Geology 209 After Midterm 2

the study of rock layers and layering. it deals with the classification, correlations and interpretations of stratified ricks which can be sedimentary, igneous, or metamorphic

first steps toward understanding the strata architecture in earth's subsurface. Studied the rocks in Tuscany in the decade after the establishment of the royal society of london. Established the theoretical basis of Stratigraphy

1. lithostratigraphy: rock physical characteristics to study rock strata

2. biostratigraphy: Fossil Evidence to correlate and interpret rock strata

introduced the principle of actuals - present is key to the past

produced first geological map of england, wales and southern scotland

proposed principle of catastrophism

1. mineral exploration

2. Hydro carbon exploration

3. coal mining

4. engineering Geology

a) road contruction

b) tunneling

c) bridges

1. principle of layer superposition

2. principle of successive layer formation

3.prinicpal of original layer horizontality

4. principal of original layer continuity

5. principal of inclusion

6. principal of cross cutting relationships

7. principal of rock cooking

in an undisturbed sequence older layers at the bottom and younger layers at the top

when a layer is forming no layer exists above it other than fluid which layer material were precipitated

layers of sedimentary rocks were originally deposited horizontally or near horizontal to earths surface, and deposition on steep slope will be washed away before lithification. inclined layers and folded layers are results of disturbance since original deposition

assumes that layers were deposited over entire basin (over extensive area) demonstrating lateral continuity and the layers terminate by thinning at basin margins or grading into another type of sediment

states that inclusions within igneous rocks are older than rocks that include them. Inclusions are termed Xenolith

rock fragments that are identifiably different from the rock in which they are enveloped

states that younger features or rock cut across older feature or rocks prominently used in characterizing viens, dykes in igneous rocks

an igneous body that thermally alters a body of rock is younger than the altered rock

structures die to sedimentary processes with consistent upward or downward orientation

1. enable reconstruction of stratigraphical succession

2. indicate top and bottom of sedimentary layers

3. indication of disturbance in sedimentary layers

sedimentary structures in fine sediment that opens upwards (layer top) and narrows downward (layer bottom) to indicate the top and bottom direction in a layer

structures produced by organisms in sediments in the course of their life activities. The burrows as a rule opens toward the top of a layer and closes towards the bottom of a layer

sedimentary structures formed as a result of current action on unconsolidated particles at the top of a layer. they exhibit a structure that narrows toward the top of the layer and widens towards the bottom of a layer

they are buried erosional or non depositional surfaces between two rock layers. represent break in sedimentation or deposition within rock successions

1. erosional surfaces showing relief

2. hard grounds

3. discordant dip angles

4. fossil record

5. turncation of bedding planes, dykes and faults

6. Ferrugination structures

the missing time in stratigraphic succession representing the time in which there was a break in deposition

Lacuna

1. crustal movements

2. erosion

3. igneous intrusions

unconformity between parallel sedimentary layers. Break in deposition followed by uplift, erosion, and the deposition of the top layer

results from the overlaying of eroded igneous or metamorphic rock surfaces formed deep beneath the earth surface by sedimentary layers

formed between tilted and un-deformed sedimentary layers involves the deposition of layers horizontally or near horizontal, uplift and tilted followed by erosion and the deposition of a new horizontal bed

system of chronological measurement that relates stratigraphy to time. Used for describing the timing and relationship between events in earths history

1. biblical age - bishop Ussher - 4004 BC

2. relative age

3. radiometric dating

i) marie and pierre currie

ii) absolute age

iii) isotopes

a) half life

b) parent and daughter atoms

1. eons

2. eras

3. period

4. age

1. largest unit

2. 4 eons

3. subdivided into eras

1. hadeon

2. archean

3. proterozoic

4. phanerozoic

1. oldest eon in earth history

2. 4.5 -4 BYA

3. no rock recorf

4. began with our planet formation

5. only molten matter present

1. oldest record on earth

2. 4-2.5 BYA

3. fossil record established

1. AKA Precambrian

2. oldest macro fossil record recorded

3. 2.5 - 0.5 BYA

1. youngest eon in earths history

2. .5 - 0 billion years old

3. beginning of visible large fossils

4. eras

i. paleozoic

ii. mesozoic

iii. cenozoic

1. Paleozoic

2. mesozoic

3. cenozoic

1. small resemblance in fossils and modern fauna and floras

2. 500-250 MYA

3. 7 periods

1. cambrian

2. ordovician

3. silurian

4. denonian

5. mississippian

6. pensylveanian

7. permian

1. some resemblance in fossils to modern fauna and floras

2. 250-65 MYA

3. 3 periods

1. Triassic

2. Jurassic

3. Cretaceous

90% of species in seas and oceans became extinct

extinction of major fossil groups

ex. Dinosaur

1.clear resemblance in fossils and modern fauna and floras

2. 65-0 MYA

3. 3 period

1. paleogene

2. Neogene

3. Quarternary

the study of establishing geochronological relationship between different regions based on geological investigations of rock successions

lithological characteristics

use of fossil record

1. physical naturally occurring and induced properties of rock

2. well logging, geophysical investigations

absolute dating

the change in the inherited characteristics of organisms or biological groups over succession of generations leading to diversity in species, morphologies and genetics

Documentation of life history by fossils

The study of the principles used in species classification at any hierarchal level

