Antarctichron/Chronothon 2019

2019 Antarctichronothoneers in Aravaipa Canyon, 4th of July 2019:

Back L to R: Serhiy Buryak, Carson Kinney, Stuart Thomson, Kyle Parsons, Kathy Licht, Connor Watkins, Donglai Yang, Bailey Nordin, Sam Kodama, Sidney Hemming;
Front L to R: Stephen Cox, Pete Reiners, Lydia Bailey, Alex Pritika, Luca Grewe;
NP: Chris Mallery

Antarctichron/Chronothon 2019
Student Presentations
Monday 8 July 2019, 9 am - 12 noon
Gould-Simpson 203, University of Arizona

9:00-9:15

Lydia Bailey

University of Arizona

The mystery of Temple Mountain

9:15-9:30

Serhiy Buryak

University of Alberta

(U-Th)/He and U-Pb dating of Pleistocene tephra beds in Northwest North America

9:30-9:45

Kyle Parsons

Auburn University

Time-temperature paths for the exhumation of basement rocks within the Miller Range using U/Pb, 40Ar/39Ar, and (U-Th)/He

9:45-10:00

BREAK

10:00-10:15

Chris Mallery

Indiana Univ - Purdue Univ Indianapolis

Inferring the bedrock history of Red Raider Rampart via glacial moraine till

10:15-10:30

Bailey Nordin

Columbia University

Glacial erosion and uplift in the Central Transantarctic Mountains

10:30-10:45

Carson Kinney

University of Waterloo

The quandary of the Marie Byrd Land dome: Discoveries from double dating of on-land  and offshore crystalline rocks

10:45-11:00

BREAK

11:00-11:15

Connor Watkins

Indiana Univ - Purdue Univ Indianapolis

Tracing the origin of an Iceberg Alley dropstone and its implicaitons for Antarctica’s glacial history

11:15-11:30

Donglai Yang

Wesleyan University

“Hunt the groundhog” — What can the no-where-to-find craton enlighten us about ice flow paths following Oi-1 glaciation?

11:30-11:45

Sam Kodama

Columbia University

Erosional history of Wilkes Land Subglacial Basin using detrital apatite thermochronology

11:45-12:00

Luca Grewe

University of Bremen

Cenozoic Cooling History of Mt. Murchison, Mountaineer Range (TAM)


Our 2019 geo/thermochron workshop
will focus on Antarctic geo/thermochronology but will also provide opportunities for students interested in using (U-Th)/He dating (and possibly U/Pb, FT, 40Ar/39Ar dating) applied to other regions.

As with previous incarnations of our summer workshops, students will participate in an intense 2-week "chronothon" of analysis, interpretation, modeling, and presentation of thermochronology (mostly (U-Th)/He dating-focused). Students will bring their own mineral separates from their projects, and will prepare and analyze apatite, zircon, and other minerals for He dating. There may be opportunities to combine these with FT, U/Pb, and Ar dates too, through collaborations with co-instructors.

Antarctichron/Chronothon 2019 is aimed primarily at advanced undergraduate and early-career graduate students who are working on their senior theses or are in the early phases of their graduate research. The goals of the workshop are 1) to provide an opportunity for students to perform geochronologic and thermochronologic analyses on their own samples and 2) to provide some training and experience in the fundamentals of geochronology/thermochronology, diffusion, and analytical techniques, and 3) to provide an integrated perspective on geologic processes and phenonomena in Antarctica that can be addressed through radioisotopic dating.

 

Information on previous workshops (e.g.,HeDWaY and HeDWaAZ), or Antarctichron 2011, or Multichron)

Antarctichron/Chronothon 2019 Tentative Dates
24 June - 8 July
(arrival 23 June, departure 9 July)

Instructors: Peter Reiners, Stuart Thomson, Sidney Hemming, Kathy Licht, Stephen Cox
with help from Uttam Chowdhury, Mark Pecha, George Gehrels, and Christine Siddoway

 

 

Rationale and general description

The goal of this workshop is to introduce undergraduate and graduate students to geo- and thermochronology through some applications to the geology of Antarctica (though projects focused on other regions will be considered too). Students will analyze and interpet their own samples and data, in the context of their own research projects. Through both hands-on analyses and interpretations, as well as informal lectures and discussions, students will learn fundamentals of radioisotopic dating, laboratory techniques, analytical instrumentation, basics of thermochronologic modeling, the geology of Antarctica, and each others' research projects. Each student's project during the workshop will focus on a small set of samples to be dated by (U-Th)/He, U/Pb, Ar/Ar, and in some cases, fission-track methods. Ideally, a student's accomplishments at this workshop should complement a larger research project supervised by the student's faculty advisor at his or her home institution.

 

Important points

[1] Unless other arrangements have been made, students must arrive with mineral separates already prepared and ready to pick under the microscope. We will not perform mineral separations here, so please insure that good clean mineral separates are completed and available well before the workshop starts. For students wishing to perform U/Pb analyses, it would be a good idea to have your grain mounts made, characterized by SEM if necessary, and ready to rock once you arrive. If this isn't possible, please make sure you've made arrangements beforehand.

 

[2] If you want to do (U-Th)/He dating be prepared for the possibility that your chosen samples/field area may not have usable material for (U-Th)/He dating. This is especially important for apatite He dating, as the method has stringent requirements of crystal morphology and purity. Think about a backup plan, and bring several sets of samples so that you have a better chance of obtaining some data that are useful and interesting.

 

[3] There is no requirement for direct faculty involvement in the workshop, beyond general supervision of student research and help with data interpretation at the student's home institution. If faculty would like to attend and participate in the workshop however, they are certainly more than welcome at any point, to learn about the technique and to facilitate future use of the lab by other students or themselves.

