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TECTONIC EVOLUTION OF THE FLYSCH OF THE CHUGACH TERRANE ON BARANOF ISLAND, ALASKA (YEAR THREE) John Garver (Union College) Cameron Davidson (Carleton College) 2012 Keck Geology Consortium Proposal (for Summer 2013 to Academic year 2013-14) 1.0 Executive summary This four-student project focuses on the tectonic evolution of the Chugach-Prince William terrane in Southeast Alaska, and it is a continuation of our 2011, and 2012 projects and builds on our growing experience in Alaska. This thick accretionary complex is dominated by Campanian-Paleocene (c. 75-55 Ma) trench fill turbidites likely derived from the uplift and exhumation of terranes to the south (BC, Washington, perhaps farther) and then arrived in Alaska in the Eocene after coast-parallel translation. Near-trench plutons of the Sanak-Baranof belt imprinted a distinctive thermal event on these rocks and are a key indicator of plate position between 61-50 Ma. The primary study area for 2013 is the Sitka Graywacke in Sitka, Alaska, and the nearby and presumed metamorphosed equivalent, Baranof Schist in Whale Bay in the South Baranof Wilderness Area. Student projects will be focused on metamorphism and thermal evolution of these rocks, and sedimentary provenance including U/Pb dating of detrital zircon. 2.0 Geologic Overview This multi-year Keck project is focused on understanding the tectonic evolution of the Chugach-

Prince William terrane in south central Alaska. This overall effort has been co-funded by the Keck Consortium and by the National Science foundation through parallel grants to Garver and Davidson entitled “Provenance and thermal evolution of the Chugach-Prince William terrane flysch, southern Alaska.” Our work on this belt started in 2009 in Kake, Alaska on the Kootznahoo Fm., (Davidson, Wirth, White Keck project) and since that time we have focused efforts on similar aged-strata in the more outboard units of the Chugach and Prince William terranes. The 2011 Keck project included a successful 4-week field season in Prince William Sound and Kodiak Island. The 2012 Keck project was focused on Maastrictian rocks of the Valdez Group in Seward (Kenai), and the Shumagin Fm. on Nagai Island. The effort here is to evaluate the provenance along strike of the entire belt (see field sites, Fig. 1 - * means non-Keck funded).

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The Chugach-Prince William (CPW) composite terrane is a Mesozoic-Tertiary accretionary complex that is well exposed for ~2200 km in southern Alaska and is inferred to be one of the thickest accretionary complexes in the world (Plafker et al., 1994; Cowan, 2003). The CPW terrane is bounded to the north by the Border Ranges fault, which shows clear evidence of Tertiary dextral strike slip faulting, and inboard terranes of the Wrangellia composite terrane (Peninsular, Wrangellia, Alexander) (Pavlis, 1982; Cowan, 2003; Roeske et al., 2003). In the west, the southern margin of the CPW terrane is defined by the offshore modern accretionary complex of the Alaskan subduction zone, but east of Prince William Sound the Yakutat block (yellow unit, Fig. 1) is colliding into the CPW and this young collision has significantly affected uplift and exhumation of inboard rocks (Enkelmann et al., 2010).

