April 22, 2023 is the 54th World Earth Day, and the theme of this year's Earth Day is "Cherish the Earth, Harmony between Man and Nature". To further guide the whole society to establish the ecological civilization concept of "respecting nature, adapting to nature and protecting nature", promote the construction of beautiful Qianshan, and jointly build an earth home where people and nature live in harmony, Tianzhushan Global Geopark and Shuzhou Primary School of Qianshan City will jointly hold a series of thematic publicity activities for the World Earth Day 2023.
In
2019, Dr. Guo Shun, from Institute of Geology and Geophysics, Chinese Academy
of Sciences, published an article on the famous international periodical Geochimica
et Cosmochimica Acta,GCA, in which tourmaline-bearing
ultrahigh pressure eclogites were reported to be found in Hanchangchong
(Shuanghe) - Baiyangling area within Tianzhushan UGGp. This is the first case
of tourmaline-bearing eclogite to be found in the largest ultrahigh pressure
metamorphic belt in the world --- Dabieshan Ultrahigh Pressure Metamorphic
Belt, and this is also the first discovery of tourmaline-bearing eclogite exposed
in marble throughout the world.
Tourmaline,
one of the most important hosts of boron in crustal rocks, has rarely been
found in natural high-pressure and ultrahigh pressure eclogites. The first
finding of tourmaline-bearing UHP ecologites and veins in the Dabie terrane
occur exclusively in impure UHP marbles. Investigations on the
eclogite-vein-marble system provide important insights into the origin, flow,
and metasomatic effects of eclogite-facies, B-rich fluids in continental
subduction zones. Petrologic and geochemical evidence indicates that tourmaline
in the eclogites formed by metasomatism due to the infiltration of a B-rich
fluid under conditions of ca. 2.2-2.6
GPa and 610-6600 C. The HP veins, containing euhedral tourmaline and
occurring at the eclogite-marble contacts or in the interiors of eclogite
lenses, represents the crystallized products of the infiltrating fluid.
Systematic compositional variations along the profile from the interiors of the
eclogite lense to their margins and mass-balance calculations indicate large
inputs of B, carbon, large ion lithophile elements and light rare earth
elements to the eclogites during fluid infiltration. This is a newly-added rock
type of UHP metamorphic rocks found within Tianzhushan UGGp.
Tianzhushan
UGGp is an important area for the research of typical UHP metamorphic belt and
continental subduction zone of China, and many domestic and foreign scholars
have made fruitful researches. In last century, coesite and diamond were
successively found in eclogites in Bixiling area and Xindian area within
Tianzhushan UGGp, which were respectively the third case in the world and the
second case to be found in metamorphic rocks.
Numerous
ultrahigh pressure metamorphic rocks, such as coesite-bearing eclogite,
diamond-bearing eclogite, jadeite quartzite, garnet peridotite, gneiss, marble,
metamorphic granite and serpentinite, have been found in Tianzhushan UGGp,
which has become a treasure trove for the study of continental dynamics. In recent
years, in order to protect the precious geoheritage and disseminate geosciences,
Tianzhushan UGGp has held many academic symposiums and UHP field trips,
cooperated with University of Science and Technology of China and Nanjing
University, etc.
Paper
links:
https://www.sciencedirect.com/science/article/abs/pii/S0016703719301516