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Learning GOAL You will analyze and interpret sedimentary rock from the edge of the Grand Canyon A Analyze the images in Fig. A6.7.1, which are from the South Rim of the Grand Canyon near Grand Canyon Village. The edge of the canyon here is formed by a fossiliferous limestone composed of sand-sized clastic grains, called the Kaibab Limestone. deposited about 270 million years ago during the Permian Period Brachiopod shells Crinoid stems related to starfish) Hom coral Figure A6.7.1 1. Notice that some of the beds in the outcrop are cross-bedded. Draw an arrow on the picture to show the direction that the water moved here to make this cross bedding Refer to Fig. 6.26 as needed. 2. Does this cross bedding indicate a steady flow of air or water, or does it indicate an oscillating (back and forth) flow? (Fig. 6.26) B REFLECT & DISCUSS Describe your ideas about what the environment might have been like here about 270 million years ago (e.g., Figs. 6.27 and 6.28) and the evidence and logic that you used to reach your conclusion. 179
Crinoid stems (related to starfish) Figure A6.7.1 Brachiopod shells Horn coral 6 9 29 stear tog of bed cross ( XXX
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