Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
251 Cards in this Set
- Front
- Back
|
GSSP |
Acronym for Global Standard boundary Section and Point |
|
|
How does vertical stacking of strata provide clues to depositional environments? |
1. Suites of closely associated rocks are needed in order to identify an ancient environment |
|
|
Walther's Law |
Lithologies that comfortable overlie one another must have accumulated in adjacent depositional environments. |
|
|
What sedimentary features result from deposition in particular non-marine environments? |
1. Some types of ancient soils reflect the climatic conditions under which they formed |
|
|
What are the distinctive features of marginal marine + continental shelf deposits?
|
Where a river meets a lake or ocean, it forms a delta |
|
|
What are the characteristics of deep sea sediments?
|
1. Beyond the edge of the continental shelf, turbidity currents intermittently sweep own continental slopes out to the continental rise + abyssal plain (forming turbidites) |
|
|
Time units of stratigraphy
|
1. Eras |
|
|
What is a rock facies?
|
A set of characteristic strata that formed in a particular event
- A formation may be a single, or two adjacent facies |
|
|
What rocks and fossils in Africa + S. America suggest that those two continents were connected to each other as parts of Gondwanaland in late Paleozoic?
|
1. Many kinds of non-marine organisms (Glossopteris:fern, mesosaurus: reptile)
2. Rock sequence in Africa was identical to Brazil 3. Matching mountain belts |
|
|
How does paleomagnetism demonstrate that the continents have been moving over time?
|
1. Magnetism frozen into ancient rocks is not aligned with the Earth's present magnetic field
|
|
|
How does continental rifting begin, and what environments of deposition does it produce?
|
1. Fracturing of continents often begins with doming of crust in the middle
- each dome fractures and becomes a three-arm system and rifting begins |
|
|
Ophiolite
|
The remnant of a sea floor
|
|
|
How did the Andes form?
|
The Andes rose up as a result of subduction of an oceanic plate along the west coast of S. America
|
|
|
Pyrenees
|
Collision of Iberia + Eurasia
|
|
|
What fundamental principles guide geologists as they reconstruct Earth's history?
|
Actualism
- fundamental to natural science, asserts that the laws of science do not vary over the course of time |
|
|
What are the basic kinda of rock and how are they interrelated?
|
1. Sedimentary
2. Igneous 3. Metamorphic |
|
|
How do geologists unravel the age of rocks?
|
1. Principles of horizontality
2. Principle of superposition 3. Original Lateral Continuity 4. Chemical dating |
|
|
Eras + Times of the Phanerozoic
|
1. Paleozoic (524-251 mya)
2. Mesozoic (251-65.5 mya) 3. Cenozoic (65.5 mya- ) |
|
|
Periods of the Paleozoic
|
1. Cambrian
2. Ordovician 3. Silurian 4. Devonian 5. Carboniferous 6. Permian |
|
|
Periods of the Mesozoic
|
1. Triassic
2. Jurassic 3. Cretaceous |
|
|
Periods of the Cenozoic
|
1. Paleogene
2. Neogene 3. Quaternary |
|
|
Cambrian
|
(542-488.3 mya)
Cambrian explosion (lifey sea, barren land) |
|
|
Ordovician
|
(488.3-443.7 mya)
Gondwana Taconic Mountains Mass extinction of planktonic forms Trilobites/brachiopods/cephalopods/ crinoids |
|
|
Silurian
|
(443.7-416 mya)
Jawed + Bony fish Stable + warm vascular plants on land Patchy reefal systems ** These are the rocks from the field trip |
|
|
Devonian
|
(416-359 mya)
Adaptive Radiation of terrestrial life + fish diversity warm (high seas) THE AGE OF FISH terrestrial arthropods |
|
|
Carboniferous
|
359.2-299 mya
Terrestrial life Amphibians Large Arthropoda Pangea bivalves important evolution of egg |
|
|
Permian
|
299-251 mya
Trilobites extinct Pleycosaurs + amphibians Cynodonts + synapsids! |
|
|
Triassic
|
251-199.6 mya
2 Major extinctions (start + end) Permian-Triassic extinction event (252mya) - 96% marine life, 70% terrestrial - 'disaster taxa': Taxa that colonize the land after a major disaster (primary colonizers) |
|
|
Jurassic |
199.6-145.5 mya
AGE OF REPTILES Pangea split into Laurasia (North) and Gondwana (South) FIRST BIRDS |
|
|
Cretaceous |
145.5-65.5 mya |
|
|
Paleogene
|
65.5-23.03 mya
Mammals No more dinos Rocks = "Paleogene System" SO MANY MAMMALS |
|
|
Neogene
|
23.03-2.588 mya |
|
|
Quaternary
|
2.588 mya- now
Short glaciations in N. Hemisphere Pleistocene, Holocene, (Anthropocene?) Recognizable humans |
|
|
P(COSDCP)
M(JTC) C(PNQ) |
you know it
|
|
|
Biostratigraphy
|
- Fossil record in the rocks
Fossil records can help correlate rocks through morphologies |
|
|
Lithostratigraphy
|
- Lithostratigraphic units are time-transgressive
|
|
|
Lithification
|
Involves compaction; as sediment is deposited, the weight of the overlying sediment compacts an lithifies older layers
|
|
|
Cementation
|
Involves the precipitation of minerals out of water, which glues grains together and further reduces pore spaces |
|
|
Wacke/ (Greywacke)
|
* CONTAINS MUD
- Laid down by turbidity currents - Contains poorly sorted levels of gravels, muds and sands - Grey |
|
|
Arenite
|
Sedimentary clastic rock
No Mud |
|
|
What is a Basin?
