Help
Options
Didn't know it?
click below
click below
Knew it?
click below
click below
Don't Know
Remaining cards (0)
Know
retry
shuffle
restart
0:00
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
Sed Final
Fuck
| Question | Answer |
|---|---|
| • Origins of sediments | weathering, erosion, ion transport in ground or surface water, ions enter sea, deposition, diagenesis and burial, uplift and exposure. Chemical or mechanical weathering. Biological influences. Climate/exposure time. |
| • Types of sediments: | Sands, Rocks, Clays, Silts. Siliclastic and carbonaceous |
| • Factors controlling siliclastic: | Composition – provenance (provenance determined by looking at % composition of quartz, feldspar, & lithic fragments), climate/type weather • Textural maturity – # of cycle, type of sediment • Compositional maturity – weathering stability, provenance |
| • First-cycle vs multi-cycle sands | First cycle would have chemically unstable species, angular, poor sorting. Immature. • Multi-cycle would have chemically stable, rounded, well-sorted species. Mature. |
| • Origin of carbonate grains | Talk about ooids, peloids, intraclasts. Formed where deposited Controls = loss/precipitation of CO2 (high water temp, shallow water, agitation), organic activity (exhalation, photosynthesis), and whether it is has low siliclastic sedimentation rates |
| • Laminar vs turbulent flow | Laminar- flat, turbulent – wiggly. |
| • Tranquil vs rapid flow | Tranquil – slow, rapid – fast |
| • Lower and upper flow regimes | Low – ripples. Cross laminated sand. Like subcritical flow. • High – parallel laminated sand, scalloped lower boundary, massive granules to sand (rapid deposition) |
| • Reynolds number | Is between <500 and >2000 |
| • Froude number | >1 or <1 |
| • Paleocurrent data and interpretation | Indicates flow direction, type. • Can be seen through cross bedding, ripples, imbrication, prod marks, etc |
| • Rose diagrams | Indicates direction, unimodal vs bimodal |
| • Paleocurrent indicators | cross bedding, ripples, imbrication, prod marks, flute marks, cross lamination, dunes |
| • Debris flows | Sediment gravity flow. Large particles. Can move as fast as water. Found near alluvial fans, sometimes in braided rivers |
| • Turbidity currents | Sediment gravity flow. sediment supported by turbulence of fluid within the flow. mass of water with suspended sediment is denser than water. typically produces normal graded beds. consists of head, body, tail. cloud of death |
| • Unidirectional flow | Going one way. Indicated by things like imbrication, cross bedding, prod marks, flute marks, cross lamination, dunes, ripples |
| • Oscillatory flow | Going 2 ways. Indicated by symmetrical dunes and ripples. Occurs between fairweather and storm wave bases |
| • Tidal currents | Going in and out. • ebb & flood tidal deltas – deposit on either side of an inlet formed by tidal currents • Ooids • Tidal flats |
| alluvial fan | Moderately well sorted. Horizontal strat. Cross bedding. Base of tectonically active upland area. Immature deposits, grain size decreased down fan. |
| Meandering | Higher velocity/erosion on outside, deposition on inside. Ripples on the point bar side. Dunes on the floor. Cross bedding, fining upward sequence. Floodplain - vertical accretion, mud, shales, carbonate nodules, root casts, and mudcracks. |
| Braided | Even x-section. Rapid migration over time. Sandy conglomerates. Bars in middle of channel floor, build outward laterally. Vertical stacking of transverse deposits. Planar and/or trough cross bedding. Some fining upward (< meandering). Sheets of sand. |
| beach | laminar bedding, sloping slightly upward, with some fossils, especially skolithos |
| tidal flat | sequence from lenticular to wavy to flaser bedding is transgressive |
| deltaic Highstand (yellow) | builds out longways and slumps down continental shelf. Offshore marine & fluvial facies. during higher sea level |
| deltaic Transgressive (green) | is mostly longways/leftways and doesn’t really go down continental shelf. during transition from lower to higher sea level. Coastal plain/nearshore & fluvial facies. Occurs mainly landward |
| deltaic Lowstand (blue) | builds in troughs and post-inflection point (seaward) and is mostly down the continental shelf. during lower sea level. Deep sea & fluvial facies. Occurs mainly seaward. |
