Goldschmidt Conference Abstracts
Mineralogical Magazine www.minersoc.org
1242
Phlogopite/matrix, Cpx/matrix and
Cpx/phlogopite trace element
partitioning in true lamprophyres
M. KRMÍ)KOVÁ
1
*, L. KRMÍ)EK
2
, V. KANICKH
3
,
T. VACULOVI)
3
AND M. GALIOVÁ
3
1
Institute of Geotechnics, Brno University of Technology,
Brno, CZ-602 00, Czech Rep
(*correspondence: m.halavinova@gmail.com)
2
Institute of Geological Sciences, Masaryk University, Brno,
CZ-61137, Czech Rep
3
Department of Chemistry, Masaryk University, Brno, CZ-
61137, Czech Rep
Introduction
Partition coefficients for true lamprophyres (i.e. in their
original sense [1]) are poorly known. Therefore,
mineral/matrix and mineral/mineral partition coefficients were
determined by LA-ICP-MS for clinopyroxene (Cpx) and
phlogopite crystals from a Variscan calc-alkaline (agpaitic
index = 0, 6) lamprophyre of minette-type from the Bohemian
Massif (KIí,anovice locality, Bohemicum). Quantification
was performed using the glass reference material NIST SRM
612 as external standard, and microprobe analyses of Si as
internal standard.
Results
Cpx/matrix partition coefficients (D) for 23 trace elements
have values ~1 (0.9-1.1) for the HREE only. This suggest that
HREE can be concentrated in clinopyroxene during
crystallization from lamprophyre melts [2]. The coefficients
differ significantly from published D-values for HREE (~0.3-
0.4) in clinopyroxenes growing from ‘lamprophyric’ melt of
alkaline composition [3].
In phlogopite, only 14 elements had concentrations above
detection limit. Phlogopite/matrix partition coefficients have
average values higher than 1 for Ba (D = 1.1), Rb (D = 1.7)
and Ti (D = 1.5). On the other hand, D-values for LREE are
extremely low (D < 0.02) and it was not possible to determine
D-values for the majority of HREE.
During simultaneous crystallization of clinopyroxene and
phlogopite phenocrysts, Th, Zr, Hf and REE are preferentially
partitioned into clinopyroxene. The main reason for the
behaviour of these elements may be found in the lack of a
suitable crystallographic site in the phlogopite structure [5].
[1] Krmí-ek (2011) MinMag, this volume. [2] Plá Cid et al.
(2005) Contrib Mineral Petrol 148, 675–688. [3] Foley et al.
(1996) Geochim. Cosmochim. Acta 60, 529–538. [5] Schmidt
et al. (1999) Earth Planet. Sci. Lett. 168, 287–299.
Chronology of climate archives –
A never-ending story
BERND KROMER
Curt-Engelhorn Centre for Archaeometry, C 4,8, D-68159
Mannheim, (bernd.kromer@cez-archeometrie.de)
Accurate dating of climate archives is essential for the
reconstruction of past climate and to infer rates of climate
change. Of special interest is the time range of the last Glacial
and the transition into the Holocene, during which strong
climate fluctuations are evident. Chronology of these archives
is based on a number of dating systems, such as radiocarbon,
U/Th and layer counting. Each clock has its strengths and
limitations, and in the past decade important progress has been
achieved to resolve inconsistencies within a dating method
and between the methods. This keynote lecture will focus on
this fascinating venture and the current status of establishing
firm and consistent chronologies in the past 50.000 years.