 

[4] Please bear in mind that actually accomplishing everything we want to do and obtaining real, good, usable data with geologic significance for everyone requires proper alignment of various cosmic bodies, good karma, properly functioning analytical equipment, lack of power outages, fully functioning and healthy instructors and lab managers, and you name it. We have done this before and know how to take appropriate steps to maximize the chances of all this. But be aware that sometimes feces happens. We will all work together to avoid and ameliorate fecal outcomes, but there's no guarantee.

 

Accomodations, food, other logistics

[1] Room and board will be covered by Antarctichron, through funds from NSF's Antarctic Earth Sciences Program. Students will stay on campus in dorms. These are very close (easy walking distance) to Gould-Simpson and PAS where we will be working. These are pretty standard dorm rooms, and full linen service will be available. Yes, there is air conditioning.

 

[1.5] Students should plan on showing up at Coronado Hall, see map (https://map.arizona.edu/), on 23 June. Someone will be there to let you in and make sure you get settled. If you can't make this arrival/check-in time, please make sure you've arranged this with me (Pete). Then let's meet at 9 am on 24 June in PAS 534.

 

[2] Students will eat in cafeterias and other on-campus food venues that are within easy walking distance. You will have ID cards that allow you to spend a certain amount (should be more than enough for plenty of sustenance!) each day.

 

[3] Internet and email access is available through the UA Public Wifi. Computers will be available for student use in Gould-Simpson, but if you have a laptop, it might be a good idea to bring it.

 

[4] We will provide a chemical and laboratory safety training the first day of the workshop, to acquaint students with lab safety and hazards.

 

[5] There will be a one-day field trip on July 4th, to take a break from labwork and lectures, and to see some regional geology. This will be iin Aravaipa Canyon. We will provide vehicles and transportation. It will be hot. Bring some old sneakers for hiking in a shallow stream.

 

[6] UA map, and see links under "More Resources" for other helpful info.

 

[7] If you intend to bring your own vehicle, contact Pete for information on parking.

 

 

Tentative schedule

The general daily routine will be a combination of laboratory work and one or two lectures and discussions, broken up by lunch.

 

In order to accomplish everything we need to do and make sure everyone gets at least some data to ponder, the beginning of the workshop will be pretty hectic. The first day will include some orientation, lab safety training, and an overview of Antarctic geology. We will also start with sample preparation, and probably some U/Pb analyses right away that day.

 

A lot of you will spend time doing picking on the microscopes, followed by analyses on the He lines, followed by ICP-MS analyses for U-Th-Sm. Some of you will also do U/Pb dating in the Arizona Laserchron Center. This mostly involves sample picking under the microscopes for the first few days. Because we only have three picking microscopes, and also because no one can or wants to pick for more than a few hours at a time, students will take turns picking, and doing some library research in the first few days. As samples become ready, students will process them on the He line. This means running the laser to extract He, and operating the programs that spike, purify, and measure the gas.

 

Students will then perform wet chemistry involved with spiking, dissolution, and measurement of U, Th, and Sm on the high-resolution ICP-MS. After calculating ages from their measured data, and making corrections for alpha ejection, students will learn how to interpret He ages, in terms of forward and inverse thermal models, complexities that arise from topography, non-constant geothermal gradients, and other factors.

 

Finally, students will compile and synthesize their data and relate them to their larger project, and prepare a short presentation for the group on their results.

 

Tentative Schedule: Antarctichron/Chronothon 2019 (subject to change as plans evolve)
Sunday Monday Tuesday Wednesday Thursday Friday Saturday

June 23

arrive

check into dorm

June 24

intro lectures, lab safety

picking clinic

Lecture: Intro to geology of Antarctica (Siddoway)

June 25

Picking zircs He line (zircs)

Lecture: IODP cruise adventures and science (Siddoway)

June 26

Picking zircs He line (zircs)

Lecture: (U-Th)/He dating (Reiners)

June 27

Picking zircs He line (zircs)

Lecture: Glacial history of Antarctica (Licht)

June 28

He line (all remaining zirc samples)

Lecture: EAGLE project (Thomson)

June 29

spike/acidify zircons; all zircons into oven

Lecture: Circum-Antarctic detrital sources, iceberg armadas (Hemming)

June 30

Picking aps He line (aps) aps spiked, dissolved

zircs HF day 1

Lecture: 21Ne and 4He/3He chronometry (Cox)

July 1

Picking aps He line (aps) aps spiked, dissolved ICP-MS (aps)

zircs HF day 2

Lecture: Fission-track dating (Thomson)

July 2

zircons HF day 3

Oven off Picking aps, He line (aps) aps spiked, dissolved ICP-MS (aps)

Lecture: U/Pb tracing of ice flow (Licht)

July 3

zircs out oven, dried
zircs in HCl, back in oven

He line (all remaining aps)

Lecture: 40Ar/39Ar dating and Antarctic applications (Hemming)

July 4

FIELD TRIP ALL DAY

oven off
ICP-MS aps

all remaining aps spiked, dissolved
data interpretations

July 5

ICP-MS (all remaining aps)
zircos out of oven, dried, dissolved in HNO3, diluted
data interpretations

ICP-MS

Lecture: U/Pb dating (Gehrels)

July 6

ICP-MS (zircs)

data interpretations
prepare presentations

July 7

data interpretations

prepare presentations

July 8

FINAL PRESENTATIONS

July 9

check out of dorm in morning

depart

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Last updated 8 June 2019