Time and tempo of melt segregation from a magma mush: evidence from the Takidani pluton (Japan)

2020 ◽  
Author(s):  
Federico Farina ◽  
Daniela Rubatto ◽  
Eva Hartung ◽  
Luca Caricchi
Keyword(s):  
High Precision ◽  
Time Lag ◽  
Magma Reservoir ◽  
Gradual Transition ◽  
Age Difference ◽  
Central Japan ◽  
Melt Extraction ◽  
Zircon Crystallization ◽  
Melt Segregation ◽  
Residual Melt

<p>The Takidani pluton is a Pleistocene intrusion representing a nearly 2 km-thick shallow level magma reservoir located in the Central Japan Alps. The pluton, which is associated with caldera-forming eruptions, is vertically zoned and composed of six distinct lithological units ranging from hornblende-bearing granodiorite to biotite granite, with silica content varying from ca. 65 to 76 wt.%. In its upper part, the intrusion is characterized by the gradual transition between equigranular and porphyritic granodiorites. Textural and geochemical evidence indicates that the porphyritic unit represents a lens of residual melt extracted from the underlying equigranular granodiorite (Hartung et al., 2017).</p><p>The time and tempo of melt extraction is determined using both high precision and high-spatial resolution U-Pb zircon geochronology, performed by CA-ID-TIMS and SIMS respectively. High precision <sup>206</sup>Pb/<sup>238</sup>U zircon ages for the two units are similar, with grains from both rocks exhibiting an age spread as large as 200-300 kyr, from ca. 1.2 to 1.5 Ma. In-situ U-Pb dating obtained by SIMS using a spot size of 20 μm reveal systematic age difference between cores and rims, highlighting two events of zircon crystallization with no substantial difference between the two units. Zircon cores from the porphyritic and equigranular granodiorites give identical ages at ca. 1.45 ± 0.06 Ma. Spot U-Pb ages from magmatic rims range between 1.29 and 1.07 Ma, with a peak of the distribution density at around 1.20 Ma.</p><p>This information, combined with Zr saturation temperatures and phase equilibria modelling, suggests that zircon cores crystallized from the magma reservoir before rheological locking and melt segregation were achieved. The segregation of the interstitial melt from the mush took place in the ca. 250 kyr between the two events of zircon crystallization. The extracted residual melt was depleted in Zr and carried entrained crystals of plagioclase and zircon from the mush. The low Zr content of this melt hindered zircon crystallization that was only possible after a time lag of 250 kyr. The youngest event of zircon crystallization at ca. 1.2 Ma was contemporaneous in the segregated melt and in the underlying mush.</p><p> </p><p>Reference: Hartung, E., Caricchi, L., Floess, D., Wallis, S., Harayama, S., Kouzmanov, K., Chiaradia, M., 2017. Evidence for residual melt extraction in the Takidani Pluton, Central Japan. J. Petrol.58, 763–788.</p>

scholarly journals Evidence for Residual Melt Extraction in the Takidani Pluton, Central Japan

2017 ◽  
Vol 58 (4) ◽  
pp. 763-788 ◽  
Author(s):  
Eva Hartung ◽  
Luca Caricchi ◽  
David Floess ◽  
Simon Wallis ◽  
Satoru Harayama ◽  
...  
Keyword(s):  
Central Japan ◽  
Melt Extraction ◽  
Residual Melt

scholarly journals Transient rhyolite melt extraction to produce a shallow granitic pluton

2021 ◽  
Vol 7 (21) ◽  
pp. eabf0604
Author(s):  
Allen J. Schaen ◽  
Blair Schoene ◽  
Josef Dufek ◽  
Brad S. Singer ◽  
Michael P. Eddy ◽  
...  
Keyword(s):  
Time Scales ◽  
Explosive Eruptions ◽  
Upper Crust ◽  
Saturation Model ◽  
Granitic Pluton ◽  
Melt Extraction ◽  
High Silica ◽  
Melt Segregation ◽  
Zircon Saturation

Rhyolitic melt that fuels explosive eruptions often originates in the upper crust via extraction from crystal-rich sources, implying an evolutionary link between volcanism and residual plutonism. However, the time scales over which these systems evolve are mainly understood through erupted deposits, limiting confirmation of this connection. Exhumed plutons that preserve a record of high-silica melt segregation provide a critical subvolcanic perspective on rhyolite generation, permitting comparison between time scales of long-term assembly and transient melt extraction events. Here, U-Pb zircon petrochronology and 40Ar/39Ar thermochronology constrain silicic melt segregation and residual cumulate formation in a ~7 to 6 Ma, shallow (3 to 7 km depth) Andean pluton. Thermo-petrological simulations linked to a zircon saturation model map spatiotemporal melt flux distributions. Our findings suggest that ~50 km3 of rhyolitic melt was extracted in ~130 ka, transient pluton assembly that indicates the thermal viability of advanced magma differentiation in the upper crust.

