Staircase 40/Ar39Ar spectra of fine-grained white mica: Timing and duration of deformation and empirical constraints on argon diffusion

Kirschner, David; Cosca, Michael A.; Masson, Henri; Hunziker, Johannes C.

doi:10.1130/0091-7613(1996)024<0747:saasof>2.3.co;2

Cited by 224 publications

(158 citation statements)

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“…The formula and the parameters suggested by Dodson (1973) and Robbins (1972), respectively, were used to calculate the closure temperatures. These temperatures are consistent with the previously reported retention temperatures of 350 -430 °C for white mica (Purdy and Jäger, 1976;McDougall and Harrison, 1988;Blanckenburg et al, 1989;Kirschner et al, 1996). The peak metamorphic conditions of the high -P/T metamorphic rocks of the Heilongjiang Complex have been estimated by Bai et al (1988).…”

supporting

confidence: 81%

40Ar/39Ar ages of the high-P/T metamorphic rocks of the Heilongjiang Complex in the Jiamusi Massif, northeastern China

Liu¹,

Takasu²,

Liu

et al. 2009

Journal of Mineralogical and Petrological Sciences

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supporting

confidence: 81%

40Ar/39Ar ages of the high-P/T metamorphic rocks of the Heilongjiang Complex in the Jiamusi Massif, northeastern China

Liu¹,

Takasu²,

Liu

et al. 2009

Journal of Mineralogical and Petrological Sciences

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“…Shear concentrated on both sides of the basement block, mainly along the Penninic thrust, the Diablerets thrust and the Mont Blanc shear zone, showing intense shearing during D2, post-dating nappe emplacement. Crespo-Blanc et al (1995) and Kirschner et al (1996) argue that ductile shear along the Diablerets thrust and the base of the Morcles nappe ceased around 15-17 Ma, which would mean that the main shearing in the study area also took place before that time (i.e. in Early to mid-Miocene times).…”

Section: Discussionmentioning

confidence: 99%

The structural history of the Mont Blanc massif with regard to models for its recent exhumation

Egli

Mancktelow

2013

Swiss J Geosci

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The tectonic evolution of the Mont Blanc range with regard to its cooling and exhumation history has been discussed and debated over many years and is still controversial. Recently, several low-temperature thermochronology studies have determined the cooling history of the massif in considerable detail and various tectonic models proposed to explain the young and fast exhumation signal established from these studies. Here we present detailed field data from the wider Mont Blanc area and assess possible exhumation processes in terms of these field constraints. Our observations indicate that none of the major faults or shear zones around the Mont Blanc massif (i.e. Mont Blanc shear zone, Mont Blanc back-thrust, Penninic thrust) was active in Late Neogene times and that young exhumation is therefore not controlled by movements along these structures. We demonstrate that the position of Mont Blanc in the bend of the western Alps plays an important role in its tectonic history and that simple 2D models are insufficient to explain its evolution. Interference between NW-SE compression and orogenparallel extension along the Rhône-Simplon fault system resulted in a complex regional structural pattern, with strike-slip movements on both sides of the Mont Blanc massif. Young brittle faults are predominantly strike slip without significant vertical offset. The young (\2 Ma) rapid exhumation of Mont Blanc is more broadly distributed and cannot be directly linked to discrete faults bounding the massif. The mechanisms driving this recent accelerated exhumation must similarly be of broader scale.

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“…The 40 Ar/ 39 Ar ages are presumed to be cooling ages because all of the dates reported in this paper are from plutonic rocks with high crystallization temperatures; two exceptions to this are the (sub)volcanic rocks 1709C06c and 89CNT08, for which the hornblende ages likely approximate the crystallization age. The hornblende, muscovite, and biotite samples cooled at rates of ∼10 K/Myr (see below) and have grain sizes of 100-500 microns, implying closure temperatures of ∼510°C-575°C, 425°C-475°C, and 300°C-350°C, respectively, based on the work by Harrison [1981], Harrison et al [2009], Kirschner et al [1996], Grove and Harrison [1996] and Dunlap [2000]. The Sm-Nd and LuHf ages reported are also cooling ages because these systems probably closed at temperatures of 700°C-750°C [Ganguly and Tirone, 1999;Scherer et al, 2000;Van Orman et al, 2002;Kylander-Clark et al, 2007, below the peak temperatures of 800°C-1000°C [Hacker et al, 2008].…”

Section: Closure Temperaturesmentioning

confidence: 99%

Thermochronology of the Talkeetna intraoceanic arc of Alaska: Ar/Ar, U‐Th/He, Sm‐Nd, and Lu‐Hf dating

et al. 2011

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[1] As one of two well-exposed intraoceanic arcs, the Talkeetna arc of Alaska affords an opportunity to understand processes deep within arcs. This study reports new Lu-Hf and Sm-Nd garnet ages, 40 Ar/ 39 Ar hornblende, mica and whole-rock ages, and U-Th/He zircon and apatite ages from the Chugach Mountains, Talkeetna Mountains, and Alaska Peninsula, which, in conjunction with existing geochronology, constrain the thermal history of the arc. The oldest U-Th/He zircon ages are ∼137 to 129 Ma, indicating no Cenozoic regional heating above ∼180°C. Although the signal is likely complicated by Cretaceous and Oligocene postarc magmatism, the aggregate thermochronology record indicates that the thermal history of the Talkeetna arc was spatially variable. Onedimensional finite difference thermal models show that this kind of spatial variability is inherent to intraoceanic arcs with simple construction histories. Citation: Hacker,

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Staircase 40/Ar39Ar spectra of fine-grained white mica: Timing and duration of deformation and empirical constraints on argon diffusion

Cited by 224 publications

References 0 publications

40Ar/39Ar ages of the high-P/T metamorphic rocks of the Heilongjiang Complex in the Jiamusi Massif, northeastern China

40Ar/39Ar ages of the high-P/T metamorphic rocks of the Heilongjiang Complex in the Jiamusi Massif, northeastern China

The structural history of the Mont Blanc massif with regard to models for its recent exhumation

Thermochronology of the Talkeetna intraoceanic arc of Alaska: Ar/Ar, U‐Th/He, Sm‐Nd, and Lu‐Hf dating

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