The ANDRILL McMurdo (MIS) and Southern McMurdo Sound (SMS) Drilling Projects themed issue Amphibole-bearing metamorphic clasts in ANDRILL AND-2A core: A provenance tool to unravel the Miocene glacial history in the Ross Embayment (western , )

Franco M. Talarico1, Donato Pace1, and Sonia Sandroni2 1Dipartimento di Scienze della Terra, Università degli Studi di Siena, Via Laterina 8, 53100 Siena, Italy 2Museo Nazionale dell’Antartide, Università degli Studi di Siena, Via Laterina 8, 53100 Siena, Italy

ABSTRACT able, near-fi eld record of dynamic paleoenvi- cene to Pleistocene, which is punctuated by sev- ronmental history through the Miocene. eral disconformities, not clearly defi ned yet but A petrological investigation of amphibole- with an accumulative loss of 7–8 m.y. (Harwood bearing metamorphic clasts in the ANDRILL INTRODUCTION et al., 2008–2009; Acton et al., 2008–2009 with AND-2A core allows a detailed comparison modifi cations as in ANDRILL SMS Science with similar lithologies from potential source The ANDRILL Southern McMurdo Sound Team, 2010) (Fig. 2). The succession includes regions, leading to the identifi cation of three (SMS) project (Harwood et al., 2008–2009) is several intervals of massive and stratifi ed sandy distinct provenance areas in the present-day the last one of several scientifi c Antarctic drill- diamictites (lithofacies 8 and 7, respectively, segment of the ing projects (DSDP, DVDP, MSSTS-CIROS, as defi ned by Fielding et al., 2008–2009), with between the Byrd and the Blue Gla- CRP; Hambrey et al., 2002, and references variable local internal deformation, fossil con- cier (Mulock- area, the Bri- therein; AND-1B, Naish et al., 2007) that recov- tent and bioturbation, and mainly interpreted tannia Range, and the Koettlitz-Blue glacier ered signifi cant sections of the latest Eocene to as glaciomarine sediments that accumulated at area in the Royal Society Range). A key role Pleistocene sedimentary succession deposited varying proximity to grounded ice, but almost in the comparison is played by the wide range in the Basin (Cooper and Davey, always at some distance. However, evidences of Ca-amphibole compositions, type of intra- 1985), a structural half-graben, ~350 km long, of few and short-lived grounding events are crystalline zoning, mineral assemblages, and bounded on its western side by the Transantarc- documented above 225 mbsf and below 650 fabrics, which refl ect different bulk rocks tic Mountains (TAM) front (Barrett, 1979; Wil- mbsf (Passchier et al., 2010). Other common and metamorphic conditions. Ca-amphibole son, 1999; Fig. 1). lithologies include (lithofacies 5), compositions and zonations also offer the The ANDRILL SMS project drilled the AND- interstratifi ed siltstone and (lithofa- opportunity for the application of geother- 2A drill hole from a site located in the south- cies 3), siltstone to very fi ne-grained sandstone mobarometry methods, which, consistent ern part of McMurdo Sound, ~30 km west of (lithofacies 2), and interbedded conglomerate with literature data, provide further evidence McMurdo Station (77°45.488′S; 165°16.613′E) and sandstone (lithofacies 9). that the three provenance regions corre- near the termination of Koettlitz and Blue gla- The AND-2A core represents the fi rst thick spond to distinct metamorphic terrains with ciers (Fig. 1). Regional seismic-refl ection sur- Miocene section recovered from an ice- proximal pervasive medium-pressure amphibolite- veys show that the penetrated succession is setting, and it provides a unique physical record grade conditions restricted to the Britannia composed of a series of clinoform sets produced for reconstructing the Antarctic paleoclimatic Range. The study contributes new insights by uplift and erosion as a result of renewed rift- evolution and the behavior of its ice sheets dur- into the depositional processes in a variety ing of the Terror Rift (Fielding et al., 2008). ing the critical climatic events of the late Ceno- of glacial environments ranging from open Accommodation for sediment was produced zoic. As demonstrated by several studies in other marine with icebergs to distal, proximal, and through fault- and fl exure-related subsidence Victoria Land Basin cored sedimentary sections subglacial settings. The results also highlight associated with rifting. The active rifting and (e.g., Talarico and Sandroni, 2009) and in gla- the record of two distinct glacial scenarios passive thermal subsidence during the early and cigenic successions of the Antarctic continental refl ecting either short-range (<100 km) fl uc- middle Miocene produced the accommodation margin elsewhere (e.g., Reinardy et al., 2009), tuations of paleoglaciers in the Royal Society for the accumulation of this Neogene succession compositional and distribution patterns of gravel Range with dominant fl ows from W to E, or (Fielding et al., 2008). fraction throughout the AND-2A core play a larger volume of ice sourced from southern- With a recovery of ~98%, the AND-2A core key role in the identifi cation of potential prov- more outlet from the Skelton-Byrd recovered an almost 1140-m-long succession enance regions and reconstruction of ice-fl ow glacier area with fl ow lines running N-S close including a thick and fairly continuous lower to patterns. Moreover, distribution patterns and to the Transantarctic Mountains front. Both middle Miocene lower part (~1140–225 mbsf textural analysis of the gravel fraction provide scenarios demonstrate the importance of the [meters below sea fl oor]) and an upper part relevant additional information to sedimento- AND-2A core to reveal a hitherto unavail- (above 225 mbsf), ranging in age from late Mio- logical models for subglacial and glacial-marine

Geosphere; August 2011; v. 7; no. 4; p. 922–937; doi: 10.1130/GES00653.1; 6 fi gures; 3 tables; 1 supplemental table.

922 For permission to copy, contact [email protected] © 2011 Geological Society of America

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depositional settings and processes (e.g., Cowan tics of a distinctive group of metamorphic clasts in the Ross Embayment during Miocene time, et al., 2008; Reinardy et al., 2009). (i.e., Ca-amphibole–bearing metasedimentary which, as indicated by proxy records, includes In this paper, we especially concentrate on and metaigneous rocks) to track provenance several events of paleoenvironmental changes, the provenance history recorded in the clast- changes documented in the Miocene to Plio- such as the mid-Miocene climatic optimum rich diamictite units and, subordinately, in other cene AND-2A core section (between 150 and (ca. 17–14 Ma; Billups and Schrag, 2002; Hol- fi ner-grained lithofacies, and use the detailed 1140 mbsf). The results are signifi cant for their bourn et al., 2007; You et al., 2009) and the petrographical and mineralogical characteris- implications for the glacial evolution recorded Mi1a and Mi1b glaciations (Miller et al., 1996).

A 65°S W 0° E Indian Ocean B Atlantic Ocean AN WEDDELL T ARCTAR SEA C T IICC PEN P PRYDZ LegLeg 178178 EN BAY E ANTARCTIC LegLeg 178188178 9 11 LegLeg 119 90° W AANTARCTICNTARCTIC 90° ICEICE SSHEETHEET Pacific Ocean 20002 0 0 100010 0 00 0 0 0 0 Fig.Fig. 1B1B 0 0 LegLeg 7878 20002 10001

DSDP/ODP drill holes ROSS SEA IODP Leg 318 Figure 1. (A) The Antarctic continent Transantarctic Mountains with present-day glacial fl ow lines Boundary between E & W Antarctic ice W 180° E 65°S Ice flow direction WILKESLAND (after Drewry, 1983; Barrett, 1999), location of McMurdo Sound (boxed), and of geological drill sites on land and on the Antarctic continental shelf. (B) Geological map (after War- ren, 1969a, 1969b; Craddock, 1970; Borg et al., 1987; Carosi et al., 2007). Also shown are the location of Cape Roberts Project drill hole CRP-1, ANDRILL drill holes AND-1B and AND-2A, and the location of samples with petrographical features closely matching those of the AND-2A core basement clasts. Present-day glacial fl ow lines of major outlet glaciers into the are after Fahne- stock et al. (2000) and Drewry (1983), and inferred catchments are based on elevation data from Drewry (1983). Abbreviations: BI—Black Island; CG—Carlyon Glacier; MM—Mount Morning; MiB—Minna Bluff; MD— Mount Discovery; RSR—Royal Soci- ety Range; TI—Teall Island; WI— White Island.

McMurdo Volcanic Group Ross Orogen: metamorphic Beacon and Ferrar basement Supergroups Byrd Group Ross Orogen: Granite Horney Formation Harbour Intrusive Koettlitz Gp. & Skelton Gp. Complex with minor metamorphic rocks 100 km

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GEOLOGICAL SETTING ney Formation (Carosi et al., 2007). Low-grade

Ma Depth Clay Silt Sand Gravel metasediments, including extensive exposures of (m) The southern McMurdo Sound is surrounded metalimestone and metaconglomerates (Crad- with terrains characterized with a broad vari- dock, 1970; Goodge et al., 2004), are the domi- ety of rock types. Late Cenozoic (ca. 19 Ma to nant lithologies south of (Fig. 1). recent) alkali volcanic rocks, mainly basanites 100 >4.5 of the McMurdo Volcanic Group, form several MATERIALS AND METHODS volcanic centers exposed to the south and east of 169.20 the AND-2A drill site. The emplacement of Ross In the AND-2A core, a total number of 177.68 Island volcanoes resulted in signifi cant modifi ca- 103,759 clasts ranging in size from boulder 200 185.36 tion of the McMurdo Sound paleogeography and to granule class (>2 mm) were counted and, <7-8 14.20 fl exural loading with related basin subsidence for each clast, information such as occurrence 243.16 (Kyle, 1981, 1990). In contrast, the Transant- depth, lithology, 2-D dimensions, and shape arctic Mountains to the west and southwest are were logged on the cut surface of the working- 14.80 285.28 16.00 300 composed primarily of late Proterozoic–Cam- half core (Panter et al., 2008–2009). A prelimi- 328.27 brian metamorphic rocks (Koettlitz and Skelton nary clast sample collection conducted while 352.93 Groups, Gunn and Warren, 1962; Findlay et al., on the ice was later enlarged by a more exten- 1984; Cook and Craw, 2001, 2002; Horney For- sive sampling at the Antarctic Marine Geology 16.45 400 mation, Borg et al., 1987) and Cambrian–Ordovi- Research Facility (Florida State University, cian granitoids of the Granite Harbour Intrusive Tallahassee, U.S.A.), where the AND-2A core 16.55 Complex (Gunn and Warren, 1962). In the west- boxes are stored. ernmost part of the Transantarctic Mountains, Petrographical analyses by means of 500 this basement is unconformably overlain by sedi- polarized-light microscopy of 530 basement mentary rocks, mainly nonmarine sandstones, clast samples, distributed throughout the whole quartzites, and siltstones of the Devonian to Tri- AND-2A core interval, allowed the identifi cation