|
- Any geographical feature (container) exhibiting subsidence (sinking) and infilling by sedimentation
- As more sediment is deposited, the weight of it may cause the basin to subside further Example: Mississippi Delta - Continues to have sediment deposited in it, and continues to subside (resulting in a basin km in thickness) |
|
|
Plate Tectonics Theory
|
Scientific theory that the lithosphere is cracked and composed of pieces that interact with each other as they float on the asthenosphere
|
|
|
Plate Motion
|
Plates move 1-7cm a year, causing plates to converge/ diverge/ slide
|
|
|
Wilson Cycle
Formation of a basin and then the process of its destruction |
1. Stable craton
2. Early rifting 3. Full ocean basin 4. Subduction zone 5. Closing ocean basin 6. Orogeny collision |
|
|
Isostatic Changes
|
Less dense crust will tend to ride topographically higher than areas of denser material
(Crust responds to addition of sediment/water/ice) |
|
|
Eperic Basins
|
Semi-circular downwards in continental interiors
Causes: Underlying rifts, large-scale fault blocks, cooling after intrusion, mantle cold spots, phase changes Example: Caspian sea |
|
|
Why/ how are carbonate sediments "born"?
|
- Carbonate sediments are created through biological growth and not made like their clastic counterparts, by weathering of parent material
- Made from the biological precipitation of calcium out of seawater |
|
|
Allochems (Bioclasts) |
Silt, sand, and gravel sized carbonate particles that form the framework of rock: |
|
|
Insitu Bioclasts
|
Corals, algae that have not been transported (in situ), and sediment has infilled around the skeletons
|
|
|
Oolithic Sands
|
Oolite grains can be so abundant that they form oolite sands
Example: Most Carribean islands are oolithic sands |
|
|
Peloids
|
Carbonate fecal pellets; no internal layering, form in quiet environments
|
|
|
Folk Classification
|
Allochems vs. Orthochems
** Learn to draw this |
|
|
Dunham Classification
|
Based on the concept of the grain
|
|
|
Evaporites
|
Gypsum (calcium sulfate dihydrate)
Anhydrite (calcium sulfate) Halite (often called rock salt) Found in bed form Sea water needed to form |
|
|
Chert
|
Nodules of chert might be present in limestones
- Chert is from siliceous micro-organisms-diatoms, radiolarans and some sponges * The siliceous skeletons accumulate in beds, which dissolve and re-precipitate as crypto-crystalline or microcrystalline chert |
|
|
Primary sediment structures are the result of sediment movement by:
|
- Water (unidirectional-current/oscillatory-tidal)
- Ice - Gravity - Wind - Biological activity |
|
|
Particle Entrainment
|
Critical threshold for grain movement depends on:
- Boundary shear stress - Fluid viscosity - Particle size/ shape/ density |
|
|
What type of rock has a mud matrix:
- wacke - mudstone - lithic wacke - wackestone - ALL |
ALL
|
|
|
A crinoid has a segmented:
-root -stem -shell -valves -none |
stem
|
|
|
The Paleozoic ended with the:
-Triassic - Cambrian - Ordovician -Carboniferous |
none (the answer is Permian)
|
|
|
What came after the Ordovician?
- Silurian - Devonian -Cambrain -Permain -Jurassic |
Silurian
|
|
|
Corals live in: |
ALL
|
|
|
Planktic means |
Swim (float)
|
|
|
Wave Base |
Water depth at which there is no wave movement
|
|
|
Fair-weather wave base |
depth beneath the average daily waves
|
|
|
Storm Wave Base |
depth beneath storm driven waters
|
|
|
Why do thin laminations often occur in hypersaline rocks?
|
Very few organisms can live in hypersaline conditions, Therefore there is no bioturbation to churn the rock into a massive body
|
|
|
Normal grading
|
Finer moving upward
- most common |
|
|
Reverse grading
|
Coarser grains moving to finer grains
|
|
|
Dropstones
|
Indicative of icebergs, slow water environment |
|
|
Trace Fossils
|
Evidence of biological activity, without the organism
- Tracks, trails, burrows |
|
|
What are the two mineral groups which contribute most to the rock record?
|
Silicates
Carbonates |
|
|
Silicate Minerals
|
Dominant group in igneous, sedimentary, and metamorphic rocks
|
|
|
Carbonate Minerals
|
- Containing calcium, magnesium, iron, or other ions adhered to a carbonate ion
- Important in sedimentary rocks |
|
|
What are fossils?
|
Fossils incluse hard parts of organisms, which have sometimes been chemically altered, as well as the molds of those structures
|
|
|
Anhydrite
|
Evaporite
- Calcium sulfate - Colourless to pale blue/violet - Fibrous parallel veins |
|
|
Intraclasts
|
Pieces of previously formed limestone or lithified sediment that has been eroded from the sea bed or comes from older limestone outcrops in the area
|
|
|
Limestone types + environment:
Basin |
Mudstone + chalks
|
|
|
Limestone types + environment:
Foreslope |
Grainstone |
|
|
Limestone types + environment
Large waves |
Boundstone
|
|
|
Limestone types + environment
Carbonate shoals (large waves, tidal currents) |
Grainstone/ Packestone
|
|
|
Limestone types + environment |
Mudstone/ wackestone
|
|
|
Allochemical Rocks |
Allochems: transported some ways, includes |
|
|
Orthochemical Rocks
|
Orthochemical: grown biologically
|
|
|
Polymorphic species
|
Look similar but cannot interbreed (convergent evolution)
|
|
|
How to tell a carbonate rock from a siliceous rock:
|
Use some HCL
Carbonate will fizz siliceous will not EXAMPLE: Dolostone (limestone) will fizz, and chert (silicified limestone) will not |
|
|
GOBE
|
Great Ordovician Biodiversity Event
|
|
|
Jolly Cut Formations
|
Silurian
Lockport Rochester Irondequoit Reynales Thorold Grimsby |
|
|
Transgression
|
Rise of sea level and submergence of the continent under seawater
|
|
|
Regression
|
A drop of sea level and withdrawal of water from the land |
|
|
Aeolian Deposition |
Distinct cross bedding |
|
|
Playa/ Evaporitic Lakes
|
Typically occur in arid settings |
|
|
Glacial Landscapes |
Very sandy |
|
|
Alluvial Fans
|
Cone shaped, formed in areas of high relief (base of mountain ranges) where sediment supply is abundant (arid, semi-arid)
