Annotated Geologic Time Scale
this page is under construction!
This annotated geologic time scale is presented to provide a perspective on the mineral and fossil specimens at Taos Rockers, and on the geological formations and events that shaped the Taos area. For the most accurate geologic time scale for North America, see the GSA (Geological Society of America) time scale
The numerical time spans of each era, period and epoch are under continuous revision by geologically small numbers of years, so you will notice slight discrepancies in the years listed in different sources.
Note that "mya" is the abbreviation for "millions of years ago."
Few fossil remains exist in rocks of this era; many of the scarce fossil flora and fauna are represented in the Ediacaran and Cryogenian periods. Organisms had not developed significant hard parts and soft tissue is rarely preserved in the fossil record
Geological features near Taos
- The Picuris Mountains
- The Sangre de Cristo Mountains (parts)
- The Harding Pegmatite
Paleozoic Era 539 – 252 mya
The term paleozoic means “ancient life.” This era saw the evolutionary “explosion” of life on earth, both animal and plant forms. Most forms of life that evolved in this era are now extinct.
Near Taos: Paleozoic age rocks in the Sangre de Cristo Mountains contain abundant fossils. These cannot be collected legally.
Cambrian Period 529 – 485 mya
This period started with the evolutionary “explosion” of life forms – both animals and plants. Most animal phyla evolved in this time period, although the modern forms may not look like their Cambrian ancestors. Some of the most notable:
Phylum Arthropoda (trilobites and others)
Phylum Brachiopoda (shelled organisms)
Phylum Echinodermata (crinoids, starfish)
Phylum Cnidaria (corals)
Phyum Mollusca (molluscs)
Phylum Porifera (sponges)
Phylum Chordata – jawless fish (Agnatha)
Ordovician Period – 485 – 444 mya
Silurian Period – 444 – 419 mya
Devonian Period – 419 – 359 mya
Carboniferous Period – 359 – 299 mya
Permian Period – 299 – 292 mya
Mesozoic Era – 252 – 66 mya
Triassic Period – 252 – 201 mya
Jurassic Period – 201 – 145 mya
Cretaceous Period – 145 – 66 mya
Cenozoic Era – 66 mya – present
Paleogene Period – 66 – 23 mya
Neogene Period – 23 – 2.6 mya
The megalodon sharks lived
Early eruptions in the Rio Grande Rift area near Taos
Quaternary Period – 2.6 mya – present
The Sangre de Cristo Mountains were uplifted