Most of the Chugach-Prince William terrane is comprised of imbricated trench-fill turbidites deposited over a relatively short interval of time (Campanian to Paleocene – c. 75-55 Ma) and by some estimates the volume of sediment is between 1-2 million km3 (i.e. Decker, 1980; Sample and Reid, 2003). The turbidites are imbricated with oceanic igneous rocks (pillow basalts and locally full ophiolitic suites of Resurrection Bay and Knight Island) that provide important clues about the nature and location of adjacent oceanic lithosphere. Two projects in 2011 were directed toward understanding the paleomagnetism (Steve Espinosa, UT-El Paso) and geochemistry (Lucy Miner, Macalester) of this ophiolite. In the study area, primary units of this thick flysch facies are the Campanian-Maastrictian Valdez Group (project of Pettiette, 2012) and Shumagin Fm (projects of Roe and Deluca, 2012), and the more outboard Paleocene Orca Group (projects of Hannah Hilbert-Wolf, Carleton; Ben Carlson, Union; and Sarah Olivas, UT-El Paso – all 2011). Very soon after imbrication and accretion to the continental margin, rocks of the CPW were intruded by near-trench plutons of the Sanak-Baranof belt (SBB) that has a distinct age progression starting in the west (61 Ma in the Sanak-Shumagin areas) and progressively younger to the east (50 Ma on Baranof Island) (Keck project of Alex Short, ongoing; Bradley et al., 2003; Haeussler et al., 2003; Kuskey et al., 2003; Farris et al., 2006). Following structural burial and intrusion of the SBB plutons, the entire assemblage was progressively and diachronously exhumed with the youngest exhumation ages east of Prince William Sound in the St. Elias Range, and is the focus of the NSF-funded STEEP project (Garver has been involved with this project from its beginning) (Enkelmann et al., 2009, 2010). Paleomagnetic and geologic data indicate that the CPW has experienced significant coast-parallel transport in the Tertiary, although this conclusion is controversial (cf. Cowan, 2003 and Haeussler et al., 2003). The CPW has apparent equivalents to the south, and this geologic match suggests that in the Eocene, the southern part of the Chugach-Prince William terrane was contiguous with the nearly identical Leech River Schist exposed on the southern part of Vancouver Island (Cowan, 1982; 2003). The geological implication of this hypothesis is profound yet elegant in the context of the Cordilleran tectonic puzzle: the CPW is the Late Cretaceous to Early Tertiary accretionary complex to the Coast Mountains Batholith Complex (CMBC) that intrudes the Wrangellia composite terrane (WCT, or Insular superterrane) and North America. Thus, the CPW is inferred to have accumulated in a flanking trench to the west and then soon thereafter these rocks were accreted to the margin and translated north. This geologic match is elegant because it suggests that the CPW accumulated outboard the Coast Mountains Batholith Complex (Gehrels et al., 2009) and that the CPW essentially is the erosional remnants of that orogenic belt. Although elegant, it may be wrong. Soon to be published paleomagnetic data from Kodiak will show paleolatitudes of Paleocene rocks as far south as California (Housen and Roeske, unpublished), hence we need to search far and wide for candidate source rocks. Thus the focus of our effort is on the very thick rocks of the CPW accretionary terrane that were intruded by near trench plutons and then translated some controversial distance along the North American margin in the early Tertiary. Recall that this is year three of a three-year effort to sample similar rocks along the entire belt. This year we proposed look at the easternmost rocks, which are likely the most complicated (why we saved these for last).

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Our Previous work for this Keck project: A large fraction of our effort has been focused on evaluating the provenance and thermal history of the Campanian to Eocene flysch in Prince William Sound (Orca Group, Valdez Group), and correlatives on Kodiak Island (Kodiak, Ghost Rocks, Sitkalidak). For single grain U/Pb dating we have thus far dated 2888 single grains from these sedimentary units and of those single grain ages, and 801 are U/Pb and ZFT double dates. We also have successfully dated six plutons in Prince William Sound. Our data set also includes 903 single fission track ages centered on rocks in the Prince William Sound area. In addition, we have evaluated single-grain crystallinity using Raman spectroscopy on 537 U/Pb dated zircons. For our paleomagentic study on the Knight Island Ophiolite and nearby Eshamy pluton, we collected from 25 sites and had mixed results from about half of them. For whole rock geochemistry, we used the Macalester XRF laboratory to analyze 25 samples from the Paleocene Knight Island Ophiolite and related rocks, and 22 samples from the Late Eocene Eshamy Suite Plutons. For this entire process, we have guided six students through the research project that led to senior thesis research, and we are currently mentoring five students in our 2012-13 project: this effort is ongoing. 3.0 STUDY AREA – Baranof Island For the 2013 field season (2013-14 project) we plan to target two areas on Baranof Island near Sitka with a goal of understanding the relationship between the Sitka Graywacke and the Baranof Schist, and to address the timing of post-metamorphic cooling. The geology of Baranof Island SW of the Neva Straight Fault (Fig. 2) is our primary target and there are three basic units we need to consider: 1) Sitka Graywacke, 2) Crawfish Inlet Pluton (Eocene); and 3) Baranof Schist. Bedrock in and around Sitka consists of the Sitka Graywacke. Recent detrital zircon U/Pb work (Haeussler et al., 2005) on these prehnite-pumpyllite grade flyschoid rocks suggests that the flysch strata have two different ages (Fig. 2). Those rocks to the SW have zircon as young as 72 to 74 Ma (Campanian-Maastrictian or younger), and more inboard rocks have older young ages of around 97-105 Ma (Albian-Cenomanian or younger). Thus this initial work has demonstrated that the outboard rocks of the Sitka greywacke are likely Campanian-Maastrictian, and hence correlative to the Valdez Group (ongoing work by Keck student Petiette), the Kodiak Formation (work of Olivas in 2012), and the Shumagin Formation (ongoing work by Keck students DeLuca, Roe). The older unit (Albian-Cenomanian) is more complicated, and this unit is new to us (in fact it has no correlatives west of Yakutat Bay). Our preliminary ZFT ages on these rocks show thermal resetting at ~50 Ma – similar to rocks to the west. To the south/southeast, the 51 Ma Crawfish Inlet Pluton intrudes these two units of the Sitka Graywacke, and the contact aureole is sharp and narrow (but not well studied). South, southeast of the pluton is the widely exposed Baranof Schist, which is inferred to be the metamorphic correlative of the Sitka Graywacke. The Baranof Schist is relatively well studied, and it provides some key insight into the metamorphic evolution of this area (Loney et al., 1975; Loney and Brew, 1987; Zumsteg et al., 2003). The most detailed recent study of the Baranof Schist identifies two key metamorphic events that have affected these rocks (M4 and M3; see Zumsteg et al., 2004). The last metamorphic event (M4) is related to contact metamorphism and regional heating by what are inferred to be Eocene near trench plutons (here the Crawfish Inlet Pluton, 51 Ma). This metamorphism is well-dated because it is recognized as contact metamorphism adjacent to the pluton, and it resulted in high-temperature mineral assemblages of sillimanite and andalusite. This late high T metamorphism (M4) appears to overprint a regional burial metamorphism (M3) that resulted in Biotite and Garnet facies metamorphic assemblages that extend 12 and 25 km out from the pluton (and hence are inferred to predate plutonism). This is where the problems start. The biotite to garnet-grade metamorphism is inferred to be driven by regional burial in a subduction wedge, and elsewhere in this area M3 is inferred to be mid-Cretaceous (91-106 Ma) based on dated metamorphic actinolite and sericite. However, these dates are from rocks relatively far away and on the north side of the Nevi Fault and therefore probably do not apply to our proposed study area.

