A new partial substitution mechanism of CO 3 2? /CO3OH3? and SiO 4 4? for the PO 4 3? group in hydroxyapatite from the Kaiserstuhl alkaline complex (SW-Germany)

Sommerauer, J.; Lehnert, Kerstin

doi:10.1007/bf00374692

Cited by 40 publications

(13 citation statements)

References 18 publications

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“…Their low Cl contents (≤ 0.55% m/m) corresponded to the fact that the observed fission tracks looked similar to tracks from fluorine-rich apatites that are commonly found in most rocks. The compositional variation was in agreement with data from Sommerauer and Katz (1985). For the analysed apatite grains, the presence of xenolithic material is possible, as the analysed apatites were not handpicked, but taken from the separated 0.3-0.5 mm fraction (Figure 2c), and such xenolithic grains may account for some of the very high F contents.…”

Section: Mineral Compositionsupporting

confidence: 86%

A New Multi-Mineral Age Reference Material for⁴⁰Ar/³⁹Ar, (U-Th)/He and Fission Track Dating Methods: The Limberg t3 Tuff

Kraml

Pik

Rahn

et al. 2006

Geostand Geoanalyt Res

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The phonolitic Limberg t3 tephra (Kaiserstuhl Volcanic Complex, Germany) was previously dated by the conventional K/Ar method yielding inconsistent results. We have re‐dated this tephra layer with three independent methods. Fission Track (FT) external detector analyses on single apatite crystals (16.8 ± 1.3 Ma, 2s) and (U‐Th)/He measurements on titanite and apatite (16.5 ± 1.0 Ma, 2s and 16.8 ± 1.0 Ma, 2s, respectively) are in close agreement with laser Ar/Ar dates on incrementally heated single crystals of sanidine (16.3 ± 0.4 Ma, 2s). Due to very rapid cooling, the He, FT and Ar thermochronometers provide one single age representing the eruption event. The different minerals are characterised by favourable properties with respect to their chemical composition, grain size and shape. In particular for the t3 sanidine, homogeneity has been demonstrated by electron microprobe analysis and on a grain‐to‐grain and grain‐internal scale by single crystal incremental laser heating. Based on the agreement between independent methods and the mineral yield of this unit, the Limberg t3 tephra is proposed as multi‐method age reference material for single grain laser Ar/Ar, FT and (U‐Th)/He dating.

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Section: Mineral Compositionsupporting

confidence: 86%

A New Multi-Mineral Age Reference Material for⁴⁰Ar/³⁹Ar, (U-Th)/He and Fission Track Dating Methods: The Limberg t3 Tuff

Kraml

Pik

Rahn

et al. 2006

Geostand Geoanalyt Res

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“…Starting with a simplified formula of the type Cal0(PO4)6(F, CI, OH)2 , the apatite analyses have been recalculated to structural formulae assuming Ca + Na + La + Ce + Nd = 10.000 cations (Le Bas and Handley, 1979). This gives P + Si in the range 5.71-6.28, so, although substitution of carbon in the form of CO3, CO3OH or CO3F groups replacing PO4 tetrahedra is possible in apatite (McConnell, 1973;Le Bas and Handley, 1979;Sommerauer and Katz-Lehnert, 1985b;Binder and Troll, 1989), it must be very small or negligible here. The CO3F substitution will not therefore have any significant effect on the total fluorine content.…”

Section: Resultsmentioning

confidence: 97%

Temperature-HF fugacity trends during crystallization of calcite carbonatite magma in the Fen complex, Norway

Andersen

Austrheim

1991

Mineral. mag.

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Calcite carbonatite (scvite), associated apatite cumulates and contact metasomatic phlogopite-rocks in the Fen complex (S. Norway) contain coexisting apatite and phlogopite. Two distinct compositional groups are recognized: fluorapatite (XF = 0.5--0.8) coexists with hydroxy-phlogopite with XF = 0.11--0.26, whereas hydroxyapatite (XF = 0.34-0.44) coexists with low-F hydroxy-phlogopite (XF --~ 0.03). Apatite-biotite geothermometry suggests that the minerals equilibrated at igneous temperatures (less than 1200 to ca. 625 ~ and were not significantly disturbed by late low-temperature re-equilibration. This, combined with HF-barometry based on apatite-fluid and phlogopite-fluid F-OH exchange equilibria, makes it possible to recognize two crystallization trends at different levels of hydrogen fluoride fugacity. The existence of such trends reflects internal buffering of the HI: fugacity by apatite and/or phlogopite. The recorded differences in HF fugacity suggest that two or more independent or semi-independent lines of magmatic descent gave rise to calcite carbonatite magma in the Fen complex. Combined apatite-phlogopite geothermometry and hydrogen fluoride barometry is a useful tool enabling us to see through post-magmatic alteration of carbonatites, and to establish primary magmatic controls even in cases where carbonate and iron-titanium oxide minerals have re-equilibrated at much lower temperatures.

