generis wrote:
At several locations on the northwest coast of North America are formations known as chevrons—wedge-shaped formations of mounded sediment—pointing toward the ocean. Most geologists take them to have been formed by erosion, but recently other scientists have proposed that they were thrown up from the ocean by massive waves triggered by meteor impacts in the Pacific Ocean.
Which of the following, if discovered, would most help in deciding which hypothesis is correct?
A) Chevron-like structures which are not currently near glaciers, large rivers, or other bodies of water
B) The presence, in chevrons, of deposits of ocean microfossils containing metals typically formed by meteor impacts
C) Oral-history evidence for flooding that could have been caused by ocean waves
D) The fact that exact data about the location and depth of any meteor impact craters on the Pacific seabed is lacking
E) The fact that certain changes in the shape and location of maritime sand dunes have been produced by the action of wind and waves
CR59590.02
Phenomenon - Wedge shaped structures on the coast.
Hypothesis 1 - Erosion formed these (perhaps the impact of the waves on rocks)
Hypothesis 2 - Thrown up from oceans by meteor impact
The presence of what will help in deciding which hypothesis is correct (strong support for one and weaken the other)
A) Chevron-like structures which are not currently near glaciers, large rivers, or other bodies of water
If we find similar structures away from water bodies, it doesn't support either hypothesis. Both hypotheses are based on impact of water or water bodies. Since such structures would have been found far from water bodies, they would support neither hypothesis.
Since hypothesis 1 doesn't specifically say 'erosion by water,' we could imagine erosion being wind erosion but then "wedge-shaped formations of mounded sediment—pointing toward the ocean" doesn't make sense. It ought to have something to do with ocean. So not convincing at all.
B) The presence, in chevrons, of deposits of ocean microfossils containing metals typically formed by meteor impacts
Chevrons have ocean microfossils (so likely they came out of the ocean) and they contain metals formed by meteor impact then it seems that meteor impact caused them to come out of the ocean. This strongly supports hypothesis 2 and also weaken hypothesis 1. If they were rocks on the coast and were formed by erosion by waves, how would they contain ocean microfossils? Hence, it helps us in deciding which hypothesis is correct.
C) Oral-history evidence for flooding that could have been caused by ocean waves
The moment we read 'oral history,' this option should be frowned upon. Oral history is narrated history by a person as per his/her impressions. This becomes more like 'opinion' than a 'fact.' So will it provide evidence? I am already doubtful.
D) The fact that exact data about the location and depth of any meteor impact craters on the Pacific seabed is lacking
A lack of data is not evidence. Perhaps it is there but has not been found yet. Perhaps there is none but it actually did happen.
E) The fact that certain changes in the shape and location of maritime sand dunes have been produced by the action of wind and waves
No comparison is given between chevrons and sand dunes. We don't know whether they are similar in any way so any data about sand dunes doesn't help us.
Answer (B)