sediment transport occurs infrequently - violent episodes streams, sheet flood, debris flows and mass wasting
Massice to graded sediments ranging from coarse gravels to boulders to finer sands and muds |
|
|
Lacustrine |
Lacustrine Plains (or lake plains) are lakes that get filled by incoming sediment
Facies: Mostly shales + mudstones, but also limestones. |
|
|
Alluvial Facies (braided vs meandering) |
Facies - Braided - coarse gravel cobbles and larger, poorly sorted framework supported, large scale planar beds, graded, cut and fill stratigraphy common
Meandering- muds + sands, poorly sorted, planar beds, asymmetric cross stratification, may be graded, cut and fill stratigraphy common |
|
|
Factors affecting marine environments |
- Waves |
|
|
Turbidity Currents |
Density currents- suspension of sediments which are denser than the surrounding water flow downslope eroding + transporting sediment |
|
|
Thermohaline Circulation
|
Density differences in surface water due to temperature or salinity create vertical circulation of water masses in oceans
Circulation initiated in high latitudes as cold surface water sinks to bottom and flows south. |
|
|
Paleontology
|
Paleontology is founded upon the collection, identification, and environmental interpretation of the remains or traces of ancient organisms
|
|
|
Paleo-environmental Analysis
(3 steps) |
1. Document the species in the fossil assemblage |
|
|
Taxonomic Hierarchy
|
Kingdom |
|
|
Endoskeleton
|
Internal frame for tissue and muscles
- Calcium phosphate |
|
|
Exoskeleton
|
External covering for protection and frame to told tissue and muscles, may be segmented |
|
|
Accretion
|
Skeletons grow by accretion- adding new material onto the surfaces or edges of previously grown skeletal elements
|
|
|
Addition |
Some organisms have compound skeletons that consist of differnt elements such as plates/ spines |
|
|
Life Modes:
Benthic Planktic Nektic Neritic Pelagic Infaunal Epifaunal |
Benthic: Live on the sea floor (on or in sediment) |
|
|
Name some limiting factors that control the proliferation of organisms in a marine setting:
|
Salinity |
|
|
Stenohaline
|
Taxa that can live in a narrow range of salinities
|
|
|
Euryhaline
|
Taxa that can live in a wide range of salinities |
|
|
Taphonomy
|
Process of fossilization |
|
|
Evidence of fossil transport
|
- Fragmentation |
|
|
Fossilization: Replacement
|
Silicification, pyritization
|
|
|
Fossilization: Recrystalization
|
Aragonite to calcite
Calcite to dolomite |
|
|
Fossilization: Permineralization
|
Addition of minerals to pore spaces
- common in porous bone/ wood |
|
|
Fossilization: Phosphatization
|
Thin organic shelled organisms may be replaced or overgrown by a sheet of phosphate
- occurs in anoxic environments |
|
|
Fossilization: Concretion
|
Usually carbonate masses forming around fossil shortly after burial
|
|
|
What types of corals were abundant in the Paleozoic?
|
Rugose + Tablulate corals |
|
|
Brachiopods |
Paleozoic
Look like clams Benthic marine Bilateral top symmetry |
|
|
Gastropods
|
Trocospiral/ planispiral shells
Earliest were from Cambrian Benthic bottom feeder * Distinction between cephalopods: Gastropoda do not have a chambered shell |
|
|
Bivalves
|
Still around today
- Showed up in Ordovician - infaunal/ epifaunal - Sessile |
|
|
Cephalopods
|
Important in mesozoic (index fossils) |
|
|
Sponges
|
Benthic sessile filter feeders that utilize cells to pump water through canal systems
Needle like spicules often preserved in rocks (chert nodules) |
|
|
Graptolites
|
Cambrian to Pennsylvanian
-Planktic or benthic - Index fossils - Typically found within black shales |
|
|
Bryozoans
|
Mossy texture
- Paleozoic to recent - Benthic marine/ brackish - Branching (low energy area) - Encrusting (high energy areas) |
|
|
Trilobites
|
Dominant from Cambrian to Upper Permian (Great index fossil for Paleozoic) |
|
|
Invertebrate Fossil Trends with Environment: Freshwater
|
Moderate to low diversity
- Mostly benthic stenohaline |
|
|
Invertebrate Fossil Trends with Environment: Brackish coastal
|
Low to moderate diversity, mostly benthic brackish euryhaline taxa, including a mixture of marine + freshwater |
|
|
Invertebrate Fossil Trends with Environment: Marine Shelf
|
High diversity, abundance, mostly benthic + nektic marine stenohaline
- Form mostly shell beds |
|
|
Invertebrate Fossil Trends with Environment: Marine coral reef
|
High diversity and abundance of shelly material
Shell beds, but also corals and shells in growth position |
|
|
Invertebrate Fossil Trends with Environment: Deep marine
|
Mostly microfossils- plankton, but also nektic + benthic
- Accumulation of most fossil debris |
|
|
On any coastline, reconstructing sea level from the stratigraphic record is a function of:
|
1. Water volume
2. Changing shape of the basin that holds the water 3. Stability of the sides of the basin 4. Distribution of the water in the basin |
|
|
Factors leading to global sea level change
|
1. Quantity of water
- Glacio-Eustatic, Tectono-Eustatic 2. Sedimentation Rates |
|
|
Factors leading to Local/ regional sea level change
|
1. Isostatic variations
2. Tectonic Variations 3. Sediment compaction 4. Water surface elevation changes |
|
|
Glacial Eustacy |
- Largest global factor of sea-level change
- Involves differences in ocean level of ~ 100 m over the last interglacial period |
|
|
Tectono Eustacy
|
Long term sea level changes affects the shape + extent of the oceanic basin
1. Plate tectonics: convergence (subduction of crustal plates) 2. Variation in ocean spreading rates, continental breakup |
|
|
Sedimentation rate (factors affecting sea level)
|
The volume of ocean basins is controlled by sedimentation
- Filling of ocean basins with continental sediments is a relatively slow way of reducing ocean basin capacity |
|
|
Isostacy: |
Isostacy: Depression/ rebound of crust |
|
|
Prokaryote
|
No distinct membrane bound nucleus or membrane-bound organelles
- DNA is not organized into chromozomes |
|
|
What type of life dominated the Archean?