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Here is the problem: The relationship between the Sitka Graywacke NNW of the Crawfish pluton and the Baranof schist to the SSE of the pluton is not known, but it has long been thought that they are essentially the same, but for some reason different metamorphic levels are exposed (S. Karl, pers. com, 2012). If this is the case, then the Baranof Schist (SSE of pluton) is as young as Campanian-Maastrictian (Upper Cretaceous), and hence the early metamorphism (M3) cannot be mid-Cretaceous in age, but rather must to Late Cretaceous or younger. Given our experience with rocks elsewhere in this belt, we suspect that the burial metamorphism is Early Eocene, and this was quickly followed by thermal metamorphism in the Early to Middle Eocene. In other words, it was accreted, buried, metamorphosed, and then slab window heating affected the sequence at 50 Ma. If this scenario is correct, then there is an older sequence of rocks (mid-Cretaceous) that have a mid-Cretaceous regional metamorphism, which are unrelated to the flysch of the CPW terrane, but are more likely allied with the Wrangellia Composite terrane.

Figure 2: Simplified geologic map of Baranof Island showing primary geologic relationships south of the Neva Straight Fault. Field work starts in Sitka, and we will re-examine the rocks studied by Hauessler et al. (2004), and then focus on Whale Bay which transects different metamorphic grades of the Baranof schist, and then Crawfish Inlet Pluton (modified from Loney et al., 1975; Loney and Brew, 1987; Zumsteg et al., 2003).

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4.0 GOALS AND SIGNIFICANCE OF THE PROJECT The goal of this project is to determine the tectonic history of the CPW terrane. This goal involves several distinct objectives that include: 1) determining the depositional setting and source of the flysch of the Chugach terrane; and 2) evaluating the intrusive history of the belt. Part of our strategy of sampling the age correlative Shumagin and Valdez rocks is to compare the provenance of these rocks along strike so that we can evaluate their assumed correlation. This project is significant because it will allow students to work in units that are classic in Cordilleran tectonics, and the results will directly feed into ideas of terrane translation and development of the Cordilleran tectonic collage. The project has broader significance because the translation, intrusive history, and exhumation of the Chugach terrane is directly related to deposition in flanking basins, including the hydrocarbon rich Cook Inlet basin. 5.0 STUDENT PROJECTS Although the basic geological relationships are known for much of this area, there has been little analytical work with modern techniques on these rocks. See the Appendix for detailed descriptions of the student projects briefly outlined below. 5.1) Exhumation of the CPW. A key to understanding the evolution of the CPW is the timing and nature of exhumation revealed through cooling ages of zircon and apatite. The two study sites are ideally situated for thermochronology because their thermal history is poorly known and far enough apart to allow us to see changes on either side of the pluton (1-2 projects). 5.2) Provenance of the sandstones and conglomerates of the CPW. A major question is whether the sediments of the CPW flysch are the erosional remnants of the Coast Mountains Batholithic Complex in Southeast Alaska and British Columbia. U-Pb dating of detrital zircon from the Sitka Graywacke and also the Baranof Schist will provide important insight into the source of these sediments. (1-2 projects). 5.3) Tectonic significance of young, near trench plutons. The flysch in both study locations is intruded by the Crawfish Inlet Pluton. The age of this pluton is well established, and we are interested in understanding the geochemistry of this pluton (and others in the belt), and depth of emplacement (1-2 projects). 6.0 SYNTHESIS This work will be synthesized in papers and meeting presentations as it is part of our larger ongoing research in southern Alaska. Garver have been involved with the STEEP (St. Elias tectonics and erosion Project) continental dynamics project since 2005, and numerous publications have come from that work. Davidson has worked for years in SE Alaska, and likewise he has a good publication record from those projects. 7.0 PROJECT LOGISTICS • Project Leaders: John I. Garver (Union) (tectonics, thermochronolgy, sedimentation and tectonics) and Cameron Davidson (Carleton) (metamorphic petrology, structural geology and tectonics). • Four (4) student project. • Dates: 15 June – 12 July 2013 (tentative).