1. classification based on morphological resemblance

2. systema Naturae - 1758 publication

i. hierarchial classifications

ii. higher rank groups more inclusive or diversified

iii. lower rank groups less inclusive less diversified

3. species as fundamental

1. kingdom

2. class

3. order

4. Genus

5. Species

1. kingdom

2. phylum

3. class

4. order

5. family

6. genus

7. species

1. significant variation in population of same specie

2. environment and morphological changes

3. inheritance of useful organ

4. adaptation

1. first coherent theory of evolution

2. observation

i. significant morphological variability in species

ii. inheritance of some morphological variation

iii. more individuals born than can survive

3. Species means by natural selection

1. oldest layers usually devoid of fossils

2. microscopic fossils

3. older fossils simple and primitive

4. younger fossils

i. complex

ii.multicellular

iii. exoskeletons

earliest life are single celled evolved from inorganic substances through evolution

1. patchy fossil record

2. small fragments of fossils

3. metamorphic processes affected rocks destroy fossils

4. molecules are not fossilized

1. gradual increasing morphology related to geological events

2. rock formation related to changes in atmospheric composition

CHON

1. carbon C

2. Hydrogen H

3. Oxygen O

4. Nitrogen N

1. sulphur S

2. Phosphorus P

30

1. CH4

2. NH3

3. CO2

4. H2O

organic molecules

1. CHON formed before life forms

2. reducing atmosphere - accumulation of organic molecules

3. organic molecules dissolves into water to form primordial Soup

1. hydrogenated gases dominant in primordial atmosphere

i. CH4, NH3, CO2, H2O

2. formation of amino acids in the lab

3. polymerization

the theory that explains the features and large scale motion of the earth's lithospheric place in the present and the past. it combines the concepts of continental drift and sea floor spreading

the movement of the earth's continents relative to each other

the process by which new oceanic crusts are formed by volcanic activities at the mid ocean ridge

the permanent magnetism of rock or sediment during formation preserving the record of the earths magnetic field

1. super continent during late Paleozoic

2. surrounded by super ocean Panthalassa

3. broke up by rifting

i. laurasia

ii. Gondwana

Panthalassa

1. therasid Lystosarus found in A africa, india and australia

2. glossopteris Flora - equator to polar circle

reconstructed polar wandering path

continuity ion mountian ranges appalachian to caledonians of ireland, britain, and scandanavia

started in 1968

glomar challenger

- atlantic

- pacific

- indian

- jean baptiste lamarck 1744-1829

started in 1985

started in 2001 significant variation in population of same specie

1. validation of sea floor spreading

2. validation for continental drift

3. scientific understanding

a. earth history

b. climate change

c. geohazard

1. sonar sounding

2. coring

1. abyssal plains

2. mid oceanic ridge

3. oceanic trenches

4. seamount

5. island arc

4-4.5 km in depth, planar with very low slope

1. mountain chain towards the centre of the ocean

2. several km in length and ~ 2 km in height

3. associated with volcanic eruption and earth quakes

1.deepest part of oceans

2. can be 11.5 km in depth

3. elongate structures covering small area

4. associated with earthquakes

1. small sized structures

2. several thousand meters in Altitude

3. can rise above level to form island

4. tops can be eroded to form flat topped mountains

5. associated with volcanic activities

1. elongate chains of small sized islands

2. usually parallel to oceanic trench

3. situated away from continents

4. proximal areas associated with volcanic and earth quake activities

1. distinct pattern in sediment age distribution

2. age increase as distance from the mid oceanic ridge increases

3. youngest sediment closest to the mid oceanic ridge

4. oldest sediment closest to the continent

5. symmetrical age distribution relative to the mid ocean ridge

minerals align to magnetic fields during crystallization or deposition

1. normal polarity

2. reverse polarity

magnetic north/south pole and the geographic north/south pole in the same hemisphere

magnetic north/south pole and geographic north/south pole in different hemisphere

polarity zones parallel to mid ocean ridge

1. common at plate boundaries

2. associated with seamounts

3. associated with island arcs - indonesia

4. can occur in clusters - iceland

concentrated along plate boundaries

the study of the process which control the structure of the earth's crust and its evolution focuses on the movement of the crust and the forces initiating motion

1. divergent

2. convergent motion

3. transform motion

1. lithospheric plates move AWAY from eachother

2. leads to BREAK of continent

3. mid atlantic ridge

4. ascending current from the asthenosphere initiates movement

5. molten matter from the earth's interior brought to the surface

6. formation of ocean basin

1. ocean crust is formed

2. seafloor spreading

3. 1-5 cm per year ocean crust formed

1. continental uplift

2. continental rift formation

3. ocean basin initiation

4. mature ocean formation

1. ascending current from asthenosphere

2. elevated altitude

1. continents stretching and thinning

2. formation of elongate depression zones

3. faulting

4. volcanism

1. continental crust split into two

2. sea floor spreading generated by molten influx

1. continued sea floor spreading

2. more new crust formed

-abyssal plain expansion

movement of plates against each other

1. collision of two oceanic crust - one sunken and the other along an inclined plane

2. inclined plane called benioff or subduction plane

3. collision zone marked as ocean trench on seas floor

4. accretionary prism formed

5. earth's interior heat and friction lead to melting of subduction crust to produce magma

6. volcanic activity as result and lead to island arcs formation

1. collision between continental and oceanic crust

2. oceanic crust subducted beneath the continental crust

3. marked by ocean trench parallel to shore line

4. accretionary prism formed

5. associated with earthquakes and magma generation

6. deepest part of oceans

7. can be 11.5 km deep

8. elongate structures covering small area

9. associated with earth quakes

1. collision between two continental crusts

2. associated oceanic crust subjected

3. narrows and closes ocean

4. mountain chains formed parallel to collision zones

5. earth quakes and volcanism associated with zone

6. himalayas mountains - eurasia and india collision

the cycle of ocean initiation, expansion and closure

John Tuzo Wilson

divergent motion

subduction

convergent