plz help me with my earth science? part 2?

Question

1. The Earth's magnetic record is recorded in minerals that align themselves with the Earth's __________ __________(two words).

2. what is Normal polarity and reverse polarity?

3. Is the San Andreas fault a transform boundary?

4. The theory of seafloor spreading is supported by what kind of evidence?

Plz answer which ever one you can and put the number next to it. thx

Answer 1

1. The Earth's magnetic record is recorded in minerals that align themselves with the Earth's __________ __________(two words).
I want to say (Magnetic Field) http://www.msu.edu/~tuckeys1/highschool/earth_science/magnetic_reversals.pdf based on this site it is (read 1st paragraph to make sure if you like)

2. what is Normal polarity and reverse polarity?
Standard polarity establishment and horizon identification are two essentials in meticulous seismic data interpretation or oil geophysical prospecting. every so often the Earth's magnetic poles reverse.

3. Is the San Andreas fault a transform boundary?
Transform fault boundary

4. The theory of seafloor spreading is supported by what kind of evidence?
mainly age of the youngest crust is near faultline and older crust is pushed away from the faultline by new crust (formerly magma)

Answer 2

1. magnetic field

2. I find this question somewhat ambiguous, but my guess is that "normal" polarity is the magnetic polarity our earth exhibits now. It flips every now and again (with many thousands of years in between, according to that geologic record referred to in the first question). So I would assume that "reverse" polarity, in earth science terms, refers to anytime in the past (or future) that the earth's magnetic field is opposite to the field it exhibits now.

3. I forget the proper terms, but my guess is yes. The San Andreas fault is an example of two land masses sliding in opposite directions from each other. The western side is slowly sliding further north of the eastern side. I can't remember the right terms for the other kinds of rifts - two plates moving into each other (which inevitably means one sliding under the other) (and I'm pretty sure the prefix "sub" is involved), or two plates moving away from each other (like the seafloor spreading rifts mentioned in the fourth question), but I'm pretty sure neither of those other two types of rifts are called "transform" boundaries. So by my own process of elimination, the San Andreas fault is a transform boundary.

4. Well, to begin with, there are huge volcanic rifts splitting the earth under the oceans all over the world, constantly spitting up new land, including Islands like Hawaii. But the most noticeable signs are all the mountain ranges formed by the expanding crust pushing into (under and over) existing land.

Answer 3

No one has definitively answered question #3, yet.
Here is the most straight-forward answer:

The San Andreas fault of southern California is a large transform fault connecting the East Pacific Rise off the coast of California with a segment of the ridge in the Gulf of California.

Answer 4

You shouldnt have people on yahoo answers do your homework for you. I'm guessing these are all in your book so instead of surfing the internet waiting for people to do your homework, try to actually find the information yourself? I mean seriously you are asking people not to guess so at least make an effort

Answer 5

You can get your answer from a weblog and the members.
they are geology students in BS , MS and Phd levels and aware of most of questions.

Answer 6

1. magnetic field
3. no
4. drilling samples from the ocean floor, magnetic stripes, and molten rock