|
Life was dominated by prokaryotes
|
|
|
Important steps by Proterozoic Life Forms
|
Heterotrphy is how eukaryotic cells formed (symbiosis)
- Evolution of skeletons for protection |
|
|
Why is heterotrophy so important for the evolution of life?
|
Heterotrophy gained its importance as the probably means by which the eukaryotic cell initially evolved (through the symbiotic association of predator + undigested prey)
- Later, heterotrophy became a major driver in the evolution of skeletons + behavioural strategies in animals |
|
|
Stromatolites |
Sheet like mats and domes buildups of marine microbes- colonies of photosynthesizing cyanobacteria
- Only found in very "harsh" environments today (no gastropods to consume them) |
|
|
Early Eukaryotes |
Eukaryotes: cell type with a true nucleus |
|
|
What is the significance of the Ediacaran (in the formation of life?) (edicarian is last period in neoprotozoic) |
First multicellular organisms
Before the end of the Ediacaran Period, the cloudiniids, evolved small conical skeletons of hard calcium carbonate, to reduce the threat of predation.
|
|
|
The Ediacaran-Cambrian Transition
|
Stage 1: Trace Fossils |
|
|
Burgess Shale |
Located in the Canadian Rockies of BC
- exceptional preservation of the soft parts of fossils - one of the earliest fossil beds containing soft parts |
|
|
Preservation of soft bodied organisms |
Found in laminated sediments - no disruption of sediments - hostile to invertebrates - no bioturbation
Preservation: tissues broken down by microrganisms rapidly - unless buried quickly and no oxygen.
However, anaerobic microbes can still exist - in case of Burgess, preservation probably relates to nature of transport - clays incorporated into all cavities during transport leaving the impression of the soft tissue |
|
|
What is the Fossil Bias? |
The fossil bias is the disproportionate amount of hard bodied organisms preserved in the fossil record. This is because soft bodied organisms (mostly belonging to Pre-Cambrian biota) are not preserved due to their physical makeup. |
|
|
Cambrian Explosion: WHY? |
Physical environment: oxygenation allowed evolution of complex organisms, chemistry of oceans allowed skeletons to be secreted |
|
|
What is one important aspect of sea level in the Ordovician? |
Global sea levels reached some of the highest positions ever
Shifting plates delivered big changes to the Ordovician world
Iapetus - The proto-Atlantic Ocean. |
|
|
Ordovician Marine Life |
Cephalopods = top predator
Flooded cratons produced shallow seas
First fish were the ostracoderms, a now extinct group of jawless fishes that appeared
Chordates - animals including all vertebrates having a dorsal in the Cambrian nervous cord. - evolved in Cambrian |
|
|
Early forays onto land |
The first evidence of plants colonizing the land comes from the Cambrian |
|
|
Ordovician Glaciation |
At the end of the Ordovician, global temperatures dropped + ice caps expanded
it precipitated one of the most severe mass extinctions in Earth history. As glaciation reached a maximum, some brachiopods, bryozoans, corals, trilobites, conodonts, and nautiloids (a type of cephalopod) disappeared in large numbers. |
|
|
Caledonian orogeny |
Silurian-Devonian orogenic activity that affected western Europe from the British Isles through Scandanavia |
|
|
Acadian orogeny |
Orogenic activity during the Devonian along the Appalachian margin of Laurentia |
|
|
Silurian |
Glaciation at the end of the Orodovician decimated many shallow marine invertebrates, but recovery came rather soon as marine water flooded shelf areas, opening new habitats.
- Trilobites still important
Corals, especially the massive, fast-growing tabulate corals, and coralline sponges, both refilled vacant niches and diversified into unfilled niche space. |
|
|
Silurian Fish |
Marine life underwent an ecological arms race between predator and prey |
|
|
When did the complete transition to land by plants + animals occur? What are the 2 waves? |
Started at the end of the Silurian and completed by Devonian
Life on land - different requirements than for water.
1st wave - Arthropods Eurypterids or sea-scorpions - may have occasionally ventured on land (Silurian dolostones) tracheae: one of the tubules forming the respiratory system of most insects and many arachnids
2nd waves- Insects
Insect - An arthropod having three pairs of legs and wings, at least primitively.
The evolution of winged insects from non-wing-bearing Terrestrial hexapods (six legged arthropods) around the Middle Devonian marks the beginning of evolution’s greatest animal success story
By the end of the Carboniferous Period inscest speciation had exploded
|
|
|
Amphibians |
cold-blooded vertebrate typically living on land but breeding in water; aquatic larvae undergo metamorphosis into adult form
Vertebrates made transition to land in Late Devonian - first were amphibians |
|
|
CarboniferousPermian tectonics/ sea level |
The late Paleozoic was a time of important tectonic change
Each of the mountain building events (the Taconic orogeny in the Ordovician Period, the Acadian orogeny in the Devonian Period, and the Alleghanian orogeny in the Carboniferous and Permian periods) was followed by the opening of an ocean basin |
|
|
Plants and Coal in Carboniferous |
The most conspicuous terrestrial life forms of the Carboniferous and Permian were plants. During warmer intervals, especially in the late part of the Carboniferous, forests flourished in extensive coastal wetlands of the tropics
The world’s coal reserves come from thick peat deposits, which were lithified to coal seams, deposited in these settings |
|
|
Reptiles (eggs and internal fertilization)
|
Reptiles appeared in the late Carboniferous, and in the Permian, they began diversifying into the groups we know as squamates (lizards and snakes), archosaurs (crocodiles, dinosaurs, and flying reptiles), and others.
The synapsids first appeared in the late Carboniferous and diversified in the Permian
|
|
|
Devonian Marine Life |
The seas were rich in brachiopods, bryozoans, and mollusks. Trilobites were no longer diverse, but some species were locally abundant.
In the Carboniferous (Mississippian) deposits of crinoid-rich limestones or encrinites were abundant. |
|
|
Joggins Formation |
The entire food chain of the terrestrial "Coal Age" ecosystem is represented at Joggins, from the plants to invertebrates + tetrapods |
|
|
Permian-Triassic Extinction (P-T Boundary) |
More than 80% of all marine species extinct |
|
|
Triassic Sea Level |
low initially at start then rose 100m then fell back down again
Orogenies in Eurasia completed the assembly of Pangea.