scholarly journals Relative Ages from Horizontal-Branch Morphology: Revisited

2002 ◽  
Vol 207 ◽  
pp. 110-112
Author(s):  
Young-Wook Lee ◽  
Hyun-chul Lee ◽  
Suk-Jin Yoon ◽  
Soo-Chang Rey ◽  
Brian Chaboyer
Keyword(s):  
High Precision ◽  
Globular Clusters ◽  
Age Dating ◽  
Age Difference ◽  
Stellar Systems ◽  
Horizontal Branch ◽  
Ccd Photometry ◽  
Relative Age ◽  
New Models ◽  
Branch Morphology

We present our recent revision of model constructions for the horizontal-branch (HB) morphology of globular clusters, which suggests the HB morphology is more sensitive to age compared to our earlier models. We also present our high precision CCD photometry for the classic second parameter pair M3 and M13. The relative age dating based on this photometry indicates that M13 is indeed older than M3 by 1.7 Gyr. This is consistent with the age difference predicted from our new models, which provides a further support that the HB morphology is a reliable age indicator in most population II stellar systems.

Effects of a severe nutritional check in early post-natal life on the subsequent growth of sheep to the age of 12–14 months

1985 ◽  
Vol 105 (3) ◽  
pp. 551-562 ◽  
Author(s):  
D. L. Hopkins ◽  
N. M. Tulloh
Keyword(s):  
Body Weight ◽  
Time Lag ◽  
The Body ◽  
Cellular Growth ◽  
Control Group ◽  
Age Difference ◽  
Restricted Feeding ◽  
Wool Production ◽  
Significant Difference ◽  
Surface Measurements

SUMMARYThe growth of 26 castrated ram lambs was severely restricted for the first 5 weeks of post-natal life. Subsequently, these lambs (group R) were fed ad libitum on the same high quality diets as fed to a control group of 26 similar lambs (group C) from birth.At regular intervals lambs were weighed, X-rayed and surface measurements were aken. At the age of 12–14 months, covering the body-weight range of 63–83 kg, ten animals from each group were slaughtered for dissection and measurement. These data were used to compare the skeletal growth of the two groups of animals. Measurements of skeletal dimensions by dissection were compared with measurements obtained by surface and radiographic techniques. After slaughter, the brain, kidneys, liver, the left semitendinosus and gastrocnemius muscles from each lamb were used for the following analyses: dry matter, ash, fat, protein, DNA and RNA contents.At the end of the period of feed restriction, there was a mean body-weight difference between groups of 9·2 kg (63%).This represented a weight for age difference of 36 days, which was reduced to 29 days at the conclusion of the experiment, restricted animals not having fully recovered from the period of underfeeding.Clean wool production per day was significantly (P < 0·05) depressed by the restricted feeding, lambs in group C producing 11·07 g/day during the first shearing interval compared with 10·07 g/day from group R lambs. There was no difference between groups in clean wool produced during the second shearing interval.Restricted feeding caused a reduction in the rate of bone growth but, during subsequent regrowth (apart from minor exceptions), it did not disrupt the relationship of skeletal dimensions to fleece-free body weight (FFBW). Surface measurements showed that during recovery, group R animals were significantly narrower (P < 0·05) at the hips and wider (P < 0·05) at the shoulders than group C animals. The results obtained from the radiographs for length of foreleg were similar to those obtained from surface measurements. Metacarpal width (measured at two sites) and weight were significantly greater in group R than in group C animals. With the exception of width at hips and although not statistically significant (P > 0·05), the skeletal measurements of group R were slightly greater than those of group C animals. This may have been due to the slightly greater age of group R at slaughter and to an effect of restricted feeding.There was no significant difference between groups R and C in the DNA content of the tissues investigated. Neither was there any difference between the groups in cell size as indicated by the protein: DNA and tissue weight: DNA ratios. Even though hyperplasia and hypertrophy were slowed by the period of restricted feeding, this effect was transient, full recovery apparently occurring as indicated by tissue weights and composition at the time of slaughter. The RNA and the protein contents of the tissues were similar in both groups. In addition, the similarity of the RNA:DNA ratios suggests that tissues in each group possessed the same capacity to synthesize protein.In practical terms, the recovery of group R was associated with a time lag in reaching any particular body weight and a loss of wool production. Both of these consequences are of economic importance. At the time the experiment ended, no skeletal stunting was evident in these sheep and, apparently, they had recovered in terms of cellular growth.