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• Location: Entirely in Alaska. [1] Gathering in University of Alaska (Anchorage) and field trips, [2] drive with gear east across Alaska to the Yukon, south to Haines [3] Travel by ferry to Sitka; [4] Whale Bay, Baranof Island; [5] return Anchorage, pack, and depart. Canada travel is part of this effort, so a passport is required. 8.0 ALASKAN SAFETY ISSUES AND OTHER (AND WEB DISCLAIMER) Davidson and Garver have been doing research in the northern Pacific Rim for over 20-25 years (each) with primary field areas in Kamchatka, Alaska, British Columbia, and Washington. Thus we are familiar with safety issues, especially those related to Bears and Boats. There is little question that there are a host of inherent risks in this proposed work: here we briefly address the most common concerns. 8.1 Bears. The primary issue of concern is Black and Brown Bears on Baranof. In Whale Bay we will spend the bulk of our time in coastal waters as a group, hence our exposure is reduced. Our field season coincides with the Sockeye run, so almost all bears (black or brown) are fully pre-occupied with fish. We train the students in the use of bear deterrents. We will have bear bangers (a small pen-sized explosive charge) and Bear Spray for all students. These items (Bangers and Spray) are in hand, which is why they were not budgeted. We will not carry guns as they present their own unique hazard with students that we feel is bigger than the hazard of well-fed bears. We will train students in dealing with bear encounters in the orientation in Anchorage. In Brown Bear country, group size will be 3, which statistically has only small issues compared to parties of 2 or less (i.e. USGS bear safety training). Given that this particular season will provide a challenge with bears, we will purchase an electric fence for camp. Students are prohibited from personal use of MP3 players in bear country and are required to sleep with bangers and mace.

8.2 Boats and Communication. We will be using two 14 ft Zodiac inflatable boats with aluminum floors and 30 hp 4-stroke engines (one belongs to Carleton; one Union: both are currently in storage in Anchorage). As in 2011 and 2012, Students will be instructed in safe boating practices and will be required to wear life jackets when on the water (which we have). The boats are fully equipped and safety features onboard each boat conform to US Coast Guard regulations for Alaska marine waters. Students are also instructed in the use of signal flares, required by the US Coast guard. Finally, students are required to know protocol for VHF radio

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use and distress signaling. Whale Bay in the South Baranof Wilderness area is very remote and we will rent a Satellite phone for emergencies. 8.3 (this is the Web disclaimer) WORKING CONDITIONS: Fieldwork will be in remote and isolated areas in Alaska that have special logistical challenges - please read this section carefully. We will use boats for fieldwork around Baranof Island in remote SE Alaska. Weather will be wet, rainy, and cold, so participants must be prepared with complete rain gear and rubber boots and gear for SE Alaska. You must be comfortable with camping in remote harsh conditions with no nearby facilities or communication with the outside world (no internet or cell coverage); we will have a satellite phone for emergency use only. Personal music devices (i.e. iPod or equivalent) are prohibited in the field while in bear country. There will be required hiking and work in steep terrain with significant elevation, we camping with no electricity/refrigeration, and there is a high probability of bear encounters. Certain dietary restrictions may be accommodated, but many essential meals will be based on fish. You might be required to travel in small fixed-wing aircraft, and field studies will be in part in Zodiac inflatable boats in cold marine conditions that require onsite safety training. A valid passport is required for this project because travel is in part in Canada. 8.4 (this is the Web disclaimer) RECOMMENDED COURSES/PREREQUISITES: We are looking for rising seniors with an interest in Tectonics and those with a high degree of comfort in rough outdoor settings. To be accepted on this program you must be a rising senior who will complete course credit for a senior thesis (or equivalent) in the following year (2013-14) as part of this research effort. Suggested, but not required are those core courses in the Geology major: Historical Geology, Structure/Tectonics, Stratigraphy, Mineralogy and Petrology. Experience at a field camp or in a field geology course is strongly recommended but not required. Work from this project must carry over into the senior year (2012-13) as a required senior thesis (or equivalent) and the supporting letter from the on campus advisor must indicate how a thesis requirement figures into the senior year course load. Helpful, but not required in the letter from the on campus advisor is an indication of how well the applicant will function considering the special conditions outlined above.