17.20 579.42 assic (Barrett, 1991). In the and selection of 19 samples, all characterized by 600 Jurassic, sills of the Ferrar Dolerite intruded base- Ca-amphibole–bearing mineral assemblages. 622.68 ment and sedimentary cover contemporaneously Provenance inferences were based on detailed with their extrusive equivalent, the Kirkpatrick petrographical comparisons of investigated 692.00 Basalt (Elliot, 1992; Elliot et al., 1995). clasts with petrographically similar lithologies 700 In the region comprised between Byrd and sampled in 45 localities in the crystalline base- 17.55 698.67 Ferrar glaciers, the crystalline basement con- ment exposed between Byrd and Ferrar glaciers. 17.72 765.51 sists of a variety of lithologies with prominent The used rock sample collection consists of over changes of both metamorphic grade and granit- 600 samples (comprehensive of both metamor- 17.80 767.58 18.70 800 oid fabrics throughout the region (Stump, 1995; phic and intrusive basement rocks) and thin Goodge, 2007; Talarico and Sandroni, 2009 sections stored at the Italian Antarctic National and references therein for a detailed descrip- Museum–Earth Science section in Siena. 866.79 tion of the most abundant basement lithologies) A selection of ten samples from outcrops, 900 (Fig. 1). In the Royal Society Range, basement representative of the most widespread Ca- rocks comprise mainly upper amphibolite-grade amphibole–bearing metamorphic rocks, and the metasediments and orthogneisses (Koettlitz 19 clast samples were analyzed for their micro- 19.80 965.26 20.05 Group, Findlay et al., 1984), variably deformed structures and mineral compositions using an 1000 996.65 granodiorites of the Bonney Pluton (Cox, 1993), X-ray energy-dispersive system (EDAX-DX4) minor mafi c intrusions and alkaline intrusives attached to a scanning electron microscope (Phil- 1048.38 (Cooper et al., 1997). ips XL30) at the Dipartimento di Scienze della 1075.20 The Mulock-Skelton glacier region is charac- Terra of Siena (Italy). Analytical conditions were 1100 terized by lower greenschist– to lower amphibo- 20 kV of accelerating voltage, 25 µA of emis- 1122.22 lite–facies metasediments of the Skelton Group sion current, and a beam spot size of 0.2 µm. 20.25 (Gunn and Warren, 1962; Cook and Craw, 2001) Natural minerals were used as standards. In each Figure 2. Distribution of investigated and minor, mainly alkaline type, quartz syenites, sample, at least 20 analytical spots from at least amphibole-bearing metamorphic clasts in and granites (Rowell et al., 1993), including four crystals were collected for each mineral. the AND-2A core. Lithology and stratig- biotite ± hornblende porphyritic varieties (e.g., Representative core and rim compositions are raphy follow Fielding et al. (2008–2009), Teall Island, area; Cottle and listed in Table 3 and the Supplemental Table1. Acton et al. (2008–2009, with modifi cations Cooper, 2006; Carosi et al., 2007). reported by ANDRILL SMS Science Team, Farther south, between Darwin Glacier and 1Supplemental Table. Excel fi le of Chemical 2010) and Di Vincenzo et al. (2010). Green— Byrd Glacier, medium- to high-grade metasedi- Compositions of Representative Ca-Amphiboles in diamictites; brown—sandstones; gray— ments (banded gneisses, schists with Ca- silicate AND-2A Metamorphic Clasts. If you are viewing the PDF of this paper or reading it offl ine, please mudstones; yellow—diatomite; orange— layers, migmatites, and minor amphibolite and visit http://dx.doi.org/10.1130/GES00653.S1 or the volcaniclastic sediments (including basaltic marbles) and variably deformed (foliated to full-text article on www.gsapubs.org to view the lava in the uppermost 35 m). mylonitic) granitoids are common in the Hor- Supplemental Table.

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Amphiboles were classifi ed following the assemblages occur in a wide range of lithologies diamictites, conglomerates, and minor silt- nomenclature by Leake et al. (1997); mineral including both low-grade metasediments (e.g., stones; Panter et al., 2008–2009). analyses were normalized to 23 oxygens and metasandstones) and medium-grade rock types In the 19 investigated intervals, the intrusive sum (T1 + T2 + M1 + M2 + M3) = 13 as detailed (schists, amphibolites, and paragneisses and rock clasts comprise granule to pebble of domi- by Triboulet (1992), with Fe3+ estimated as max- orthogneisses). Mineral assemblages (type of nant monzogranites and granodiorites (unde- imum according to Papike et al. (1974). mineralogical phase and its modal content and formed to foliated in texture), diorites, gabbros, composition) and fabric (grain size and type of and tonalites (undeformed to foliated in texture) RESULTS foliation) show several variations, which con- with minor occurrences of syenogranites, felsic sistently refl ect the variable metamorphic grade porphyries, and aplites. The metamorphic rocks The AND-2A Amphibole-Bearing and bulk rock composition (Table 2). Quartz, range in size from granule to cobble and include Metamorphic Clasts: Distribution and Ca-amphibole, and plagioclase are commonly orthogneisses and paragneisses, granofels, mar- Sedimentological Features of accompanied by biotite and K-feldspar. Clino- bles, schists, quartzites, a large variety of low- the Host Core Intervals pyroxene is restricted to four samples including grade metasediments, and minor metarhyolites, a metasandstone, a schist, an orthogneiss, and metatonalites, metadiorites, and amphibolites. Clast logging and sampling revealed the a Ca-silicate granofels, where the Mg-richest The sedimentary rocks range in size from gran- occurrence of 19 core sections with one or sev- compositions occur. Titanite and opaque min- ules to pebbles sourced from the Beacon Super- eral amphibole-bearing metamorphic clasts, erals are common accessory minerals. Clinozo- group (arkose, lithic arkose, and arkosic litha- ranging in size from small pebbles to cobbles, isite and/or epidote and calcite are rare second- renite; quartz arenite; subarkose) or unknown and angular to well rounded in shape. ary minerals. sources (hybrid and/or mixed arenite, biomicrite Nineteen samples, one from each core interval Metasandstones are heterogranular, very and/or wackestone; Cornamusini, 2010). The characterized by a single homogeneous lithofa- fi ne to fi ne grained, interlobate granoblastic dolerites include coarse- to fi ne-grained variet- cies, were selected in this study, the only excep- to granolepidoblastic in texture, with quartzite ies and show the largest range in the clast size, tion being core interval between 756.19 and lithics and detrital mineral grains including sub- occurring as granules to cobbles. The volcanic 774.94 mbsf where two samples were considered angular quartz and plagioclase. Ca-amphibole rocks are represented by granule- to cobble-size (Fig. 2). The studied clasts are listed in Table 1, poikiloblasts defi ne a spotted texture, most clasts of lavas ranging from mafi c, intermedi- together with detailed information concerning likely as the result of a thermometamorphic ate to felsic compositions, and from aphanitic their morphological features (dimension and overprint (Fig. 3). to porphyritic and nonvesicular to vesicular in shape), and associated clast assemblages (includ- Schists are heterogranular, very fi ne to fi ne textures (for further details, see Panter et al., ing clast dimension and shape data) in the core grained, nematogranoblastic, with isoriented 2008–2009; Di Vincenzo et al., 2010). sections corresponding to the specifi c host lithofa- amphibole idioblasts (tremolite to green horn- The occurrence of primary volcanic prod- cies intervals with top and bottom boundaries as blende in composition) and interlobate to sub- ucts, such as pumice and lapilli, was reported at defi ned by Fielding et al. (2008–2009). polygonal plagioclase and quartz; a composi- several depths in the investigated core sections Ca-amphibole–bearing metamorphic clasts tional layering is commonly present. (Panter et al., 2008–2009; Di Vincenzo et al., are scattered throughout most of the AND- Paragneisses are heterogranular, fi ne to 2010). This clast component was not consid- 2A core between 166.20 and 1122.22 mbsf, medium grained, from interlobate and/or subpo- ered in data analysis; nevertheless, counts of the spanning in age from Pliocene–late Mio- lygonal granoblastic to granonematoblastic in smaller volcanic clasts could also include some cene (>4.5 Ma, <7–8 Ma) to Early Miocene texture (Fig. 3), and they are sometimes charac- primary volcanic products. (ca. 20 Ma) (Table 1). terized by compositional layering. Comparison of clast compositions in the The size of the analyzed clast samples ranges Orthogneisses are heterogranular, fi ne to most represented, clast-rich, and lithologically from 2 to 12 cm (longest axis visible on the cut medium grained, syenogranitic to tonalitic in similar core sections (i.e., stratifi ed diamictites) surface of the working-half core). The degree composition, with porphyroclastic to mylonitic throughout the investigated record indicate of roundness is variable, from angular to well textures (Fig. 3). The clinopyroxene-bearing prominent differences between diamictite inter- rounded, with no evidence of relation between variety shows tonalitic composition and is char- vals above 774 mbsf (characterized by more lithology and degree of rounding. Host litholo- acterized by relict clinopyroxene porphyroclasts abundant and varied basement clast assem- gies include dominant sandy diamictite and and rare green hornblende associated with bio- blages, and high amounts of Beacon Sandstone minor conglomerates, sandstones, and mud- tite within the matrix. and Ferrar Dolerite) and those below 981 mbsf, stones. The diamictites occur as units of variable Amphibolites are heterogranular, fi ne grained, which show high amounts (60%–95%) of vol- thickness (~1.5–27 m) and, mainly in the core nematoblastic, or decussate in texture (Fig. 3). canic clasts. The volcanic component is also sections above 225 mbsf and below 650 mbsf, Ca-silicate granofels are heterogranular, very very important in mudstone-dominated intervals they show variable evidence of internal defor- fi ne to fi ne grained rocks showing interlobate to (i.e., 846–872 mbsf) whereas sandstone-rich mation interpreted as indicating subglacial dep- subpolygonal granoblastic textures (Fig. 3). intervals show variable clast compositions with ositional settings (Fielding et al., 2008–2009; The investigated Ca-amphibole–bearing basement clasts ranging between 25% and 75%. Passchier et al., 2010; Table 1). metamorphic clasts are a minor component of the lithologically varied clast assemblages, Comparison with Potential Source Rock Mineralogical Features of Amphibole- which, as reported in Table 1, can be con- Units and Provenance Implications Bearing Metamorphic Clasts and veniently described in terms of seven main Associated Clasts lithological groups, including intrusive, meta- Preliminary petrographical investigations morphic, sedimentary, and volcanic rocks, (Panter et al., 2008–2009) followed by more In the AND-2A core gravel fraction, Ca- dolerites, quartz (likely derived from intrusive detailed petrographical analyses on ~530 amphibole–bearing metamorphic mineral rocks), and intraclasts (coarse sandstones, clast samples evenly distributed throughout