| deltaic lithology | deep sea fan facies, coastal plain and nearshore facies, fluvial facies, and offshore facies |
| shelf | HCS, tidal dunes |
| submarine fans/deep sea basin | Turbidites |
| • Geologic time scale (periods in each era) | Come over some day maybe play poker, three jacks cover, two queens |
| Come over some day maybe play poker, three jacks cover, two queens | Pz Cambrian Ordovician Silurian Denovian Mississippian (carboniferous) Pennsylvanian (carboniferous) Permian Mz Triassic Jurassic Cretaceous Cz Tertiary Quaternary |
| eustatic vs relative sea level change | • eustatic sea level change = global – glacial melt, or slow sea floor spreading (size of basin) • relative sea level change = local – if you have a lot of sediment being brought in, or uplift, that would be lowering |
| • Walther’s Law | “only those facies can be superimposed with can be observed beside each other at the present time” Used to justify strat sections. Null if there are unconformities. |
| • Unconformities | disconformity erosional unconformity surface of erosion is a gap in time indicated by a wiggly line nonconformity sedimentary rock overlaying non-sedimentary rock angular unconformity folding/tilting and then erosion/deposition later |
| • Lithofacies maps and their interpretation | Was on March 12/13 lab. Kind of like drawing contour lines only with rock types |
| evolution | •Descent w/ genetic mod through adapt •Allele = type/version of gene •Mech & evidence for pattern •Survival of best adapt •Fossils • direct evidence for change • “ for relationships among species • “ of transitional forms |
| • Mesozoic rift basins | Alluvial fan deposits first. So conglomerate (all kinds of clasts, whatevers exposed on the surface will tumble down into the basin. Then sandstones from rivers. Shale facies formed in the middle. |
| Triangle diagram of arenite composition | Continental block = from feldspar & qtz to just qtz. Magmatic arc is from equal mix of the 3 to mostly lithics with some of the other two. Recycled orogeny is from lithics and quartz with some bits of feldspar to just lithics and quartz, to just quartz. |
| φ (Phi) | Phi scale is log scale. It has to do with showing sand particle size in mm. Bigger phi, smaller particle. Sands from -1 to 4. |
| Reynolds number | deals with the geometry of the flow. p = fluid density, u = flow velocity, l = flow depth, U = dynamic viscosity (which is shear stress/rate of strain). Re < 500 laminar (straight), Re > 2000 turbulent (squiggly). |
| Froude number | deals with how fast the flow moves. u = flow velocity, d = flow depth, g = gravitational acceleration. Fr < 1 subcritical flow (tranquil, low velocities, waves can move upstream). Fr > 1 supercritical flow (rapid, shooting). |
| Bedforms with increasing velocity | Ripples, then dunes, then plane beds, then antidunes. The grains would get more rounded as the flow increased, and the bedforms would be squiggly instead of laminar. |
| Increasing velocity of flow: | ripples → dunes → plane bed → antidunes |
| Unidirectional flow (rivers, streams, turbidites) | ripples have erosion in trough, building at peak. height of less than a few cm (<4). wavelength up to 50 cm (5-20m) |
| Subaqueous dunes (rivers) | height and wavelength related to water depth |
| Upper plane bed | not actually a planar depositional feature. small, fast moving, low amplitude, long wavelength ripples. horizontal lamination |
| Antidunes | grains deposited on upstream side → low angle faint cross lamination that dips upstream. preservation potential. movement opposite of migration |
| Tidal influence | herringbone cross stratification. mud drapes or cross beds. reactivation surface |
| Shallow waves | sediment in symmetrical ripples (lots of back & forth) |
| Deep waves | motion decreased with depth. wave base is half wavelength |
| Wind dominated environment | ripples & dunes. wind blows in one direction. migration shows steep side as side that the wind was blowing from |
| Glaciation | loess. till deposition (extremely angular). outwash from glaciers in small streams/braided rivers |
| Sediment gravity flows | (turbidites, debris flow, fluidized flow). evidence of sediment and liquid flowing fast. happen in alluvial fans |
| Mudflows/debris flows | slurry of poorly sorted, highly concentrated sediment & water. Happen in alluvial fans |