Large portions of Pangea, ones far from ocean waters, formed arid deserts. |
|
|
Triassic Marine Life |
- Everything was large Extinction at the end of the Permian Period wiped out great numbers of marine organisms
Recovery from the Permian extinction event was a protracted process for most marine animals |
|
|
Plesiosaur |
Triassic reptile
|
|
|
What three land vertebrates appeared during the Early Triassic? |
- Amphibians (frogs)
Archosaurs |
|
|
When did the rifting of Pangea occur? |
Late Triassic through Jurassic |
|
|
Ichthyosaurs |
Reptiles that could not leave the water to lay eggs
- Bore young live - Looked similar to dolphins- convergent evolution |
|
|
When did mamals first appear? |
Late Triassic |
|
|
Jurassic Period |
The period opened with global sea level at one of its lowest points in geologic history
Pangea was beginning to rift apart, and both marine and terrestrial ecosystems were being reshaped.
|
|
|
Jurassic Marine Life |
In the Jurassic Period, marine predator-prey systems reached the top of the Mesozoic Marine Revolution
Swimming predatory mollusks (ammonoids) and relatives of the squids called the belemnoids appeared
Fishes of the Mesozoic Era were mostly carnivorous. Sharks and rays, holdovers from the Paleozoic Era, increased in number in the Jurassic and Cretaceous periods |
|
|
Jurassic Benthic Marine Life |
Other benthic or nekto benthic carnivores included some gastropods and crustaceans
Echinoderms - starfish (epi-faunal), sea-urchins (epi-faunal), sea-biscuits (infaunal)
Brachiopods and stalked echinoderms (crinoids) fell into great decline, and they never again achieved more than a minor role in marine ecosystems |
|
|
Jurassic Nektic Marine Life |
Plesiosaurs had developed into a major threat
Plesiosaurs had four flippers likely used for propulsion
Ichthyosaurs were among the top predators
|
|
|
Jurassic Planktic Marine Life |
Phytoplankton called coccolithophorids = calcareous nanoplankton that have platelets of calcium carbonate |
|
|
Dinosaurs |
Characterized by upright posture, legs below the body, skill with two openings behind the eye. |
|
|
Saurischian Dinosaurs: Theropods |
A clade of saurischian dinosaur with a bipedal gait + teeth adapted for carnivory
- Warm blooded - Includes birds |
|
|
Saurischian Dinosaurs: Sauropodomorphs |
Herbivores |
|
|
Ornithischian Dinosaurs |
Range from the late Triassic to the end of the Cretaceous
Nests and eggs laid by dinosaurs are known from many areas of the world.
bipedal ornithopods: Iguanodon, the duckbills (Hadrosaurs), Parasaurolophus, Corythosaurus, and Maiasaura, among others.
|
|
|
Pterosaurs |
Late Triassic-Cretaceous |
|
|
Hadrosaurs |
Wide toothless bills similar to ducks
- Hollow crests on their skull with extending nasal passages (maybe for improved smell/ sounds) |
|
|
What is the significance of archaeopteryx? |
Oldest known bird fossils
Jurassic - Related to theropods - Feathers = asymmetrical arrangement along a central shaft; suggests a flight function compared to other feathered dinosaurs |
|
|
End of Triassic |
mass extinction occurred in marine ecosystems. Extinction coincides with floral evidence for a climatic shift to arid conditions in terrestrial environments of Gondwana, and with a large drop in sea level |
|
|
Cretaceous Period |
✤ Supercontinent break-up and rifting accelerated during the Cretaceous, Pangea continued fracturing into its modern drifting continents. Then Gondwana and Laurasia broke apart
High sea level, greenhouse climatic conditions, driven by undersea volcanoes spewing their content, warmed the oceans beyond the tropics, and planktonic microorganisms bloomed in the seas until the end of the period. |
|
|
Western Interior Seaway |
✤ Large subduction zone in western N. America formed
Rifting and drifting of Pangea fragments caused spreading ridges to increase along with sea-level rise flooding the continental shelves. |
|
|
Cretacous Tectonics & Sea Level |
Sea-level peaked in mid-Cretaceous
Rifting may have caused increased CO2 into atmosphere and greenhouse conditions
End of Cretaceous sea level dropped precipitously |
|
|
When did sea level reach its highest? |
Cretaceous
|
|
|
Cretaceous Marine Life |
Diatoms also radiated during the Cretaceous
Mollusks continued to evolve quickly in the Cretaceous
Rudist - A type of Mesozoic clam (bivalve) having unequal valve sizes that often formed reefs in the Cretaceous.
Many modern gastropods appeared in the Cretaceous Period
Swimming carnivorous mollusks
The Cretaceous Period witnessed an arthropod predator: the modern crabs. |
|
|
Mosasaur |
appear around 90 million years ago |
|
|
Cretaceous Terristrial Life |
Dinosaurs ruled the land during the Cretaceous Period.
