High-resolution P-T-t paths from δ18O zoning in titanite: A snapshot of late-orogenic collapse in the Grenville of New York

Bonamici, Chloë; Kozdon, Reinhard; Ushikubo, T.; Valley, John W.

doi:10.1130/g32130.1

Cited by 30 publications

(47 citation statements)

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“…It appears that the S 2 and S 3 fabrics formed in rapid succession over a period ≤10 my, and possibly ≤5 my. Oxygen isotope zoning in T2 grains shows that at least the S 2 shear zones formed concurrently with rapid cooling brought on by tectonic exhumation of the Adirondack Highlands from beneath the Lowlands along the CCMZ (Bonamici et al, 2011(Bonamici et al, , 2014. Thus, the S 2 and S 3 fabrics are the structural record at Harrisville of late-Ottawan gravitational collapse (Fig.…”

Section: Dating Structures Fluids and Tectonic Events At Harrisvillementioning

confidence: 88%

“…Experimental data thus appear to successfully predict the relative diffusivities of O and Pb in natural hydrothermal samples that experienced cooling rates of~30-70°C/m.y. (Bonamici et al, 2011(Bonamici et al, , 2014. The lower blocking temperature of O indicates that δ 18 O zoning can be a useful tool for identifying preserved U-Pb age domains within high-temperature titanites.…”

Section: Relative Rates Of O and Pb Diffusion; Age Preservationmentioning

confidence: 96%

“…Titanite grains for this study were sampled from two outcrops within the Carthage-Colton Mylonite Zone (CCMZ) near Harrisville, New York ( Fig. 2; Cartwright et al, 1993;Lamb, 1993;Bonamici et al, 2011Bonamici et al, , 2014. The CCMZ is a major NNE-striking structure that juxtaposes the upper-amphibolite-facies Adirondack Lowlands to the northwest and the granulite-facies central Adirondack Highlands to the southeast ( Fig.…”

Section: Geological Setting and Backgroundmentioning

confidence: 99%

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Combined oxygen-isotope and U-Pb zoning studies of titanite: New criteria for age preservation

et al. 2015

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Titanite is an important U-Pb chronometer for dating geologic events, but its high-temperature applicability depends upon its retention of radiogenic lead (Pb). Experimental data predict similar rates of diffusion for lead (Pb) and oxygen (O) in titanite at granulite-facies metamorphic conditions (T = 650-800°C). This study therefore investigates the utility of O-isotope zoning as an indicator for U-Pb zoning in natural titanite samples from the Carthage-Colton Mylonite Zone of the Adirondack Mountains, New York. Based on previous field, textural, and microanalytical work, there are four generations (types) of titanite in the study area, at least two of which preserve diffusion-related δ 18 O zoning. U-Th-Pb was analyzed by SIMS along traverses across three grains of type-2 titanite, which show well-developed diffusional δ 18 O zoning, and one representative grain from each of the other titanite generations. Type-2 and type-4 titanites show broadly core-to-rim decreasing 206 Pb/ 238 U zoning, consistent with Pb diffusion at higher temperatures, and uniform or even slightly increasing 206 Pb/ 238 U near grain rims, indicating subsequent recrystallization and/or new growth below the Pb blocking temperature. Type-2 and type-4 grain cores preserve ca. 1160 Ma ages that correlate with the anorthositemangerite-charnockite-granite magmatic phase of the Grenville orogeny, whereas grain rims give ca. 1050 Ma 206 Pb/ 238 U ages that coincide with the culminating Ottawan phase. The type-3 titanite grain was sampled from a vein and yields 206 Pb/ 238 U dates older than the syenite into which the vein was emplaced; accordingly, its 206 Pb/ 238 U dates are interpreted as indicating excess uncorrected common Pb. Type-2 grains with recrystallized or shear-eroded margins show truncated or reversed 206 Pb/ 238 U zoning but retain symmetrically decreasing δ 18 O zoning, consistent with grain margin modification following arrest of Pb diffusion but before arrest of O diffusion. It is concluded that O diffusion was slightly faster than Pb diffusion in Adirondack titanites at the conditions of (local) peak Ottawan metamorphism, making δ 18 O zoning a useful discriminator of closed-system age domains that did not suffer Pb loss. In addition, the small offset in the O and Pb partial retention zones constrains the timing and temperature of oblique-slip deformation along the Carthage-Colton Mylonite Zone: the details of porphyroclast microstructure and zoning data show that the oblique-slip shear zones were active at ca. 1050 Ma, with deformation initiating near the peak of Ottawan metamorphism at~700°C and continuing through the O blocking temperature at~550°C.Published by Elsevier B.V.

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Section: Dating Structures Fluids and Tectonic Events At Harrisvillementioning

confidence: 88%

Section: Relative Rates Of O and Pb Diffusion; Age Preservationmentioning

confidence: 96%

Section: Geological Setting and Backgroundmentioning

confidence: 99%

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Combined oxygen-isotope and U-Pb zoning studies of titanite: New criteria for age preservation

et al. 2015

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“…The latest displacement along the Carthage-Colton shear zone has been shown to be top down to the northwest ca. 1047 Ma (Selleck et al, 2005), and to have proceeded very rapidly (Bonamici et al, 2011). The Lowlands are part of Rivers (2008) collapsed "orogenic lid" (i.e., orogen suprastructure) and exhibit only minor, low-grade Ottawan metamorphism, whereas the Highlands belong to the high-grade infrastructure of the large, hot allochthonous polycyclic belt that forms the hinterland of the Ottawan orogen (Fig.…”

Section: Introductionmentioning

confidence: 99%

Megacrystic Gore Mountain–type garnets in the Adirondack Highlands: Age, origin, and tectonic implications

McLelland

Selleck

2011

Geosphere

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“…3). Owing Darling 2013) to slow cooling rates inferred for the Adirondack highlands, temperatures remained above 600 °C for 50-100 million years (Mezger et al 1991;Bonamici et al 2011). If P-T conditions during metamorphism at the Hooper Mine were based on cristobalite inclusions in garnet, one would interpret the garnets to have formed at T > 1470 °C and P < ~0.5 GPa, resulting in an error in inferred formation conditions of ~0.7 GPa and >600 °C and well outside the stability field of the host garnet.…”

Section: Sample Selectionmentioning

confidence: 97%

Significance of “stretched” mineral inclusions for reconstructing P–T exhumation history

Ashley

Darling

Bodnar

et al. 2015

Contrib Mineral Petrol

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polymorph kyanite also has the capacity to retain tensile stresses if exhumed to Earth's surface after being trapped as an inclusion in plagioclase at P-T conditions within the kyanite stability field, with the stresses developed during exhumation sufficient to produce a transformation to andalusite. These results highlight the elastic environment that may arise during exhumation and provide a potential explanation of observed inclusions whose stability fields are well removed from P-T paths followed during exhumation.

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High-resolution P-T-t paths from δ18O zoning in titanite: A snapshot of late-orogenic collapse in the Grenville of New York

Cited by 30 publications

References 25 publications

Combined oxygen-isotope and U-Pb zoning studies of titanite: New criteria for age preservation

Combined oxygen-isotope and U-Pb zoning studies of titanite: New criteria for age preservation

Megacrystic Gore Mountain–type garnets in the Adirondack Highlands: Age, origin, and tectonic implications

Significance of “stretched” mineral inclusions for reconstructing P–T exhumation history

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