Geosphere, August 2011 925

Downloaded from http://pubs.geoscienceworld.org/gsa/geosphere/article-pdf/7/4/922/3340417/922.pdf by guest on 01 October 2021 Talarico et al. size (cm) size Maximum clast LASTS Clast shape ned by Fielding et al. (2008–2009). Age after (2008–2009). Fielding et al. ned by Average clast Average number/10 cm . Abbreviations: mbsf—meters below sea fl oor; Met—metamorphic rocks; Met—metamorphicoor; rocks; sea fl mbsf—meters below Abbreviations: . unded; r—rounded; RSR—Royal Society Range; SM—Skelton-Mulock glacier SM—Skelton-Mulock Society Range; RSR—Royal r—rounded; unded; 9). *Lithofacies numbers as defi *Lithofacies 9). Age (Ma) Clast composition (%) (mbsf) Base depth (mbsf) 162.58176.28 172.90181.82 177.98 >4.5 238.89 187.19 249.83 7284.42 <7 7 14.45 ca. 288.30 30 34 3328.10 18 14.80 ca. 13 15 328.36 45 8 2 2352.90 8 15.90 ca. 2 5 11 6 353.24 34 1 25 35 1 34 16.45 ca. 579.33 6 1 50 8 2 580.97 8 26 75 1621.20 17.20 ca. 18 15 2 22 1 27 622.80 39 4681.92 x 15 17692.89 19 692.08 2 x x756.19 25 699.02 10756.19 x x 774.94 5 2 17.55846.06 x 68 x x x 774.94 17.7 5 18 x 872.70 x x 3 17.8 2964.86 6 15 14 62 3 x x 19 965.43 22981.01 37 1 x 2 19 x 15 16 14 11 >19.8 4 996.69 x 16 11 3 68 2 9 x 2 11 8 1 10 7 4 x 19 8 1 48 5 x 21 36 x 5 48 1 x 2 5 3 48 x 2 x 7 2 3 1 9 x 13 1 87 68 9 x 13 x 1 x x x x 1 x x x x 95 x 1 x x 4 15 x x x x 5 7 x 12 8 x x 12 x x x x x 7 x 5 x 9 Hosting interval Associated clast assemblages 1044.061065.91 1064.471109.47 1076.15 1124.93 <20.25 6 3 12 2 9 6 11 1 1 2 1 71 1 4 85 85 9 7 x 11 x x x x x x x x x 5 2 14 Top depth Top Lithology

(lithofacies)* diamictite (7) diamictite (7) diamictite (8) diamictite (8) diamictite (7) clast-rich sandy diamictite (7) clast-poor sandy diamictite (7) ne sandstone fi with dispersed clasts (5) ne to medium fi sandstone with dispersed clasts (5) clast-poor sandy diamictite (7) fine to medium sandstone with dispersed clasts (5) diamictite (7) diamictite (7) diamictite (7) diamictite (7) (siltstone) with dispersed clasts (2) conglomerate (9) diamictite, (7) black diamictite (7) Shape TABLE 1. SEDIMENTOLOGICAL AND PETROLOGICAL FEATURES OF AND-2A CORE SECTIONS HOSTING THE INVESTIGATED CA-AMPHIBOLE METAMORPHIC C CA-AMPHIBOLE METAMORPHIC THE INVESTIGATED OF AND-2A CORE SECTIONS HOSTING FEATURES AND PETROLOGICAL SEDIMENTOLOGICAL 1. TABLE Size Size (cm) : Clast composition after Sandroni and Talarico (2011). Lithofacies and clast dimension and shape after Fielding et al. (2008–0 and clast dimension shape after Fielding et al. Lithofacies (2011). Talarico Clast composition after Sandroni and : Note Clast sample Acton et al. (2008–2009) with modifi cations as in ANDRILL South McMurdo Sound Science Team (2010) and Di Vincenzo et al. (2010) et al. Vincenzo (2010) and Di Team cations as in ANDRILL South McMurdo Sound Science (2008–2009) with modifi Acton et al. s-r—subro s-a—subangular; a—angular; Intrac—intraclasts; rocks; Volc—volcanic Dol—dolerite; Qtz—quartz; Intrus—intrusive rocks; BR—Britannia Range. area; 1075.201122.22 6 5 s-a Clast-poor sandy r Clast-poor sandy MetIntrus Qtz Sed Dol Volc Intrac a166.20 s-a178.68 s-r 3185.35 r 3243.16 r 12 s-r Clast-rich sandy 4 285.28 r Clast-rich muddy Clast-rich sandy r 2328.27 Volcanic-bearing, s-a 1 Diatom-bearing, 352.93 s-r 4 Siltstone and 579.42 s-a Volcanic-bearing, 2622.68 s-a 2 Volcanic-bearing, 692.00 a698.67 5 Volcanic-bearing, 765.51 3767.59 r 1866.79 s-r Clast-poor sandy 8 Clast-poor sandy r 2965.26 s-r Clast-poor sandy s-a Clast-poor sandy 996.65 3 Sandy mudstone 1048.38 3 r 2 Sandy r s-r Clast-poor sandy Clast-poor sandy

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Cpx 0.67 0.030.84 0.02 0.68 0.06 0.75 0.03 vfg-fg0.87 Metasandstone 0.03 fg-mg Bt-Cam schist s: mbsf—meters below sea fl oor; XMg—Mg/(Mg+Fe2+); vfg—very fi ne grained; ne grained; vfg—very fi XMg—Mg/(Mg+Fe2+); oor; sea fl mbsf—meters below s: (%) (%) (%) (%) XMg (%) (%) (%) (%) XMg >40% Cam Kfs Qtz Opm Grt Ttn Czo-Ep Grain size Lithology

Bt 0.650.37 0.00 0.56 0.03 0.680.55 0.01 0.52 0.02 0.01 0.66 0.01 0.76 0.01 0.00 0.620.67 0.01 0.590.66 0.03 0.67 0.06 0.64 0.02 0.67 0.04 0.02 0.06 0.640.65 0.00 0.00 0.680.580.47 0.00 0.49 0.00 0.40 0.00 0.32 0.03 0.00 0.01 = 16÷ 40% Pl Bt Cam Kfs Qtz Cpx Opm Cal Ttn Czo-Ep Grain size Lithology Pl = 2 ÷15% (52) (63)(76) (62) (77) (54)(40) (41) (45-79)(30-62) (48-84) (23-27)(77-82) (24-26) (25-33) (74-79) (62-64) (28-32) (27-29) (61-74) (28-31) (28-29) (43-89) (29-30) (63-84) (45-81) (38-43) (76-83) (39-53) (39-40)(67-72) (24-34) (55-65) (35-45)(85-95) (31-53) (42-46) (79-98) (39-65) (41-51) (50-66) (37-40) (53-64) (45-46)(82-82) (46-47) (37-44) (82-83) (37-44) (36-43) (39-42) (%) Core (an) Rim (an) (%) XMg (E) (E) = 0 ÷ 1% Longitude Longitude titude (S) (S) Latitude BEARING METAMORPHIC ROCKS FROM OUTCROPS IN THE CRYSTALLINE BASEMENT OF THE ROSS OROGEN IN THE REGION COMPRISED BETWEEN FERRAR A IN OROGEN THE ROSS BASEMENT OF THE CRYSTALLINE IN OUTCROPS FROM ROCKS BEARING METAMORPHIC ne-grained; mg—medium-grained; cg—coarse-grained. mg—medium-grained; ne-grained; TABLE 2. MINERALOGICAL ASSEMBLAGES OF INVESTIGATED CA-AMPHIBOLE–BEARING METAMORPHIC CLASTS IN AND-2A CORE AND OF REPRESENTATIVE CA-AMPHIBOLE–BEARING METAMORPHIC OF INVESTIGATED MINERALOGICAL ASSEMBLAGES 2. TABLE Note: Mineral abbreviations according to Kretz (1983), with the addition of Opm to indicate opaque minerals. Other abbreviation according to Kretz (1983), with the addition of Opm indicate opaque minerals. Mineral abbreviations Note: (mbsf) (%) Core (an) Rim (an) (%) XMg Sample (AND-2A) La 765.51 21-01-06T2 79°02’52” 161°53’04” 692.00 1122.22 177.68 185.36 243.16 285.28 328.27 352.93 579.42 622.68 698.67 767.58 866.79 965.26 996.65 1048.38 1075.20 Sample (outcrops) 23-12-03RF27B 78°03’18”18-12-03F7 164°11’38” 23-12-03RF18 78°08’01” 78°11’01” 163°56’30” 162°44’18” 17-12-03FR1312-12-00T4 78°49’50” 162°26’06” 19-01-06T220-01-06T1 80°11’58”20-01-06T2 159°13’00” 80°23’14” 157°09’50” 79°55’24” 158°20’42” 79°55’24” 158°20’42” 169.20 18-12-03F22B 77°52’49” 163°55’37” fg—fi

