Summary of results. Joint NTGS-GA geochronology project : Tanami Region, Arunta Region, Pine Creek Orogen and Halls Creek Orogen correlatives, January 2005- March 2007
Worden, KE; Carson, CJ; Close, DF; Donnellan, NC; Scrimgeour, IR; Worden, KE; Carson, CJ; Close, DF; Donnellan, NC; Scrimgeour, IR
Northern Territory Geological Survey; Northern Territory Geological Survey
E-Publications; E-Books; PublicationNT; NTGS Record
2008; 2008
Arunta Region; Pine Creek Orogen; Tanami Region
Made available via the Publications (Legal Deposit) Act 2004 (NT); Available from GEMIS - Geoscience Exploration and Mining Information System; Made available via the Publications (Legal Deposit) Act 2004 (NT)
English
Geochronology; Arunta Region; Pine Creek Orogen; Tanami Region
Northern Territory GovernmentNorthern Territory Government; Commonwealth of Australia; Northern Territory Government
Darwin
NTGS Record
2008-003
application/pdf
9780724571697; 9780724571697
1443-1149; 1443-1149
Attribution International 4.0 (CC BY 4.0)
Northern Territory Government; Commonwealth of Australia; Northern Territory Government
https://creativecommons.org/licenses/by/4.0/; https://creativecommons.org/licenses/by/4.0/
https://geoscience.nt.gov.au/gemis/ntgsjspui/handle/1/82446 [GEMIS]; https://geoscience.nt.gov.au/gemis/ntgsjspui/handle/1/82446
https://hdl.handle.net/10070/794392; https://geoscience.nt.gov.au/gemis/ntgsjspui/handle/1/82446
https://hdl.handle.net/10070/794416
35 Massfractionationcorrection: Nil Notes: A retardation lens was used in the acquisition of this data; it may have a slight impact on the 207Pb/206Pb ratios. U-Pb isotopic results Given the metamict appearance of the zircons, an analysis was undertaken to ascertain whether the zircons are amenable to isotopic dating. It revealed a composition containing 2230 ppm U and 8% discordant (table 19), confirming that the zircons are highly metamict, and have probably undergone significant lead loss. No further analyses were acquired. Garnet granite, east of Mount Alooarjara Sample information GAsampleID: 200508953 NTGSsampleID:IC05DFC27A 1:250000mapsheet: ILLOVGWA CREEK 1:100000mapsheet: QuaRTz Region: east Arunta Region Gridreference: 554460mE 7407962mN Formalname: unnamed Lithology:megacrystic biotite garnet granite Rock description, notes Coarsegrained, strongly foliated, megacrystic, hornblende biotitegarnet granite, characterized by mantled Kfeldspar phenocrysts up to 0 cm in size. Foliated hornblendebearing mafic dykes intrude the granite. Zircon description Zircons from this granite are colourless, transparent, and range up to 220 m in length. They are subhedralanhedral and generally featureless, with few cracks and inclusions, and no clear evidence of corerim relationships or concentric zoning in transmitted light (Figure 48). However, the zircons have complex internal trace element zoning patterns, as revealed by cathodoluminescence imaging. Oscillatory zoning and homogenous zoning patterns are prevalent. Those with oscillatory zoning are either completely oscillatoryzoned, or contain oscillatoryzoned cores. These cores can be euhedral, resorbed, or partly embayed, and are variably recrystallised. Recrystallisation is indicated by Figure 47. Representative zircons from leucogranite intruding Albarta Metamorphics, sample 200508952. Cathodoluminescence image on the left, transmitted light photomicrograph on the right. Figure 48. Representative zircons from garnet granite, east of Mount Alooarjara, sample 200508953. Cathodoluminescence image on the left, transmitted light photomicrograph on the right.