Skip navigation
Skip navigation

Archaeomagnetic and radiocarbon studies of aboriginal fireplaces

Barbetti, Michael Francis

Description

This thesis presents the results of the first detailed archaeomagnetic and radiocarbon study of ancient Aboriginal fireplaces in Australia. A furnace, designed and built during the present study, is described in detail, and a reappraisal is made of the method of calculating radiocarbon ages. A pilot study of some undated Aboriginal fireplaces demonstrated the suitability of their baked clay ovenstones for Thellier palaeointensity studies, and allowed estimates of their ages to be...[Show more]

dc.contributor.authorBarbetti, Michael Francis
dc.date.accessioned2017-05-15T01:44:34Z
dc.date.available2017-05-15T01:44:34Z
dc.date.copyright1973
dc.identifier.otherb1014165
dc.identifier.urihttp://hdl.handle.net/1885/116893
dc.description.abstractThis thesis presents the results of the first detailed archaeomagnetic and radiocarbon study of ancient Aboriginal fireplaces in Australia. A furnace, designed and built during the present study, is described in detail, and a reappraisal is made of the method of calculating radiocarbon ages. A pilot study of some undated Aboriginal fireplaces demonstrated the suitability of their baked clay ovenstones for Thellier palaeointensity studies, and allowed estimates of their ages to be made by comparing the measured ancient field intensities with the known prehistoric fluctuation of the Earth's magnetic field. Measurements on oriented clay-sand ovenstones from a series of ovens exposed on the open plains revealed that the ovenstones had not been displaced since the time of last cooling, and provided a preliminary archaeo-secular variation curve for southeastern Australia. A comparison of these results with those from other parts of the world suggests that the non-dipole contribution to the field in southeastern Australia was small during the period 1500 yr to 500 yr B.P Measurements were also made on a series of fireplaces exposed by modern erosion of ancient sediments in the Lake Mungo lunette. The fireplaces recorded a geomagnetic excursion occurring between 31,000 yr and 25,000 yr B.P. It appears that there were two excursion loops, one characterized by a high geomagnetic moment (about 50 x 10²⁵ gauss.cm³ ), and a second loop at a time of low dipole moment (about 50 x 10²⁵ gauss.cm³ ). During both these excursion loops, the geomagnetic field rotated more than 90° away from the axial dipole configuration. The evidence suggests that the geomagnetic field was dipolar during both excursion loops. The excursion at a time of low dipole moment may be an aborted reversal of the field, while the observed excursion with a large dipole moment is thought to be a rare and perhaps new type of dynamo behaviour. The similarity of virtual geomagnetic pole positions in both types of excursion to those observed in other excursions or polarity transitions during the last 15 million years suggests that some common mechanism is controlling or restraining the processes occurring in the Earth's core.
dc.format.extent1 v.
dc.language.isoen
dc.subject.lcshAboriginal Australians Antiquities
dc.subject.lcshRadiocarbon dating
dc.subject.lcshMagnetometry in archaeology
dc.titleArchaeomagnetic and radiocarbon studies of aboriginal fireplaces
dc.typeThesis (PhD)
dcterms.valid1973
local.description.notesThis thesis has been made available through exception 200AB to the Copyright Act.
local.type.degreeDoctor of Philosophy (PhD)
dc.date.issued1973
local.contributor.affiliationDepartment of Geophysics and Geochemistry, Institute of Advanced Studies, The Australian National University
local.identifier.doi10.25911/5d73959cbb81f
dc.date.updated2017-05-12T01:15:10Z
local.mintdoimint
CollectionsOpen Access Theses

Download

File Description SizeFormat Image
b10141650_Barbetti_Michael_Francis.pdf22.6 MBAdobe PDFThumbnail


Items in Open Research are protected by copyright, with all rights reserved, unless otherwise indicated.

Updated:  19 May 2020/ Responsible Officer:  University Librarian/ Page Contact:  Library Systems & Web Coordinator