The permeability of magma mush assembled from anisotropic tabular crystals

2021 ◽  
Author(s):  
Eloïse Bretagne ◽  
Fabian B. Wadsworth ◽  
Katherine J. Dobson ◽  
Jérémie Vasseur ◽  
Jason P. Coumans
Keyword(s):  
Numerical Simulation ◽  
Granular Medium ◽  
Granular Media ◽  
Pore Space ◽  
A Priori ◽  
Spherical Particles ◽  
Natural Systems ◽  
Melt Extraction ◽  
Melt Segregation ◽  
Melt Accumulation

&lt;p&gt;The extraction of melt from a mush in a magma reservoir is of wide interest. All models for melt extraction from a mush require knowledge of mush permeability, and yet this remains poorly constrained. This permeability is typically calculated using the Kozeny-Carman model or variants thereof, which require a priori knowledge of the microstructural geometry. Such models are not calibrated or tested for packs of crystals of a range of shapes found in natural mush piles, leading to the potential for oversimplification of complex natural systems.&lt;/p&gt;&lt;p&gt;Essentially, a magma mush with minimal crystal-crystal intergrowth is composed of packed crystals where the pore space is filled with interstitial melt. Therefore, this can be studied as a granular medium. We use numerical methods to create domains of closely packed, randomly oriented cuboids in which we keep the short and intermediate axes lengths equal (i.e. square cross section) and vary the long axis magnitude. Our synthetic &amp;#8216;crystals&amp;#8217; therefore cover the range from oblate to prolate, passing through a cubic shape. We supplement these with 3D numerical packs of spherical particles in cubic lattice arrangements or random arrangements. For the sphere packs we use various polydispersivity of sphere sizes. The permeability of all of these pack types is calculated using a numerical simulation (both LBflow and Avizo-based algorithms) with imposed periodic boundary conditions. The preliminary results suggest that the permeability of a granular medium scales with the specific surface area exclusively, without requiring prior knowledge of the geometry and size distribution of the particles.&lt;/p&gt;&lt;p&gt;We suggest that the model toward which we are working will allow magma mush permeability to be modelled more accurately. If our approach is embedded in existing continuum models for mush compaction and melt extraction, then more accurate estimates of melt accumulation rates prior to very large eruptions could be found.&lt;/p&gt;&lt;p&gt;Keywords: melt segregation, compaction, granular media, fluid flow, numerical simulation&lt;/p&gt;

scholarly journals Postcumulus processes in layered intrusions

1985 ◽  
Vol 122 (5) ◽  
pp. 555-568 ◽  
Author(s):  
R. S. J. Sparks ◽  
H. E. Huppert ◽  
R. C. Kerr ◽  
D. P. McKenzie ◽  
S. R. Tait
Keyword(s):  
Fluid Dynamic ◽  
Pore Space ◽  
Layered Intrusion ◽  
Magma Reservoir ◽  
Solidification Velocity ◽  
Characteristic Time Scale ◽  
Layered Intrusions ◽  
Mineral Compositions ◽  
Residual Melt ◽  
Compositional Convection

AbstractDuring the postcumulus stage of solidification in layered intrusions, fluid dynamic phenomena play an important role in developing the textural and chemical characteristics of the cumulate rocks. One mechanism of adcumulus growth involves crystallization at the top of the cumulate pile where crystals are in direct contact with the magma reservoir. Convection in the chamber can enable adcumulus growth to occur to form a completely solid contact between cumulate and magma. Another important process may involve compositional convection in which light differentiated melt released by intercumulus crystallization is continually replaced by denser melt from the overlying magma reservoir. This process favours adcumulus growth and can allow adcumulus growth within the pore space of the cumulate pile. Calculations indicate that this process could reduce residual porosities to a few percent in large layered intrusions, but could not form pure monomineralic rocks. Intercumulus melt may also be replaced by more primitive melt during episodes of magma chamber replenishment. Dense magma, emplaced over a cumulate pile containing lower density differentiated melt may sink several metres into the underlying pile in the form of fingers. Reactions between melt and matrix may lead to changes in mineral compositions, mineral textures and whole rock isotope compositions. Another important mechanism for forming adcumulate rocks is compaction, in which the imbalance of the hydrostatic and lithostatic pressures in the cumulate pile causes the crystalline matrix to deform and intercumulus melt to be expelled. For cumulate layers from 10 to 1000 metres in thickness, compaction can reduce porosities to very low values (< 1%) and form monomineralic rocks. The characteristic time-scale for such compaction is theoretically short compared to the time required to solidify a large layered intrusion. During compaction changes of mineral compositions and texture may occur as moving melts interact with the surrounding matrix. Both compaction and compositional convection can be interrupted by solidification in the pore spaces. Compositional convection will only occur if the Rayleigh number is larger than 40, if the residual melt becomes lower in density, and the convective velocity exceeds the solidification velocity (measured by the rate of crystal accumulation in the chamber). Orthocumulates are thus more likely to form in rapidly cooled intrusions where residual melt is frozen into the pore spaces before it can be expelled by compaction or replaced by convection.

scholarly journals Residual Melt Extraction and Out-of-sequence Differentiation in the Bushveld Complex, South Africa

2018 ◽  
Vol 59 (12) ◽  
pp. 2413-2434 ◽  
Author(s):  
Ben Hayes ◽  
Grant M Bybee ◽  
Mpho Mawela ◽  
Paul A M Nex ◽  
Deon van Niekerk
Keyword(s):  
South Africa ◽  
Bushveld Complex ◽  
Melt Extraction ◽  
Residual Melt
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