Tuesday, February 18, 2020

Zealandia

 In the six hundredth year of Noah's life, in the second month, the seventeenth day of the month, the same day were all the fountains of the great deep broken up, and the windows of heaven were opened. Genesis 7:11

"Zealandia has 1.9 million miles of landmass and once made up approximately 5% of the area of the supercontinent Gondwana, the ancient supercontinent that includeed Antarctica and Australia. Roughly 94% of the area of Zealandia currently is submerged.


But fossils in the drillcores collected by the IODP Expedition 371 indicate that during the early Cenozoic, portions of northern Zealandia rose 0.6-1.2 miles while other sections subsided about the same amount before the entire continent sank deep underwater.

The timing of these topographic transformations coincides with a global reorganization of tectonic plates evidenced by the bend in the Emperor-Hawaii seamount chain, the reorientation of numerous mid-ocean ridges, and the onset of subduction — and the related volcanism and seismicity — in a belt that still encircles much of the western Pacific.

Because this timing predates the global tectonic plate reorganization, scientists need to find an explanation for how subduction began across such a broad area in such a short time.

The study authors propose a new mechanism: a ‘subduction
rupture event,’ which they argue is similar to a massive, super-slow earthquake. “We don’t know where or why, but something happened that locally induced movement, and when the fault started to slip, like in an earthquake the motion rapidly spread sideways onto adjacent parts of the fault system and then around the western Pacific,” Dr. Sutherland said..... “The process has no modern analogue and because the subduction rupture event is linked to a time of rapid, global plate tectonic change, other instances of such change in the geologic record may imply that comparable events have occurred in the past,” Dr. Sutherland said."
SciNews