Chap.1-7 Notes.Hist. Geology
Terms
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- deals with the evolution of the Earth and its’ life forms.
- Historical Geology
- deals with classification of Earth materials and the processes that form the Earth’s landscapes and ocean floors.
- Physical Geology
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- Observation
- Formulation of hypothesis
- Testing
- Construction of Theories
- Scientific Laws (after validation of theories~200 years) - Scientific Method
- early dating without the use of absolute numbers
- Relative (Qualitative dating)
- (Nicolaus Steno) Oldest bed on bottom and youngest bed on top.
- Principle of superpositon
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(James Hutton, Father of Geology):
- The Earth has evolved in a constant and uniform manner
- “Present is the key to the Past†Formation of geologic features found on the Earth in the past can be explained by natural processes that occur - Principle of Uniformitarianism
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Each period of time has an unique and characteristic set of fossils.
- Fossils succeed one another in a definite and recognizable order.
- The younger the rock the more complex the fossil - Principle of Biological Succession
- (Sir Charles Lyell) This principle states that geologic features such as faults, veins, and dikes must be younger than the rocks or features across which they cut.
- Principle of Cross Cutting Replationship
- (Lyell)Principle of ______(rock fragments) are always older than the host rock. Fragments within larger rock masses are older than the rock masses in which they are enclosed. Whenever two rock masses are in contact, the one containing pieces of the other
- Principle of inclusion
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Sediments are deposited in flat, horizontal layers.
(Steeply dipping or folded rock layers indicate tectonic disturbance after deposition.) - Principle of Original Horizontality
- Sediments are deposited over a large area in a continuous sheet. Rock layers extend continuously in all directions, until they thin out at the edge of the depositional basin, or grade into a different type of sediment.
- Principle of Original Lateral Continuity
- Study of layered rocks, including their texture, composition, arrangement, and correlation from place to place.
- Discipline of Stratigraphy
- Determining the equivalence of two rocks in two different localities
- Use of Correlation
- Time of no life
- Precambrian
- Age of ancient life
- Paleozoic Era
- Middle life such as the age of the dinosaurs
- Mesozoic Era
- Recent life (such as mammals and flowering plants). Age of the mammels
- Cenozoic Era
- Nearly flat‑lying strata overlying eroded edges of inclined or tilted older strata. Produces a gap in time known as a hiatus
- Angular Unconformity
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igneous or metamorphic rocks overlain by horizontal sedimentary rock. The intrusive igneous or metamorphic rocks are older than the overlying sedimentary rocks.
Example: Grand Canyon - Nonconformity
- beds above and below the unconformity are parallel and horizontal to one another. The beds are separated by an erosional surface creating a hiatus
- Disconformity
- Atoms that spontaneously decay
- Isotopes
- The time in which one-half of an original amount of a radioactive atoms decays to daughter products.
- Half life
- The radioactive isotope which undergoes decay is
- Parent element
- The parent element undergoes radioactive decay to form a
- Daughter element
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- EX: U238 to Pb206 (uranium to lead).
- Atomic number decreases due to decay of the nucleus - Decay from Parent Product to Daughter Product
- Is 4.6 Billion Years Old (Lunar & Meteorite Samples)
- Age of Earth
- Life as we may know it, began 600 million years ago (4 billion years to set the “Stage for Lifeâ€
- Life began...
- Accounts for 87% of Geological Time
- Precambrian time
- record the rise and fall of the ocean. Form by lithification of sediments. (Rock fragments, Chemical Precipitates, Organic material) Can be deeply buried and subjected to heat and pressure that converts them to metamorphic rocks.
- Sedimentary rocks
- Record thermal events. Form by solidification. Can be weathered and eroded to form sediment (gravel, sand, silt, clay).
- Igneous rocks
- Record folding and mountain building events. Form by heat, pressure, and chemical activity. May be heated to temperatures so great that they melt.
- Metamorphic rocks
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The process by which loose sediment is converted to coherent solid rock by any of several processes: precipitation of a cementing material around individual grains, compaction, or crystallization.
Includes: Weathering
⬢Erosion
⬢Trans - Lithification
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Conglomerate or Breccia
Sandstone
Siltstone
Shale or Claystone - Clastic Texture of Sedimentary rocks
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Carbonate
Evaporitic
Biogenic - Non Clastic Texture Sedimentary Rocks Composed of Chem Precips & Organics
- Include Shields & Platforms. The long-stable region of a continent, commonly with Precambrian rock, either at the surface or only thinly covered with younger sedimentary rocks.
