processes through time and the corollary necessity for a great antiquity of the Earth

Charles Lyell

Uniformity of causes + uniformity of intensity

Charles Lyell

father of Principles of Geology

Charles Lyell

Established the age of the earth In 1953

Clair C. Patterson

>is a minor irregular surface separating parallel strata on opposite sides of the surface. >It indicates a history of uplifting above sea (water) level, undergoing erosion, and lowering below the sea level again.

Disconformity

Types of unconformities

Disconformity, Nonconformity, Angular Unconformity, Paraconformity

who justified Lamaitre's theories? and how?

Edwin Hubble by observations that the Universe is continuously expanding; galaxies are moving away from each other

who proposed the nebular hypothesis?

Immanuel Kant and Pierre Simon de Laplace in the 18th century

who proposed walthers law

JOHANNES WALTHER

>Cyclic view of Earth change >The Earth can rejuvenate itself

James Hutton

Father of Modern Geology

James Hutton

proposed uniformitarianism

James Hutton

If pieces of rock A are included in rock B, rock A formed before rock B.

LAW OF INCLUSIONS / INCLUDED FRAGMENTS

An unconformity represents a long period during which deposition ceased and erosion removed previously formed rocks before deposition resumed

LAW OF UNCONFORMITIES

FOUNDER of the basic stratigraphic principle

Nicolaus Steno

When a fault cuts through rocks, or when magma intrudes and crystallizes, we can assume that the fault or intrusion is younger than the rocks affected.

PRINCIPLE OF CROSS-CUTTING RELATIONSHIPS

>Systematic sequence of fossils with time. Extinct fossils do not reappear in younger rocks. >Groups of fossil animals and plants occur the geologic history in a definite and determinable order and a period of geologic time can be recognized by its characteristic fossils.

PRINCIPLE OF FAUNAL AND FLORAL SUCCESSION

Relationship between vertical and lateral variations. The fact that there is lateral variation in facies leads to vertical variation in facies

WALTHER'S LAW

Lateral variations are expressed in the vertical due to the succession of facies Only those lithofacies which are a product of sedimentary environments found adjacent to one another in the modern can be occur superimposed in continuous, uninterrupted stratigraphic succession."

Walther's Law of Correlation of Facies

"FATHER of Stratigraphy"

William "strata" Smith

Credited with creating the 1 st detailed, nationwide geologic map & showing the rock strata in England and Wales (1815)

William Smith

Famous for the Principle of Faunal and Floral Succession

William Smith

earth's outermost layers

atmosphere, hydrosphere, and biosphere

theory proposed by the belgian priest Georges Lamaitre in the 1920s

big bang theory

>sudden, worldwide catastrophes are the agents of change that change the earth's physical features >earth remains unchanged between these changes

catastrophism, proposed by Baron Georges Cuvier

When layers of rock formed without interruption, we call them

conformable

minor temporary pauses or breaks in deposition with little or no erosion before resumption of deposition

diastem

2 Greek words etymology of Geology

geo (earth) and logos (discourse)

geologic time not represented in strata

hiatus

deals with the history of the Earth. This includes the Earth's origin, relative and absolute timing of events that has shaped the Earth, as well as the life forms that has appeared in Earth's history

historical geology

gap or break in strat record as part of the strat record is removed by erosional surface

lacuna

2 words etymology of stratigraphy

latin stratum (strata) greek graphia (writing/drawing)

>states that the beds can be traced over a long interval if the basins were open >a BED will extend laterally until: 1. Pinches out. 2. Abuts against older rock. 3. Truncated by erosion. 4. Cut by fault.

law of lateral continuity

>Layers of sediment are generally deposited in a horizontal position >exceptions have been moved into that position by crustal disturbances sometime after their deposition

law of original horizontality

>In an undeformed sequence of sedimentary rocks, each bed is older than the one above and younger than the one below. >The rule also applies to other surface-deposited materials such as lava flows and volcanic ashes.

law of superposition

Stenos laws

law of superposition law of original horizontality law of lateral continuity

rocks had settled out of a large ocean whose level gradually dropped over time

neptunism, amplified by Abraham Gottlob Werner

is a break surface that developed when igneous or metamorphic rocks were exposed to erosion, and younger sedimentary rocks were subsequently deposited above the erosion surface.

nonconformity

earth's major surface features

ocean basins and continents

>Where the beds are parallel and the contact between the stratified rocks is just a simple bedding plane >Are biostratigraphic discontinuities within sequence of parallel strata, based and evaluated solely on paleontologic evidence.

paraconformity

involved in the study of the material composition, appearance, structure and processes of the Earth

physical/dynamic geology

2 branches of geology

physical/dynamic geology historical geology

4 basic concepts in the history of geology

plutonism neptunism catastrophism uniformitarianism

Rocks were formed by heat concealed within the Earth's interior

plutonism by James Hutton

Seaward movement of shoreline (shallowing)

regression

how did patterson come up with the earth's age?

reporting the ratio of lead types found Canyon Diablo meteorites and comparing them to lead ratios found in the other rocks on the Earth and other meteorites, >>the age of the solar system, when the Earth formed, to be 4.55 billion years old, give or take 70 million years.

Major structural units of the earth

solid inner core liquid outer core lower mantle upper mantle continental and oceanic crust

branch of geology which studies rock layers (strata) and layering (stratification)

stratigraphy

What does the study of geology deal with

the study of the earth's composition, structure, history, past life forms and processes responsible for the present configuration of processes

Landward movement of shoreline (deepening)

transgression

"The present is the key to the past." >the Earth is continuously modified by geologic processes that have always operated throughout time (albeit at different rates), and that by studying them we can understand how the Earth has evolved through time

uniformitarianism, proposed by James Hutton

was catastrophism accepted?

yes by theologians in the early 1800s because of the similarity with biblical events (Noachian Flood)