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AABB

1 mm 1 mm CCDD

1mm 1mm

EEFF

ActAct

1mm 1 mm

Figure 3 (continued on following page). Microphotographs of the most representative Ca-amphibole–bearing metamorphic clasts (left column) and of petrographically similar lithologies (right column) from the potential source rock units in the basement exposed in the region between Ferrar and Byrd glaciers (see Fig. 1 for their location) (all taken with crossed polarizers). (A) and (B) Ca-amphibole– bearing diopside-plagioclase granofels: (A) clast 698.67 mbsf, (B) sample 23-12-03RF18 (Miers , Royal Society Range); (C) and (D) amphibolite: (C) clast 996.65 mbsf, (D) sample 23-12-03RF27B (Garwood Valley, Royal Society Range); (E) and (F) Ca-amphibole– bearing metasandstone: (E) clast 622.68 mbsf (with randomly oriented poikiloblasts of actinolite [Act]), (F) sample 21-01-06T2 (Teall Island, Skelton Glacier).

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GGHH

1mm 1 mm

IIJJ

1mm 1mm

Figure 3 (continued). (G) and (H) Ca-amphibole–bearing orthogneiss: (G) clast 767.58 mbsf, (H) sample 20-01-06T1 (Darwin Glacier, Bri- tannia Range); (I) and (J) Ca-amphibole–bearing paragneiss: (I) clast 579.42 mbsf, (J) sample 19-01-06T2 (Byrd Glacier, Britannia Range).

the AND-2A core (Zattin et al., 2010; San- alogical similarities are generally accompanied The composition of amphibole coexisting droni and Talarico, 2011), provided evidence by striking microstructural (Fig. 3) and compo- with plagioclase (Table 3 and the Supplemental of a number of diagnostic lithologies that sitional analogies as indicated by the good fi t of Table [see footnote 1]) is a good tool to semi- closely match the lithological variability of the most Ca-amphibole compositions in the clasts quantitatively estimate P-T conditions attend- crystalline basement in South Victoria Land (including the commonly present slight intra- ing the formation of these mineral assem- and strongly support a provenance from the crystalline zoning; see the Supplemental Table blages. Actually, Si, Al, and Na distribution in region between the present-day Blue-Koettlitz [see footnote 1]) within the compositional fi elds amphibole structural sites depends on physi- and Mulock glaciers (Fig. 1). defi ned by representative samples from the out- cal conditions during crystallization. While The mineralogical and microstructural fea- crops (Fig. 4). Si4+ decreases, Ti, VIAl, and NaA increase with tures of investigated AND-2A Ca-amphibole– In Britannia Range samples (and in petro- temperature (T), and IVAl and NaB rise with bearing metamorphic clasts generally show graphically similar clasts from the AND-2A pressure (P) (Raase, 1974; Brown, 1977; Hol- signifi cant similarities with compositionally core), Ca-amphibole displays sometimes a land and Richardson, 1979; Spear, 1980). The comparable lithologies from outcrops located in slight zonation with pargasite, tschermakite, or Ca-amphiboles in our samples can be com- the main exposure areas of the South Victoria Mg-hornblende in cores and Fe-tschermakite or pared with those reported by Zenk and Schulz Land basement. Table 2 includes ten samples Fe-pargasite in rims. In contrast, samples from (2004), who provided detailed microstruc- that are part of a collection of over 600 samples the Royal Society Range and those from the tural, mineral chemical, and thermobarometric collected from 65 localities and that are repre- adjacent Skelton-Mulock glacier area (and the data on Ca-amphibole–bearing assemblages sentative of three regions with partly different petrographically similar AND-2A clasts) show from the classical Barrovian metamorphic metamorphic and lithological features (Royal weak zonations with Mg-hornblende in cores zones in the Dalradian Group in Scotland. As Society Range, Skelton-Mulock glacier area, and Mg-hornblende with lower IVAl or actinolite in the Dalradian Group, our samples similarly and Britannia Range; Fig. 1). The close miner- or tremolite in rims. show the coexistence of Ca-amphiboles with

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1.00 1.00 A 0.90 B 0.90 0.80 0.80 0.70 0.70 0.60 RSR 0.60

g 0.50 0.50

XM

XMg 0.40 0.40 0.30 0.30 0.20 0.20 0.10 0.10 0.00 0.00 8.00 7.75 7.5 7.25 7.00 6.75 6.50 6.25 6.00 5.75 8.00 7.75 7.5 7.25 7.00 6.75 6.50 6.25 6.00 5.75 Si (a.p.f.u.) Si (a.p.f.u.)

1.00 1.00 C 0.90 D 0.90 0.80 0.80 0.70 0.70 0.60 SM 0.60

g 0.50 0.50

XMg

XM 0.40 0.40 0.30 0.30 0.20 0.20 0.10 0.10 0.00 0.00 8.00 7.75 7.5 7.25 7.00 6.75 6.50 6.25 6.00 5.75 8.00 7.75 7.5 7.25 7.00 6.75 6.50 6.25 6.00 5.75 Si (a.p.f.u.) Si (a.p.f.u.)

1.00 1.00 E 0.90 F 0.90 0.80 0.80 0.70 0.70 0.60 BR 0.60

g 0.50 0.50

XM

XMg 0.40 0.40 0.30 0.30 0.20 0.20 0.10 0.10 0.00 0.00 8.00 7.75 7.5 7.25 7.00 6.75 6.50 6.25 6.00 5.75 8.00 7.75 7.5 7.25 7.00 6.75 6.50 6.25 6.00 5.75 Si (a.p.f.u.) Si (a.p.f.u.)

Figure 4. Compositional diagrams showing the compositional variability of Ca-amphibole in AND-2A clast samples (A, C, and E) and their similarity with samples from potential rock units in the Royal Society Range (B), Mulock-Skelton glacier area (D), and Britannia Range + (F) (nomenclature after Leake et al., 1997). Symbols in (E) and (F) (•, #) refer to Ca-amphiboles characterized by (Na K)A<0.50; Ti<0.50, + ≥ 2 and (Na K)A 0.50; CaA<0.50 parameters, respectively. XMg = Mg/(Mg + Fe +); a.p.f.u. = atoms per formula unit.

plagioclases ranging in composition from oli- than those obtained using the Gerya et al. the highest P and T values (up to 7–8.8 kb, goclase (typical of the biotite zone) to, more (1997) barometer. 660 °C) were obtained using the composition frequently, andesine and/or labradorite (garnet In most samples the variation ranges of esti- of Fe-tschermakite rims, whereas the minimum or kyanite zone). mated P-T values are within the absolute error values (4.1–5.5 kb and 560–595 °C) are due to Results of the application of the empirical ranges (±1.2 kb and ± 37 °C) of both geother- Mg-hornblende or edenite/Fe-edenite composi- Ca-amphibole geothermobarometry using mobarometric methods. However, all samples tions preserved in core grains. In all other clasts the analytical expression given by Zenk and show a certain variability of P-T values with sys- and samples from outcrops (i.e., those from the Schulz (2004) and Gerya et al. (1997) are tematic trends refl ecting intracrystalline com- Royal Society Range and Mulock-Skelton gla- listed in Table 3 and shown in Figure 5. The positional variations of Ca-amphibole grains cier area), maximum P and T values are given two methods gave similar T results, whereas according, as described above, to two distinct by core compositions, whereas rim composi- P values calculated with Zenk and Schulz’s zoning patterns. In samples from the Britan- tions yield lower P-T values. The overall P-T (2004) geobarometer are 1–1.5 kb higher nia Range and petrographically similar clasts, estimates are signifi cantly lower (~2–4 kb,

