I was happy to locate this site for my children, and then I thought
I might as well ask a question. I coordinate an archaeological project
in central Jordan. We have a major "topographic feature" in the
500-square-mile Kerak plateau, a feature called JEBEL SHIHAN. Some
folks call it an extinct volcano (though there is no cone), while others
refer to Shihan as a volcanic vent with outlying dykes. Basalt is strewn
all over the thin soil or limestone bedrock in our district. The basalt
was used as a building material and to make tools, bowls, etc.
Can you clarify these terms for me--or point me to the best sources
that I could read. Thank you for any advice you can offer.
Gerald L. (Jerry) Mattingly
Hi Jerry,
Sorry for having taken so long to answer your question. I have looked in
a number of volcanology books but haven't found anything on young
volcanoes in Jordan. According to "Volcanoes of the World" by Tom Simkin
and Lee Seibert, there are volcanoes in southern Syria. It looks like they
get almost down into Jordan but end above the boarder.
That certainly does not mean that Jebel Shihan is not a volcano, only that
there are no reports of it having erupted. Since the human history of
that place goes back a long time (as you obviously know) the indication is
that Jebel Shihan hasn't erupted for quite a while. In fact, your
archeological work might turn up evidence for past eruptions.
Certainly basalt lava is only produced by volcanic activity so if there is
basalt all around then the area was volcanic. A dyke (or dike in American
English) is a sheet-like body of magma that slices its way through the
sub-surface to feed an eruption. Dikes usually cool slowly since (unlike
the surface flows they feed), they are well-insulated. This means that
they form rock that is more resistant to erosion. When erosion does take
place the dikes are often exposed as positive topographic features
sticking up out of the ground or out of the wall of a valley. If there
are dikes exposed around Jebel Shihan, then presumable a lot of erosion
has taken place, and this is more evidence that it is quite an old volcano.
I hope this has helped a little bit.
Sincerely,
Scott Rowland
Other Categories
Other Questions
To VolcanoWorld