The giant sauropods were all gone, but ceratopsians and ornithopods expanded in numbers. Carnivorous theropods also prowled the landscape
Flying reptiles and birds were the largest animals in the air
placentals and marsupials, had evolved, yet they remained small and inconspicuous |
|
|
True/False: |
Yes! But mammals were on the uprise (placentals/ marsupials)
|
|
|
When did angiosperms evolve? What are they? |
Close to the Jurassic-Cretaceous transition
gymnosperms (seeds not enclosed in a reproductive chamber) gave rise to the flowering plants (angiosperms). Gymnosperms reproduce in yearly cycles
Rise of the flower
Fruits |
|
|
Bolide Impact (Chicxulub crater) |
The impact of a bolide from outer space at the end of the Cretaceous may have crippled ecosystems that were already in fragile condition. ✤ Streaking toward Earth 65.5 million years ago was probably an asteroid that had fallen from its orbit, finally crashing into the northern tip of the Yucatan Peninsula of Mexico. |
|
|
Cenozioc Continued Fragmentation of Pangea |
In the early part of the Cenozoic Era, fragmentation of Pangea was nearly complete and the world’s continents were approaching the configuration they have today
Separation of Gondwana occurred at a critical phase in the history of mammals. Australia drifted from the rest of Gondwana just before the diversification of placental mammals, leaving the island continent to be inhabited by marsupials. Elsewhere, the marsupials were largely outcompeted by placental mammals
|
|
|
Mediterranean and Himalaya |
As the African Plate forged northward, it collided with the southern margin of Europe in the Mediterranean region, and the Alps, Apennines, and other mountain ranges of southern and central Europe
In the Neogene Period, the Indian subcontinent rammed into Asia, producing an impressive array of geologic features that classically illustrate the effects of continentcontinent collision
|
|
|
Western N.A. |
Mountain building occurred during Paleogene along Pacific margin from Canada to Mexico - Laramide Orogeny which resulted in uplift of Rocky Mountains |
|
|
What is meant by a transgression/ regression? What conditions are needed for them to occur? How does Walther's Law help us understand the stratigraphic representation of these processes? |
Transgression: Rise in sea level + submergence of a continent under water |
|
|
Sea level in Cenozoic |
Sea level at the beginning of the Paleocene Epoch was low, but it rose through the epoch, only to fall again in the Oligocene as the circumpolar current became established around Antarctica. ✤ From that point forward, Cenozoic sea level history has been one of rapid and large fluctuations, driven mostly by the waxing and waning of continental glaciers in polar regions.
|
|
|
Paleogene
|
Extinctions at the end of the Cretaceous Period opened the way for adaptive radiations among the survivors, and with those radiations came life forms of increasingly modern character
continents were near present postition |
|
|
Paleogene Marine Life |
Paleogene oceans were filled with life forms that are quite modern in appearance.
Whales, or cetaceans, made the transition from carnivorous land mammals to aqueous carnivores during the Eocene Epoch.
Bivalves, gastropods, echinoderms (eg. sea-urchins), bryozoans, coccolithophores, foraminifera (planktic and benthic) expanded
Birds, the only surviving lineage of landdwelling theropod dinosaurs, also had a few representatives in aqueous settings (penguins)
|
|
|
Paleogene Terrestrial Life |
Mammals emerged in the Paleocene Epoch and diversified. Within 10 to 15 million years, the mammals had inhabited most terrestrial ecosystems.
Three important groups of land-dwellers diversified in the Paleogene: mammals, angiosperms (flowering plants), and insects
Primates were in existence by the early part of the Paleogene Period
The fossil record of birds in the Paleogene Period includes large flightless forms. Some species reached the dimensions of modern ostriches and emus,
Early carnivores (i.e. order of mammals called Carnivora), the forerunners of modern wolves, dogs, cats, bears, pandas, minks, and others, appeared in the Eocene Epoch, and radiated in the Oligocene Epoch |
|
|
Perissodactyl |
An odd-toed ungulate mammal such as a horse, rhinoceros, hippopotamus, or tapir |
|
|
Artiodactyl |
An even-toed ungulate mammal such as a deer, sheep, goat, pig, cow, camel, llama, or giraffe |
|
|
Ruminant |
A cud-chewing ungulate mammal such as a bison, cow, or giraffe |
|
|
Grass |
One of biggest terrestrial innovations in the Paleogene was the evolution of grasses (angiosperms) in the Paleocene. ✤ Earliest grasses had discontinuous growth - similar to most plants ✤ By late Oligocene, early Miocene they evolved to continuous growth. ✤ This allowed grasses to recover from grazing herbivores. |
|
|
Neogene Period (tectonics) |
During this period, the Earth essentially reached its modern plate configuration, developed much of its modern biota, and Himalaya Rocky Mountains continue to build
Uplift of the Colorado Plateau in the western United States stimulated downcutting through the stratigraphic layers by the Colorado River (in 10 million years)
Grand Canyon - steep-sided canyon (450 km long, up to 29 km wide) carved by the Colorado River in Arizona |
|
|
Messinian Salinity Crisis |
It is now widely accepted that these evaporites, which formed during the Messinian (late Miocene) – between 5.96 and 5.33 m.y. - resulted from the closure of the marine passages between the Atlantic and the Mediterranean, and the subsequent (and repeated) complete (or near-complete) desiccation of the Mediterranean Sea. |
|
|
Neogene Marine Life + plankton + Scleractinian Reefs |
One striking aspect of Neogene to Quaternary marine fossils is their increasingly modern species composition
Much of the framework of coral reefs is formed by scleractinians and coralline sponges and they exist in clear, shallow tropical waters - they are the primary reef-builders. |
|
|
Neogene Terrestrial Life |
Two major factors influenced changes in the terrestrial biota of the Neogene Period: changing climatic conditions, and changes in food supplies. ✤ Two groups of plants, the herbaceous plants, or herbs, and grasses, proliferated in response to changing climate during across the Paleogene-Neogene transition. ✤ Deer, antelopes, cattle, sheep, pigs, camels, giraffes, and their kin —all having long teeth— were beneficiaries of the expansion of silica-rich grasses into open plains
The rise of new herbivorous ungulates was probably connected to changes among carnivores. ✤ Frogs, rodents, songbirds, and some snakes (mostly the poisonous vipers) all radiated during the Neogene Period. ✤ Insects also make up a large part of the diet of frogs. For snakes, major food sources are frogs and rodents. |
|
|
Quaternary Period |
The most recent 2.5 million years of Earth history is dubbed the Quaternary Period. It consists of two epochs, the Pleistocene, or most recent Ice Age; and the Holocene, or “recent,” the present time. ✤ Glaciers sculpted the landscape of North America and Eurasia, and mantled the land with rocky sediment (till and outwash). |
|
|
Rancho La Brea |
- High quality of fossil preservation at Rancho La Brea occurred because the bones were buried rapidly by the asphalt and sediments. - Subsequent sea-level drop and accumulation of sediment through the erosion of the emergent hills, causes the crude oil to seeping out of the ground through conduits and fissures in the coastal plain sediments. - Animals would step on the camouflaged asphalt becoming trapped. Stranded animals would then be easy prey for carnivores. Some of the predators would then become trapped themselves.