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~400–600 °C) than those estimated for the Bri- metasandstones show general petrographic fea- In the Royal Society Range, the metamorphic tannia Range samples. In contrast, samples from tures consistent with a low-grade regional meta- pattern includes a wide region of high-grade the Royal Society Range and those from the adja- morphic peak, but the microstructural features of conditions with more restricted areas of medium cent Skelton-Mulock glacier area show perfectly Ca-amphibole (occurring as randomly oriented to low grade confi ned to the area including the overlapping P-T results. Nevertheless, published poikiloblasts) indicate its post-tectonic growth upper Walcott and Radian glaciers (Fig. 6A). As P-T estimates (Talarico et al., 2005; Cook and likely as the result of contact metamorphism indicated by the investigated samples, the high- Craw, 2001, 2002) and the distinctly differ- under higher T conditions. According to the grade region also suffered lower-grade reequili- ent fabrics of the samples from the two regions Ca-amphibole geothermobarometry, this con- bration and, as commonly observed in similar indicate signifi cantly different initial regional tact-metamorphic event would have occurred at metamorphic terrains (Vernon, 1976; Miyas- metamorphic conditions and variably devel- P <4 kb. Similar values are reported by Wynyard hiro, 1994; Bucker and Frey, 1994; Vernon and oped contact-metamorphic effects (Fig. 6A). In (2004) as emplacement depth of post-tectonic Clarke, 2008), the low-grade overprint may be the Skelton-Mulock glacier area, investigated granitoids in the region. often complete enough to erase early high-grade

(kb)

(kb)

Pressure

Pressure RSR

Temperature (°C) Temperature (°C)

(kb)

(kb)

Pressure

Pressure SM

Temperature (°C) Temperature (°C)

kb)

(kb)

(

essure

Pressure

Pr BR

Temperature (°C) Temperature (°C)

Figure 5. Pressure-temperature (P-T) data and P-T paths from Ca-amphibole mineral assemblages in AND-2A meta- morphic clasts (left) and representative samples from their most likely provenance regions (right). RSR—Royal Society Range; SM—Skelton-Mulock glacier area; BR—Britannia Range. Thermobarometric data are affected by minimum error of 38 °C/1.2 kb. Arrows indicate P-T evolution trends according to amphibole core-to-rim zonations (the arrow

head indicates rim compositions). Al2SiO5 phase boundaries in broken lines according to Spear (1993).

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A B

McMurdo Volcanic Group

Beacon and Ferrar Supergroups Plutonic and metamorphic rocks (Ross Orogen)

Regional metamorphic zones Upper amphibolite facies Lower amphibolite facies Greenschist and/or amphibolite facies

Greenschist facies

Contact metamorphism

C

AND-2AAND-2A

CRP-1

Figure 6. (A) Metamorphic pattern of the Ross Orogen in South Victoria Land. The map is based on the results of petrological investigations reported in Talarico et al. (2007) (Byrd Glacier area); Carosi et al. (2007) (Britannia Range); Cottle (2002) (Carlyon Glacier area); Cook and Craw (2002), Wynyard (2004) (Skelton-Mulock glacier area); Cook and Craw (2001), Talarico et al. (2005), Findlay et al. (1984) (Royal Society Range); Allibone (1992), Cox (1992) (Ferrar-Mackay glacier area). (B) and (C) show two schematic glacial scenarios for the supply of debris to the AND-2A drill site from the different provenance regions indicated by the clast petrology in the AND-2A core sections below 650 mbsf. The present-day paleogeography has been modifi ed by omitting volcanic centers with age <17 Ma. Gl.—Glacier.

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paragenesis and/or mineral compositions from Correlative strata in CRP-1 (Florindo et al., Potentially correlative diamictites in AND-1B the rock metamorphic record. Advanced to 2005) include diamictites that are devoid of core indicate a provenance from the Skelton- complete low-grade reequilibrations are gen- volcanic clasts and carry basement clast litholo- Mulock glacier area (Talarico et al., 2011), erally more common in highly deformed rock gies mirroring the local lithological range of the leaving the possibility for ice sourced from the volumes (i.e., from shear zones) and in pelitic Mackay Glacier area (Talarico and Sandroni, Royal Society Range during glacial maxima in and/or semipelitic bulk rock compositions. Such 1998). From this perspective, the regional evi- the regional glacial scenario. compositions are typical of most of the investi- dence of local-ice lobes fl owing from W to E In contrast, the well-dated core section gated clast samples. (Fig. 6B), rather than with fl ow lines running (below 225 mbsf; 20.2–14.2 Ma; Acton et al., N-S close to the Transantarctic Mountains front, 2008–2009, with modifi cations reported by INTERPRETATIONS AND DISCUSSION would be more consistent with fl uctuations of the ANDRILL SMS Science Team, 2010; Di East Antarctic Ice Sheet local outlet glaciers Vincenzo et al., 2010) offers a better oppor- The results of petrological investigations than with the presence of an ice sheet covering tunity to provide constraints to glacial sce- on Ca-amphibole–bearing metamorphic clasts the entire Ross Embayment. Given its apparent narios. Investigated clasts in this core section provide evidence of three distinct provenance timing, the AND-2A core section with a Royal comprise six samples, with variable shape and regions for the supply of these basement clasts Society Range provenance (~1050 mbsf to the size (Table 1). Skelton Glacier-sourced clasts, to the AND-2A drill site area. All three regions hole bottom; ~20.1–20.2 ± 0.15 Ma as maxi- represented by angular lonestones hosted in are located in the Transantarctic Mountains mum; Acton et al., 2008–2009, with modifi - sandstone (at 622.68 mbsf), can be interpreted segment comprised between Ferrar and Byrd cations reported by ANDRILL SMS Science as iceberg-rafted debris (IRD). The occur- glaciers, and include from N to S and at Team, 2010; Di Vincenzo et al., 2010) may rence of pebbles of volcanic lavas in the same increasing distance from the AND-2A drill record the latter stages of the Mi1a glaciation short (10 cm) core interval indicates that major site: the Royal Society Range, the Skelton- (Miller et al., 1996). calving processes should have been active Mulock glacier area, and the Britannia Range mainly in the proto–Mount Morning area (or (Figs. 1 and 6A). Although the study demon- The Skelton-Mulock Glacier Provenance other volcanic centers underneath the Ross Ice strates the value of the mineralogical features and Britannia Range Provenance Shelf), where both metamorphic and volcanic of the investigated clast assemblage as a use- bedrock could have been potentially present ful provenance tool, a deeper analysis and dis- Analyzed samples indicative of provenances at the time indicated by recovered sediments. cussion of the results need the consideration from the Skelton-Mulock glacier area and Bri- The rounded cobble in thin conglomerate at of a number of additional constraints refl ect- tannia Range are scattered throughout the AND- 965.26 mbsf shows a similar association with ing the observed variability in terms of clast 2A core. Occurrences in the uppermost 225 m abundant volcanics. In this case, the sedimen- shapes, host sedimentary lithofacies, overall are represented by subrounded to well-rounded tological interpretation of this lithofacies, indi- clast compositions, and distribution in the host clasts that occur near the top of 2- to 10-m-thick cating ice-proximal environments in the pres- lithological unit (i.e., position at the base or massive or stratifi ed diamictites. Based on their ence of meltwater (Fielding et al., 2008–2009), top; Table 1). In the following sections, each petrological affi nity, the investigated clasts could is consistent with reworking of pristine diamic- clast group indicating the three distinct prov- indicate the deposition from ice sourced in the tites with Skelton Glacier–sourced debris that enances will therefore be discussed taking into present-day region comprised between Skelton are documented in the underlying core interval account these various aspects with consequent and Byrd glaciers. However a number of inde- (at ~975–995 mbsf). implications for the depositional settings and pendent lines suggest that they are most likely The Britannia Range–sourced clasts occur processes and for glacial reconstructions based reworked debris. First, they represent a very rare as either angular and/or subangular small on the AND-2A core record. occurrence and are mixed with other more abun- pebbles at the base of thin (1.5–4 m) strati- dant basement clasts including several varieties fi ed diamictites, or as subrounded to rounded The Royal Society Range Provenance of granitoids, which, based on petrographical pebbles in a 19-m-thick unit of massive data reported in Panter et al. (2008–2009) and diamictites. The occurrence of angular clasts Among the ten analyzed clast samples show- in Zattin et al. (2010), closely match the litho- at the base of a diamictite unit is consistent ing a Royal Society Range provenance signa- logical variability of the Royal Society Range. with glacial processes occurring in more ice- ture, most are subrounded to well rounded and Second, high concentrations of intraclasts occur distal locations, beyond the maximum extent occur in several stratifi ed diamictite (lithofacies closely associated to the analyzed clast samples of glacier advance as described by Fielding et 7) intervals, 6–24 m thick, either near the base (within the 1- to 0.1-m-long host core sections). al. (2008–2009). The association with volca- (e.g., 1048.30 mbsf) or more often in the upper- Third, the intraclasts commonly include clasts nic pebbles and metamorphic rocks indicating most part. Angular or subangular clasts mainly of diamictites with abundant volcanic lith- mixed (Skelton Glacier and Royal Society occur as lonestones in fi ne-grained and clast- ics and small pebbles of metasandstones of a Range) provenance requires a complex evolu- poor lithofacies (e.g., lithofacies 5 and 2). likely Skelton Glacier provenance (Panter et al., tion in order to have the observed fi nal clast Down-core distribution of clast samples 2008–2009). The combination of these various composition at the initial phase of deposi- highlights a main concentration of these clasts features corroborates the conclusion that prov- tion. Moreover, similarly to the core section below 1000 mbsf and, consistent with prelimi- enance signatures deduced for the three clasts above 225 mbsf, core sections hosting the two nary provenance inferences (Panter et al., 2008– above 225 mbsf cannot provide valuable con- occurrences show mixed debris indicating 2009), indicate a well-documented time win- straints to glacial reconstructions. both Skelton-Mulock glacier source and local dow (between 20.2 and 20.1 Ma, Acton et al., Due to the poorly constrained model age, the sources (i.e., Royal Society Range and vol- 2008–2009 with modifi cation as in ANDRILL AND-2A core section above 225 mbsf can only canic centers in the McMurdo Sound). Con- SMS Science Team, 2010) with ice mainly be very approximately compared to other previ- sequently, the meaning of the two Britannia sourced from the Royal Society Range. ous drill cores in the McMurdo Sound region. Range occurrences remains obscure. The very

