Stregthen1

Question

Many geologists theorize that the trail of volcanic craters and cinder cones along the Snake River plain of southern Idaho was produced as the North American Continent slid westward over a stationary "plume," a vertical channel through which molten rock rose intermittently from the Earh's core to burst through its crust.

Which of the following, if true, tends to support the geologists' theory of how the trail was produced?

A. the largest craters and cinder cones are on the eastern margin of the trail
B. the most violent volcanic activity apparently occured at the western margin of the trail
C. the craters and cinder cones are evenly spaced throughout the extent of the trail
D. the newest craters and cinder cones are on the eastern margin of the trail
E. the craters and cinder cones on the western margin of the trail generally took longer to form than did those on the eastern margin

anandnk · Answer

I will go with C here. This gives the support for formation of the trail. All others talk about volanic activity and not the consistency in the volcanic activity which is required for the formation of trail.

IF C is right then here is my explanation.

A) May be largest but does not explain why trail is formed in a line(approx). May be the sight was active with large vocanos
B) Same as A
D) This to some extent refutes the argument but you can shoot it down by saying may be the volanic activity in eastern region came into play nrecently in geological terms.
E) This cannot support the argument. No one is talking aout time here.

Makky07 · Answer

D here.

anandnk · Answer

hi ndidi04,

Can you please post your reasoning. If the land is moving towards west then new cones and volcanic bursts occur on the eastern side? I am begining to believe D is right. The only reason I chose C is that the cones and craters are not hapazardly distributed. But since all the choices talk about trail then D may be correct.

Anand.

Makky07 · Answer

Yes, my reasoning is exactly that as the continent is moving westward, the new craters and cones will form on the eastern margin.

batliwala · Answer

the trail of volcanic craters and cinder cones along the Snake River plain of southern Idaho 

Where is Snake River plain of southern Idaho located (on the eastern or western margin of trail)??

I will go for D if it on the eastern margin of trail else C.

Stregthen1

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