The presence of one alkali perthitic feldspar is compatible with an hypersolvus granite Bowen and Tuttle, ; Tuttle and Bowen, This unit comprises gray tonalites to granodiorites as the main facies, with subordinate granites and quartz-diorites. Poma et al. These are microdioritic in composition and the material is hybridized in various degrees. Field relationships indicate that during emplacement the silicic melt incorporated mafic material; additional textural evidence indicates in some localities that the granitic intrusion was probably coeval with the mafic magmatism.
The rocks are hypidiomorphic, with inequigranular medium to coarse grains. In some granitic rocks monzonitic textures are common showing poikilitic quartz and K-feldspar enclose euhedral plagioclase and prismatic amphibole. The most abundant mineral is zoned oligoclase An 26 28 with light sericitic alteration; alkali feldspar crystals orthoclase are perthitic. In the granodiorite facies, plagioclase occasionally shows a myrmekitic intergrowth at grain boundaries with alkali feldspar.
Accessory minerals are idiomorphic sphene, apatite, zircon and opaque minerals. Zr shows a positive correlation with SiO 2. The REE diagram Fig. A distinguishing characteristic is their high Rb, Th and U contents and low Sr. Zircon contents show a random distribution versus SiO 2.
The discrimination diagram of Pearce shows Fig. Zr values decrease with increasing SiO 2 indicating a normal negative trend. The REE diagrams Fig. Dating young zircons Phanerozoic faces the problems of low counts of Pb and the difficulty to detect deviations from slightly older cores and from subtle amounts of Pb loss. Most of the data group reasonably in the Concordia plots, with few analyses deviating from the Concordia line.
All Concordia ages are within error with the TuffZirc ages. These ages are presented as insets in the Concordia plots. Rocks of this unit are relatively rich in zircon. The zircon grains are simple and back-scattered electron images show no evidence of older inherited cores or of younger metamorphic rims or zones.
Examples of dated zircon are provided in figures 6a to d. Grains b.
Navigation menu
Grain b. This age is considered the age of crystallization of the gabbro-diorite body. Zoning is subtle but present in all grains. Some grains such as b. These areas are sealing fractures and represent a later event in the rock. Only one of these patches was analyzed b. Table 2. The recrystallization patches may have resulted from the activity of late-magmatic fluids, which may have occurred shortly after the cooling of the granite up to 1 or 2 Ma later. U-Pb ages have been determined for zircon and titanite from a granodiorite. The mineral is U-rich average is ppm. The results Table 2 are concordant.
Common lead i. The age obtained for the titanite is within uncertainty of the age of the zircons, suggesting that the minerals were co-magmatic. Juvenile magmas are defined as those generated from the depleted mantle or by re-melting of material recently extracted from it Belousova et al.
Such model ages indicate the crustal residence time for the rocks that hosted the zircon. The grains were selected according to the degree of concordance and lower common lead content. Ten measurements for Hf isotopes were undertaken on zircons from red granite. The Hf T DM c ages obtained range between 1. T DM ages obtained range between 0. These data indicate that the crustal source of the granodiorite has an important juvenile component of Cryogenian age. Results obtained in Argentina also show two main episodes of magmatism, with different geochemical and Hf isotope signatures.
When comparing the Hf results for both ages' groups Fig. The chemistry of high-silica Llullaillaco rocks indicates crustal participation in their parental melts and within-plate extensional affinities. The lack of inherited xenocrysts should be noted and may result from high magmatic temperatures. The Llullaillaco granites are representative of a prevailing crustal component without excluding some juvenile mantelic input at the time of magmatism.
- popular dating apps Melbourne Australia;
- dating south in Shenyang China!
- Exclusive dating service Sargodha Pakistan.
- COVID-19 pandemic in Argentina;
- Access options.
- Introduction;
The dominant crustal source and shallow emplacement are displayed by their geochemical and textural features. The REE pattern is representative of high-silica evolved magmas with LREE depletion caused by minor accessory minerals and strong plagioclase fractionation, consistent with the hypersolvus-like features recognized.
