- melt is produced,
forming a
nepheline syenite,
where orthoclase is
replaced by a
feldspathoid such as
leucite,
nepheline or analcime.
Conversely in certain...
- at
Julianehaab in
Greenland with sodalite-
syenite; at
their margins they
contain pseudomorphs after leucite. The
lujaurites frequently have a parallel-banding...
-
Leucite also is rare in
plutonic rocks and **** rocks, but
leucite syenite and
leucite tinguaite bear
witness to the
possibility that it may
occur in...
- pyroxene-melanite
bearing nepheline syenite variety which contains nepheline-alkali
feldspar pseudomorphs interpreted to be
after leucite which occur as con****uous...
-
transitions between syenites of
ordinary type and
nepheline — or
leucite —
syenite, and
between gabbro or
dolerite and
theralite or es****ite. But, as...
- is a
variation of the
igneous rock
trachyte that
contains nepheline or
leucite rather than quartz. It has an
unusually high (12% or more) Na2O + K2O content...
- minerals. For example, a
syenite with
significant nepheline present can be
termed a nepheline-bearing
syenite or
nepheline syenite, with the term nepheline...
-
igneous rocks.
These include nepheline syenite, foidite, and phonolite. It is
often found along with
leucite, sodalite, pot****ium feldspars, and sodium-rich...
- them as the
nepheline syenites have to the phonolites. A
leucite-augite rock,
resembling ijolite except in
containing leucite in
place of nepheline,...
-
rocks such as
nepheline syenites. It is ****ociated with
other minerals typical of silica-undersaturated environments,
namely leucite,
cancrinite and natrolite...