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10.0 PRINCIPLE REFERENCES Amato, J.M., and Pavlis, T.L., 2010. Detrital zircon ages from the Chugach terrane, southern Alaska, reveal multiple

episodes of accretion and erosion in a subduction complex; Geology; v. 38; no. 5; p. 459–462.

Bol, A.J., Coe, R.S., Grommé, C.S., Hillhouse, J.W., 1992. Paleomagnetism of the Resurrection Peninsula, Alaska: Implications for the tectonics of southern Alaska and the Kula-Farallon ridge, J. Geophys. Res. v. 97, p. 17213-17232.

Bradley, D.C., Kusky, T.M., Haeussler, P.J., Goldfarb, R.J., Miller, M.L., Dumoulin, J.A., Nelson, S.W. & Karl, S.M. 2003, Geologic signature of early Tertiary ridge subduction in Alaska; Geology of a transpressional orogen developed during ridge-trench interaction along the North Pacific margin, Special Paper - Geological Society of America, vol. 371, pp. 19-49.

Bradley, D.C., Haeussler, P., O’Sullivan, P., Friedman, R., Till, A., Bradley, D., and Trop, J., 2009, Detrital zircon geochronology of Cretaceous and Paleogene strata across the south-central Alaskan convergent margin, in Haeussler, P.J., and Galloway, J.P., Studies by the U.S. Geological Survey in Alaska, 2007: U.S. Geological Survey Professional Paper 1760-F, 36 p

Coe, R. S., B. R. Globerman, P. W. Plumley, and G. A. Thrupp, 1985, Paleomagnetic results from Alaska and their tectonic implications, in Howell, D.G., ed., Tectonostratigraphic terranes of the Circum-Pacific region, Amer. Assoc. Petrol. Geol., Circum-Pacific Council for Energy and Mineral Resources Series, 1, 85-108.

Cowan, D.S.,1982, Geological evidence for post-40 m.y. B.P. large-scale northwestward displacement of part of southeastern Alaska, Geology, v. 10 p. 309-313.

Cowan, D.S., 2003, Revisiting the Baranof-Leech River hypothesis for early Tertiary coastwise transport of the Chugach-Prince William terrane. Earth and Planetary Science Letters, v. 213, 463-475.

Decker, J.E., Jr., 1980. Geology of a Cretaceous subduction complex, western Chichagof Island, Southeastern Alaska. PhD. Thesis, Stanford University, 135 p.

Dusel-Bacon, Cynthia, Csejtey, Béla, Jr., Foster, H.L., Doyle, E.O., Nokleberg, W.J., and Plafker, George, 1993, Distribution, facies, ages, and proposed tectonic associations of regionally metamorphosed rocks in east- and south-central Alaska: U.S. Geological Survey Professional Paper 1497-C, 73 p., 2 pls., (1:1,000,000-scale colored map).

Enkelmann, E., Zeitler, P.K., Garver, J.I., Pavlis, T.P. and Hooks, B.P, 2010. The thermochronological record of tectonic and surface process interaction at the Yakutat–North American collision zone in southeast Alaska; American Journal of Science, v. 310, p. 231-260.

Enkelmann, E., Zeitler, P.K., Pavlis, T.L., Garver, J.I., Ridgway, K.D. 2009. Intense Localized Rock Uplift and Erosion in the St. Elias Orogen of Alaska. Nature Geoscience 2, no. 5, p. 360-363.

Farris, D.W., Haeussler, P., Friedman, R., Paterson, S.R., Saltus, R.W. & Ayuso, R. 2006, Emplacement of the Kodiak Batholith and slab-window migration, Geological Society of America Bulletin, vol. 118, no. 11-12, pp. 1360-1376.

