Paralic (Marginal Marine) Siliciclastic Depositional Systems - PowerPoint PPT Presentation

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Paralic (Marginal Marine) Siliciclastic Depositional Systems

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Paralic (Marginal Marine) Siliciclastic Depositional Systems Modern and Ancient * * Coasts: Depositional vs. Erosional Rocky (consolidated) vs. dis- or partially ... – PowerPoint PPT presentation

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Title: Paralic (Marginal Marine) Siliciclastic Depositional Systems


1
Paralic (Marginal Marine) Siliciclastic
Depositional Systems
  • Modern and Ancient

2
Coasts
  • Fluvial energy/sediment input vs. Marine
    energy/sediment input
  • Marine energy Wave vs. Tide dominated
  • Transgressive vs. Regressive
  • Depositional vs. Erosional
  • Rocky (consolidated) vs. dis- or partially
    aggregated substrates
  • Terrigenous vs. biochemical

3
Inter/non-deltaic Siliciclastic Shorelines
Paralic Environments
  • Ancient deposits
  • Modern Environmental Hazards

4
Inter/non-deltaic Siliciclastic Shorelines
Paralic Environments
  • Importance of Holocene Transgression on modern
    coastal environments

5
Shoreline Geomorphology in Non-Deltaic Coasts
  • Reflects the interaction b/w sediment supply vs.
    marine reworking
  • Marine reworking is accomplished mainly by
  • Fair weather waves
  • Tides
  • Storm waves

6
Barrier Islands/Lagoons
  • Most Typically associated with low sediment
    supply and rising sea level
  • Lagoon landward estuaries
  • fluctuating water salinity, temperature, and
    level typically highly biologically productive
  • influence on lagoon ecology
  • abundance/diversity
  • flood tidal deltas
  • tidal channels, mudflats
  • bay deltas

7
Barrier Islands/Lagoons
  • Barrier Island Massif
  • Wave Dominated beach-shoreface
  • washover channels and fans
  • Main dune ridge and fore dunes

8
Zonation of the (Wave Dominated) Shoreline Profile
  • Wind Waves Main source of energy to most open
    ocean coasts

9
Barrier Island Facies
  • Synoptic map
  • Time series sections

10
Barrier Islands/Lagoons
  • Tidal channels, inlets or passes (most abundant
    and more stable in mesotidal settings)
  • Drumstick barrier model
  • Ebb tidal (tide dominated) vs flood tidal (wave
    dominated) deltas

11
Transgressive Barrier Island Sequences

12
Regressive Barrier Island Sequences

13
Coasts in Crisis
  • Coastal land loss and the increasing occupation
    of the coastal zone

14
Coasts in Crisis
  • Coastal erosion at widely varying rates affects
    all 30 coastal States and all of the U.S. Island
    Territories.
  • During the past 200 years, more than half of our
    valuable wetlands have been lost due to a
    combination of natural processes and human
    intervention.
  • Pollution of coastal areas has forced the closing
    of one-third of the Nation's shellfish beds, has
    restricted beach use, and has permanently
    contaminated ground water in some communities.
  • In many coastal urban areas, hard-mineral
    resources such as sand and gravel for
    construction and
  • beach nourishment are no longer
  • available onshore. Offshore
  • deposits may provide an
  • alternative but pose environmental
  • and economic dilemmas.
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