El-Shazly, February, 12
FIELD TRIP TO SAIH HATAT
HOMEWORK PROBLEM # 5
HIGH PRESSURE METAMORPHISM IN SAIH HATAT
This field trip is aimed at examining some of the high pressure, low temperature
metamorphic rocks which occur in the Saih Hatat area (structurally underlying the
Semail ophiolite), and at illustrating some of the deformational and metamorphic events
that predated or were contemporaneous with the Semail ophiolite emplacement.
High pressure, low temperature (high P/T) metasediments from this area were first
reported by Michard et al. (1982). Blueschists were then described by Lippard (1983).
More detailed petrologic studies by Le Métour et al. (1986), Goffé et al. (1988), El-
Shazly et al. (1990) and El-Shazly and Liou (1991), Searle et al. (1994) have led to the
proposition of several tectonic models for the area (e.g. Lippard et al., 1986; Le Métour
et al., 1990; El-Shazly and Coleman, 1990; El-Shazly and Lanphere (1992), El-Shazly
(1994)). Keep in mind that all these models are controversial, and that the relationship
between deformation and metamorphism remains poorly understood.
Following this field trip, you are supposed to write a short essay (3-5 pages long) on
high pressure metamorphism in Saih Hatat. The questions on this handout are designed
to help you write this essay, so be sure to have them all answered before you leave each
stop! In this essay, you should point out the different mineral assemblages occurring in
rocks of different bulk compositions that you have seen, the tectonostratigraphic
positions of these units or rock types and the directions of increase in metamorphic
grade throughout Saih Hatat (detected by mineralogical changes in rocks of the same
composition). Afterwards, you should:
1- plot the different mineral assemblages on Figs. 1 and 2
2- identify the "index minerals" characteristic of certain rock types in each area, and
label what you think may be metamorphic zones accordingly. How do your
metamorphic zones compare with those of Le Métour et al. (1990), shown on Fig. 3?
3- Prepare a paragenetic sequence diagram for metapelites in all of your metamorphic
zones (similar to the one shown on the last page of this handout, copied from Le Métour
et al. (1990) for metabasites).
4- Based on field relations, you should then critique one or two of the tectonic models
mentioned above, keeping in mind that you do not have to agree with any of these
models! Use the papers cited above to your advantage!