Arizona State Parks

Arizona State Parks---Kartchner Caverns

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 Map 1 – This map shows the geology of the Kartchner Caverns State Park area, including the area for which rezoning is proposed. The geology is from Creasey (1967). On this map the Kartchner Block is shown as a block of blue, green, and brown that extends from the Park property north into the parcel proposed for rezoning and onto State Trust Land. In addition to the rock units, it also shows some of the faults that cut the block. This representation of the Kartchner Block should be regarded as a minimum extent for the Kartchner Block. The actual boundaries of the block on the north, east, south, and southwest are covered with younger sediments (shown in yellow). The figure also shows the end of the Creasey B-B’ cross-section that extends through the Kartchner Block.

The geologic units are as follows (with explanation as to what they are)
From oldest to youngest

pCp (brown) -- Precambrian age Pinal Schist -- a metamorphic rock unit about 1.7 billion years old

pCa (pink) -- Precambrian age Alaskite -- a granite-like rock about 1.4-1.45 billion years old

pCm (orange) -- Precambrian age Monzonite -- another granite-like rock about 1.4-1.45 billion years old.

Cb (orange) -- Cambrian age Bolsa Quartzite -- a sandstone that formed as an ancient beach about 510 million years ago

Ca (pinkish) -- Cambrian age Abrigo Limestone -- a limestone that formed near the shore of an ancient ocean about 505 million years ago

Dm (purple) -- Devonian age Martin Formation -- a mix of limestone and sandstone that was formed in shallow portions of an ocean about 368 million years ago.

Me (green) -- Mississippian age Escabrosa Limestone -- a thick limestone that was formed as the floor of an open ocean between about 350 and 325 million years ago. This is the rock unit in which the cave is developed.

Phl (blue) -- Pennsylvanian age Horquilla Limestone -- a limestone that formed in shallow portions (less than 100 ft deep) of an ocean
about 310-290 million years ago.

Qt and Q (yellow) -- generally unconsolidated gravels and mudstones deposited from off the mountains or by the San Pedro River
over the last 5 million years.

q (green) -- quartz deposit (unknown age) which was mined at Ricketts Mine

The block with the Pinal, Bolsa, Abrigo, Martin, Escabrosa, and Horquilla to the east of the fault (thick black line) that runs along the west border of Kartchner Caverns State Park and the rezone one is the Kartchner Block.

Map 2 – This map also shows the geology of the Kartchner Caverns State Park area. However, the geologic interpretation is that of Reynolds (1988, as digitized by the Arizona Land Resources Information Systems). This is a much more generalized representation of the Kartchner Block, but it attempts to provide an estimate of the covered extent of the block. This estimate of the block size also shows most of the parcel proposed for rezoning on the Kartchner Block.