Yesterday 11:06 PM
Earth’s geological record is missing hundreds of millions of years. UOW scientists think they know why
https://www.uow.edu.au/media/2026/earths...ow-why.php
INTRO: Research led by a University of Wollongong (UOW) PhD candidate may have solved one of Earth’s most perplexing geological mysteries – what caused the Great Unconformity?
Published in Nature, the study argues the gentle rise and fall of whole continents over hundreds of millions of years, caused by hot currents deep below the Earth’s crust, led to the confounding disappearance of huge swathes of Earth’s geological record.
PhD candidate and lead author Santosh Dhungana said the Great Unconformity had long puzzled scientists but theories about the geological gap had not been thoroughly tested.
“Imagine a book where a huge section in the middle has been ripped out. The Great Unconformity is that gap in Earth’s story, with the narrative jumping from the early chapters straight to a much later part of the story. Our research suggests these pages weren’t lost by chance,” he said.
Layers of rock usually stack up in chronological order, with oldest at the bottom and youngest at the top. But in locations throughout the world, sedimentary rocks of the Cambrian period, from around 540 million years old, sit directly on top of much older crystalline rocks such as granite, which can be more than a billion years old. The gap between the two periods is the Great Unconformity.
One of the most striking examples of the Great Unconformity is found in the Grand Canyon in the United States, once part of the ancient continent known as Laurentia (modern North America). Evidence of the geological gap has also been found in Europe, Australia, Africa and Asia. Depending on the location, the missing record stretches from 200 million years to well over a billion.
By modelling patterns of mantle convection over hundreds of millions of years, Mr Dhungana and co-author and supervisor Associate Professor Nicolas Flament were able to piece together the puzzle of the Earth’s history and geological formation... (MORE - no ads)
https://www.uow.edu.au/media/2026/earths...ow-why.php
INTRO: Research led by a University of Wollongong (UOW) PhD candidate may have solved one of Earth’s most perplexing geological mysteries – what caused the Great Unconformity?
Published in Nature, the study argues the gentle rise and fall of whole continents over hundreds of millions of years, caused by hot currents deep below the Earth’s crust, led to the confounding disappearance of huge swathes of Earth’s geological record.
PhD candidate and lead author Santosh Dhungana said the Great Unconformity had long puzzled scientists but theories about the geological gap had not been thoroughly tested.
“Imagine a book where a huge section in the middle has been ripped out. The Great Unconformity is that gap in Earth’s story, with the narrative jumping from the early chapters straight to a much later part of the story. Our research suggests these pages weren’t lost by chance,” he said.
Layers of rock usually stack up in chronological order, with oldest at the bottom and youngest at the top. But in locations throughout the world, sedimentary rocks of the Cambrian period, from around 540 million years old, sit directly on top of much older crystalline rocks such as granite, which can be more than a billion years old. The gap between the two periods is the Great Unconformity.
One of the most striking examples of the Great Unconformity is found in the Grand Canyon in the United States, once part of the ancient continent known as Laurentia (modern North America). Evidence of the geological gap has also been found in Europe, Australia, Africa and Asia. Depending on the location, the missing record stretches from 200 million years to well over a billion.
By modelling patterns of mantle convection over hundreds of millions of years, Mr Dhungana and co-author and supervisor Associate Professor Nicolas Flament were able to piece together the puzzle of the Earth’s history and geological formation... (MORE - no ads)