| Turbidity currents, specifically | sediment supported by turbulence of fluid within flow. Produces normal graded beds. Happens on the ocean floor. shorter duration, bouma sequence, marine fossils, bioturbation, cross lamination, graded bedding |
| Bouma sequence | mud, laminated silt, cross laminated sand, parallel laminated sand, and massive granules to sand |
| Sole Marks | formed at the base of a sandstone bed. Steeper leftways if flowing from right. |
| Alluvial Fans | cone-shaped bunch of sediment extending from an upland area across an adjacent downland. Typically in sparsely vegetated, semiarid region. Mod well sorted. Horz strat. x bedding. Base of tect active upland. Immature deposits, grain size - down fan. |
| Meandering Streams/Rivers cross section | Higher velocity/erosion on outside (bigger chunks), deposition on inside (scour face). Ripples on the point bar side. Dunes on the floor (result in cross bedding). Fining upward sequence (lateral accretion). Unidirectional rose diagram. Asymmetrical |
| Meandering Streams/Rivers floodplain | vertical accretion of mud, shales, carbonate nodules, root casts, & mudcracks. Shoestring sands. longer duration, scroll marks, fining upward, unidirectional dip toward river channel, cross bedding, root casts, terrestrial fossils, paleosols. |
| Braided Streams/Rivers | Even cross-section. Rapid migration over time. Sandy conglomerates. Bars in middle of channel floor, builds outward laterally. Vert stacking of transverse deposits. Planar and/or trough cross bedding. Some fining upward (< meandering). Sheets of sand. |
| Delta plain (modern, upper) | gradational w/ floodplains, lacks marine influence, large flood basins, commonly with lakes & freshwater peats. River evidence, channels, and sands, cross bedding, cross lamination, and gravels. Bar finger sands. Features prograding outward. |
| Delta plain (in sed record) | m thick w horz topset beds, thicker foreset diag beds, and horz bottomset beds. Homogenous muds (laminated or bioturbated), slump sheet, interbedded muds/silts/sands, coarsening upward, ripple laminated silts/sands w scour surfaces, thin peat beds. |
| Delta plain (modern, lower) | marine influences. Tides, salt water intrusion, interdistributary things (shallow lagoons, marshes, mangroves). Finer mud deposits with maybe some sand. |
| Swamps, marshes, lakes, lagoons | Fine material, organic materials, vegetation, coal. |
| Tidal deposits | Ripples (look like current ripples). Can have flaser/wavy/lenticular bedding and fecal pellets. |
| Mountain building along a magmatic arc | Unroofing sequences – dissection of a magmatic arc moves from lithic arenites & wackes to quartz or feldspar rich ones foreland & forearc basin deposits, accretionary wedge deposits, igneous material, exotic terrain pyroclastic/volcanic materials, igneou |
| Foreland Basin | Flysch – dhsles interbedded with greywacke sandstone (lithic wacke). Shales & turbidites that accumulate in deep water within a foreland basin bordering an active mountain system Molasse – non marine & shallow marine sediments that overlie flysch |
| Coastal Shelf | Hummocks & swales (storms below fairweather wave base and above storm wave base) |
| Margins | shallow, warm, agitated. carbonate precipitation, coral algal reefs, carbonate mud, pellet sand & mud, ooltic & skeletal sand |
| Beach | Eolian dunes (like we see at the beach, duh). Foreshore (cross stratification) |
| Shoreface | low tide terrace, longshore trough, landward slope, longshore bar crest, seaward slope |
| Offshore | mean fairweather wave base, mean storm wave base |
| • What are the characteristics of sediments deposited by a prograding delta | From bottom to top: thickening upward interbedded ss & sh, fining upward rippled ss & conglomerate (some shale), fining upward rippled conglomerate, convoluted sand |
| Sketch a rose diagram such as you might expect from measurement of sedimentary structures in such a deposit. | It would have a general trend toward one quadrant for an alluvial fan, it would be mainly unidirectional for a fluvial system, and for a tidal flat it would be bimodal |
| What are two factors that could influence the composition of an arenite and for each, explain how that factor influences the composition. | Provenance. Where it was created -> source rock -> grains -> arenite Location/climate of depositional environment. So whether there might be rapid mechanical weatheringlike in a mountain setting or rapid chemical weathering like in a tropical setting. |
