The specimen stones were created in wide range of ancient environments and climates. Each points to an exotic world, reminding us that constant change is a constant of Earth history.

Each stone on the exhibit wall is one point on a conceptual triangle. The other two points are the state the stone was taken from, and the modern place where that stone could have formed today.  For example, the location of Specimen #15 on the exhibit wall in Connecticut links to its original location in Kentucky and to any tropical marine lagoon where a similar formative environment exists today.

 

Fossils and Mass Extinctions

Consider these three examples from the collection.

• Arizona's specimen (#2) is from its Petrified Forest National Monument. Geologically, it's from the Chinle Formation deposited during the late Triassic Period (218-202 Ma).  Ecologically, it reveals lush floodplain vegetation in a strongly monsoonal climate.  Volcanic ash likely provided the source of silica to preserve the stone. The red color is the mineral jasper, which indicates oxidation during seasonal drought.

• The extinct Devonian coral from Iowa is called a favosite (#13).  Dating to roughly 448-251 million years ago, they built reefs similar to those of today, but with a completely different fauna.

• Hash of  extinct Paleozoic shells from Kentucky (#15, photo above) showing extinct snails and brachiopods. This was once the floor of a shallow sea that covered the central United States.

 

Ancient Climates and Environments

 

Tropical seas and beaches.

• Arkansas'sPaleozoic grainstone is a sandstone made of limestone grains.  It formed  by shoaling sandy beaches like those of tropical shores today.

• Florida's Ocala Limestone (#8), a silicified Eocene shelly hash. Florida has been limy and shelly for tens of millions of years.

• Illinois's silicified limestone (#11) reveals a Paleozoic shallow sea.

• Indiana's Salem Limestone (or stand-in, #14), formed by shoaling tidal sands and beaches moving carbonate sand.

• Kentucky's shelly bottom (#15) points to when the mid-continent was submerged beneath shallow seas.

• Pennsylvania's Oriskany Sandstone (#36) is a land-derived beach sand, but usually with abundant shelly fossils. Imagine coastal plains much wider than today.

 

Coastal Plain Deltas

 

• The Crab Orchard sandstone of Tennessee (#40) indicates a broad sandy barrier-delta system with beach, back barrier, tidal flat and tidal channel sands, Lower Pennsylvanian

• The unnamed specimen from West Virginia (#46) was described by the survey as a "flaggy fluvial sandstone" likely from one such delta.

• A very ancient one is the protolith of the Baraboo Quartzite of Wisconsin (#47).

 

Inland Rivers, Lakes, and Swamps

• Arizona's (#2) Petrified Forest.

• Newark supergroup of rift in NJ (#28) and CT (#6) (NHHarkose).

• Western redbeds of Oklahoma (#34), Permian terrestrial sandstones.

 

Desert Sand Seas (ergs)

• Aztec Sandstone ((#26) from Nevada is a quartz-rich eolian sandstone, correlating with more famous early Jurassic Navaho Sandstone of the Four Corners region of Utah, Colorado, Arizona, and New Mexico.

• Navaho Sandstone (#42) from Utah, a hard pink sandstone or quartzite.

 

Ice Ages & Glaciation

• Transported glacial erratics of Kansas (#14), North Dakota (#32), and likely Minnesota (#20).

 

Active Vulcanism

Continental Rift Vulcanism

• Young gas-rich basalts from California's (#4) desert and probably New Mexico's (#29) Carrizoza plain, which is only ~5,000 years old.

• Hydrothermal circulation associated with vulcanism, Connecticut's (#6) barite breccia.

 

Mantle Hot Spot Vulcanism

• Cobble of Hawaiian basalt (#50) from one of its many beaches. This magma is derived from the mantle, delivered by hotspot melting.

• Lava flow the Snake River Plain (Idaho #10), which is adjacent to world's best exposed Large Igneous Province, LIP - the Columbia River Basalts, which had 350 flows between 16.7-5.5 Ma, covering 210 k km2.

 

Mountain Building and Uplift

 

• Pike's Peak Granite (#5) - Highest peak in the Mountain State of Colorado floats high in crust as a Proterozoic basement uplift like the Adirondacks.

• Delaware's Brandywine Blue Gneiss (#7) - the Ordovician uplift of the Appalachians, then as massive and towering as the Cordillera.

• Maine's Devonian Acadian orogeny (388-414 Ma) creating Kahtadin Granite (#17).

• Quincy Granite (#19) from MA (or Milford, Chemslford) indicates Lower Devonian (390 Ma) mountain building.

• Undeformed quartz vein from NH (#27) is likely from White Mountain Magma Series, Cretaceous (180-120 Ma).

• Classic molasse of Massillon Sandstone ((#33) from Lower Pennsylvanian of Ohio contains the debris of the continental collision creating the Appalachians.

• Henderson gneiss of South Carolina (#38) is orogenic plutonic root of Ordovician age (460-450 Ma).

• Vermont, a Devonian (364 Ma) intrusion, part of the New Hampshire Plutonic Suite.

• Granodiorite from the deep railroad tunnel through the Cascade Arc.

 

Landscapes

 

Exfoliation Domes

• Stone Mountain Georgia (#9), a Carboniferous intrusion 300-350 Ma during the early in-gathering of Pangea.

• Llano uplift of central Texas underlain by Texas Pink (#41) is a bornhardt..

• Mountain top "balds" of Ceasar's Head and Table Rock in South Carolina underlain by plutonic rocks, the Henderson Gneiss (#38).

 

Salt Domes

• Salt dome uplifts in Louisiana (#16) bring Cretaceous to surface.

 

Link to Articles about Connecticut's Landscape