S P Crater is a cinder cone

Cinder cone

According to the , Cinder Cone is the proper name of 1 cinder cone in Canada and 7 cinder cones in the United States:In Canada: Cinder Cone In the United States:...

 volcano

Volcano

2. Bedrock3. Conduit 4. Base5. Sill6. Dike7. Layers of ash emitted by the volcano8. Flank| 9. Layers of lava emitted by the volcano10. Throat11. Parasitic cone12. Lava flow13. Vent14. Crater15...

 in the San Francisco volcanic field

San Francisco volcanic field

The San Francisco volcanic field is an area of volcanoes in northern Arizona, north of Flagstaff, USA. The field covers 1,800 square miles of the southern boundary of the Colorado Plateau. The field contains 600 volcanoes ranging in age from less than 6 million years old to less than 1,000 years ,...

, 25 miles (40 km) north of Flagstaff, Arizona

Flagstaff, Arizona

Flagstaff is a city located in northern Arizona, in the southwestern United States. In 2010, the city's population was 65,870. The population of the Metropolitan Statistical Area was at 134,421 in 2010. It is the county seat of Coconino County...

. It is surrounded by several other cinder cones which are older and more eroded. It is a striking feature on the local landscape, with a well-defined lava flow that extends for 7 kilometres (4.3 mi) to the north.

Name

The naming of the mountain is a bit of lore from the Old West. S P Crater can be climbed, and the lava flow can be viewed from the crater rim. C. J. Babbit, an 1880s rancher and early landowner of the mountain, expressed his opinion that the mountain resembled a pot of excrement (Shit Pot), and this became the accepted local name. When viewed from certain angles on the ground, the combination of the smooth round shape of the cone, the dark lava spatter on the rim, and the long dark lava flow extruding from the base do indeed resemble a toilet catastrophe. Mapmakers refused to spell out the full name, and the mountain has been shown on maps and other literature with the abbreviated name.

Geology

S P Crater is a 820 foot high cinder cone of basaltic andesite

Andesite

Andesite is an extrusive igneous, volcanic rock, of intermediate composition, with aphanitic to porphyritic texture. In a general sense, it is the intermediate type between basalt and dacite. The mineral assemblage is typically dominated by plagioclase plus pyroxene and/or hornblende. Magnetite,...

. The cone is capped by an agglutinate rim that helps to protect its structure. A lava flow extends to the north of the cone for ~7 km and originated from the same vent. Some workers consider the lava flow to have slightly predated the cinder cone because of geochemical data that suggests the flow is more silica rich than the cinders and based on the observation that the cone overlaps the lava flow and shows no sign of deformation. However, there is some debate about the relationship between the cone and flow as it is not uncommon to form cinder cones during the early phase of an eruption as a magma degasses, and then to have lava push through the side of a cone during a late phase of eruption.

K/Ar dates on the lava are ~ 70 ka, but are considered unreliable because of excess Ar and the un-weathered young appearance of the cone.

External links

• S P Crater at VolcanoWorld, photo gallery
• S P Crater at geology.com, maps and imagery