CLIMATIC AND TECTONIC INSIGHTS FROM LOW-TEMPERATURE THERMOCHRONOMETRY ACROSS THE HIMALAYAN RAIN SHADOW EVEREST REGION NEPAL AND TIBET

Project: Research project

Description

Work Plan U.S. personnel for the project described in this proposal will include the PI and a Ph.D. student at Arizona State University. The PI has a 12-month appointment at ASU; as a consequence, no funds are requested for his salary even though he will spend several weeks each year directly involved in the research (in addition to his mentoring responsibilities for the student). The budget includes funds for tuition and stipend for the student. Todd Ehlers from the University of Tbingen will be an important international collaborator, making his laboratory available for fission track dating and leading the thermokinematic modeling efforts (see letter of support). Ehlers will receive no NSF funds for his personal contributions and will bear all of his own thermochronologic and modeling research costs. As his letter of support shows, he is submitting a parallel proposal to the German Science Foundation (DFG) for this work. As his letter indicates, however, Todd is committed to the success of this project and in the event that the DFG proposal is not funding or if funding is delayed will redeploy some resources other sources already in hand to ensure the success of the ASU component of the project proposed here. The field component of the proposed research will be conducted in both central Nepal (on the southern approaches to Everest) and in southern Tibet (in the Rongbuk valley). The fieldwork in Nepal will be conducted during Year 1 with the assistance of Bhim Chand of Earth-Paradise Treks& Logistics in Kathmandu. My students and I have been fortunate enough to work with Bhim in Nepal for over a decade, and he is masterful at negotiating the intricacies of permitting and logistics. As is our standard practice for Nepal research, we will coordinate with geologists at both Tribhuvan University in Kathmandu and the Nepal Department of Mines& Geology. We have budgeted for the PI and the student to spend three weeks in Nepal collecting samples and mapping their geologic context. This budget, developed in consultation with Bhim, includes: 1) international roundtrip airfare from Phoenix to Kathmandu; 2) domestic roundtrip airfare from Kathmandu to Lukla, the nearest small airport to the study area; 3) nominal food and accommodation costs (in simple teahouses along the major trekking routes in this region); and 4) sample shipping back to the United States. No funds are being requested for the fieldwork in Tibet, which will be piggybacked onto on-going research on the Indus-Yarlung suture zone already funded by NSF through the Continental Dynamics program. Our established Chinese collaborator on that project, Ding Lin of the Institute of Tibetan Plateau Research, will also collaborate with us on the Everest work. The Tibetan fieldwork will be done sporadically during Years 1-2 because only a small portion of my field time in Tibet each year can be devoted to this side project as my colleagues and I travel to and from key field areas along the suture zone. Despite this logistical issue, piggybacking the north side research onto the Continental Dynamics project substantially reduces the field cost of this project. Sample characterization and (U-Th)/He analytical work for this project will be conducted in the Noble Gas Geochronology and Geochemistry Laboratories (NG3L) at Arizona State. As noted above, our teams intention is that all zircon and apatite samples also will be dated by the fission track work method at the University of Tbingen. Analytical work on collected samples will be done throughout the three years of the project. Based on conversations with Todd, our best estimation of the data necessary for characterization of the exhumation pattern in the study area, as well as for robust thermokinematic modeling, we have budgeted for noble gas and fission track dating of four different minerals in 30 samples using 6 mineral-isotopic systems. This represents a tremendous amount mineral separation and analytical time, especially since we produce 3-5 replicates of each helium or fission track date for each mineral in a sample. Each zircon, monazite, xenotime, or apatite crystal will be characterized by thermoluminesence and backscattered electron imaging prior to dating. Sample characterization and analytical costs are based on established grant-supported usage fees for NG3L. These items include mineral separation costs and the costs of grain mount preparation. Note that the budgeted amount is substantially less than the cost would be if we simply multiplied the total number of dates (several hundred) by our nominal per date laboratory rates because of economies of scale. In Year 2, we have also budgeted international travel funds for the ASU student to visit Tbingen for fission track and modeling work.
StatusFinished
Effective start/end date4/1/143/31/19

Funding

  • National Science Foundation (NSF): $245,808.00

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tectonics
student
cost
fieldwork
fission track dating
mineral
noble gas
suture zone
apatite
modeling
logistics
zircon
rain
project
xenotime
economy of scale
monazite
airport
shipping
exhumation