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small thickness of the hosting diamictites glaciation (Miller et al., 1996) and a prominent dominant fl ows from W to E of local (<100 km (1.5–4 m) appears to be more consistent with decrease (up to 20 m) of the sea level (Kominz from the drill site) paleoglaciers in the Royal IRD than distal deposition related to a mas- et al., 2008). Society Range, or fl uctuations of ice grounded sive ice sheet sourced from areas as distant at the regional scale in the Ross Embayment as the Britannia Range. If mixed assemblages CONCLUSIONS with fl ow lines running N-S close to the Trans- could be explained as for the core section atlantic Mountains front at times for more than above 225 mbsf (i.e., primary Royal Society (1) The gravel fraction in the AND-2A core 500 km during glacial maxima. Both scenarios Range glacial activity and reworking of Skel- contains a small group of Ca-amphibole– further demonstrate the importance of the AND- ton Glacier or Britannia Range debris), the bearing metamorphic small pebbles and cobbles 2A core to reveal a hitherto unavailable, near- preservation of angular shapes would indicate (angular to well rounded in shape and occur- fi eld record of dynamic paleoenvironmental that some clasts could have escaped extensive ring in different lithofacies) that are scattered history during signifi cant steps in the Antarctic abrasion during reworking. throughout the early Miocene to Pliocene sec- glacial evolution through the Miocene climatic In contrast, the two subrounded to rounded tion. This clast lithology shows a rather wide events indicated by proxy records. pebbles and the overall clast compositional fea- range of Ca-amphibole compositions, type of tures in the thick unit of massive diamictites at Ca-amphibole intracrystalline zoning, mineral ACKNOWLEDGMENTS 756–775 mbsf can be explained in terms of a assemblages and fabrics refl ecting different bulk The ANDRILL Program is a multinational collab- regional-scale ice-fl ow pattern refl ecting a most rocks and metamorphic conditions. The clasts oration between the Antarctic programs of Germany, likely thicker ice sourced from Transantarctic have been compared with petrographically Italy, New Zealand, and the United States. Antarctica Mountains outlet glaciers between Mulock and similar rock types from potential source areas in New Zealand is the project operator and developed Byrd glaciers and with fl ow lines mainly N-S the crystalline basement exposed in the region the drilling system in collaboration with Alex Pyne at aligned parallel to the Transantarctic Moun- between Ferrar and Byrd glaciers. Victoria University of Wellington and Webster Drill- ing and Exploration Ltd. Antarctica New Zealand tains front (Fig. 6C). This diamictite unit is part (2) In spite of the limited number of occur- supported the drilling team at Scott Base; Raytheon of a thick diamictite-dominated core section rences, the petrological study of the AND-2A Polar Services Corporation supported the science between 637 and 778 mbsf that consistently Ca-amphibole metamorphic clasts reveals team at McMurdo Station and the Crary Science and shows the same clast composition and domi- the key role of this lithology in the identifi ca- Engineering Laboratory. The ANDRILL Science Management Offi ce at the University of Nebraska– nant Skelton-Mulock glacier area provenance. tion of three distinct provenance areas of the Lincoln provided science planning and operational Actually the two investigated clasts constitute present-day segment of the Transantarctic support. Scientifi c studies are jointly supported by the a minor and nonpersistent component of the Mountains including the Koettlitz-Blue glacier U.S. National Science Foundation (NSF), New Zea- basement clast assemblages comprising granit- area in the Royal Society Range, the Mulock- land Foundation for Research, Science and Technol- oids and metamorphic rocks that are similar to Skelton glacier area, and the Britannia Range. ogy (FRST), the Italian Antarctic Research Program (PNRA), the German Research Foundation (DFG), the rock units exposed in the Skelton-Mulock Ca- amphibole compositions and zonations also and the Alfred Wegener Institute for Polar and Marine glacier area (Zattin et al., 2010; Sandroni and provide a tool to semiquantitatively estimate Research (AWI). This study was supported with the Talarico, 2011). This core interval shows a P-T conditions attending the formation of meta- fi nancial support of the Italian Programma Nazionale prominent hiatus (ca. 1 Ma) at its base (Acton et morphic mineral assemblages in both outcrop di Ricerche in Antartide (PNRA) and PRIN 2008 (F.M. Talarico) grants. The very helpful reviews by al., 2008–2009, with modifi cations reported by and clast sample parageneses. The results of the R. Carosi and B. Storey are gratefully acknowledged. ANDRILL SMS Science Team, 2010), and, as application of empirical Ca-amphibole geother- interpreted by Passchier et al. (2010), it would mobarometry contribute new P and T estimates REFERENCES CITED represent glacially-dominated depositional envi- that are essential for a better understanding ronments with periods of grounded ice, major of the regional metamorphic patterns and the Acton, G., Crampton, J., Di Vincenzo, G., Fielding, C.R., Florindo, F., Hannah, M., Harwood, D., Ishman, S., ice growth to volumes larger than the present metamorphic evolution in the three provenance Johnson, K., Jovane, L., Levy, R., Lum, B., Marcano, day, and only brief intervals of ice-free coasts. regions. In agreement with literature data, the M.C., Mukasa, S., Ohneiser, C., Olney, M., Riessel- Interestingly, correlative diamictite sections in new results provide further information support- man, C., Sagnotti, L., Stefano, C., Strada, E., Taviani, M., Tuzzi, E., Verosub, K.L., Wilson, G.S., Zattin, M., CRP-1 (Florindo et al., 2005) show a signifi - ing the coincidence of the three regions with dis- and ANDRILL-SMS Science Team, 2008–2009, Pre- cant amount of volcanic clasts (Smellie, 1998) tinct metamorphic terrains showing partly dif- liminary integrated chronostratigraphy of the AND-2A most likely sourced from the Mount Morning ferent metamorphic evolutions. Importantly, the core, ANDRILL Southern McMurdo Sound project, Antarctica: Terra Antarctica, v. 15, p. 211–220. (Martin et al., 2010), and clay fraction with data provide the fi rst evidence that intermediate- Allibone, A.H., 1992, Low-pressure/high-temperature peaks in smectite concentration that were inter- P medium-grade conditions are documented in metamorphism of Koettlitz Group schists, Taylor Valley and upper area, South Vic- preted by Ehrmann et al. (2005) as indicating the Britannia Range. toria Land, Antarctica: New Zealand Journal of the same southern provenance. In this context, (3) Analysis of the down-core distribution Geology and Geophysics, v. 35, p. 115–127, doi: the ice-fl ow pattern can be confi dently traced at of the investigated clasts and combinations of 10.1080/00288306.1992.9514506. ANDRILL SMS Science Team, 2010, An integrated age a regional scale over the entire McMurdo Sound their provenance with clast shape, position in model for the ANDRILL-2A drill core: Erice, Italy, (including AND-2A and CRP-1 drill sites) with the host lithological units, nature of the main ANDRILL Southern McMurdo Sound Project Science fl ow lines running very close and parallel to the host lithofacies and composition of associated Integration Workshop, Program and Abstracts, 6–11 April 2010, ANDRILL Contribution, v. 16, p. 12–13. Transantarctic Mountains front (Fig. 6C). In basement clasts provide insight into the deposi- Barrett, P., 1999, Antarctic climate history over the last 100 light of the model age (ca.17.8 Ma at 778 mbsf tional processes with a variety of settings from million years: Terra Antarctica Reports, v. 3, p. 53–72. Barrett, P.J., 1979, Proposed drilling in McMurdo Sound: and ca. 17.3 ± 0.14 Ma at 626 mbsf; Acton et open marine with icebergs to distal, proximal, Memoir of the National Institute of Polar Research, al., 2008–2009, with modifi cations reported by and subglacial. v. 13, Special Issue, p. 231–239. the ANDRILL SMS Science Team, 2010; Di (4) The study contributes further evidence Barrett, P.J., 1991, The Devonian to Triassic Beacon Super- group of the Transantarctic Mountains and correla- Vincenzo et al., 2010), it is possible that this that the AND-2A core records two distinct gla- tives in other parts of Antarctica, in Tingey, R.J., ed., core section preserves evidence of the Mi1b cial scenarios refl ecting either fl uctuations with The Geology of Antarctica, Oxford Monographs on

