Thursday, January 24, 2013

Geological State Symbols Across the US - #3 Arizona

The next state up is Arizona. Here are the stats:

                                                                                        Year Established
State Gemstone: Turquoise                                                        1974
State Fossil: Petrified Wood (Araucarioxylon arizonicum)        1988

Arizona appears to have several unofficial state minerals (copper and/or fire agate) but I will only talk about the official ones.

State Gemstone: Turquoise
Turquoise is a blue to green mineral made up of copper, aluminum, and hydrous phosphate (CuAl6(PO4)4(OH)). Turquoise has long been considered a valuable gemstone and is one of the oldest known gemstones. It is formed by the flowing of groundwater through copper deposits and so is often associated with copper in arid (desert) environments. In Arizona, almost all turquoise deposits are associated with copper mines and are usually mined in association with the copper or leased out to other companies by the copper mine. It is known that the Native Americans (the Anasazi and the Hohokam) mined the turquoise in Arizona to use in jewelery and for trade. Arizona is also home to one of the largest domestic turquoise mines in Kingman.

State Fossil: Petrified Wood (Araucarioxylon arizonicum)  
"Petrified" in this instance does not refer to scared (although I'm sure it has been used that way in the past), the term "Petrified Wood" can refer to any type of tree that has been mineralized (turned into stone), the specific species of petrified wood (Araucarioxylon arizonicum) is an extinct conifer that is found throughout Arizona and New Mexico. There is a problem with the state fossil though, the original name of the species was based on three different species. This means that although one of the three was correct, two had to be renamed, resulting in several of the trees identified since the initial 1889 description were also likely named incorrectly. Proper identification can only be made with thin sections and close analysis so that is not likely going to happen for a majority of the samples, at least not any time soon. Arizona is host to one of the largest assemblages of petrified logs found partially in Petrified Forest National Park (~10% of all the petrified wood in northeastern Arizona). The concentrations of logs in PFNP are a result of log jams that flowed down rivers. The woody material was then replaced by silica (quartz) by silica rich waters flowing through the logs.


Previous States:

No comments:

Post a Comment

Due to the large number of spam comment (i.e. pretty much all of them). I have turned off commenting. If you have any constructive comments you would like to make please direct them at my Twitter handle @Jazinator. I apologize for the inconvenience.

Note: Only a member of this blog may post a comment.