- Cratons
- Large areas of exposed ancient crystalline rocks. (Canadian shield) A component of cratons.
- Shield
- Basement rock covered with sed. Rock (US Midwest). That part of a craton covered thinly by layered sedimentary rocks and characterized by relatively stable tectonic conditions.
- Platforms
- Linear mountain systems formed through compression. Great linear tracts of deformed rocks, primarily developed near continental margins by compressional forces accompanying mountain building.
- Orogenic Belts
- Ocean
- Marine environment
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Nearly flat, smooth surfaces extending from the shoreline to 600 feet in water depth. The flooded edge of the continent. Flooding occurred when the glaciers melted at the end of the last Ice Age, about 10,000 years ago.
Relatively flat (slope < - Continental shelves
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Steep slopes that extend from the seaward edge of the continental shelves down to a water depth of 6000 feet. The steeper slope at edge of the continent.
Located seaward of the continental shelf.
Boundary between continental and oceanic crust - Continetal slopes
- Deposited by turbity currents that flow down submarine canyons
- Deep sea fans
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Large fluvial depocenters at the lands edge.
Fan-shaped accumulations of sediment
Formed where a river flows into a standing body of water, such as a lake or the sea
Coarser sediment (sand) tends to be deposited near the mouth of the ri - Delta
- Are those environments at or near the transition between the land and the sea
- Transitional environments
- Delta front composed of sands and clays (very diversified marine fauna)
- Foreset beds
- Continental deposition
- Nonmarine environments
- river environments consisting of point bar deposition and cutbank erosion
- Fluvial
- What color are we taling about? Black or dark-gray coloration indicate high levels of organic material –Ex: Shale
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Color: Black
(Color of sedimentary rocks provides useful clues to the depositional environment) - Brown, red green indicate the presence of iron oxide minerals and oxidation (exposure of the rock to oxygen in the atmosphere) –Ex: Red Beds (Clays and Sandstones)
- Color: Red (Color of sedimentary rocks provides useful clues to the depositional environment)
- Well sorted sand within a narrow size range indicates a mature sandstone (a long process of transportation and deposition as in beach deposits, eolian dune deposits, and some fluvial deposition)
- Maturity includes; Size and sorting
- Rounding and Sphericity: Angular grains as in conglomerates indicate immature sedimentation close to the source area
- Maturity includes; Grain shape
- Size, Sorting, Grain Shape and Color. Can be deposited in marine and nonmarine environments.
- Sandstones
- Limestones are predominantly deposited in a marine environment
- Carbonates
- Black coloration due to organic content. Can be deposited in marine and nonmarine environments
- Shales
- Determining the equivalence of two rock bodies in two different localities. May use lithologic position, lithology, or fossils in correlation. Used in the construction of Geologic Columns and Cross-Sections
- Correlation
- Primarily indicates a generalized Environment of Deposition.
- Formations
- Include Eons, Eras, Periods and Epochs
- Time Units
- Map showing the geography of an area at a specific time in geological past. Shows the distribution of land and water during specific periods of time.
- Paleogeographic map
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What type of map shows thickness? Shows the changes in thickness of the formation or stratigraphic unit. The zero isopach represents the boundary of the rock unit.
–Erosional
–True Basin Edge (Presence of Sand!)A map depicting the thickne - Isopach map
- Rock that strongly indicates the Environment of Deposition (Marine or Nonmarine). A particular aspect of sedimentary rocks that is a direct consequence of sedimentation in a particular depositional environment. It allows identification of the environment
- Facies
- Interpretations, i.e. land and ocean. When the differentiating characteristics are lithologic (rather than biologic), facies can be designated as lithofacies
- Lithofacies maps
- Molecular exchange of the original organic material with inorganic minerals (SiO2) –Ex: Petrified Wood A fossilization process in which the original skeletal substance is replaced after burial by inorganically precipitated mineral matter
- Replacement
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Soft tissues are persevered as thin films of carbon
–Ex: preservation in shale. The concentration of carbon during fossilization - Carbonization
- Impression of organisms left in the rock
- Molds and casts
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Tracks, trails, burrows, and other markings made in now lithified sediments by ancient animals.
Shows the animals behavior –Examples: Biped or Quadruped?
–Feeding behavior - Trace fossil
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- Classification of life based on Morphology (anatomy of the organism).
- Utilizes the Linnaean System of binomial nomenclature (genus and species) Organisms are grouped based on their similarities into taxonomic groups or taxa.
