Jemez Mountains, Sandoval County, New Mexico, USA

This shell has been partly replaced by red botryoidal agate the center has a limestone matrix. I found this on the north side of NM-4 near Battleship Rock in the fall of 1996. This was found in the Madera Group (Limestone) which is Pennsylvanian in age.

Basalt matrix with clear Hyalite opal coating. This is fluorescent (Green) under short wave but no fluorescence under long wave. No phosphorescent noted . The basalt has a slight pull to a rare earth magnet. I collected this near Spence Hot Springs. Child photos show close up and SW fluorescence.

Basalt matrix with clear Hyalite opal coating. This is fluorescent (Green) under short wave but no fluorescence under long wave. No phosphorescent noted . The basalt has a slight pull to a rare earth magnet. I collected this near Spence Hot Springs. Child photos show close up and SW fluorescence.

Obsidian with possible cristobalite filling the gas cavities. Specimen collected at Valles Caldera, known locally as "Obsidian Ridge". Collection and photo Rui Nunes, June 2024.

© Rui Nunes 2024

Dark gray discoid shell with 3 coils that have nice growth lines and very minor almost nonexistent nodes . These are found in the Madera limestone which is Pennsylvanian in age. Self collected in 1996 N. side of NM-4E near Battleship Rock, Jemez Mountains. Amphiscapha subrugosa (Meek & Worthen 1873)

Basalt matrix with clear Hyalite opal coating. This is fluorescent (Green) under short wave but no fluorescence under long wave. No phosphorescent noted . The basalt has a slight pull to a rare earth magnet. I collected this near Spence Hot Springs. Child photos show close up and SW fluorescence.

Nice fully inflated gray shell Neospinifer alatus (Wagner ,2023) with both halves. The growth lines and ribs are visible there is very little of the wing tips missing. These are found in the Madera limestone which is Pennsylvanian in age. Self collected in 1996 N. side of NM-4E near Battleship Rock, Jemez Mountains

Fusiform shaped fusilinid foraminifera (d'Orbigny 1826) external shell called a Test, these were usually made out of calcium carbonate or from sediment particles. These were single cell organisms that lived on or in the the seafloor sediment. There are over 40,000 recognized fossil species of foraminifera, some which floated at different levels ...

Biconvex fully inflated well preserved shell. The growth lines are well visible as is the Pedicle foramen on the beak (Opening near the hinge line for a foot like muscle to extend and attach to the sea floor) These are found in the Madera Group (Limestone) which is Pennsylvanian in age. I found this near Battleship Rock on the opposite side of 4 ...

Dark gray discoid shell with 3 coils that have nice growth lines but the aperture and last whorl are damaged. The limestone matrix also has many very small crinoid stems . These are found in the Madera limestone which is Pennsylvanian in age. Self collected in 1997 N. side of NM-4E near Battleship Rock, Jemez Mountains.

Volcanic activity in the Jemez Mountains began around 25 Ma with the onset of major activity around 15 Ma. This activity culminated in the caldera forming eruption of the Bandelier Tuff at 1.1 Ma. Ash from this eruption spread across the Great Plains and has been identified in Oklahoma, Kansas, and Texas. A few minor eruptions have occurred since ...

© Nathalie Brandes

The earliest volcanic activity in the area occurred ~18 to 25 Ma with the eruption of basaltic lava flows. A major phase of activity occurred from 10 to 15 Ma with eruptions of basalt, andesite, dacite, and rhyolite. Eruptions of rhyolitic lava continued to around 2 Ma. At 1.8 Ma, an explosive eruption formed the San Diego Canyon Tuff. The Otowi ...

© Nathalie Brandes