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“…However, since the Hegau volcanic activity is related to the Kaiserstuhl by their common position along the Bonndorf graben and its similar intraplate igneous character (Keller 1984), one may perhaps draw a comparison to those of the Kaiserstuhl. The Kaiserstuhl apatites from silicate magmatites have a large compositional range between F and OH end member (Sommerauer & Katz 1985;Kraml et al 2006). Cl-rich apatites, as found in the volcanic Mein, 1999) and the polar magnetic reversals and seawater stratigraphy (both after Gradstein et al 2004).…”

Section: Apatite Compositional Variation and Division Of Ash Levelsmentioning

confidence: 99%

“…Furthermore, Hofmann (1967) suggested the bentonite to be contemporaneous with the upper bentonite in the Hegau area that was dated at 12.5 Ma ). An origin from the Kaiserstuhl can be excluded, because magmatic activity in the Kaiserstuhl area ceased at around 15 Ma (Keller et al 2002), and the youngest Kaiserstuhl tuffs contain F-OH apatites (Sommerauer & Katz 1985;Kraml et al 2006). Occurrences of volcanic material with apatite dominated heavy mineral fractions have been reported from OSM rocks in the Tabular Jura (Hofmann 1961;Stumm 1964), i.e.…”

Section: Osm Sedimentation Rate and Origin Of The Volcanic Materialsmentioning

confidence: 99%

Absolute dating of the youngest sediments of the Swiss Molasse basin by apatite fission track analysis

Rahn

Selbekk

2007

Swiss j geosci

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A set of ash layer samples within the uppermost Upper Freshwater Molasse (OSM) sediments (N and E of Frauenfeld, Switzerland) was dated by apatite fission track (FT) means. The ages indicate an early Tortonian (perhaps latest Serravallian) eruption and sedimentation age of 11.5 ± 0.3 Ma. The age is in agreement with time constraints by Mammalian relicts which point to MN7-8. Due to the position of the ash layers close to the erosional gap and overlying Quaternary cover, the age represents a maximum age for the cessation of OSM sedimentation in the Swiss Molasse Basin. However, the end of Molasse sedimentation in this region had not stopped before the cover of OSM sediments by volcanic ash layers at the Höwenegg volcano (southern Germany), an event further constrained by an apatite FT age of 9.8 (-0.7/+0.8) Ma from a hornblende-bearing ash layer at Höwenegg. An isolated bentonitic ash layer occurring 25 km to the WSW of the main set of dated ashes (near Humlikon) has an age component identical to the OSM ash layers near Frauenfeld. The age suggests a source for this material within the Hegau, but is too young to be related to the volcanic activity at the Kaiserstuhl.The apatites from the ash layer samples show two distinct compositional populations, one very close to a Cl end member and one with apatites of equal proportions of Cl and OH end member. These populations are interpreted to have possibly originated from at least two distinct igneous sources for the ashes, separated by their eruption site or eruption time or both. The distinct compositional data on the volcanic apatites may provide a basis to clarify their origin in future work.

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A new partial substitution mechanism of CO 3 2? /CO3OH3? and SiO 4 4? for the PO 4 3? group in hydroxyapatite from the Kaiserstuhl alkaline complex (SW-Germany)

Cited by 40 publications

References 18 publications

A New Multi-Mineral Age Reference Material for⁴⁰Ar/³⁹Ar, (U-Th)/He and Fission Track Dating Methods: The Limberg t3 Tuff

A New Multi-Mineral Age Reference Material for⁴⁰Ar/³⁹Ar, (U-Th)/He and Fission Track Dating Methods: The Limberg t3 Tuff

Temperature-HF fugacity trends during crystallization of calcite carbonatite magma in the Fen complex, Norway

Absolute dating of the youngest sediments of the Swiss Molasse basin by apatite fission track analysis

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A new partial substitution mechanism of CO 3 2? /CO3OH3? and SiO 4 4? for the PO 4 3? group in hydroxyapatite from the Kaiserstuhl alkaline complex (SW-Germany)

Cited by 40 publications

References 18 publications

A New Multi-Mineral Age Reference Material for40Ar/39Ar, (U-Th)/He and Fission Track Dating Methods: The Limberg t3 Tuff

A New Multi-Mineral Age Reference Material for40Ar/39Ar, (U-Th)/He and Fission Track Dating Methods: The Limberg t3 Tuff

Temperature-HF fugacity trends during crystallization of calcite carbonatite magma in the Fen complex, Norway

Absolute dating of the youngest sediments of the Swiss Molasse basin by apatite fission track analysis

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A New Multi-Mineral Age Reference Material for⁴⁰Ar/³⁹Ar, (U-Th)/He and Fission Track Dating Methods: The Limberg t3 Tuff

A New Multi-Mineral Age Reference Material for⁴⁰Ar/³⁹Ar, (U-Th)/He and Fission Track Dating Methods: The Limberg t3 Tuff