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.TOURING

COLORADO GEOLOGY

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TABLE EXPLANATION

An explanation for the small tables that appear in the upper right portion of each of the tours.  The highlighted cells for each tour indicates what ages and rock types can be found in the area.

Geologic Time
       

Eras

Period/Sub-eras

Million Years ago (approx.)*

  

C

Q

  

Cenozoic

Quaternary

 0 - 2  

T

  

Tertiary

 2 - 65  

M

C

  

Mesozoic

Cretaceous

 65 - 144  

J

  

Jurassic

 144 - 213  

T

  

Triassic

 213 - 248  
 

P

P

  

 

Paleozoic

Permian

 248 - 286  

C

  

Carboniferous

 286 - 360  

D

  

Devonian

 360 - 408  

S

  

Silurian

 408 - 438  

O

  

Ordovician

 438 - 505  

C

  

Cambrian

 505 -  590  
P-C    

Pre-Cambrian

   590 +  

* Harland et al., 1982

LITHOLOGIES
       

Rock Type

Sub-Types

Examples

I

Int

    

Igneous

Intrusive

Granite, Diorite, Gabbro

Ext

    

Extrusive

Rhyolite, Andesite, Basalt, Obsidian, Pumice

S

Cla

    

Sedimentary

Clastic

Conglomerate, Sandstone, Siltstone, Shale, Mudstone

Org

    

Organic

Limestone, Coal

Eva

    

Evaporites

Limestone, Gyprock, Rock Salt

M

Fol

    

Metamorphic

Foliated

Gneiss, Schist, Phyllite, Slate

N-F

    

Non-Foliated

Marble, Quartzite, Anthracite, Metaconglomerate

Updated 07/19/01

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