Research output: Contribution to journal › Review article › peer-review
Agate genesis : A continuing enigma. / Moxon, Terry; Palyanova, Galina.
In: Minerals, Vol. 10, No. 11, 953, 11.2020, p. 1-26.Research output: Contribution to journal › Review article › peer-review
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TY - JOUR
T1 - Agate genesis
T2 - A continuing enigma
AU - Moxon, Terry
AU - Palyanova, Galina
N1 - Funding Information: Funding: This research was funded by the Ministry of Science and Higher Education of the Russian Federation within the framework of the state assignment of the Sobolev Institute of Geology and Mineralogy of Siberian Branch of Russian Academy of Sciences (topic no. 0330-2016-0001). Publisher Copyright: © 2020 by the authors. Copyright: Copyright 2020 Elsevier B.V., All rights reserved.
PY - 2020/11
Y1 - 2020/11
N2 - This review covers the last 250 years of major scientific contributions on the genesis of agates found in basic igneous host rocks. From 1770 to 1955, the genesis question was frequently limited to discussions based on observations on host rock and agate thick sections. Over the next 25 years, experimental investigations examined phase transformations when silica glass and various forms of amorphous silica were heated to high temperatures. This work demonstrated that the change from the amorphous state into chalcedony was likely to be a multi-stage process. The last 40 years has seen modern scientific instrumentation play a key role in identifying the physical and chemical properties of agate. The outcome of this work has allowed limited evidence-based comment on the conditions of agate formation. There is a general consensus that agates in these basic igneous hosts form at <100◦C. However, the silica source and the nature of the initial deposit remain to be proven.
AB - This review covers the last 250 years of major scientific contributions on the genesis of agates found in basic igneous host rocks. From 1770 to 1955, the genesis question was frequently limited to discussions based on observations on host rock and agate thick sections. Over the next 25 years, experimental investigations examined phase transformations when silica glass and various forms of amorphous silica were heated to high temperatures. This work demonstrated that the change from the amorphous state into chalcedony was likely to be a multi-stage process. The last 40 years has seen modern scientific instrumentation play a key role in identifying the physical and chemical properties of agate. The outcome of this work has allowed limited evidence-based comment on the conditions of agate formation. There is a general consensus that agates in these basic igneous hosts form at <100◦C. However, the silica source and the nature of the initial deposit remain to be proven.
KW - Agate
KW - Age
KW - Chalcedony
KW - Crystallite growth
KW - Genesis
KW - Moganite
KW - XRD
KW - CRYSTALLIZATION
KW - crystallite growth
KW - SILICA POLYMORPH
KW - YUCCA MOUNTAIN
KW - SKELETON COAST
KW - moganite
KW - X-RAY-DIFFRACTION
KW - VOLCANIC-ROCKS
KW - agate
KW - genesis
KW - ORIGIN
KW - MICROCRYSTALLINE QUARTZ
KW - KAROO VOLCANICS
KW - chalcedony
KW - age
KW - OXYGEN-ISOTOPE ZONATION
UR - http://www.scopus.com/inward/record.url?scp=85094919892&partnerID=8YFLogxK
U2 - 10.3390/min10110953
DO - 10.3390/min10110953
M3 - Review article
AN - SCOPUS:85094919892
VL - 10
SP - 1
EP - 26
JO - Minerals
JF - Minerals
SN - 2075-163X
IS - 11
M1 - 953
ER -
ID: 26005862