|
|
|
Human Evoloution |
Homo erectus, the ancestor of our own species, appeared about 1.8 million years ago. This species migrated to Africa, Europe, and Asia, and existed until about 200,000 years ago. ✤ Homo erectus had a different skull shape than our species. The skull was more elongate, and had a low, sloping forehead. Brain was also smaller. ✤ Neanderthals show even more similarities to modern Humans than does Homo erectus. Neanderthal fossils first appear in Pleistocene sediments dated at about 200,000 years. They coexisted with Homo sapiens for a long time until becoming extinct about 30,000 years ago.
|
|
|
Glaciations |
Most Recent glacial period marks the beginning of the Pleistocene with glacial advance occurring approx. 2.588 million years ago. ✤ Alternations between cold glacial vs in warmer interglacials ✤ Mostly recorded in oceanic sediments (foraminifera) but also in ice cores ✤ During glacial maximums ice coverage was as much as 30% of the earth Surface - ice reached 3 km thick ✤ In warmer areas large lakes developed - called pluvial lakes. ✤ Last period - the Holocene likely reflects an interglacial (approx. last 11.8 thousand years) |
|
|
Discuss the facies expected in an estuary environment: |
In an unbroken sequence, vertically superimposed lithofacies were laterally adjacent at the time of deposition |
|
|
Discuss the facies expected in a marsh environment |
- Intertidal area |
|
|
Describe the factors contributing to sea level change |
Global |
|
|
What major evolutionary features define the Eras of the Phanerozoic? Describe all major trends + their linkage with geological processes |
Global |
|
|
What are the different types of unconformities, and how can you differentiate them in the rock record? |
An unconformity is a surface of separation between two strata that marks an interruption in sedimentation |
|
|
What are ways in which one can correlate stratigraphic units from location to location? |
Stratigraphic units can be correlated in different locations by comparing: - Rock type (regional) |
|
|
What are ways in which one can correlate stratigraphic units from location to location? |
Early animal + plant prokaryotes/ eukaryotes |
|
|
What evolutionary innovations occurred leading up to the start of the Phanerozoic? |
Burgess Shale, BC |
|
|
What covered most of Laurentia during the Paleozoic? What kind of environment was it, and what were some of the major groups? |
An epeiric (inter-cratonic) sea covered most of Laurentia in the Paleozoic. It was a warm shallow sea that was very conducive to life. |
|
|
What covered most of Laurentia during the Paleozoic? What kind of environment was it, and what were some of the major groups? |
Skeletons/ complex animal behaviour. |
|
|
Describe + discuss the major evolutionary changes that occurred during the early-mid Paleozoic, which forever changed the nature of the stratigraphic record?
|
A bolide 10 km in diameter smashed into the ocean around Mexico's Yucatan Peninsula. This created an immense amount of damage to the Earth's surface, ultimately creating a 180 km wide crater in the Gulf of Mexico. Shockwaves were felt around the Earth, and immense storms radiated around the continents (creating a 3 year winter). This was the most prominent aspect of the dinosaur extinction, and the impact is though to have been the "nail in the coffin" for an ecosystem already in decline. |
|
|
What cause the mass extinction at the end of the Cretaceous? (K-Pg boundary) |
Burgess Shale, B.C |
|
|
Lagerstatten are deposits that contain an extraordinary fossil abundance. Describe + discuss two prominent Lagerstatten examined in the course + how they formed. |
Deep ocean sediments contain millions of planktic skeletons that have accumulated over millions of years. Taking a deep ocean core from Cenozoic period rocks would reveal the microfossils of forms of planktic formanifera. These tiny species are/ were sensitive to water temperature (there were different species present for different water temperatures, and their shell coiled specifically as a result of temperature). Moreover, oxygen and other chemical isotopes in the shells reflect changing chemical composition of the water. The paleoenvironment can be relatively reconstructed using these fossils. |
|
|
What is the advantage of deep ocean basin sediments for the reconstruction of glacial/interglacial climate change in the Cenozoic? What types of fossils can be used for this purpose? |
sediment types and texture, sedimentary structures and fossil evidence may cross environments (i.e. facies may overlap).
Stacking pattern of facies or Walther’s law provides further refinement on environment - referred to as facies associations |
|
|
Facies Associations |
sediment types and texture, sedimentary structures and fossil evidence may cross environments (i.e. facies may overlap).
Stacking pattern of facies or Walther’s law provides further refinement on environment - referred to as facies associations |
|
|
3 Types of Ancient Enviroments |
1. non marine environments 2. transitional marine-nonmarine environments 3. marine environments |
|
|
Soils (what it is + facies) |
Shelf will be wider in a passive vs active margin
Sediments spend time in coastal and shelf areas then exported to deep ocean.
Coarse to fine going towards the water |
|
|
Shelf Profile |
Shelf will be wider in a passive vs active margin
Sediments spend time in coastal and shelf areas then exported to deep ocean.
Coarse to fine going towards the water |
|
|
Waves Stuff + longshore drift |
rise - referred to as the flood tide fall - referred to as the ebb tide
Movement of water affects coastal and shelf areas
spring tides: - moon and sun are inline and gravitational forces are added
neap tides: - moon and sun appear at right angles and gravitational forces oppose each other |
|
|
Tides |
rise - referred to as the flood tide fall - referred to as the ebb tide
Movement of water affects coastal and shelf areas
spring tides: - moon and sun are inline and gravitational forces are added
neap tides: - moon and sun appear at right angles and gravitational forces oppose each other |
|
|
Delta (front vs plain) |
Mixture of sub-environments - lagoons, marshes, estuaries, floodplains, beaches, dunes
Delta Plain - river processes dominate swamps, marshes, tidal flats, interdistributary bays, -fine-grained organic muds, laminated, graded flood deposits, mudcracks , cross bedding, bioturbated, freshwater - brackish fossils (shells).
