New technique unlocks ancient history of Earth from grains of sand


Date:
March 1, 2022
Source:
Curtin University
Summary:
Researchers have developed a new technique by studying the age of
ancient grains of sand from beaches, rivers and rocks from around
the world to reveal previously hidden details of the Earth's
distant geological past.



FULL STORY ========================================================================== Curtin researchers have developed a new technique by studying the age
of ancient grains of sand from beaches, rivers and rocks from around
the world to reveal previously hidden details of the Earth's distant
geological past.


==========================================================================
Lead researcher Dr Milo Barham, from the Timescales of Mineral Systems
Group within Curtin's School of Earth and Planetary Sciences, said the
team devised a metric, which determines the 'age distribution fingerprint'
of minerals known as zircon within sand, shedding new light on the
evolution of the Earth's surface over the last few billion years.

"While much of the original geological record is lost to erosion, durable minerals like zircon form sediments that effectively gather information
from these lost worlds to paint a vivid picture of the planet's history, including changing environments, the development of a habitable biosphere,
the evolution of continents, and the accumulation of mineral resources
at ancient plate boundaries," Dr Barham said.

"This new approach allows a greater understanding of the nature of ancient geology in order to reconstruct the arrangement and movement of tectonic
plates on Earth through time.

"The world's beaches faithfully record a detailed history of our planet's geological past, with billions of years of Earth's history imprinted
in the geology of each grain of sand and our technique helps unlock
this information." Co-author Professor Chris Kirkland, also from the Timescales of Mineral Systems Group within Curtin's School of Earth and Planetary Sciences, said the new method can be used to trace the Earth's history with greater detail than previously achievable.

"Zircons contain chemical elements that allow us to date and reconstruct
the conditions of mineral formation. Much like human population
demographics trace the evolution of countries, this technique allows
us to chart the evolution of continents by identifying the particular
age population demographics of zircon grains in a sediment," Professor
Kirkland said.

"The way the Earth recycles itself through erosion is tracked in the
pattern of ages of zircon grains in different geological settings. For
example, the sediment on the west and east coasts of South America are completely different because there are many young grains on the west side
that were created from crust plunging beneath the continent, driving earthquakes and volcanoes in the Andes. Whereas, on the east coast,
all is relatively calm geologically and there is a mix of old and young
grains picked up from a diversity of rocks across the Amazon basin."
Dr Barham and Professor Kirkland are affiliated with The Institute for Geoscience Research (TIGeR), Curtin's flagship Earth Sciences research institute and the research was funded by the Minerals Research Institute
of Western Australia.

========================================================================== Story Source: Materials provided by Curtin_University. Original written
by Lucien Wilkinson.

Note: Content may be edited for style and length.


========================================================================== Journal Reference:
1. M. Barham, C.L. Kirkland, A.D. Handoko. Understanding ancient
tectonic
settings through detrital zircon analysis. Earth and Planetary
Science Letters, 2022; 583: 117425 DOI: 10.1016/j.epsl.2022.117425 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/03/220301131155.htm

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