Geology Reference
In-Depth Information
Figure 7.17. Examples of intra-plate volcanism in the Pacific that has more com-
plex morphology and age relationships than a classic hotspot track like Hawaii.
The Mid-Pacific Mountains do not form a linear array, and show two zones of
splayed ridges. They were erupted at 120-90 Ma ago. The Line Islands show at
least two separate volcanic episodes at 68-73 Ma and 81-86 Ma, and the Tuamotus
show irregularities and splayed ridges. From Natland and Winterer [79]. Copyright
by the Geological Society of America.
They link Easter to the eastern Mid-Pacific Mountains, Louisville to the Ontong-
Java Plateau, and, with less confidence, marquesas to Hess Rise and Shatsky
Ridge. In addition, the Hawaii hotspot track is interrupted by the Kamchatka sub-
duction zone, and a remnant obducted flood basalt may exist there. Several are
indeterminate. Seven do not connect with any obvious ocean plateau, giving rise
to the term 'headless plume'.
