Penrose Conference on Arc Crustal Genesis and Evolution
Valdez, Alaska, July 9-15
Conveners: Peter Kelemen & Brad Hacker
The Penrose Conference on arc crustal genesis and evolution will be held in
Valdez, in south-central Alaska, from July 9–15. The Conference will be
limited to about 80 participants, and participants must apply to attend.
Presentations will integrate recent results on well-exposed arc crustal
sections – in the Jurassic Talkeetna arc in south central Alaska, and in
the Cretaceous Ladakh–Kohistan arc in northern Pakistan and India – with
important new developments in active-arc geochemistry, petrology and
geophysics. The Talkeetna and Ladakh–Kohistan arcs provide exposures of
relatively complete sections from Moho depth (30 to 40 km in both cases),
to volcanic rocks and volcaniclastic sediments. Both have been the subject
of large, multi-disciplinary projects over the past decade, and provide
depth sections and temporal progressions that are not accessible in active
oceanic arcs.
Intensive, recent investigations of arc plutonic suites elsewhere
complement these projects. New data from the US MARGINS Initiative, Sierra
Nevada Continental Dynamics Projects, Aleutian studies, and similar
international initiatives provide constraints on crustal thickness and
volcanic fluxes in active arcs. Advances in the study of melt inclusions
have dramatically improved understanding of volatiles in primitive arc
magmas. Studies of ultra-high pressure metamorphic rocks and new
experimental methods have yielded insights into mantle wedge melt
generation, and subduction zone dehydration and anatexis. This conference
will provide an opportunity to synthesize these results, with a focus on
using direct observations of arc crustal sections, from the uppermost
mantle to the volcanics, to constrain arc processes and their role in the
genesis and evolution of continental crust.
The enthusiastic response of keynote speakers – only one out of twenty-four
declined the request for letters of commitment – indicates to us that the
time is right for this conference, and that it will attract an excellent
group of well informed participants with much to discuss.
To complement research presentations, the Conference will include at least
two field trips, to accessible outcrops of volcanic and the Moho sections
of the Talkeetna arc. Depending on the level of interest, there may also be
another (expensive, helicopter supported, multi-day) field trip to the
Klanelneechina field trip, open to participants with experience in
backcountry travel in alpine terrain.
Tentative Conference Schedule
Sun July 9: Bus trip from Anchorage, Sheep Mountain Field trip along the way
Mon July 10: Setting the stage: Alaska tectonics, geochronology, arc
tectonics
Tue July 11: Crustal bulk composition, conditions & processes of
crystallization
Wed July 12: Bernard Mtn Field Trip and informal discussions, all day
Thu July 13: Metamorphic petrology, deformation, & arc geophysics
Fri July 14: Crustal dynamics, mantle dynamics, melt production
Sat July 15: Bus trip back to Anchorage
Beginning of possible multi-day field trip to
Klanelneechina klippe
Logistical information
To apply: please contact the conveners by email at [log in to unmask]
and [log in to unmask] with a letter of intent that includes a brief
statement of interests the relevance of the applicants recent work to the
themes of the Conference, the subject of a proposed presentation, and
contact information. Interested graduate students are strongly encouraged
to apply; partial support is available for student attendees from GSA. Once
you have been selected to participate, we will forward your contact
information to the GSA Penrose organization, and they will send you
detailed registration information.
Application deadline is Friday, March 31, 2006
Travel and costs: Buses will meet participants at the Anchorage
International Airport, and one or two downtown locations to be announced,
on the morning of July 9, and buses will return participants to these
locations on the afternoon or early evening of July 15. We will stay in the
Best Western Valdez Harbor Inn, and the conference, together with lunch and
dinner, will take place at the Civic Center in Valdez, one block from the
Inn. The cost will be $1125 per person, from Anchorage, round trip, based
on double occupancy. Those requesting a single room (limited availability)
will pay an additional $350 for the week.
The relatively easy air access to Anchorage, and somewhat modest hotel,
make this a normal cost for Penrose Conference participants despite the
rather remote location. We are still in the process of applying for and
allocating additional funding to help defray travel costs for some
participants, so the cost could go down. If cost is a major problem, and
makes the difference between attending and not being able to come, please
let the Conference conveners know via email.
Some participants may wish to make their own plans for travel back from
Valdez to Anchorage, for example via the Alaska State Ferry system from
Valdez to Whittier,
(ferry info at http://www.dot.state.ak.us/amhs/schedres/scheds/S06.htm)
and then by bus or train from Whittier through the new tunnel to Anchorage
(info at http://www.themagicbus.com/ and http://www.alaskarailroad.com/)
HOWEVER, if you decide to choose this option (1) you may wish to make
bookings on the train or bus soon, because the "public" transportation can
fill up with cruise ship groups, and (2) PLEASE let the conference
organizes know as soon as possible via email so that we can potentially
save some money on the bus from Valdez to Anchorage.
Field trips: Weather permitting, there will be a field trip to look at
outcrops of the volcanic section of the Jurassic Talkeetna arc, accessible
via a short bushwack from the highway about halfway from Anchorage to
Valdez on July 9. There will also be an all day, mid-week field trip to
look at some Moho depth exposures of gabbronorite, mafic garnet granulite,
pyroxenite and residual harzburgite in the Talkeetna arc section, starting
at a trailhead about two hours drive from Valdez on July 12 (with a
possible rain date for one or the other field trip on July 15). Both field
trips will involve some moderate, off-trail hiking (brush on July 9, talus
on July 12) and are, of course, optional.
Depending on the level of interest, we may also offer an optional
(expensive, helicopter supported, overnight) field trip to the lower
crustal rocks of the Klanelneechina klippe for participants experienced in
alpine back-country travel. Lithologies record equilibration at about 700°C
and 7 kb, and include garnet two-pyroxene quartz diorites (AKA granulites)
and garnet tonalite veins. Garnet is igneous in both of these lithologies,
as revealed by heavy rare earth element enrichment. There are also variably
retrogressed granulite-facies mylonites in the klippe. Let the Conference
conveners know if you are interested.
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