[Folda] Fwd:?==?utf-8?q? [Jhi]?==?utf-8?q? Bryndís Yr Gisladóttir's MS lecture - this Friday 2pm

[Siqi Li]

-------- Original Message -------- 
Subject: [Jhi] Bryndís Yr Gisladóttir's MS lecture - this Friday 2pm 
Date: Wednesday, January 17, 2018 09:54 GMT 
From: "Eniko Bali" <eniko at hi.is> 
To: <jhi at hi.is> 
 
 
Dear All,

I would like to inform you that shortly after the Friday seminar of Bryndís
Brandsdóttir another Bryndís will also give a talk describing her Master’s
project.

 

Bryndís Yr Gisladóttir’s MS lecture is scheduled at 2pm in Askja in lecture
room N-129. (There was a very brief e-mail on this, which might have slipped
the attention of most people who are interested).

 

Her thesis title is (very long): Magma storage conditions and the
composition of the crust below Eyjafjöll based on clinopyroxene macrocrysts
and gabbro xenoliths from Seljalandsheiði and Brattaskjól, Iceland; In
Icelandic: Gerð kvikugeyma og samsetning jarðskorpunnar undir Eyjafjöllum
byggt á klínópýroxenstórdílum og gabbróhnyðlingum frá Seljalandsheiði og
Brattaskjóli

 

Her examiner will be Ingvar Atli Sigurðsson from Nátturstófa Suðurlands. Her
advisor was myself and the other member of her MS committee was Sæmi.

 

In order to make this lecture more attractive I also copy in the abstract of
Bryndís’ thesis:

“Large clinopyroxene macro- and megacrysts along with gabbroic-xenoliths
were discovered in the Upper Pleistocene “ankaramite” outcrops of
Seljalandsheiði and Brattaskjól from Eyjafjallajökull, in the Eastern
Volcanic Zone of Iceland. The pyroxenes are mostly of augite composition,
though a few can be classified as diopside. The pyroxenes display a
considerable range in magnesium-values (Mg#: 57.9-83.3) and also in their
minor oxides such as TiO2 (0.00-2.46 wt%), Al2O3 (0.03-6.28) and Cr2O3
(0.0-0.99). Most pyroxenes are strongly zoned where normal-, reverse-,
oscillatory-, sector- and patchy zoning was observed. Magma mixing can
possibly explain the presence of inverse zoning patterns. The
gabbroic-xenoliths are of two types, olivine-bearing gabbro and olivine-free
gabbro.

Crystallization depths were obtained using a newly published
clinopyroxene-melt thermobarometer from Neave and Putirka (2017).
Clinopyroxene macro- and megacrysts crystallized at 1035-1150°C and 0.0-5.8
kbars pressure, corresponding to 0.0-16.24 km depth. The crystallization
conditions of these macrocrysts are thus very similar to those observed for
crystals of the 2010 flank eruption of Fimmvörðuháls and the summit eruption
of Eyjafjallajökull. This suggest that crystallization depths beneath
Eyjafjallajökull has not change significantly since the Upper Pleistocene. 

In contrast, olivine-bearing gabbroic-xenoliths crystallized at a more
restricted depth range of 3.8-5.6 kbars and 1140-1160°C (10.6-15.6 km depth)
whereas olivine-free xenoliths are likely to be widespread in the middle to
upper crust beneath Eyjafjallajökull, forming between 1070-1180°C and
0.1-5.3 kbars (0.0-14.8 km depth).”

Cheers,

Enikö

 

 

Enikö Bali

Associate Professor of Geology

(Mineralogy and Petrology)

Faculty of Earth Sciences

University of Iceland

Askja building, Sturlugata 7

101 Reykjavik, Iceland

 

Web: http://english.hi.is/von/faculty_of_earth_sciences/main_menu/home

Personal web page: enikobali.hupont.hu