M. Santosh talks with
ScienceWatch.com and answers a few questions about
this month's Fast Breaking Paper in the field of
Geosciences. The author has also sent along images of
Article Title: Discovery of sapphirine-bearing
Mg-Al granulites in the North China Craton: Implications
for paleoproterozoic ultrahigh temperature
M;Tsunogae, T;Li, JH;Liu, SJ
Journal: GONDWANA RES
Year: APR 2007
* Kochi Univ, Fac Sci, Dept Nat Environm Sci, Akebono Cho
2-5-1, Kochi 7808520, Japan.
(addresses have been truncated)
Why do you think your paper is highly
Possibly because it presents a new discovery in a thrust area field study
of global interest. This is the first time that rocks metamorphosed at
extreme temperatures of around 1,000 degrees Celsius in the Earth's crust,
and, characterized by certain diagnostic mineral assemblages, are being
reported from the North China Craton. The paper has wider implications
within the plate tectonic framework in understanding the evolution of the
Would you summarize the significance of your paper in
The North China Craton, from where the new discovery is reported in this
paper, is a part of the fundamental Precambrian nucleus of Asia and is also
a fragment of a supercontinent (large continental mass) termed "Columbia"
that existed around two billion years ago on the surface of the globe. The
time of the formation of Columbia marks several important changes in the
Earth's history and include the surface environment, as well the evolution
of primitive life.
This paper presents the discovery of a special type of high-grade
metamorphic rocks from the northern margin of the North China Craton,
within the Inner Mongolia region, carrying mineral assemblages diagnostic
of formation under extreme thermal conditions associated with the
collisional amalgamation of the North China Craton within the Columbia
supercontinent. The results have important implications for the tectonics
of the North China Craton, the history of the evolution of continents
within the Precambrian nucleus of Asia, as well as in understanding the
history of the two-billion-year-old supercontinent Columbia.
How did you become involved in this research, and were
there any problems along the way?
I was invited to participate in a symposium held in Beijing a few years
ago, when I had an opportunity to collaborate with my counterparts in China
and, during the course of routine studies related to my fields of
specialty, I came across these spectacular rocks which had not been
reported before from this region of the world.
I had previous experience studying similar rocks from much younger terranes
belonging to the 550-million-year-old "Gondwana" supercontinent and
recognized the importance of the discovery from the North China Craton in
tracing the much older geological history of the Earth. We obtained quite
interesting analytical results and decided to publish these findings in
Gondwana Research, which is the flagship journal for research
related to the evolution of continents and supercontinents.
Where do you see your research leading in the
We consider this discovery to be just the tip of the iceberg. There is much
more to be discovered, and if similar findings can be revealed all along
the northern margin of the North China Craton, as well as in other crustal
fragments attached to the supercontinent Columbia, it would lead to
interesting models on the assembly of supercontinents in the past, and
would also revolutionize the existing concepts and models on the tectonic
history of the North China Craton.
Eventually, these would contribute to the growing interest on the dynamics
of the solid Earth with regard to plate, plume, and anti-plate tectonics in
increasing our understanding of global material circulation on a
whole-Earth scale in relation to processes from the mantle to the surface
of the Earth, including the environment.
Do you foresee any social or political implications for
This finding has already triggered considerable enthusiasm and interest
throughout the global community, and has also paved the way for the
initiation of several new research projects in China in related fields. We
hope that this would generate better facilities, enhanced research levels,
and the increased participation of student communities and researchers,
increasing research and job opportunities, wider international
collaborations, all ultimately contributing to the enhancement of knowledge
for the benefit of human society.
M. Santosh, Ph.D., D.Sc.
Department of Natural Environmental Science
Faculty of Science
Keywords: north china craton, diagnostic mineral assemblages,
plate tectonic framework, precambrian nucleus of asia,
two-billion-year-old supercontinent columbia, high-grade metamorphic
rocks, inner mongolia region, mineral assemblages