This file is part of the following reference:

Quentin de Gromard, R. (2011) The Paleozoic tectono-metamorphic evolution of the Charters Towers Province,

North Queensland, Australia. PhD thesis, James Cook University.

Access to this file is available from:

http://eprints.jcu.edu.au/22000

The author has certified to JCU that they have made a reasonable effort to gain permission and acknowledge the owner of any third party copyright material

included in this document. If you believe that this is not the case, please contact ResearchOnline@jcu.edu.au and quote http://eprints.jcu.edu.au/22000

ResearchOnline@JCU

Section A R. Quentin de Gromard

- SECTION A -

TEXTURAL DEVELOPMENT OF MICA RICH PSEUDOMORPHS AFTER

CORDIERITE

BHB

CMB

44 30' 7015

'

7000

'

7030

'

7045

'

45 00'

N

377

377

370389

453

404

408

408

361

404

404

404

370

Bronson Hill belt (BHB)

Central Maine Belt (CMB)

Migmatite domain

Leucogranite - biotite granite - granodiorite

Monzodiorite

Diorite to gabbro

Cordierite rocksPluton ages

Sugar loaf pluton

Redington pluton

Philips pluton

Eastern

AFZ

Central AFZ

CMB rocks

Adamstown pluton

Mooselookmeguntic

igneous

complex

Western

AFZ

BHB rocks

10 Km

tecton

ite

zone

New

Ham

pshireM

aine

Flagsta

ff lake ig

neous complex Lexington com

posite pluton

AFZ Zone of apparent flattening strain (zones of apparent constrictional strain between)

100 km

N

V T

NH

MA

CTR I

ME

B oston

Canada

Canada

NY

72 70

42

44

46

ACT

CMBBH

B

N

Norumbega fault s

ystem

CMBA CT B HB NAvalon Composite

TerraneCentral Maine

B eltB ronson Hill

B eltNashoba Terrane

Figure 1: Simplified geological map of western Maine and its location within the Central Maine Belt (inset) showing the location of cordierite bearing rocks. Modified from Tomascak et al. (2005).

Section A R. Quentin de Gromard

2

Clarke River Fault

0 25 5012.5 Km

Metamorphic RocksGranitoidsSedimentary Rocks

Neoproterozoic - CambrianOrdovician - DevonianSilurian - DevonianOrdovician - Devonian

Cambrian - OrdovicianDevonian - Carboniferous

Highway Railway

PhanerozoicPrecambrian146°00’E

20°00’S

145°30’E

19°30’S

Broken River Province

Ravenswood Batholith

Charters Towers

Seventy Mile Range Group

Charters Towers Province

Lolworth Batholith

Townsville

Cordierite rocks

Townsville

CTP

500 km

TFBS

Section A R. Quentin de Gromard

Figure 2: Simplified geological map of the Charters Towers Province of NE Queensland (inset) showing the location of cordierite bearing rocks within the Seventy Mile Range Group. Modified from Fergusson et al. (2007).

3

Crd

St

St

Bt

Ms+Bt±CrdQtz+Ms+Bt

Qtz+Ms+Bt

1mm1mm(a) (b)

Cordierite core

Reaction rimMatrix

Matrix

Ms+Bt±CrdReaction rim

Gt

Crd

Cordierite core

Section A R. Quentin de Gromard

Figure 3: Photomicrographs showing typical mica rich partial pseudomorphs after cordierite near Mooselookmeguntic pluton (western Maine) with staurolite inclusion (a) and garnet inclusions (b). The pseudomorph consists of a cordierite core surrounded by a reaction rim.

4

0

0.5mmRQ77

(g) 0

0.5mmRQ77

(h)

And

And

Ms

Ms

Ms

RQ83

70

1mm

(e)

RQ83

70

1mm

(f)

Chl

Il

Chl

Chl

Chl + Ms

0

0.5mm

0

0.5mmRQ13 RQ13

(c) (d)

Chl + Ms

Chl

Chl

150

1mm

(a)

RQ8

150

1mmRQ8

(b)

Chl

Chl

Chl

Bt + Ms + Chl

Section A R. Quentin de Gromard

Figure 4: Photomicrographs and line diagrams showing representative pseudomorphs after cordierite and andalusite from rocks of the Seventy Mile Range Group (NE Queensland). See text for details.

5

(a) 0.5mm

subgrain 1

subgrain 2

Bt

Ms

crack tip

(b) 0.25mm

subgrain 1

subgrain 2

Bt

Ms

(c) 0.25mm

subgrain 1

subgrain 2

Bt

Ms

n=431Outer circle 13%

(d)

Qtz

Pl

Crd

(e)

Ms

Qtz

Pl

Crd

Ms Bt(g)

Crd

Qtz

Bt

Ms+BtMs+Bt

(f)

Section A R. Quentin de Gromard

6