Garver, J.I., Enkelmann, E., Kveton, K.J., 2010. Uplift and exhumation of the Chugach-Prince William Terrane, Alaska, revealed through variable annealing of fission tracks in detrital zircon; Geological Society of America Abstracts with Programs, vol. 42, no. 4, p. 46.

Gallen, S.F., Housen, B.A., Roeske, S.M., O’Connell, K., 2007. Revisiting the Paleomagnetism of the Ghost Rocks Formation of the Kodiak Islands, Alas, Eos Trans. AGU, 88 (52), Fall Meet. Suppl., Abstract GP43C-1499.

Gallen, S.F., 2008. An investigation into the magnetic fabrics and paleomagnetism of the Ghost Rocks Formation, Kodiak Islands, Alaska; MSc. Thesis, Western Washington University, 119 p.

Gehrels, G.E., Rusmore, M., Woodsworth, G., Crawford, M., Andronicos, C., Hollister, L., Patchett, J., Ducea, M., Butler, R., Klepeis, K, Davidson, C., Mahoney, B., Friedman, R., Haggard, J, Crawford, W., Pearson, D., Girardi, J., 2009, U-Th-Pb geochronology of the Coast Mountains Batholith in north-coastal British Columbia: constraints on age, petrogenesis, and tectonic evolution. Bulletin of the Geological Society of America, v. 121, p. 1341-1361.

Haeussler, P.J., Bradley, D.C., Wells, R.E. & Miller, M.L. 2003, Life and death of the Resurrection Plate; evidence for its existence and subduction in the northeastern Pacific in Paleocene-Eocene time, Geological Society of America Bulletin, vol. 115, no. 7, pp. 867-880.

Haeussler, P.J., Gehrels, G.E., and Karl, S., 2005, Constraints on the age and provenance of the Chugach terrane accretionary complex from detrital zircons in the Sitka Greywacke, near Sitka, Alaska: in Haeussler, Peter J., and Galloway, John, eds., Studies by the U.S. Geological Survey in Alaska, 2004: U.S. Geological Survey Professional Paper 1709-F, p. 1- 24

Karl, S.K., Haeussler, P.J., Himmelberg, Glenn, and Zumsteg, C.Z., in press, Geologic map of Baranof Island, Alaska: U.S. Geological Survey Scientific Investigations Map, scale 1:250,000.

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Loney, R.A., Berg, H.C., Pomeroy, J.S., and Brew, D.A., 1963, Reconnaissance geologic map of Chichagof Island and northwestern Baranof Island, Alaska: U.S. Geological Survey Miscellaneous Geologic Investigations Map I–388, scale 1:250,000.

Loney, R.A., Brew, D.A., 1987, Regional thermal metamorphism and deformation of the Sitka Graywacke, southern Baranof Island, southeastern Alaska, USGS Bull. 1779, 17 pp.

Kusky, T.M., Bradley, D.C., Donely, D.T., Rowley, D. & Haeussler, P.J. 2003, Controls on intrusion of near-trench magmas of the Sanak-Baranof Belt, Alaska, during Paleogene ridge subduction, and consequences for forearc evolution; Geology of a transpressional orogen developed during ridge-trench interaction along the North Pacific margin, Special Paper - Geological Society of America, vol. 371, pp. 269-292.

Nelson, S.W., M.L. Miller, and J.A. Dumoulin, 1989, Resurrection Peninsula Ophiolite, in Guide to the Geology of Resurrection Bay, Eastern Kenai Fjords Area, Alaska, Guidebook, edited by S.W. Nelson and T.W. Hamilton, pp. 10-20, Geol. Soc. of Alaska, Anchorage.

O’Connell, K. 2008, Sedimentology, structural geology, and paleomagnetism of the ghost rocks formation; Kodiak islands, Alaska; M.S. Thesis, University of California at Davis, Davis, CA, United States, (USA).

Pavlis, T.L., 1982, Origin and age of the Border Ranges Fault of southern Alaska and its bearing on the late Mesozoic Tectonic Evolution of Alaska: Tectonics, v. 1, n. 4, p. 343-368.

Perry, S.E., Garver, J.I., Ridgeway, K., 2009, Transport of the Yakutat Terrane, southern Alaska, evidence from sediment petrology and detrital zircon fission-track and U/Pb double dating: Journal of Geology. v. 117, n. 3, p. 156–173.

Plafker, G., Moore, J.C. & Winkler, G.R. 1994, Geology of the Southern Alaska margin in The geology of Alaska, eds. G. Plafker & H.C. Berg, Geological Society of America, Boulder, CO, United States (USA), United States (USA).