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Geology and Geophysics 17: Oxford, Clarendon Press, products from the AND-2A core (ANDRILL Southern Holbourn, A., Kuhnt, W., Schulz, M., Flores, J.-A., and p. 120–152. McMurdo Sound Project, Antarctica): Correlations Andersen, N., 2007, Orbitally-paced climate evolution Billups, K., and Schrag, D.P., 2002, Paleotemperatures and with the Erebus Volcanic Province and implications during the middle Miocene “Monterey” carbon-isotope ice volume of the past 27 Myr revisited with paired for the age model of the core: Bulletin of Volcanology, excursion: Earth and Planetary Science Letters, v. 261, Mg/Ca and 18O/16O measurements on benthic fora- v. 72, p. 487–505, doi:10.1007/s00445-009-0337-z. p. 534–550, doi:10.1016/j.epsl.2007.07.026. minifera: Paleoceanography, v. 17, p. 1003–1013, doi: Drewry, D.J., 1983, Antarctica: Glaciological and geophysi- Holland, T.J.B., and Richardson, S.W., 1979, Amphibole 10.1029/2000PA000567. cal folio: Cambridge, United Kingdom, University of zonation in metabasites as a guide to the evolution Borg, S.G., DePaolo, D.J., Wendlandt, E.D., and Drake, Cambridge, Scott Polar Research Institute, 9 p. of metamorphic conditions: Contributions to Miner- T.G., 1987, Studies of granites and metamorphic rocks, Ehrmann, W., Setti, M., and Marinoni, L., 2005, Clay miner- alogy and Petrology, v. 70, p. 143–148, doi:10.1007/ Byrd Glacier area: Antarctic Journal of the United als in Cenozoic sediments off Cape Roberts (McMurdo BF00374442. States, v. 24, p. 19–21. Sound, Antarctica) reveal palaeoclimatic history: Kominz, M.A., Browning, J.V., Miller, K.G., Sugarman, Brown, E.H., 1977, The crossite content of Ca-amphibole Palaeogeography, Palaeoclimatology, Palaeoecology, P.J., Mizintseva, S., and Scotese, C.R., 2008, Late as a guide to pressure of metamorphism: Journal of v. 229, p. 187–211, doi:10.1016/j.palaeo.2005.06.022. Cretaceous to Miocene sea-level estimates from the Petrology, v. 18, p. 53–72. Elliot, D.H., 1992, Jurassic magmatism and tectonism asso- New Jersey and Delaware coastal plain coreholes: Bucker, K., and Frey, M., 1994, Petrogenesis of metamor- ciated with Gondwanaland break-up: An Antarctic per- An error analysis: Basin Research, v. 20, p. 211–226, phic rocks: Springer-Verlag Telos, 341 p. spective, in Storey, B.C., Alabaster, T., and Punkhurst, doi:10.1111/j.1365-2117.2008.00354.x. Carosi, R., Giacomini, F., Talarico, F., and Stump, E., 2007, R.J., eds., Magmatism and the causes of continental Kretz, R., 1983, Symbols for rock forming minerals: The Geology of the Byrd Glacier Discontinuity (Ross oro- break-up: The Geological Society of London Special American Mineralogist, v. 68, p. 277–279. gen): New survey data from the Britannia Range, Ant- Publication 68, p. 165–184. Kyle, P.R., 1981, Glacial history of the McMurdo Sound arctica, in Cooper, A.K., Barrett, P., Stagg, H., Storey, Elliot, D.H., Fleming, T.H., Haban, M.A., and Siders, M.A., area as indicated by the distribution and nature of B., Stump, E., Wise, W., and 10th International Sympo- 1995, Petrology and mineralogy of the Kirkpatrick basalt McMurdo Volcanic Group rocks, in McGinnis, L.D., sium on Antarctic Earth Sciences editorial team, eds., and Ferrar dolerites, Mesa Range region, north Victoria ed., Dry Valley Drilling Project, Antarctic Research Antarctica: A Keystone in a Changing World, Online Land, Antarctica: Contribution to Antarctic Research IV: Series 33: Washington, D.C., American Geophysical Proceedings of the Tenth International Symposium Antarctic Research Series, v. 67, p. 103–141. Union, p. 403–412. on Antarctic Earth Sciences: U.S. Geological Survey Fahnestock, M.A., Scambos, T.A., Bindschadler, R.A., Kyle, P.R., 1990, McMurdo Volcanic Group, western Ross Open-File Report 2007-1047, Short Research Paper and Kvaran, G., 2000, A millennium of variable Embayment. Introduction, in Le Masurier, W.E., and 030, 6 p., doi:10.3133/of2007-1047.srp030. ice fl ow recorded by the Ross Ice Shelf, Antarc- Thomson, J.W., eds., Volcanoes of the Antarctic Plate Cook, Y.A., and Craw, D., 2001, Amalgamation of disparate tica: Journal of , v. 46, p. 652–664, and Southern Oceans: American Geophysical Union crustal fragments in the Walcott Bay-Foster Glacier doi:10.3189/172756500781832693. Antarctic Research Series 48, p. 19–25. area, South Victoria Land, Antarctica: New Zealand Fielding, C.R., Whittaker, J., Henrys, S.A., Wilson, T.J., and Leake, B.E., Woolley, A.R., Arps, C.E.S., Birch, W.D., Gil- Journal of Geology and Geophysics, v. 44, p. 403–416, Naish, T.R., 2008, Seismic facies and stratigraphy of bert, M.C., Grice, J.D., Hawthorne, F.C., Kato, A., doi:10.1080/00288306.2001.9514947. the Cenozoic succession in McMurdo Sound, Antarc- Kisch, H.J., Krichovichev, V.G., Linthout, K., Laird, J., Cook, Y.A., and Craw, D., 2002, Neoproterozoic structural tica: Implications for tectonic, climatic and glacial his- Mandarino, J.A., Maresch, W.V., Nickel, E.H., Rock, slices in the Ross orogen, Skelton Glacier area, South tory: Palaeogeography, Palaeoclimatology, Palaeoecol- N.M.S., Schumacher, J.C., Smith, D.C., Stephenson, Victoria Land, Antarctica: New Zealand Journal of ogy, v. 260, p. 8–29, doi:10.1016/j.palaeo.2007.08.016. N.C.N., Ungaretti, L., Whittaker, E.J.W., and Youzhi, Geology and Geophysics, v. 45, p. 133–143, doi:10 Fielding, C.R., Atkins, C.B., Bassett, K.N., Browne, G.H., G., 1997, Nomenclature of amphiboles: Report of the .1080/00288306.2002.9514965. Dunbar, G.B., Field, B.D., Frank, T.D., Krissek, L.A., Subcommittee on Amphiboles of the International Cooper, A.K., and Davey, F.J., 1985, Episodic rifting of the Panter, K.S., Passchier, S., Pekar, S.F., Sandroni, S., Mineralogical Association, Commission on New Min- Phanerozoic rocks of the Victoria Land basin, western Talarico, F., and ANDRILL-SMS Science Team, 2008– erals and Mineral Names: The American Mineralogist, Ross Sea, Antarctica: Science, v. 229, p. 1085–1087, 2009, Sedimentology and stratigraphy of the AND-2A v. 35, p. 219–246. doi:10.1126/science.229.4718.1085. core, ANDRILL Southern McMurdo Sound project, Martin, A.P., Cooper, A.F., and Dunlap, W.J., 2010, Geo- Cooper, A.F., Worley, B.A., Armstrong, R.A., and Price, Antarctica: Terra Antartica, v. 15, p. 77–112. chronology of Mount Morning, Antarctica: Two-phase R.C., 1997, Synorogenic Alkaline and Carbonatitic Findlay, R.H., Skinner, D.N.B., and Craw, D., 1984, evolution of a long-lived trachyte-basanite-phonolite magmatism in the Transantarctic Mountains of South Lithostratigraphy and structure of the Koettlitz Group, eruptive center: Bulletin of Volcanology, v. 72, p. 357– Victoria Land, Antarctica, in Ricci, C.A., ed., The Ant- McMurdo Sound, Antarctica: New Zealand Journal of 371, doi:10.1007/s00445-009-0319-1. arctic Region: Siena, Italy, Geological Evolution and Geology and Geophysics, v. 27, p. 513–536. Miller, K.G., Mountain, G.S., and the Leg 150 Shipboard Processes, Terra Antarctica Publications, p. 245–252. Florindo, F., Wilson, G.S., Roberts, A.P., Sagnotti, L., and Party, Members of the New Jersey Coastal Plain Drill- Cornamusini, G., 2010, Sedimentary coarse clasts in AND- Verosub, K.L., 2005, Magnetostratigraphic chronology ing Project, 1996, Drilling and dating New Jersey 2A core, ANDRILL Southern McMurdo Sound Proj- of a late Eocene to early Miocene glacimarine succes- Oligocene–Miocene sequences: Ice volume, global ect, Antarctica: Stratigraphic distribution and prov- sion from the Victoria Land Basin, Ross Sea, Antarc- sea level, and Exxon records: Science, v. 271, p. 1092– enance: Erice, Italy, ANDRILL Southern McMurdo tica: Global and Planetary Change, v. 45, p. 207–236, 1095, doi:10.1126/science.271.5252.1092. Sound Project Science Integration Workshop, Program doi:10.1016/j.gloplacha.2004.09.009. Miyashiro, A., 1994, Metamorphic petrology: London, Uni- and Abstracts, 6–11 April 2010, ANDRILL Contribu- Gerya, T.V., Perchuk, L.L., Triboulet, C., Audren, C., and versity College Limited Press, 404 p. tion, v. 16, p. 22–24. Sez’ko, A.I., 1997, Petrology of the Tumanshet Zonal Naish, T., Powell, R., Levy, R., and the ANDRILL MIS Sci- Cottle, J.M., 2002, Evolution of a convergent margin - A pet- Metamorphic Complex, Eastern Sayan: Petrology, v. 5, ence Team, 2007, Initial science results from AND-1B, rological study of Ross orogeny magmatism in the Car- p. 503–533. ANDRILL McMurdo Ice Shelf Project, Antarctica: lyon Glacier region, southern Victoria Land, Antarctica Goodge, J.W., 2007, Metamorphism in the Ross orogen and Terra Antartica, v. 14, p. 1–328. [M.S. thesis]: University of Otago Library, 200 p. its bearing on Gondwana margin tectonics, in Cloos, Panter, K.S., Talarico, F., Bassett, K., Del Carlo, P., Field, B., Cottle, J.M., and Cooper, A.F., 2006, Geology, geochemistry M., Carlson, W.D., Gilbert, M.C., Liou, J.G., and Frank, T., Hoffmann, S., Kuhn, G., Reichelt, L., San- and geochronology of an A-type granite in the Mulock Sorensen, S.S., eds., Convergent Margin Tectonics and droni, S., Taviani, M., Bracciali, M., Cornamusini, G., Glacier area, southern Victoria Land, Antarctica: New Associated Regions: A Tribute to W. G. Ernst: Geologi- von Eynatten, H., Rocchi, S., and ANDRILL-SMS Sci- Zealand Journal of Geology and Geophysics, v. 49, cal Society of America Special Paper 419, p. 185–203. ence Team, 2008–2009, Petrologic and geochemical p. 191–202. Goodge, J.W., Williams, I.S., and Myrow, P., 2004, Prov- composition of the AND-2A core, ANDRILL Southern Cowan, E.A., Hillenbrand, C.-D., Hassler, L.E., and Ake, enance of Neoproterozoic and lower Paleozoic silici- McMurdo Sound Project, Antarctica: Terra Antartica, M.T., 2008, Coarse-grained terrigenous sediment clastic rocks of the central Ross orogen, Antarctica: v. 15, p. 147–192. deposition on continental rise drifts: A record of Plio- Detrital record of rift-, passive- and active-margin sedi- Papike, J.J., Cameron, K.C., and Baldwin, K., 1974, Amphi- Pleistocene glaciation on the Antarctic Peninsula: mentation: Geological Society of America Bulletin, boles and pyroxenes: characterization of other than Palaeogeography, Palaeoclimatology, Palaeoecology, v. 116, p. 1253–1279, doi:10.1130/B25347.1. quadrilateral components and estimate of ferric iron v. 265, p. 275–291, doi:10.1016/j.palaeo.2008.03.010. Gunn, B.M., and Warren, G., 1962, Geology of Victoria from microprobe data: Geological Society of America, Cox, S.C., 1992, Garnet-biotite geothermometry of Koettlitz Land between the Mawson and Mulock Glaciers, Abstracts with Programs, v. 6, p. 1053–1054. Group metasediments, Wright Valley, South Victoria Antarctica: New Zealand Geological Survey Bulletin, Passchier, S., Fielding, C.R., Pekar, S., Panter, K., Harwood, Land, Antarctica: New Zealand Journal of Geology and v. 71, p. 1–157. D., Browne, G., Field, B., Krissek, L., Falk, C., and Geophysics, v. 35, p. 29–40, doi:10.1080/00288306 Hambrey, M.J., Barrett, P.J., and Powell, R.D., 2002, Late Florindo, F., 2010, Facies distribution of AND-2A .1992.9514497. Oligocene and early Miocene glacimarine sedimenta- and implications for ice dynamics during early and Cox, S.C., 1993, Inter-related plutonism and deformation in tion in the SW Ross Sea, Antarctica: The record from middle Miocene Climatic Optima and the middle South Victoria Land, Antarctica: Geological Magazine, offshore drilling, in Dowdeswell, J.A., and Ó Cofaigh, Miocene climate transition: Erice, Italy, ANDRILL v. 130, p. 1–14, doi:10.1017/S0016756800023682. C., eds., Glacier-infl uenced sedimentation on high- Southern McMurdo Sound Project Science Integration Craddock, C., 1970, Tectonic map of Gondwana, in Bush- latitude continental margins: The Geological Society Workshop, Program and Abstracts, 6–11 April 2010, nell, V.C., and Craddock, C., eds., Geologic Maps of of London Special Publications, v. 203, p. 105–128. ANDRILL Contribution, v. 16, p. 79–81. Antarctica: New York, American Geographical Soci- Harwood, D.M., Florindo, F., Talarico, F.M., and Levy, R.H., Raase, P., 1974, Al and Ti contents of hornblende, indica- ety, Antarctic Map Folio Series, Folio 12, plate XXIII. eds., 2008–2009, Studies from the ANDRILL Southern tors of pressure and temperature of regional metamor- Di Vincenzo, G., Bracciali, L., Del Carlo, P., Panter, K., and McMurdo Sound Project, Antarctica: Initial science phism: Contributions to Mineralogy and Petrology, Rocchi, S., 2010, 40Ar–39Ar dating of volcanogenic report on AND-2A: Terra Antartica, v. 15, p. 5–235. v. 45, p. 231–236, doi:10.1007/BF00383440.