| Briefly list the sedimentary structures/sedimentary features you would expect to see in the rock record of a siliciclastic tidal flat? | Upper intertidal zone – mud. Lower intertidal zone – mixed mud & sand. Subtidal zone & tidal channels – sand. Supratidal zone – muddy marsh sediments. Fines toward high tide level. |
| What change in sedimentary structures would you expect in a transgressive sequence of the tidal flat? | lenticular -> wavy -> flaser. Transgressive sequence (deepening, encroaching seas). |
| Difference between alluvial fan & braided? | -alluvial – coursing upward, angular grains, larger material, wedge cross section, radial pattern. Matrix supported. -braided – planar beds, less pronounced fining upward, symmetrical cross section, unidirectional pattern, debris flow (poor sorting) |
| Difference between alluvial fan & meandering? | -meandering – dunes, cross bedding, fining upward, tilted cross section, unidirectional, clay plugs, floodplain deposits. Clast supported -alluvial – coursing upward, angular grains, larger material, wedge cross section, radial pattern. Matrix supported. |
| • lime mudstone with fenestral fabric | Openings in rock are larger than the grain size of the matrix. Found in tidal flats w carbonate mud. Gets cemented kind of early. Algal mats might be part of the sediment and then go away, and that makes there be a gap. Can also be cracks or gas bubbles |
| One possible explanation for such a chance is dissection of a magmatic arc. Explain how this would account for the change in composition. | The dissection of a magmatic arc would account for these changes because an undissected arc is mostly volcanic material, but as it erodes, it exposes plutonic rocks underneath, which are mineralogically mostly feldspars and quartz. |
| Interbedded sh & ss - fluvial | Meandering rivers. Lag deposit (conglomerates, then x bedded sands, then planar laminated sands, then x laminated sands) fining upward Mud – some sandy layers, mudcracks, carbonate nodules, paleosols, root casts |
| Interbedded sh & ss - deltaic | Muds in delta front. Prograding over, sand bodies (channel mouth bar sands, cross beds, planar beds, some bioturbation) coarsening upward. Marine fossils in prodelta shales. Bioturbation Maybe some tidal currents |
| Interbedded sh & ss - deep sea | Bouma sequences (graded bed, planar laminated beds, cross-laminated ripple, mud, ) graded bed, fining upward. Marine fossils, bioturbation. Could also be unidirectional & fanning out. |
| On the diagram, outline and clearly label one high-stand system tract, one low-stand system tract, and one transgressive system tract. Include in the outline all of the sets within that particular tract. | Yellow builds outward because it can’t build up (sea level high). Then lowstand, erosion of the landscape, deposition further offshore. Then SLR, so moving sediments onshore (transgressive) and that’s the green, and it starts to build out again. |
| (foreland basins) | A. Martinsburg Formation, Brallier Shale |
| (passive margin, except Unicoi is rift basin) | B. Unicoi, Antietam, Knox, Elbrook, New Market, Lincolnshire, Greenbrier |
| (filled-in basin) | C. Juniata,Tuscarora |
| History of coastal plain | Eastover -> Yorktown (shallow marine, shoreline offshore to subtidal). Sea level drop, then rise. Bacon's castle (fluvial channel, estuarine, silt aggrading floodplain, lenticles). Sea level rise, then drop. Shirley (fluvial estuarine, glacial cycles) |
| basalt | • clay minerals, iron oxides (chem) • olivine, pyroxene, lithic fragments (physical) |
| granite | • quartz and clays (chem) • quartz, feldspars, +- micas (phys) |
| porphyritic andesite | • amphibole, hornblende, plagioclase, fragments |
| rhyolite | • quartz & kspar +- plag, biotite, muscovite |
| muscovite schist | • muscovite, garnet, +- biotite, fragments |
| amphibolite | • hornblende +- actinolite, fragments |
| Immature | • very poor-poor sorting • very poor-poor rounding • Alluvial fan |
| Mature | • Well sorted • Well rounded • River |
| Super Mature | • Very well sorted • Very well rounded • Beach |
| Mature | • Compositionally immature • Well rounded • Well sorted • River Bank • Sand Dunes |
| Immature | • Compositionally mature • Angular • Poorly sorted • Qtz only source • Rapid mechanical weathering (alluvial fan) |
Created by:
haleyBUGoxox
Popular Earth Science sets