Magmatism in the South Sandwich arc

Leat, P. T.; Smellie, John L.; Millar, Ian L.; Larter, Robert D

doi:10.1144/gsl.sp.2003.219.01.14

Cited by 62 publications

(70 citation statements)

References 94 publications

(147 reference statements)

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“…TN057-14PC4 tephra samples are chemically similar and show enrichments in rubidium, barium, thorium, uranium, potassium, and REE, consistent with an SSI source ( Figure 4a). Rare earth element patterns further support a source within the SSI arc because the TN057-14PC4 glasses are slightly enriched in the light REEs, similar to the pattern of the Southern Thule Group (STG) within the SSI [Leat et al, 2003] (Figure 4b). High ratios of the trace elements Ba/Nb versus low ratios of Ce/Yb illus- a Isotope ratios revealed by MC-ICP-MS analysis of glass, single ash grain (SAG) and mixed clear mineral (CM) samples.…”

Section: Geochemistry Geophysicsmentioning

confidence: 63%

“…In Figure 4a the grey area encompasses the South Sandwich Island trace element variability [Leat et al, 2003;Pearce et al, 1995]. In Figure 4b, black areas encompass REE patterns from South Sandwich Islands Candlemas and Vindication Islands [Leat et al, 2003]. Dark grey area covers Southern Thule Group data (Bellinghausen, Cook, and Thule Islands) of SSI [Leat et al, 2003].…”

Section: Geochemistry Geophysicsmentioning

confidence: 99%

“…Phenocrysts from the young SSI volcanic material should Leat et al [2004], and the Southern Thule Group from Leat et al [2003]. Grey fields are modern lead data from Sangster et al [2000].…”

Section: Sources Of Clear Mineralsmentioning

confidence: 99%

“…The corresponding 87 Sr/ 86 Sr versus e(Nd) data are consistent with mixing between SSI-derived material and a continental crust Figure 7. Same as Figure 5, but focusing on the variability of our data compared to the Southern Thule Group data from Leat et al [2003] (black circles). Error bars represent long-term accuracy of standard measurements.…”

Section: Geochemistry Geophysicsmentioning

confidence: 99%

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Origin and significance of ice‐rafted detritus in the Atlantic sector of the Southern Ocean

Nielsen

Hodell

Kamenov

et al. 2007

Geochem Geophys Geosyst

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Piston core TN057‐14 from the eastern Atlantic sector of the Southern Ocean contains several layers rich in volcanic tephra that were deposited during the last glacial period. Comparison with nearby cores (TN057‐13PC4/ODP Site 1094) indicates that these tephra layers are correlative with the South Atlantic (SA) ice‐rafted detritus (IRD) layers identified by Kanfoush et al. (2000, 2002). We analyzed the tephra for major and trace elements as well as isotopic ratios of strontium, neodymium, and lead. The elemental and isotopic composition of all tephra layers examined indicates the South Sandwich Island volcanic arc (SSI) as their dominant source, with minor input from Bouvet Island. Similar analyses of clear mineral grains (mainly feldspars, quartz, and olivine) also point to the SSI as the main source. We conclude that tephra erupted from the SSI was first deposited as air fall on sea ice and multiyear ice and then secondarily rafted to the studied sites. Deposition of the tephra‐rich IRD layers was controlled by changes in sea surface temperature and sea‐ice conditions in the Polar Frontal Zone of the South Atlantic, rather than Antarctic ice sheet dynamics.

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Section: Geochemistry Geophysicsmentioning

confidence: 63%

Section: Geochemistry Geophysicsmentioning

confidence: 99%

Section: Sources Of Clear Mineralsmentioning

confidence: 99%

Section: Geochemistry Geophysicsmentioning

confidence: 99%

See 2 more Smart Citations

Origin and significance of ice‐rafted detritus in the Atlantic sector of the Southern Ocean

Nielsen

Hodell

Kamenov

et al. 2007

Geochem Geophys Geosyst

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“…Data from the Aleutian arc are interpreted to reflect a basaltic crust built around an existing oceanic plate [Holbrook et al, 1999;Lizarralde et al, 2002;Shillington et al, 2004;Van Avendonk et al, 2004]. In contrast, studies of the Izu-Bonin [Suyehiro et al, 1996;Takahashi et al, 1998;Kodaira et al, 2007aKodaira et al, , 2007b, Mariana [Takahashi et al, 2007;Calvert et al, 2008], Tonga [Crawford et al, 2003], and South Sandwich [Larter et al, 2001;Leat et al, 2003] arcs have all documented thick (∼2-8 km), low-velocity (V p = 6.0-6.5 km/s) midcrustal layers that are interpreted to represent intermediate to felsic plutonic rocks. This interpretation is corroborated by the presence of extensive tonalitic plutons in exposed middle crust from the Izu-Bonin arc, preserved in the Tanzawa plutonic complex, Japan [Kawate and Arima, 1998].…”

