Soru

Passage:

In geophysics, paleomagnetic analysis of oceanic crustal rocks has long served as a primary tool for mapping historical magnetic field reversals and quantifying seafloor spreading rates. Traditional models assumed that basaltic magma cooling at mid-ocean ridges freezes magnetic orientation rapidly and uniformly throughout the entire vertical thickness of a lava flow. However, recent ultra-high-resolution magnetic measurements of submarine lava flows have revealed significant localized variations in remnant magnetization intensity within single cooling units.

To explain these anomalies, petrologists examined the microstructural morphology of iron-titanium oxide minerals across cross-sections of submarine pillow basalts. They discovered that near the rapidly quenched outer surfaces—the chilled margins—iron oxides precipitate as sub-microscopic, dendritic magnetite crystals. Because these dendritic crystals fall within a single magnetic domain size range, they possess an exceptionally high thermal remnant magnetization. In contrast, the interior cores of the lava flows cool more slowly, allowing larger, multi-domain magnetite grains to form, which are prone to self-demagnetization and magnetic instability over geological timescales.

This microstructural disparity demonstrates that paleomagnetic intensity records obtained from bulk basalt samples can be misleading if sampling fails to account for intra-flow cooling rates. Consequently, rather than reflecting global fluctuations in the strength of Earth’s geomagnetic field, recorded variations in magnetic intensity often merely reflect localized differences in cooling dynamics. By isolating samples specifically from chilled margins, geophysicists can derive far more reliable estimates of ancient geomagnetic field strength.

Question:
Which of the following best describes the primary function of the author's reference to "dendritic magnetite crystals" in the second paragraph?