Over the past million years, Earth's globally averaged surface temperature has risen and fallen by about 5˚C in ice-age cycles, roughly every 100,000 years or so (Figure 2.1a).
I think B is the correct answer sorry if I’m wrong
Answer:
Explanation:
Banded iron formation ( BIF ) -
It is aslo called the banded inronstone formations , are the part of the distinctive units in the sedimentary rocks , which are always of the precambrian age .
volcanogenic massive sulfides ( VMS )-
A type of metal sulfide ore deposit , which have copper - zinc as the main elements , they are formed by in the submarine environments by the volcanic - associated hydrothermal events .
The types of VMS -
Mafic associated - The type of deposits associated with geological environments by mafic rocks.
Bimodal-mafic - The type deposits associated with environments dominated by mafic volcanic rocks.
Mafic-siliciclastic - The type deposits associated with sub - equal proportions of the siliciclastic and the mafia rocks .
Felsic-siliciclastic - The type deposits associated with less than 10 % mafic rock and rest siliciclastic sedimentary rock .
Bimodal-felsic The type deposits associated with more of felsic rocks than mafic rocks.