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Reinardy, B.T.I., Pudsey, C.J., Hillenbrand, C.-D., Mur- Talarico, F.M., and Sandroni, S., 2009, Provenance signa- Warren, G., 1969b, Geology of the Shackleton Coast, Ant- ray, T., and Evans, J., 2009, Contrasting sources for ture of the Antarctic Ice Sheets in the Ross Embay- arctic Map Folio Series 12: New York, American Geo- glacial and interglacial shelf sediments used to inter- ment during the late Miocene to early Pliocene: graphical Society Geology Sheet 15. pret changing ice fl ow directions in the Larsen Basin, The ANDRILL AND-1B core record: Global and Wilson, T.J., 1999, Cenozoic structural segmentation of the Northern Antarctic Peninsula: Marine Geology, v. 266, Planetary Change, v. 69, p. 103–123, doi:10.1016/j Transantarctic rift fl ank in southern Victoria Land: p. 156–171, doi:10.1016/j.margeo.2009.08.003. .gloplacha.2009.04.007. Global and Planetary Change, v. 23, p. 105–127, Rowell, A.J., Rees, M.N., Duebendorfer, E.M., Wallin, E.T., Talarico, F.M., Findlay, R.H., and Rastelli, N., 2005, Meta- doi:10.1016/S0921-8181(99)00053-3. van Schmus, W.R., and Smith, E.I., 1993, An active morphic evolution of the Koettlitz Group in the Koet- Wynyard, M., 2004, Geology of the Cocks Glacier area, Ant- Neoproterozoic margin: Evidence from the Skelton tlitz-Ferrar glaciers region (southern Victoria Land, arctica—A study of neo-Proterozoic metamorphism, Glacier area, Transantarctic Mountains: Journal of the Antarctica): Terra Antartica, v. 12, p. 3–23. deformation and magmatism during the Ross orogeny Geological Society, v. 150, p. 677–682, doi:10.1144/ Talarico, F.M., Stump, E., Gootee, B.F., Foland, K.A., Palm- in South Victoria Land [M.S. thesis]: University of gsjgs.150.4.0677. eri, R., van Schmus, W.R., Brand, P.K., and Ricci, C.A., Otago Library, 178 p. Sandroni, S., and Talarico, F.M., 2011, The record of Mio- 2007, First evidence of “Barrovian”-type metamorphic You, Y., Huber, M., Müller, D.R., Poulsen, C.J., and cene climatic events in AND-2A drill core (Antarc- regime in the Ross orogen of Byrd Glacier area, Cen- Ribbe, J., 2009, Simulation of the middle Miocene tica): Insights from provenance analyses of basement tral Transantarctic Mountains: Antarctic Science, v. 19, climate optimum: Implications for future climate: clasts: Global and Planetary Change, v. 75, p. 31–46, p. 451–470, doi:10.1017/S0954102007000594. Geophysical Research Letters, v. 36, p. L04702, doi:10.1016/j.gloplacha.2010.10.002. Talarico, F.M., McKay, R.M., Powell, R.D., Sandroni, S., doi:10.1029/2008GL036571. Smellie, J.L., 1998, Sand grain detrital modes in CRP-1: and Naish, T., 2011, Late Cenozoic oscillations of Zattin, M., Talarico, F.M., and Sandroni, S., 2010, Integrated Provenance variations and infl uence of Miocene erup- Antarctic ice sheets revealed by provenance of base- provenance and detrital thermochronology studies tions on the marine record in the McMurdo Sound ment clasts and grain detrital modes in ANDRILL core in the ANDRILL AND-2A drill core: Late Oligo- region: Terra Antarctica, v. 5, p. 579–587. AND-1B: Global and Planetary Change, doi:10.1016/j cene–early Miocene exhumation of the Transantarc- Spear, F.S., 1980, NaSi-CaAl exchange equilibrium between .gloplacha.2009.12.002 (in press). tic Mountains (Southern Victoria Land, Antarctica): plagioclase and amphibole: An empirical model: Contri- Triboulet, C., 1992, The (Na-Ca)amphibole-albite–chlorite- Terra Nova, v. 22, p. 361–368, doi:10.1111/j.1365 butions to Mineralogy and Petrology, v. 80, p. 140–146. epidote-quartz geothermobarometer in the system S-A- -3121.2010.00958.x.

Spear, F.S., 1993, Metamorphic phase equilibria and F-M-C-N-H2O. 1. An empirical calibration: Journal Zenk, M., and Schulz, B., 2004, Zoned Ca-amphiboles pressure-temperature-time paths: Washington, D. C., of Metamorphic Geology, v. 10, p. 545–556, doi:10 and related P-T evolution in metabasites from the Monograph Series 1, Mineralogical Society of Amer- .1111/j.1525-1314.1992.tb00104.x. classical Barrovian metamorphic zones in Scot- ica, 799 p. Vernon, R.H., 1976, Metamorphic processes: London, land: Mineralogical Magazine, v. 68, p. 769–786, Stump, E., 1995, The Ross orogen of the Transantarctic Murby; New York, Wiley, 247 p. doi:10.1180/0026461046850218. Mountains: Cambridge, Cambridge University Press, Vernon, R.H., and Clarke, G.L., 2008, Principles of metamor- 284 p. phic petrology: Cambridge University Press, 446 p. Talarico, F.M., and Sandroni, S., 1998, Petrography, min- Warren, G., 1969a, Geology of the Terra Nova Bay- eral chemistry and provenance of basement clasts in McMurdo Sound area, Victoria Land, Antarctic Map MANUSCRIPT RECEIVED 25 OCTOBER 2010 the CRP-1 drill core (Victoria Land Basin, Antarctica): Folio Series 12: New York, American Geographical REVISED MANUSCRIPT RECEIVED 8 MARCH 2011 Terra Antartica, v. 5, p. 601–610. Society Geology Sheet 14. MANUSCRIPT ACCEPTED 18 MARCH 2011

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