Lu/Hf apatite geochronology of mafic cumulates; an example from a Fe-Ti mineralization at Smalands Taberg, southern Sweden

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doi: 10.1016/j.chemgeo.2005.07.007
Authors:Larsson, Daniel; Soderlund, U.
Author Affiliations:Primary:
Lund University, GeoBiosphere Science Center, Lund, Sweden
Volume Title:Chemical Geology
Source:Chemical Geology, 224(4), p.201-211. Publisher: Elsevier, Amsterdam, Netherlands. ISSN: 0009-2541
Publication Date:2005
Note:In English. 33 refs.; illus., incl. 5 tables, geol. sketch map
Summary:We have employed Lu-Hf apatite chronology to determine the age of a magnetite-rich melatroctolite in southern Sweden, known as the Smalands Taberg Fe-Ti ore deposit. The melatroctolite is poor in incompatible elements and minerals forming at more advanced stages of differentiation, which precludes the use of minerals (baddeleyite, zircon, titanite or apatite) commonly used for dating the emplacement of igneous rocks. Enclaves of leucogabbro in the melatroctolite have REE patterns parallel with the host melatroctolite and identical initial Hf and Nd isotope compositions. These characteristics are conclusive evidence for a common parental magma. The leucogabbro is a slightly more evolved facies that underwent limited fractionation of olivine and titanomagnetite; the two major mineral phases in the melatroctolite. Apatite and plagioclase, separated from the leucogabbro, plus a whole-rock sample define a Lu-Hf isochron with a slope corresponding to an age of 1204.3±1.8 Ma. This result is close to the lower age boundary previously reported for this magmatic event comprising dolerites, syenites and granites. The Lu-Hf apatite chronometer merits attention as a new tool in generating accurate and precise ages for igneous, silica-undersaturated rocks that may be difficult to date with traditional techniques. Abstract Copyright (2005) Elsevier, B.V.
Sections:Age determination; Economic minerals and ore deposits
Subsections:Metallic deposits: specific
Subjects:Absolute age; Apatite; Cumulates; Dates; Gabbros; Geochemistry; ICP mass spectra; Igneous rocks; Iron ores; Lu/Hf; Mafic composition; Magmas; Magnetite; Major elements; Mass spectra; Mesoproterozoic; Metal ores; Metallogeny; Metals; Metamorphic rocks; Metaplutonic rocks; Mineral deposits, genesis; Mineralization; Oxides; Petrography; Phosphates; Plutonic rocks; Precambrian; Proterozoic; Rare earths; Spectra; Textures; Titanium ores; Trace elements; Troctolite; Upper Precambrian; Europe; Scandinavia; Smaland; Sweden; Western Europe; Leucogabbro; Smalands Taberg Deposit
Coordinates:N570000 N574500 E0143000 E0135000
Abstract Numbers:07M/1796
Record ID:2006038443
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from CAPCAS, Elsevier Scientific Publishers, Amsterdam, Netherlands
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