[Rockhounds] The lost continent of Zealandia hides clues to the Ring of Fire's birth

[Kreigh Tomaszewski]

The hidden undersea continent of Zealandia underwent an upheaval at the
time of the birth of the Pacific Ring of Fire.

Zealandia is a chunk of continental crust next door to Australia. It's
almost entirely beneath the ocean, with the exception of a few protrusions,
like New Zealand and New Caledonia. But despite its undersea status,
Zealandia is not made of magnesium- and iron-rich oceanic crust. Instead,
it is composed of less-dense continental crust. The existence of this odd
geology has been known since the 1970s, but only more recently has
Zealandia been more closely explored. In 2017, geoscientists reported in
the journal *GSA Today*
<https://www.geosociety.org/gsatoday/archive/27/3/article/GSATG321A.1.htm> that
Zealandia qualifies as a continent in its own right, thanks to its
structure and its clear separation from the Australian continent.

Now, a new analysis of chunks of Zealandia drilled from beneath the ocean
floor in 2017 reveals that this continent underwent a paroxysm of change
between 35 million and 50 million years ago. As the continental collision
process known as subduction started in the western Pacific, parts of
northern Zealandia rose by as much as 1.8 miles (3 kilometers), and other
sections dropped in elevation by a similar amount. (Subduction occurs when
one tectonic plate collides with another and sinks underneath it.)

https://www.livescience.com/zealandia-tied-to-ring-of-fire.html