1.Which is the correct age progression, from younger (first) to older(last)?A) D, E, F, B, CB) B, F, E, D, CC) C, D, E, F, BD) B, C, D, E, FE) E, F, B, C, DFeedback: The package of sediments C, D, E, F is upside-down, as shown by the footprints and mud cracks, so C is oldest, and F the youngest of these. B is above the unconformity above all of C,D, E, and F, so is the youngest of these five.Table for Individual Question FeedbackPoints Earned:0.0/1.0Correct Answer(s):B2.Which is the youngest fault:Table for Individual Question FeedbackPoints Earned:1.0/1.0Correct Answer(s):A3.Which is older:
Table for Individual Question FeedbackPoints Earned:0.0/1.0Correct Answer(s):A4.Which is younger:Table for Individual Question FeedbackPoints Earned:1.0/1.0Correct Answer(s):E5.Which is accurate about the Grand Canyon, in Arizona:A) The Coconino Sandstone that forms one of the prominent cliffs
of the canyon is the youngest rock layer known from Arizona and surrounding states.B) The rock record of the canyon contains no unconformities.C) The canyon is wider at the top and narrower at the bottom because the river was wider when the region was wetter, and hasnarrowed as deserts spread recently.D) A great thickness of sedimentary rocks exists in Death-Valley-type faulted basins, which can be seen deep in the canyon in many places.E) The oldest rocks are on top, with younger ones beneath, as shown by all of the footprints being upside-down in the rocks of the canyon walls.Feedback: Well over two miles of Precambrian sedimentary rocks can be seen in the deep part of the canyon, all slanted fromhorizontal and preserved where they were dropped by faulting. The sedimentary rocks above are right-side up, and the Coconino Sandstone is well below the Kaibab Limestone of the rim, which slants down to the north beneath the rocks of Zion, which are older than the rocks of Bryce, among others. Many unconformities exist in the walls of the Canyon, including the one below the Precambrian sediments and the one above those sediments. The idea of the river narrowing over time was the hypothesis that an interested tourist presented to one of the professors and a ranger at the Canyon a few years ago. When theprofessor asked whether the tourist would want to go out on a narrow point with a jackhammer, the tourist said no, because the rocks might fall off and slide down into the Canyon. When the professor pointed out the many places that rocks had fallen off and slid down, the quick-witted tourist figured out that the Canyon has been widened by such rockfalls as the river has cut downward.
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