New version page

TAMU GEOL 404 - Deposition Environments 2

Type: Lecture Note
Pages: 4

This preview shows page 1 out of 4 pages.

View Full Document
View Full Document

End of preview. Want to read all 4 pages?

Upload your study docs or become a GradeBuddy member to access this document.

View Full Document
Unformatted text preview:

Geol 404 1st Edition Lecture 5 Outline of Last Lecture I. Conditioning AgentsII. Energy BalanceIII. Rain Shadow EffectsIV. Depositional Sedimentary Environmentse. Continentalf. Shorelineg. MarineOutline of Current Lecture V. FaciesVI. Facies AssociationVII. Hierarchy of Depositional UnitsVIII. Limitations of FaciesIX. Deposition EnvironmentsX. Deposition Environments PaleocurrentsCurrent LectureV. Facies a. Definition- A body of rock characterized by a particular combination of lithology, grain size, texture, bedding, fossil, geometry.b. Description- Cross bedded sandstone facies, or massive pebbly siltstone faciesc. Different Types:i. Lithofacies – Based on Lithology, sedimentary attributes such as grain size, sedimentary structures, beddingii. Biofacies – Based on follil assemblage, fossil content, body fossils or trace fossilsiii. Ichnofacies – Based on trace fossil assemblageiv. Seismicfacies – Seismic reflection amplitude and continuity.These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.VI. Facies Associationa. Definitioni. Paleoenvironments involving facies associations or sequences in successions which are usually vertical of genetically related facies.b. Descriptioni. Large scale coarsening upwards sequence in a transition zone reflecting progradation of a beach.VII. Hierarchy of Depositional Unitsa. Stratigraphyi. Large scale mapping of unitsb. Facies Modeli. An interpretive device erected to explain a facies assemblage, or a block diagram of a paleogeographic/depositional model.c. Facies Associationi. Usually it’s repeated association or assemblage of complimentary sedimentary units.d. Faciesi. Is determined by looking at the physical rock composition or by interpreting the bedforms.VIII. Limitations of Faciesa. Schemes and facies association modelsi. Serve to systematize and simplify observation and classificationii. Serve to suppress innovationIX. Deposition Environments a. Nomenclature in Migrationi. Stoss Side Laminaeii. Lee or slipfaceb. Facies Descriptions for Bedformsi. Planar tabular cross stratification - Horizontally separatedii. Trough cross stratification - Very circular and wavyiii. Planar wedge shaped cross stratification - Wedge shaped, linear cuts that are not horizontal**Good to know which way current is going**c. Wave and Tide Influenced Shorelinesi. Linear Clastic Shorelines (Barrier Bars)1. Six major dep environments within a barrier island system2. Seaward side:a. Shoreface, Foreshore, Backshore3. Landward side:a. Lagoon, Tidal Inlets, Tide deltasii. Because of the amounts of sand involved, they are important hydrocarbon reservoirs even though they have very different sand body geometriesd. Linear Clastic Shorelinesi. Schematics show various facies associations developed on progradingbarrier shorelines.ii. Vertical sequences have coarsing up motif reflected grainsize.e. Shallow Marine Sandsi. Problems?1. How is the sand transported into depths of 10-100m?2. To what extent is it remolded by tidal storm and oceanographic currents?ii. Continental Shelves and Epicontinental Sea1. Pericontinental - Passive margin, divergent2. Epicontinental - Continental interrior, evaporation normally formsiii. Shallow Marine Storm Bed1. Large storm Environments will cause rip currents will pull the sediment from the top and down into the deeper part of the seaa. Suspension Currenti. Below the storm wave baseb. Storm Erosion and Redepositioni. Between the Fair weather wave base and storm wave base. c. Barometric Effecti. Above the system itselfd. Bottom Currenti. At the bottom of the sea.e. Pre storm sea bedi. At the bottom of the sea, and is weathered away by storms and gets more deep. (Drop offs.)iv. Shallow Marine Sands1. Tide Dominateda. Low to moderate intensity (North Sea)2. Ocean Current Dominated/Wave Dominateda. Low to moderate intensity3. Wave Dominated/Storm Dominateda. Increased frequency of oscillatory flowsf. Continental Margin, Slope and Ocean Basinsi. Marine waters cover 81% of earthii. 4 fundamental environments1. Radial a. The feeder channel leads to the fans where you can findthin bedded turbidites on levee, conglomerates inverse to normally graded, grade bed, graded stratified. The fanleads to Mid fan where you find proximital, classical turbidites that are thin bedded.2. Elongated3. Fan Delta4. Contourite Driftsg. Top and Bottom Markings on Individual Turbiditesi. Sip and Prod marks - make by vegetation entrained in the turbid flow (bottom)ii. Bow shaped inguoid ripples (top)iii. Flute cast marks made by swirling vortices into mud (base)X. Depositional Environments Paleocurrents -Various sedimentological regimes-Alluvial -Low Variable -Fan shaped slope controlled-Eolian -Polymodal -High Pressure systems-Deltaic -Unimodal -Regionally radiating-Shoreline -Bimodal -Longshore-Turbidies -Unimodal -Fan Shaped or along through


View Full Document
Loading Unlocking...
Login

Join to view Deposition Environments 2 and access 3M+ class-specific study document.

or
We will never post anything without your permission.
Don't have an account?
Sign Up

Join to view Deposition Environments 2 and access 3M+ class-specific study document.

or

By creating an account you agree to our Privacy Policy and Terms Of Use

Already a member?