Meteor Crater AZ, Access Road

0.0  Bridge Over Interstate Highway 40. Head south past the tourist facilities to Meteor Crater, which can be seen on the horizon to the southeast (fig. 4B.1). The access road near the tourist facilities is on Moenkopi beds and continues in the same beds as we climb slightly toward the south.

1.6  Outcrops of the basal Moenkopi Sandstone which here probably represents a bar or beach sequence as the Kaibab Sea dried up and the area was buried by tidal flats deposits of the Moenkopi Formation.

3.1  Cattle Guard, the road is still in the basal sandstone of the Moenkopi Formation.

3.8  Light-colored beach-type sandstone of the lower part of the Moenkopi sequence overlain by brick red siltstone and sandstone.

4.8  Road intersection. Continue on the paved road towards the crater.

5.4  The road now curves and starts to climb up over the very coarse debris of the crater margins toward the tourist facilities. Fragments of Coconino Sandstone and Kaibab Limestone here litter the surface around the explosive margin of the crater (fig. 4B.2).

5.9  The lower parking area for oversized vehicles. The road climbs to the brick enclosed patio of the upper parking area.

6.0  Parking Area at Meteor Crater. There is a fee to enter into the protected area where the canyon can be seen.

Meteor Crater is an unusual depression in the Colorado Plateau. The crater is broadly circular and bowl-shaped, approximately 600 feet deep and over 4,000 feet in diameter. It is surrounded by a ridge or rim that rises 100 to 200 feet above the stripped plateau surface. This elevated rim is composed, in large part, of debris ejected from the crater as the meteorite impacted. Faulted and broken Toroweap, Kaibab, and Moenkopi beds are exposed around the periphery of the crater (fig. 4B.3) but the upper part of the rim is made of angular fragments ranging from almost dust-size particles up to blocks nearly 100 feet across.

Debris on the rim is inverted from the normal stratigraphic section, that is the normal sequence, from the bottom up, inside the crater is Toroweap, Kaibab, and Moenkopi formations. The debris on the rim, splashed out by the meteorite impact, on the other hand, starts at the base with fragments of Moenkopi Formation which are overlain by debris of the Kaibab and Toroweap formation with some rocks as old as Coconino Sandstone. Thus, the bed rock stratigraphy in the canyon is preserved inverted in the debris rim just as would be expected if the

Figure 4B.1.General panoramic view of the Meteor Crater area, as seen from Mile 4.8 along the access road. The exhibit area, museum, and visitors center are in the low pass to the right of the center. Rocks in the foreground are in the lower part of the Moenkopi Formation.

Figure 4B.3.Aerial photograph of Meteor Crater, looking toward the northwest. The visitors center is on the rim, beyond the crater, on the right. Light-colored debris around the rim is from the Coconino and Kaibab formations which were blown out of the crater as the meteorite impacted (photography by W. K. Hamblin).

Figure 4B.2.Angular blocks of light-colored Kaibab Limestone and Coconino Sandstone which litter the flanks of Meteor Crater and offer evidence of the explosive origin of the hole.

  meteorite impact splashed the youngest rocks out of its way first and succeedingly older rocks as it plunged farther into the crust.

  The floor of the crater is blanketed by Quarternary material, lake beds, and landslide and slump debris from the margins of the depression. These relatively young rocks and sediments rest on a layer of fragmental material in the lower part of the crater.

  In the early 1900s some exploration for the iron-nickel meteorite took place in the crater

  and in the immediate vicinity but nothing of any major commercial significance ever became of the operation. Extensive small fragments of meteorite material have been found around the rim and in the shafts dug in the bottom of the crater. Fine-grained meteorite material estimated at about 12,000 tons, is scattered through the Quarternary alluvium and colluvium of the rim and surrounding flats.

  End of I-40 Road Guide..

Figure 4B.4.View down into Meteor Crater (Canyon Diablo) from the north rim, at the visitors center. Light-colored deposits in the base of the depression are lake silt and debris dumped from a shaft dug to explore the iron possibilities of the crater. T, Toroweap Formation; K, Kaibab Limestone; M, Moenkopi Formation.

from J. Keith Rigby, by Field Guide: Northern/Southern Colorado Plateau, Kendall/Hunt Pub. Co., 1976, 207 pages -Purchase Information
used by author's permission