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| Disconformity - an erosional channel in which sedimentary rock layers above and below the erosional surface parallel. |
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| Unconformity - Buried, ancient erosional surfaces |
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| Angular Unconformity - the sedimentary rock layers below the unconformity are tilted at an angle to the layers above the unconformity. |
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| Anticline - Large upward arch of sedimentary rock |
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| Syncline - Large downward arch of sedimentary rock |
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| Plunging Anticline - tilted with respect to the earth. |
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| Nose - When eroded, the lobate shape of a plunging anticline is called a "nose". |
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| Dome - circular or eliptical uplift, good place to find oil |
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Homocline - Sedimentary rocks dipping uniformly in one direction.
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Joint - fracture in the rocks without any movement of one side relative to the other. Improves reservoir quality of rock. Any naturally fractured rock is a potential reservoir rock |
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| Reverse Fault or Oblique Slip Fault |
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Horst - goes up
Graben - goes down |
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Term
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Definition
- Forms only by the alteration of a pre-existing limestone. Magnesium-rich waters percolating through subsurface limestone replace atoms with magnesium to form dolomite.
- Occurs next to fractures in limestone where water can run through.
- Typically good reservoir rock. Worse porosity the deeper it's found.
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Term
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Definition
| Extremely fine-grained limestone composed of microfossil shells. |
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Definition
Formed by warm fresh water flowing through/on limstone. This dissolves limestone and deposits it as karst limestone. It has excellent porosity and permeability.
They have solution pores up to several inches called vugs.
Often occurs directly below a subsurface angular unconformity. |
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Definition
| As tides flow over limestone platforms, the water gets saturated with calcium carbonate and precipitates out of the water in sand and silt-sized spheres called oolites. |
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| layer of sedimentary rock |
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