Date (Creation)

2025-09-15

Citation identifier

http://data.bgs.ac.uk/id/dataHolding/13608536

Point of contact

Organisation name	Individual name	Electronic mail address	Role
University of Southampton	Professor Stephen Roberts	not available	Originator
British Geological Survey	Enquiries	not available	Distributor
British Geological Survey	Enquiries	not available	Point of contact

Maintenance and update frequency

notApplicable

GEMET - INSPIRE themes, version 1.0

• Geology

BGS Thesaurus of Geosciences

• Apatite

• Copper deposits

• Microprobe analysis

• NGDC Deposited Data

• Rutile

dataCentre

• NGDC Deposited Data

Keywords

• NERC_DDC

Access constraints

Other restrictions

Other constraints

licenceOGL

Other constraints

Available under the Open Government Licence subject to the following acknowledgement accompanying the reproduced NERC materials "Contains NERC materials ©NERC [year]"

Use constraints

Other restrictions

Other constraints

The copyright of materials derived from the British Geological Survey's work is vested in the Natural Environment Research Council [NERC]. No part of this work may be reproduced or transmitted in any form or by any means, or stored in a retrieval system of any nature, without the prior permission of the copyright holder, via the BGS Intellectual Property Rights Manager. Use by customers of information provided by the BGS, is at the customer's own risk. In view of the disparate sources of information at BGS's disposal, including such material donated to BGS, that BGS accepts in good faith as being accurate, the Natural Environment Research Council (NERC) gives no warranty, expressed or implied, as to the quality or accuracy of the information supplied, or to the information's suitability for any use. NERC/BGS accepts no liability whatever in respect of loss, damage, injury or other occurence however caused.

Other constraints

Available under the Open Government Licence subject to the following acknowledgement accompanying the reproduced NERC materials "Contains NERC materials ©NERC [year]"

Language

English

Topic category

• Geoscientific information

Begin date

2020-10-01

End date

2023-09-01

Distribution format

Name	Version
Microsoft Excel (XLSX)	Not enetered

Distributor contact

Organisation name	Individual name	Electronic mail address	Role
British Geological Survey	Enquiries	not available	Distributor

OnLine resource

Protocol	Linkage	Name
WWW:DOWNLOAD-1.0-http--download	https://webapps.bgs.ac.uk/services/ngdc/accessions/index.html#item189925	Data

Hierarchy level

Non geographic dataset

Other

non geographic dataset

Statement

The data are electron microprobe analyses completed at the Natural History Museum London. Apatite grains from Nchanga were analysed using a JEOL JXA-8530F Plus hyperprobe electron microprobe at the NHM, London. The probe was operated using an acceleration voltage of 20kv, probe current of 20 nA and working distance of 11 mm. Spot size was governed by apatite crystal sizes and the presence of inclusions, pits and cracks. EDS element maps, CL images and TESCAN Tima maps were used for navigation. Spot locations were chosen away from any pits or inclusions. Most apatite crystals received two spots; one located close to the core and one close to the rim in order to assess compositional zoning and intra-grain heterogeneity. The elements P, Ca, F, Cl, Na, S, Sr, Fe, La, Ce, Mn, Si, Mg and Ti were measured. F, Sr, Cl, P and Ca were measured first in analytical sequence as suggested by Goldoff et al., (2012) to minimise time-dependent x-ray count variations. Natural and synthetic standards were used for calibration (Table B-2). Counting times for each element peak was 30s with background count times at 15s before and after analysis. Exceptions were for Na and K which were counted for 10s and 5s for peak and background, respectively. Peak overlaps detected between F and P, Ca and Ce and between Si and Si were corrected for by the probe software. The hydroxide (OH) content of apatite for each spot analysis was calculated by mass balance using measured F and Cl concentrations, whereby XOH = 1 – XF – XCl (XF = F wt.%/3.767, XCl = Cl wt.%/6.809; (Piccoli and Candela 2002). Cations and OH concentrations were calculated based on 25 oxygen’s using approach 2 in the spreadsheet provided by Ketcham (2015). The probe was calibrated using several in-house natural and synthetic standards prior to measurement labelled as RUT, ZIR, CAS, PNB, PTA, CRO, FEO, MNT, PVV, PWW, WOL, COR and MGO. The rutile standard was then measured repeatedly to determine accuracy prior to analysis of the unknown rutile. All totals obtained fall between 98.64-100.6 mass %. Where possible, spots were chosen on the same rutile grains as laser ablation and away from any debris.

Metadata

File identifier

3f290c61-74ac-421a-e063-3050940ab292 XML

Metadata language

English

Hierarchy level

Non geographic dataset

Hierarchy level name

non geographic dataset

Date stamp

2025-12-07

Metadata standard name

UK GEMINI

Metadata standard version

2.3

Metadata author

Organisation name	Individual name	Electronic mail address	Role
British Geological Survey		enquiries@bgs.ac.uk	Point of contact

Dataset URI

http://data.bgs.ac.uk/id/dataHolding/13608536