Kingdom: Anim - Taxonomy
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–Contains RNA
–DNA Absent
–Needs host cell to reproduce - HIV Virus
-
–Self Replicating
–Transcribes to RNA
–RNA translates to ribosomes or mitochondria
–Protein synthesis
Responsible for life - DNA
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Demonstrated that physical characteristics can jump generation
⬢Ex. Planted seeds from small pea plants which generated some tall pea plants.
⬢Ex. Two brown eyed people have a blue eyed baby.
⬢Ex. A son goes bald but the father an - Mendelain Principles of Inheritance
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- Transfers genetic information
–Composed of nucleotides
–Series of nucleotides compose a gene (factor for specific inherited traits)
– Series of genes compose a chromosome
– Chromosomes are paired
– Humans have 23 - DNA: Deoxyribonucleic Acid
- A stable and inheritable change in a gene.Spontaneous change in the chemical organization of the DNA molecule that is replicated and passed on to succeeding generations as a new gene expression (can be good or bad)
- Mutation
- a group of interbreeding individuals of the same species composing a specific gene pool. A group of individuals that live close enough together so that each individual has an equal chance to mate with all members of the opposite sex within the group.
- Population
- Population of similar individuals that can interbreed and produce fertile offspring
- Species
- The evolution of a new species via adaptive radiation (certain individuals become highly adapted to a particular environment and living strategy)
- Speciation
- Species may exist for several millions of years with little or no change and speciate rapidly in a short period of time.
- Punctualistic model or puctualistic evolution
- Species are continuously adapting, mutating, and speciating through time.
- Gradualistic model
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–Vestigial Organs
•Coccyx, Appendix, Whale Pelvis - Soemthing we don't need
- - Horse fossils
- Paleontological Clue
- Interval of time that a species exists
- Geological range
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Fossils that are restricted to a narrow range
–Short lived
–Highly adapted to environment
–Quickly become extinct.
Fossil with a wide geographical distribution but narrow stratigraphic range and thus useful in correlating st - Index fossils
- Combination of several species within a stratigraphic unit (formation) –Significantly narrows the age of the rock.
- Assemblage zones
- The study of the relationship of ancient organisms to their environment.
- Paleoecology
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Rifting of the Mesozoic Supercontinent of Pangaea
Is descriptive and does not offer a mechanical explanation for the drift - Continental Drift
- Freshwater reptile found along coastlines of Brazil and West Africa
- Mesosaurus
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Ridges: Splits in the seafloor –
Trenches: Linear depressions along coastlines - Bathymetry of Seafloor
- Seismic and volcanic activity is associated with ridges and trenches which define the Plate Boundaries
- Seismicity
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Cross-Section of Seafloor and Continental Mountain Belt
⬢Shows Divergent Ridge Boundary and Convergent Trench Boundary (Subduction) - Mechanism of Plate movemnt
- Global Movement of the Lithospheric Plates
- Plate tectonics
- Exposure of the rock to oxygen in the atmosphere
- Oxidation
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Represents the boundary of the rock unit
- Eroisonal
- True basin edge
- (Presence of sand) - Zero Isopach
- Only 10% of the bio mass is transferred across each _______. The rest is needed to live.
- Trophic Level
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Practice Photosynthesis (Plants & Phytoplankton)
(100 biomass units) - Producers
- Which trophic level? Omnivores; Respiration
- Consumers
- Which trophic level? Carnivores - meat eaters
- One Unit
- 10 Units; Herbivores;
- Consumers; Animals & Zooplankton
- Kingdom
- Animalia
- Phylum
- Chordata
- Class
- Mammalia
- Order
- Primates
- Family
- Hominidae
- Genus
- Homo
- Species
- sapien
- How many chromosomes do we have
- 46
- Females are..
- XX
- Males are...
- XY
- Humans have _____ pairs of chromosomes (half from mom and half drom Dad)
- 23
- What is life
- Self replicating
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- Embryology
- Conservative properties of DNA - Biological Clues
- Name the supercontinent of the Mesozoic?
- Pangaea
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____ are a major division of geologic time. _____ are divided into geologic periods. There are three ____ in the Phanerozoic Eon. In order from oldest to youngest, they are as follows:
Paleozoic Era - "ancient life" (such as trilobi - Eras
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Eras are divided into periods.
Permian
Cambrian
Devonian
Sulurian
Ordivician
Cambrian - Periods
- Taxonomy from largest to smallest
- Kingdom, Phylum, Class, Order, Family, Genus, species
- Anatomy of the organism
- Morphology