1 / 40

Stratigraphy

Stratigraphy. Principles of Stratigraphy Types of Stratigraphy Contacts Unconformities. Text: Manual p. 29-35. Stratigraphy. “Stratigraphy can be defined as the complete triumph of terminology over facts and common sense.”

Mercy
Download Presentation

Stratigraphy

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. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Stratigraphy • Principles of Stratigraphy • Types of Stratigraphy • Contacts • Unconformities Text: Manual p. 29-35

  2. Stratigraphy “Stratigraphy can be defined as the complete triumph of terminology over facts and common sense.” Attributed to P.D. Krynine by J. Ferm in Burton et al., 1987.

  3. Stratigraphy Stratigraphy: the study of the 3-D spatial and temporal relationships among rocks

  4. Stratigraphy • Principles of Stratigraphy • Types of Stratigraphy • Contacts • Unconformities Text: Manual p. 29-35

  5. Principles of Stratigraphy 1. Superposition The oldest rocks are found on the bottom and the youngest rocks on the top. youngest oldest

  6. Principles of Stratigraphy youngest? oldest?

  7. Principles of Stratigraphy younger older

  8. Principles of Stratigraphy 2. Original Horizontality sediments are deposited at the earth’s surface in flat layers

  9. Principles of Stratigraphy

  10. Principles of Stratigraphy cross-bedding

  11. Principles of Stratigraphy 3. Lateral Continuity a bed will extend laterally until: • Pinches out. • Abuts against older rock. • Truncated by erosion. • Cut by fault.

  12. Principles of Stratigraphy

  13. Principles of Stratigraphy 4. Cross-Cutting Relationships Rock that are cut by another geologic feature are older than the feature that cuts them. Igneous Intrusion Fault Erosion

  14. B A Principles of Stratigraphy 5. Rule of Inclusions If pieces of rock A are included in rock B, rock A formed before rock B.

  15. Principles of Stratigraphy 6. Faunal Succession Systematic sequence of fossils with time. Extinct fossils do not reappear in younger rocks. http://www.geo.utexas.edu/courses/401/

  16. Stratigraphy • Principles of Stratigraphy • Types of Stratigraphy • Contacts • Unconformities Text: Manual p. 29-35

  17. Types of Stratigraphy Type Subdivisions Property

  18. Types of Stratigraphy - Allostratigraphy

  19. Types of Stratigraphy Type Subdivisions Property

  20. Types of Stratigraphy - Lithostratigraphy Super Group Group *Formation Member / Tongue / Lentil Bed / Flow *Formation: distinct, mappable rock body with definable boundaries

  21. Types of Stratigraphy Lithostratigraphic Units lens / lentil (E. McBride)

  22. Stratigraphy • Principles of Stratigraphy • Types of Stratigraphy • Contacts • Unconformities Text: Manual p. 29-35

  23. Types of Contacts • Intrusive • Fault • Depositional • Conformable Contact • Unconformity

  24. Lateral Contacts Types of Contacts (Depositional) intercalated Vertical Contacts gradual gradation abrupt intertonguing pinchout (Boggs, p. 453)

  25. Types of Contacts (Depositional) Lateral Contacts (E. McBride)

  26. Stratigraphy • Principles of Stratigraphy • Types of Stratigraphy • Contacts • Unconformities Text: Manual p. 29-35

  27. vs Hiatus: amount of missing time vs Diastem: small amount of missing rock / time Unconformities Unconformity: buried surface of erosion; missing rock / time

  28. Unconformities Erosion – Mechanical, Chemical, Biological Drop in Sea Level Uplift of Land

  29. Unconformities Calvert Bluff / Alluvium Contact (Field Trip 1)

  30. Unconformities • Types: • Disconformity • Paraconformity • Nonconformity • Angular Unconformity

  31. Unconformities • Disconformity – sediments on sediments (same orientation) with obvious erosion

  32. 20 million years 150 million years Unconformities Disconformity Supai Group Redwall Limestone Muav Limestone

  33. Unconformities 2. Paraconformity – sediments on sediments (same orientation) no obvious erosion surface (Boggs, p. 456)

  34. Unconformities 3. Angular unconformity – sediments on sediments (different orientations)

  35. 250 million years Unconformities Angular Unconformity

  36. Unconformities Angular Unconformity Wyoming

  37. Unconformities Angular Unconformity (E. McBride)

  38. Unconformities 4. Nonconformity – sediments on crystalline igneous or metamorphic rocks Uplift, Erosion, Deposition Erosional Surface

  39. Unconformities Nonconformity 550 million years 1800 million years

  40. Canadian Shield Enchanted Rock Unconformities Nonconformity in Progress

More Related