In addition to providing polarity data, like those you interpreted in Part B, most terrestrial lava flows contain minerals that can be precisely dated using radiometric age-dating techniques. The combination of these two types of data from a large number of lava flows enables the creation of a polarity timescale, where intervals of normal and reverse polarity can be assigned numerical age ranges. These terrestrial timescales can be applied to oceanic rocks, where magnetic polarity readings can be taken rather cheaply using shipboard equipment (magnetometers), but obtaining samples for radiometric dating is far more difficult.

As a North American paleomagneticist, you have been tasked with assigning ages to oceanic rocks around the Juan de Fuca ridge based on the shipboard magnetometer readings of seafloor polarity and a magnetic polarity timescale below.

Use values from the magnetic polarity timescale to assign ages to the oceanic rocks surrounding the Juan de Fuca Ridge. The position of the active ridge is indicated with a thick red line.

Who was put in the concentration camps? and why

“dear sir: it is with great reluctance, i trouble you on a subject, which does not fall within your province; but it is a subject that occasions me more distress, than i have felt, since the commencement of the war; and which loudly demands the most zealous exertions of every person of weight and authority, who is interested in the success of our affairs. i mean the present dreadful situation of the army for want of provisions, and the miserable prospects before us, with respect to futurity. it is more alarming than you will probably conceive, for, to form a just idea, it were necessary to be on the spot. for some days past, there has been little less, than a famine in camp. a part of the army has been a week, without any kind of flesh, and the rest for three or four days. naked and starving as they are, we cannot enough admire the incomparable patience and fidelity of the soldiery, that they have not been ere this excited by their sufferings, to a general mutiny or dispersion. strong symptoms, however, discontent have appeared in particular instances; and nothing but the most acitive efforts every where can long avert so shocking a catastrophe.” what’s the central idea?

Which of the following events most directly contributed to the establishment of israel as a nation