Plafker, G., Nokleberg, W.J., Lull, J.S., 1989, Bedrock geology and tectonic evolution of the Wrangellia Peninsular, and Chugach terranes along the trans-Alaska crustal transect in the Chugach Mountains and southern Copper River Basin, Alaska: Journal of Geophysical Research, v. 94, No., B4, p. 4255-4295.

Plumley, P.W., Coe, R.S., Byrne, T., 1983. Paleomagnetism of the Paleocene Ghost Rocks formation, Prince William terrane, Alaska, Tectonics v. 2, 295-314.

Plumley, P.W., Coe, R.S., Byrne, T., Reid, M.R., and Moore, J.C., 1983. Paleomagnetism of the volcanic rocks of the Kodiak Islands indicates northward latitudinal displacement: Nature, v. 300, p. 50-52

Roeske, S.M., Snee, L.W. & Pavlis, T.L. 2003, Dextral-slip reactivation of an arc-forearc boundary during Late Cretaceous-early Eocene oblique convergence in the northern Cordillera; Geology of a transpressional orogen developed during ridge-trench interaction along the North Pacific margin, Special Paper - Geological Society of America, vol. 371, pp. 141-169.

Sample, J.C. & Reid, M.R. 2003, Large-scale, latest Cretaceous uplift along the Northeast Pacific Rim; evidence from sediment volume, sandstone petrography, and Nd isotope signatures of the Kodiak Formation, Kodiak Islands, Alaska; Geology of a transpressional orogen developed during ridge-trench interaction along the North Pacific margin, Special Paper - Geological Society of America, vol. 371, pp. 51-70.

Thrupp, G. A., and Coe, R.S., 1986, Early Tertiary paleomagnetic evidence and the displacement of southern Alaska, Geology, 14, 213-317.

Vrolijk, P., Myers, G. & Moore, J.C. 1988, Warm fluid migration along tectonic mélanges in the Kodiak accretionary complex, Alaska, Journal of Geophysical Research, vol. 93, no. B9, pp. 10-10,324.

Weinberger, J. & Sisson, V.B. 2003, Pressure and temperature conditions of brittle ductile vein emplacement in the greenschist facies, Chugach metamorphic complex, Alaska; evidence from fluid inclusions; Geology of a transpressional orogen developed during ridge-trench interaction along the North Pacific margin, Special Paper - Geological Society of America, vol. 371, pp. 217-235.

Zumsteg, C.L., Himmelberg, G.R., Karl, S.M., Haeussler, P.J., 2003. Metamorphism within the Chugach accretionary complex on southern Barnoff Island, southeastern Alaska. In: Sisson, V.B., Roeske, S.M., Pavlis, T.L. (Eds.), Geology of a Transpressional Orogen Developed During Ridge–Trench Interaction Along the North Pacific Margin. GSA Special Paper, vol. 371, pp. 253–268.

STUDENT ABSTRACTS/PAPERS (from this ongoing KECK Effort)

Garver, J.I., Davidson, C., Izykowski, T.I., Milde, E.R, 2011, Thermal evolution of flysch of the Chugach Prince William terranes, eastern Prince William Sound, Alaska" ,. Geological Society of America Abstracts with Programs, v. 43, n. 5, p. 553.

Davidson, C., Garver, J.I., Hilbert-Wolf, H.L., and Carlson, B., 2011, Maximum depositional age of the Paleocene to Eocene Orca Flysch, Prince William Sound, Alaska; Geological Society of America Abstracts with Programs, v. 43, n. 5, p. 439.

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Garver, J.I., and Davidson, C, 2012, Terrane translation in the north Pacific prior to establishment of the Aleutian- Kamchatka arc: History of the Olutorsky (Kamchatka) and Chugach- Prince William terranes (Alaska); Cordilleran Tectonics Workshop 2012, Victoria British Columbia, Abstracts and program, p. 19.

Olivas, S.J., Davidson, C., Garver, J.I., Doser, D., Hilbert-Wolf, H.L., 2012, U/Pb detrital zircon study of the Upper Cretaceous to Eocene strata of Kodiak Island, Alaska" Geological Society of America Abstracts with Programs (Rocky Mountain section meeting, Albuquerque NM), v. 44.

Carlson, B.M, 2012, Cooling and provenance revealed through detrital zircon fission track dating of the Upper Cretaceous Valdez Group and Paleogene Orca Group in Western Prince William Sound, Alaska; Proceedings from the 25th Keck Geology Consortium Undergraduate Research Symposium, Amherst

Espinosa, S., 2012, Paleomagnetism of the Knight Island Ophiolite, Southern Alaska; Proceedings from the 25th Keck Geology Consortium Undergraduate Research Symposium, Amherst MA.