Delta Front high energy processes waves, longshore currents - site of active depositionsand, cross-bedded, marine shells, shell beds common |
|
|
Estuary |
Fluvial - Gravel -Sand - mud,crossbedded, graded, coarse lags
Mixed Marine-Fluvial – sand – mud – crossbedded, bioturbated, graded, ripples, organic rich, brackish, shells maybe abundant
Marine – mostly sandy, crossbedded, bioturbated, graded, marine shell beds maybe abundant |
|
|
3 types of Estuary Facies |
Fluvial - Gravel -Sand - mud,crossbedded, graded, coarse lags
Mixed Marine-Fluvial – sand – mud – crossbedded, bioturbated, graded, ripples, organic rich, brackish, shells maybe abundant
Marine – mostly sandy, crossbedded, bioturbated, graded, marine shell beds maybe abundant |
|
|
Beach |
- sandstone - moderately high-energy depositional environment - dunes: high-angle cross-bedding from unidirectional flow, fine-med sand, well sorted. root casts burrows crosscutting stratigraphy (trace fossils) - Interdune: silty, mudcracks, root casts, may be laminated, coarse lags from deflation
|
|
|
Lagoon |
Lagoons form where coastal embayments or depressions are separated from the sea by a barrier
Barriers form by: 1. sediment material 2. vegetation 3. coral reef growth
- low-energy depositional environment - muddy to sandy, poorly sorted but abundant marine shells, shell beds are common, bioturbated - possibly organic rich, sand beds may be common - bivalve fossils
|
|
|
Marsh |
Salt marshes are intertidal ecosystems where fine-grained sediment supports halophytic plants that depend upon daily flushing of the tides for survival ✤ When the flood tide enters the marsh it flows through the tidal channels which then overtop the channels and flood the inner reaches of the marsh. ✤ Form in low energy environments in protected bays, lagoons, estuaries and deltas
Facies: Marshes form at sea level with thick vegetation accumulations called peat. In the rock record this is turned into coal. |
|
|
Coral Reefs |
continental shelf is an underwater landmass which extends from a continent, resulting in an area of relatively shallow water known as a shelf sea
- sandy progressing to muddy as you go further away from coastline - wave & tidal cross stratification, hummocky cross stratification - shell & sand storm beds are common (and thicker) above fairweather wave base, less common (and thinner) as you go deeper towards the storm wavebase - bioturbated, many horizontal tracks/trails - sediments from lower sea levels & continental sources are eroded, transported & deposited onto continental shelf through tidal action. |
|
|
Continetial Shelf |
continental shelf is an underwater landmass which extends from a continent, resulting in an area of relatively shallow water known as a shelf sea
- sandy progressing to muddy as you go further away from coastline - wave & tidal cross stratification, hummocky cross stratification - shell & sand storm beds are common (and thicker) above fairweather wave base, less common (and thinner) as you go deeper towards the storm wavebase - bioturbated, many horizontal tracks/trails - sediments from lower sea levels & continental sources are eroded, transported & deposited onto continental shelf through tidal action. |
|
|
Desert |
Desert massive to graded sediments range from coarse gravels to boulders, finer sands and muds at the bottom
Facies Dunes: hi-angle cross-bedding from unidirectional flow, fine- med sand, well sorted. Root casts, burrows crosscutting stratigraphy.
Facies Interdune - silty, mudcracks root casts, maybe laminated, coarse lags from deflation. |
|
|
Rise Ocean Basin |
Lake - low-energy depositional environment - may have symmetrical ripples near shoreline caused by oscillatory current (waves) - mostly shales (mudstones), but also has limestones (mudstone) - few fossils (bivalves, gastropods)
|
|
|
End of Protozoic (Neoproteozoic) Life Forms |
The Proterozoic Eon witnessed some of the most pivotal changes in the history of life on Earth. During the preceding Archean Eon, life was dominated by prokaryotes. As early as 3.5 billion years ago, organisms had adopted three major strategies for acquiring nutrients:
chemosynthesis (in archeans), photosynthesis (in cyanobacteria), and heterotrophy (predation, scavenging, herbivory, and breakdown of detritus in eubacteria).
Photosynthetic activity eventually led to evolution of an oxygenated atmosphere-ocean system.
✤ Heterotrophy gained in importance as the probable means by which the eukaryotic cell initially evolved (through the symbiotic association of predator and undigested prey). Later, heterotrophy (predation) became a major driving force in the evolution of skeletons and behavioural strategies in animals. |
|
|
End of Protozoic (Neoproteozoic) Prokaryotes
|
At the start of the Proterozoic, prokaryotes were the dominant life forms on Earth.
The earliest prokaryotic specimens are preserved in chert, and comprise small rounded cells and filaments formed of linked cells.
stromatolites and thrombolites. |
|
|
End of Protozoic (Neoproteozoic) Stromatolites
|
Sheet-like mats and domed buildups of marine microbes - colonies of photosynthesizing cyanobacteria (prokaryotic bacteria) ✤ They have a sticky surface or mat that traps and baffles muds.
Only found in very ‘harsh’ environments today - no gastropods to consume them. |
|
|
End of Protozoic (Neoproteozoic) Early eukaryotes (what they are, mitochondria, |
Eukaryotes (so far) are known from rocks as old as the Proterozoic (and likely older) ✤ Inside eukaryotic cells are distinct masses presumed to be remains of cell nuclei or other organelles. ✤ Eukaryotic cell - A cell type having a true nucleus. ✤ Symbiosis - Condition in which two or more dissimilar organisms live together.
- All eukaryotic cells contain mitochondria,(extractor of energy from food). Mitochondrial precursors could have been independent prokaryotic organisms captured by other cells but resistant to digestion inside the predator cells. Minor alteration allowed captured cells to adapt to a symbiotic life, transforming into cell organelles.
|
|
|
End of Protozoic (Neoproteozoic) Oxygen |
Oxygenation of the AtmosphereOcean System
Early in Earth’s history, free oxygen (O2) was released in small amounts from the breakdown of water vapor in the upper atmosphere by the Sun’s ultraviolet radiation. By about 3.5 billion years ago, photosynthetic prokaryotes (especially cyanobacteria) also began releasing oxygen to the atmosphere-ocean system.
Banded iron formations (or BIFs), which are composed of iron minerals interlayered with silica, offer further evidence of oceanic oxygen levels.
|