Section: Introductionmentioning

confidence: 99%

Intermediate to felsic middle crust in the accreted Talkeetna arc, the Alaska Peninsula and Kodiak Island, Alaska: An analogue for low‐velocity middle crust in modern arcs

et al. 2010

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Seismic profiles of several modern arcs have identified thick, low‐velocity midcrustal layers (Vp = 6.0–6.5 km/s) that are interpreted to represent intermediate to felsic plutonic crust. The presence of this silicic crust is surprising given the mafic composition of most primitive mantle melts and could have important implications for the chemical evolution and bulk composition of arcs. However, direct studies of the middle crust are limited by the restricted plutonic exposures in modern arcs. The accreted Talkeetna arc, south central Alaska, exposes a faulted crustal section from residual subarc mantle to subaerial volcanic rocks of a Jurassic intraoceanic arc and is an ideal place to study the intrusive middle crust. Previous research on the arc, which has provided insight into a range of arc processes, has principally focused on western exposures of the arc in the Chugach Mountains. We present new U‐Pb zircon dates, radiogenic isotope data, and whole‐rock geochemical analyses that provide the first high‐precision data on large intermediate to felsic plutonic exposures on Kodiak Island and the Alaska Peninsula. A single chemical abrasion–thermal ionization mass spectrometry analysis from the Afognak pluton yielded an age of 212.87 ± 0.19 Ma, indicating that the plutonic exposures on Kodiak Island represent the earliest preserved record of Talkeetna arc magmatism. Nine new dates from the extensive Jurassic batholith on the Alaska Peninsula range from 183.5 to 164.1 Ma and require a northward shift in the Talkeetna arc magmatic axis following initial emplacement of the Kodiak plutons, paralleling the development of arc magmatism in the Chugach and Talkeetna mountains. Radiogenic isotope data from the Alaska Peninsula and the Kodiak archipelago range from ɛNd(t) = 5.2 to 9.0 and 87Sr/86Srint = 0.703515 to 0.703947 and are similar to age‐corrected data from modern intraoceanic arcs, suggesting that the evolved Alaska Peninsula plutons formed by extensive differentiation of arc basalts with little or no involvement of preexisting crustal material. The whole‐rock geochemical data and calculated seismic velocities suggest that the Alaska Peninsula represents an analogue for the low‐velocity middle crust observed in modern arcs. The continuous temporal record and extensive exposure of intermediate to felsic plutonic rocks in the Talkeetna arc indicate that evolved magmas are generated by repetitive or steady state processes and play a fundamental role in the growth and evolution of intraoceanic arcs.

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Neoarchean arc‐back arc subduction system in the Indian Peninsula: Evidence from mafic magmatism in the Shimoga greenstone belt, western Dharwar Craton

Singh

Santosh

et al. 2020

Geological Journal

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The Neoarchean Shimoga greenstone belt (SGB) of western Dharwar Craton is dominated by ultramafic‐mafic‐felsic magmatic suite and sedimentary rocks. Here, we investigate the mineral chemistry and whole‐rock geochemistry of the Koppa–Herambapura mafic magmatic rocks (tholeiitic metagabbro and metabasalt) from the southern SGB in order to understand their petrogenesis and geodynamic implication. The geochemical features classify the Shimoga rocks as basaltic‐basaltic andesite with a sub‐alkaline tholeiitic signature. Both the rock types display uniform depletion in HFSE relative to LILE‐LREE, higher LILE/HFSE, and LREE/HFSE ratios (La/Nb = 1.30–8.07, Nb/Ta = 11.58–16.19, Zr/Sm = 10.24–29.77) and negative Nb–Ta, Zr–Hf, and Ti anomalies in multi‐element patterns, corresponding to magmatic arc rocks generated within intraoceanic subduction environment. Their Nb/Th (2–15), Zr/Sm (10–29), and Zr/Hf (44–233) ratios indicate a depleted to enriched mantle source, and the parental magma of the mafic rock suite was generated by low to medium degrees (~8–30%) of mantle melting at depths corresponding to spinel to garnet peridotite fields of arc‐back arc setting. Our field and analytical data suggest that the tholeiitic metagabbros were derived from depleted mantle source generated in an arc environment, whereas the metabasalts had a mantle source attributed to (a) development of juvenile back‐arc rift; (b) upwelling of MORB‐like mantle; and (c) flux‐induced melting in the compositional domain of spinel‐garnet peridotite. Based on these results, we conclude that the mafic rock suite from the southern SGB possibly marks one of the earliest Neoarchean arc‐back arc subduction in the western Dharwar Craton.

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Magmatism in the South Sandwich arc

Cited by 62 publications

References 94 publications

Origin and significance of ice‐rafted detritus in the Atlantic sector of the Southern Ocean

Origin and significance of ice‐rafted detritus in the Atlantic sector of the Southern Ocean

Intermediate to felsic middle crust in the accreted Talkeetna arc, the Alaska Peninsula and Kodiak Island, Alaska: An analogue for low‐velocity middle crust in modern arcs

Neoarchean arc‐back arc subduction system in the Indian Peninsula: Evidence from mafic magmatism in the Shimoga greenstone belt, western Dharwar Craton

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