Multiple foliations defined by different sillimanite crystal habits, partial melting and the late metamorphic development of the Cannington Ag-Pb-Zn deposit, northeast Australia

Hyeong-Soo Kim, Tim H. Bell

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

A succession of foliations defined by different sillimanite-bearing structural fabrics suggests that the macroscopic, isoclinal synform that dominates the geometry of the Cannington Ag-Pb-Zn deposit, northwest Queensland, Australia formed during D2. The five foliations in this succession, S1, to S5, are defined by aligned sillimanite with habits ranging from individual crystals in S1, through S4, to clusters of fibrolite in S5, in both the matrix and as inclusion trails within garnet and galmite (Zn-rich spinel) porphyroblasts. S1, S3, and S5, formed as sub-horizontal foliations, whereas S1a, S2 and S4 formed sub-vertically Foliation intersection/inflexion axes (FIAs) within garnet and gahnite porphyroblasts preserve a succession of trends that shifts from W-E to N-S. This succession indicates that this region experienced N-S followed by W-E bulk crustal shortening. N-S shortening occurred during D1, and D1a, and W-E shortening occurred from D2 to D5. Prismatic and rhombic sillimanite produced during D1-D4 accompanied prograde metamorphism to ca. 634±62°C and 4.8±1.3 kbar. The coexistence of fibrous, prismatic and rhombic sillimanite resulted from post peak metamorphic reactivation of the early foliations during D5. The synformal D2 fold was intensified during D4 by W-E bulk shortening. Local partial melting occurred after D1, in the appropriate bulk rock compositions, based on calculation of P-T pseudosections in the chemical systems KFMASH, KFMASHTO, NCKFMASH and MnNCKFMASH. Zn mineralization related to gahnite growth occurred during D3 through D4, and was redistributed by partial melting into structural and rheological sites during D4 and D5 shearing.

Original languageEnglish
Pages (from-to)493-509
Number of pages17
JournalGondwana Research
Volume8
Issue number4
DOIs
Publication statusPublished - 2005 Jan 1
Externally publishedYes

Fingerprint

sillimanite
foliation
partial melting
crystal
gahnite
porphyroblast
garnet
synform
prograde metamorphism
crustal shortening
reactivation
spinel
coexistence
mineralization
fold
geometry
matrix
rock

Keywords

  • Foliation intersection/inflexion axes
  • Gahnite
  • Partial melting
  • Sillimanite
  • Zn mineralisation

ASJC Scopus subject areas

  • Geology

Cite this

@article{a05964b71c1e4c24913b31e58edfb78a,
title = "Multiple foliations defined by different sillimanite crystal habits, partial melting and the late metamorphic development of the Cannington Ag-Pb-Zn deposit, northeast Australia",
abstract = "A succession of foliations defined by different sillimanite-bearing structural fabrics suggests that the macroscopic, isoclinal synform that dominates the geometry of the Cannington Ag-Pb-Zn deposit, northwest Queensland, Australia formed during D2. The five foliations in this succession, S1, to S5, are defined by aligned sillimanite with habits ranging from individual crystals in S1, through S4, to clusters of fibrolite in S5, in both the matrix and as inclusion trails within garnet and galmite (Zn-rich spinel) porphyroblasts. S1, S3, and S5, formed as sub-horizontal foliations, whereas S1a, S2 and S4 formed sub-vertically Foliation intersection/inflexion axes (FIAs) within garnet and gahnite porphyroblasts preserve a succession of trends that shifts from W-E to N-S. This succession indicates that this region experienced N-S followed by W-E bulk crustal shortening. N-S shortening occurred during D1, and D1a, and W-E shortening occurred from D2 to D5. Prismatic and rhombic sillimanite produced during D1-D4 accompanied prograde metamorphism to ca. 634±62°C and 4.8±1.3 kbar. The coexistence of fibrous, prismatic and rhombic sillimanite resulted from post peak metamorphic reactivation of the early foliations during D5. The synformal D2 fold was intensified during D4 by W-E bulk shortening. Local partial melting occurred after D1, in the appropriate bulk rock compositions, based on calculation of P-T pseudosections in the chemical systems KFMASH, KFMASHTO, NCKFMASH and MnNCKFMASH. Zn mineralization related to gahnite growth occurred during D3 through D4, and was redistributed by partial melting into structural and rheological sites during D4 and D5 shearing.",
keywords = "Foliation intersection/inflexion axes, Gahnite, Partial melting, Sillimanite, Zn mineralisation",
author = "Hyeong-Soo Kim and Bell, {Tim H.}",
year = "2005",
month = "1",
day = "1",
doi = "10.1016/S1342-937X(05)71151-5",
language = "English",
volume = "8",
pages = "493--509",
journal = "Gondwana Research",
issn = "1342-937X",
publisher = "Elsevier Inc.",
number = "4",

}

TY - JOUR

T1 - Multiple foliations defined by different sillimanite crystal habits, partial melting and the late metamorphic development of the Cannington Ag-Pb-Zn deposit, northeast Australia

AU - Kim, Hyeong-Soo

AU - Bell, Tim H.

