A Castro

A Hofmann

A Soesoo

A Tahiri

A Zeh

AE Phaup

AFM Kisters

AP Peschler

AP Singh

AR Cruden

BR Frost

C Braitenberg

C Dietl

C Subrahmanyam

CB Smith

CM Fedo

CR Anhaeusser

Cynthia J. Ebinger

DA Clark

DC Oliveira

DR Nelson

E Galadi-Enriquez

EC Ferré

EH Stettler

F Boschetti

G Ma

GRJ Cooper

GW Stuart

H Henkel

H Ramberg

HA Jelsma

HR Rollinson

I Flecha

IJ Won

J Gore

J Halla

JC Mareschal

JC Zwaan

JD Clemens

JF Dehls

JF Moyen

JF Wilson

JG Ramsay

JK Becker

JL Vigneresse

JR Ridley

K Fisk

Kathryn A. Whaler

KF Cassidy

KJW McCaffrey

L Ameglio

L Cordell

M Berger

M Haederle

MA McLean

ME Pritchard

MH Hickman

MJ Comeau

MJ Pawley

MP Coward

MSA Horstwood

N Petford

NM Harrison

NR Goulty

NT Liodas

O Gwavava

O Laurent

Oswald Gwavava

P Duuring

P Kearey

P Wellman

PA Snowden

PF Rey

PJ Kurian

PJ Sylvester

R Frei

RCA Minnitt

RF Weinberg

RJ Blakely

RT Ranganai

Rubeni T. Ranganai

S Ishihara

S Lin

English

TG Blenkinsop

SDG Campbell

WJ Collins

VK Gupta

SE Johnson

Y Li

S Lopez

S Mkweli

T Oberthür

SR Paterson

S Siegesmund

WHF Smith

Crossref

Configuration of Late Archaean Chilimanzi and Razi Suites of Granites, South-Central Zimbabwe Craton, From Gravity Modelling: Geotectonic Implications

The subsurface geometry of five representative late Archaean ‘Chilimanzi and Razi’ suite plutons in the Zimbabwe craton (ZC) has been investigated by gravity modelling constrained in part by surface geology, density measurements and seismic information, to determine their 3D configuration and infer tectonic context of emplacement. The generally K-rich, massive, homogeneous monzogranites are characterised by large Bouguer gravity lows (up to − 30 mGal amplitude) whose gradients outline their spatial extent well. The southernmost plutons and their anomalies have general trends paralleling the North Marginal Zone (NMZ) of the Limpopo orogenic belt (LB). Predictive gravity models indicate that the density contrast of the Chivi batholith (CB) adjacent to the ‘volcanic arc-like’ Belingwe greenstone belt extends to a depth of about 13 km. The nearby Razi pluton (RP) which intrudes the ZC-LB boundary appears to have been emplaced at shallower depths/levels. The gravity model suggests a thickness of about 5–6 km, and a moderate to shallow dip to the southeast under the NMZ, compatible with syn-kinematic intrusion during overthrust of the LB over the ZC. The smallest Nalatale granite (Ng) is on average 2.5 km thick under the Fort Rixon greenstone belt but includes a root up to 4.5 km thick under the anomaly peak, and a steep contact with the tonalite/gneiss to the east. These granites follow the general power-law for pluton dimension and are similar in this respect to the classical wedge-shaped plutons, extending largely in one direction, with large aspect ratios (Length (L)/Thickness (T) &gt; 7). However, the overall shape of the RP is typical of a diapir (Width (W) &lt; T), although it may have been affected by the LB deformation. Gravity modelling along a NS traverse crossing the Chilimanzi batholith (ChB), the Masvingo greenstone belt (MGB) and the Zimbabwe granite (ZG) indicate a thickness of around 6 km for the dense greenstone belt with a thickness of about 8.5 km for the adjacent ZG. The ‘complex’ shaped ChB shows a 2 km thick tabular body with a root zone extending to ~ 4.5 km depth on the south end, adjacent to the greenstone belt; typical of the so-called flat-floored plutons with a gently dipping floor towards the root zone. These two plutons roughly follow the power-law for laccolith/batholith dimensions (W/T &gt; 5; L/T &gt; 15). Overall, the CB and the ZG are interpreted as massive, deep-rooted batholithic intrusions (L/T ≅ 10), contrary to some geological interpretations of these late, post-kinematic intrusions as sheet-like bodies emplaced at relatively shallow levels in the crust. On the other hand, the ChB appears to be a tabular intrusion, probably fed by dykes; it exhibits a lateral extent much greater than the vertical one, outlining a sheeted geometry (W/T &gt; 7; L/T &gt; 18). The geophysical evidence, together with geological and fabric data, support and/or confirm the two main granite configurations: sheets and batholith; and thus also confirm the two main modes of emplacement: dyke and diapirism or ballooning plutonism. This is consistent with other known batholiths on the ZC but considered unusual for plutons of the same age and spatially close when compared to other Archaean cratons

Ranganai, Reuben

Gwavava, Oswald

Ebinger, Cynthia J.

Whaler, Kathryn

Edinburgh Research Explorer

Configuration of late Archaean Chilimanzi and Razi suites of granites, south-central Zimbabwe craton, from gravity modelling: geotectonic implications

https://www.research.ed.ac.uk/portal/files/112103024/111450031._Whaler._AAM.pdf

Configuration of late Archaean Chilimanzi and Razi suites of granites, south-central Zimbabwe craton, from gravity modelling: geotectonic implications

Abstract

Similar works

Full text

Available Versions

Crossref

Edinburgh Research Explorer