lecture 2 stratigraphic data n.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
Lecture 2: Stratigraphic data PowerPoint Presentation
Download Presentation
Lecture 2: Stratigraphic data

Loading in 2 Seconds...

play fullscreen
1 / 51

Lecture 2: Stratigraphic data - PowerPoint PPT Presentation


  • 187 Views
  • Uploaded on

Lecture 2: Stratigraphic data. Boris Natalin. Stratigrapher uses - Data from surface outcrops - Subsurface data such as cores, well logs, and seismic data Today’s topics are sedimentary rocks and their structures

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Lecture 2: Stratigraphic data' - shima


Download Now An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
slide2
Stratigrapher uses

- Data from surface outcrops

- Subsurface data such as cores, well logs, and seismic data

Today’s topics are sedimentary rocks and their structures

Classification of sedimentary rocks:- Clastic (Siliciclastic)- Biogenic- Chemical

Sedimentary structures

slide3

Sandstone

  • Clastic sedimentary rocks consist of rock and mineral grains derived from the chemical and mechanical breakdown (weathering) of pre-existing rock. They contain rock fragments and more commonly, particles of quartz and feldspar. Clastic rocks are further classified on  the basis of grain size.
classification
Classification

Phi(φ)

scale

φ= -log2 diameter (in millimeters)

0.0625 mm

classification1
Classification
  • Conglomerates (> 2mm) is consolidated gravel
    • Boulder (>256mm)
    • Cobble (65-256 mm)
    • Pebble (4-64 mm)
    • Granule (2-4 mm)
  • Sandstones (0.062-2 mm) consolidated sand
    • Very coarse (1.0 - 2.0 mm)
    • Coarse (0.5 - 1 mm)
    • Medium (0.25 - 0.5 mm)
    • Fine (0.125 - 0.25 mm)
    • Very fine (0.0625 - 0.125 mm)
  • Shales (<0.0062 mm) is consolidated mud, rich in organic matter.
    • Silt (0.0039 - 0.0625 mm)
    • Clay (0.0002 - 0.0039 mm)
shape and roundness
Shape and Roundness
  • The degree of abrasion of sedimentary particles
mudrocks or mudstone 0 06 mm
Mudrocks or mudstone (<0.06 mm)
  • Silt
  • Shale (lithified clay)
  • Bedded silt or bedded shale (>10 mm)
  • Laminated silt or laminated shale (<10 mm)
carbonates
Carbonates
  • Chemical/Biochemical
  • Limestone
  • Dolomite
chemical sedimentary rocks
Chemical sedimentary rocks
  • Evaporates
  • Siliceous sedimentary rocks (cherts)
  • Phosphorites
sedimentary structures
Sedimentary structures
  • A geologic structure is a geometric feature in rock whose shape, form, and distribution can be described
  • Large scale feature of sedimentary rocks
  • Information on origin of rocks
  • Information on younging direction
  • Information on paleocurrent direction
slide18
Beds, or strata are tabular or lenticular layers of sedimentary rock that have lithologic, textural, or structural unity that clear distinguishes them from layers above and bellow
slide20
Bedding planes
  • Groups of similar beds or cross beds are called bedsets
  • Bed termination may occur: - merging of bedding planes (pinch-out)- lateral gradation of composition (die out)- meeting of crosscutting features such as channel or unconformity
three mechanisms are responsible for the formation of bedding planes
Three mechanisms are responsible for the formation of bedding planes

1) Sedimentation from suspension

2) Horizontal accretion from a moving bed load

3) Encroachment into the lee of an obstacle

  • Bed load is a part of the stream load that moves on or immediately above the stream bed
  • Streamload is all material that is transported by a stream
slide23
Lack of bedding means:(1) bioturbation(2) deposition from highly concentrated stream load(3) rapid deposition from suspension.
graded bedding
Graded bedding
  • Commonly produced by turbidity currents
  • Turbidity current is poorly sorted material suspended in water. When flow begins to slow down, material settles according to the grain size.
bed and bedforms
Bed and bedforms
  • Bed – the smallest lithostratigraphic unit, commonly ranging in thickness from a centimeter to a meter or two and distinguishable from beds above and below (3D)
  • Bed (in sedimentology) – the floor of a body of water (2D)
  • Bed form or bedform – any deviation from a flat bed, generated by stream flow on the bed of a channel (2D)
cross stratification
Cross stratification
  • Cross stratification from Jurassic age Navajo sandstones. Wind direction is from left to right
slide41

Load casts

Flame structures

Extend downward from a sand layer into an underlying mud or very fine sand layerYounging direction

bedding plane structures
Bedding plane structures
  • Groove cast; striations, bounce, brush, prod, and roll mark
  • Flute cast
  • Parting lineation
  • Track, trails burrows
  • Mudcracks and syneresis cracks
slide45

Grooves (Oluk yapıları)

Striations

(Buzul kertikleri)

slide47

Flute marks

Load casts

Groove casts