Hilbert-Wolf, H.L., 2012, A U/Pb detrital zircon provenance of the flysch of the Paleogene Orca Group, Chugach-Prince William terrane, Alaska; Proceedings from the 25th Keck Geology Consortium Undergraduate Research Symposium, Amherst MA.

Johnson, E, 2012, Origin of Late Eocene granitiods in western Prince William Sound, Alaska,; Proceedings from the 25th Keck Geology Consortium Undergraduate Research Symposium, Amherst MA.

Miner, L., 2012, Geochemical analysis of Eocene Orca Group volcanics, Paleocene Knight Island Ophiolite, and Chenega Island volcanics in Prince William Sound, Alaska; Proceedings from the 25th Keck Geology Consortium Undergraduate Research Symposium, Amherst MA.

Olivas, S., 2012, U/Pb detrital zircon study of the Upper Cretaceous to Miocene strata of Kodiak Island, Alaska; Proceedings from the 25th Keck Geology Consortium Undergraduate Research Symposium, Amherst MA.

Kaminski, K., and Riehl, M., 2012, Raman spectroscopy applied to Zircon Dating of the Upper Cretaceous Chugach and lower Tertiary Prince William terranes in Alaska; 22nd Steinmetz Symposium, Union College, Schenectady NY.

APPENDIX - Section 5. Student Projects. This appendix expands on the scientific questions and the scientific approach of the specific student projects. 5.1) Exhumation of the Chugach terrane. The Chugach terrane has a distinct thermal/metamorphic history (i.e. Vrolijk et al., 1988; Dusel-Bacon et al., 1993; Weinberger and Sisson, 2003) A major scientific question that we are trying to address is the timing of metamorphism (prehnite-pumpyllite facies to Sillimanite facies) and subsequent exhumation of the terrane (i.e. Garver et al., 2010). Our preliminary data from reset fission tracks in radiation-damaged grains indicates a profound west to east progression in cooling that occurs between about 55 and 25 Ma. We are interested in furthering this data set with student projects aimed at documenting the time-temperature history of these rocks using fission-track, helium, or Ar/Ar dating. We are also interested in projects that address the temperature history of shale and/or sandstones using illite crystallinity (XRD) VR, fluid inclusions, or carbon/graphic thermometry (Raman). 5.2) Provenance of the sandstones. The sandstone of the Valdez Group (Campanian-Maastrictian), the Shumagin Formation (Campanian-Maastrictian), the Kodiak Formation (Maastrictian) and the Sitka Graywacke (Maastrictian) are relatively well studied by traditional analysis (i.e. sandstone compositions as in Zuffa et al., 1980). Only recently have workers started to look at U/Pb of detrital zircon (Bradley et al., 2009; Amato and Pavlis, 2010, and our work in progress). We know that both the Sitaka Graywacke is replete with zircon (Hauessler et al., 2005; Garver, unpublished). Initial studies have suggested that the zircon ages are similar to what we’d expect from the Coast Mountains Batholithic Complex (or Coast Plutonic Complex) in BC (Haeussler et al., 2005). However we’d note that the nature of our field sites would allow for the most complete across and along-strike sampling program so that the temporal changes will be more obvious. We are particularly interested in detrital zircon (actually we are only interested in zircon), because we know that will be successful and will immediately break new ground. 5.3) Tectonic significance of the Sanak Baranof plutonic belt. The Sanak-Baranof belt (SBB) is a distinctive suite of time-transgressive near-trench granitic intrusions (Bradley et al., 2003); the oldest ages are to the west on Sanak and Shumagin islands (61 Ma) and they progressively young to Baranof Island (50 Ma) (Bradley et al., 2003; Kusky et al., 2003; Farris et al., 2006). The origin of these near-trench plutons has been well-studied and many workers conclude that this plutonic belt was generated by the interaction of a spreading ridge and subduction zone along the western North American margin (Hudson,1983; Sisson et al., 2003; Bradley et al., 2003; Kusky et al., 2003). We are interested in finding out more about these plutons that are well exposed and poorly known on Baranof Island. We would like to know the overall chemistry and petrology, the depth of emplacement, and the relations of these plutons to other intrusives in this part of Alaska or farther to the south. Thus we could envision projects that involved geochemistry, petrology, U/Pb dating, and an analysis of potential correlative rocks to the SE.