PY - 2005/1/1

Y1 - 2005/1/1

N2 - A succession of foliations defined by different sillimanite-bearing structural fabrics suggests that the macroscopic, isoclinal synform that dominates the geometry of the Cannington Ag-Pb-Zn deposit, northwest Queensland, Australia formed during D2. The five foliations in this succession, S1, to S5, are defined by aligned sillimanite with habits ranging from individual crystals in S1, through S4, to clusters of fibrolite in S5, in both the matrix and as inclusion trails within garnet and galmite (Zn-rich spinel) porphyroblasts. S1, S3, and S5, formed as sub-horizontal foliations, whereas S1a, S2 and S4 formed sub-vertically Foliation intersection/inflexion axes (FIAs) within garnet and gahnite porphyroblasts preserve a succession of trends that shifts from W-E to N-S. This succession indicates that this region experienced N-S followed by W-E bulk crustal shortening. N-S shortening occurred during D1, and D1a, and W-E shortening occurred from D2 to D5. Prismatic and rhombic sillimanite produced during D1-D4 accompanied prograde metamorphism to ca. 634±62°C and 4.8±1.3 kbar. The coexistence of fibrous, prismatic and rhombic sillimanite resulted from post peak metamorphic reactivation of the early foliations during D5. The synformal D2 fold was intensified during D4 by W-E bulk shortening. Local partial melting occurred after D1, in the appropriate bulk rock compositions, based on calculation of P-T pseudosections in the chemical systems KFMASH, KFMASHTO, NCKFMASH and MnNCKFMASH. Zn mineralization related to gahnite growth occurred during D3 through D4, and was redistributed by partial melting into structural and rheological sites during D4 and D5 shearing.

AB - A succession of foliations defined by different sillimanite-bearing structural fabrics suggests that the macroscopic, isoclinal synform that dominates the geometry of the Cannington Ag-Pb-Zn deposit, northwest Queensland, Australia formed during D2. The five foliations in this succession, S1, to S5, are defined by aligned sillimanite with habits ranging from individual crystals in S1, through S4, to clusters of fibrolite in S5, in both the matrix and as inclusion trails within garnet and galmite (Zn-rich spinel) porphyroblasts. S1, S3, and S5, formed as sub-horizontal foliations, whereas S1a, S2 and S4 formed sub-vertically Foliation intersection/inflexion axes (FIAs) within garnet and gahnite porphyroblasts preserve a succession of trends that shifts from W-E to N-S. This succession indicates that this region experienced N-S followed by W-E bulk crustal shortening. N-S shortening occurred during D1, and D1a, and W-E shortening occurred from D2 to D5. Prismatic and rhombic sillimanite produced during D1-D4 accompanied prograde metamorphism to ca. 634±62°C and 4.8±1.3 kbar. The coexistence of fibrous, prismatic and rhombic sillimanite resulted from post peak metamorphic reactivation of the early foliations during D5. The synformal D2 fold was intensified during D4 by W-E bulk shortening. Local partial melting occurred after D1, in the appropriate bulk rock compositions, based on calculation of P-T pseudosections in the chemical systems KFMASH, KFMASHTO, NCKFMASH and MnNCKFMASH. Zn mineralization related to gahnite growth occurred during D3 through D4, and was redistributed by partial melting into structural and rheological sites during D4 and D5 shearing.

KW - Foliation intersection/inflexion axes

KW - Gahnite

KW - Partial melting

KW - Sillimanite

KW - Zn mineralisation

UR - http://www.scopus.com/inward/record.url?scp=27644476732&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=27644476732&partnerID=8YFLogxK

U2 - 10.1016/S1342-937X(05)71151-5

DO - 10.1016/S1342-937X(05)71151-5

M3 - Article

AN - SCOPUS:27644476732

VL - 8

SP - 493

EP - 509

JO - Gondwana Research

JF - Gondwana Research

SN - 1342-937X

IS - 4

ER -