Timeline of the COVID-19 pandemic in Argentina
The granitoids of the Chuculaqui unit show typical Cordilleran-type magmatic arc characteristics considering their geochemistry and their evolutionary trend. The data obtained are consistent with the results presented by Munizaga et al. The age of the crust in the Puna region: Iso-topic constraints. This magmatism in northwest Argentina thus confirms the presence of Mesoproterozoic crustal components mainly Ec-tasian to Calymnian 1.
Main basement blocks with ages from basement outcrops and model ages from the Gondwanan igneous rocks this paper and Munizaga et al. Other basement ages from Ramos The T DM Hf ages of zircons at around 1.
Experimental cryptococcosis in guinea pigs
Moreover, the presence of enriched mantle in the Ma range late Rodinia break-up is already known in Sierras Pampeanas Rapela et al, and the data obtained suggest that such enriched mantle was active beneath the Puna region. It should be noted that the Chuculaqui Unit lacks relict or inherited zircon that would point to reworking of ancient crust. This excludes the obtained T DM Hf ages to be interpreted as a binary mix of such an ancient crust and mantle material at the time of the generation of the granodiorite, although some Triassic juvenile input is not precluded.
Ramos, ; Fig. Loewy et al.
The studied area pertains to the southern domain, but none of these latter events have been identified, except for the to Ma juvenile magmatic episodes that could be correlated with the Ma T DM zircon Hf ages identified in the Chuculaqui Unit. The 1. The Arequipa-Antofalla massif is interpreted to be allochthonous to Amazonia cf.
Gondwanan magmatism developed between Early Carboniferous and Early Triassic times. The results obtained here are comparable to those presented by Munizaga et al. Triassic volcanic sequences are separately grouped in a synrift phase. In fact, the tectonic conditions that originated both the Permian magmatism described in this paper and that of the upper section of the Choiyoi series, as well as their geo-chemical signatures, are analogous.
The ages determined in the Puna units are slightly older than those known from further south in the Frontal Cordillera and San Rafael Block Kleiman and Japas, , suggesting that these common tectonic conditions were originated earlier in the north, with progressive migration to the south.
Experimental cryptococcosis in guinea pigs | SpringerLink
Conversely, the Triassic magmatism represented by the Ma Chuculaqui Unit in the Puna region cannot be correlated with the upper section of the Choiyoi magmatism from Frontal Cordillera and San Rafael Block, the latter being older than Ma Rocha Campos et al. Furthermore, the Triassic magmatism from the Gondwanan Cycle of similar age Ma and younger , identified in the San Rafael Block, has been grouped in the above mentioned synrift phase Rocha Campos et al, with geochemical characteristics and tectonic setting emplacement that differ from those identified for the Chuculaqui unit.
Rather, the latter could be ascribed to a poorly known continental magmatic arc segment of mostly NS trend. Although during the Pre-Andean tectonic cycle subduction along the continental margin was presumably interrupted or considerably diminished Charrier et al. Interestingly, it should be highlighted that in Chile there are porphyry Cu type deposits La Profunda and Characolla genetically related to these rocks Munizaga et al. This implies the presence of an early Triassic metallogenic belt that continues into Argentina, in the areas where the Chuculaqui magmatic event has been defined.
Detailed revisions by C. Casquet Universidad de Madrid , D. Morata Universidad de Chile and R. Pankhurst British Geological Survey greatly improved the original manuscript. Buenos Aires. Alasino, P. Early Carboniferous sub- to mid-alkaline magmatism in the Eastern Sierras Pampeanas, NW Argentina: A record of crustal growth by the incorporation of mantle-derived material in an extensional setting.
Gondwana Research Atherton, M. Bahlburg, H. Study edits or deletions are displayed in red. Study additions are displayed in green. Scroll up to access the controls.
Oversight U. FDA-regulated Drug: U. Detailed Description:. Outcome Measures Primary Outcome Measures: 1. To evaluate the effect of benralizumab on asthma exacerbations in adult patients with uncontrolled asthma.
- Sunrise and sunset times in Sargodha.
- Introduction.
- Can Carbon Dating Be Used To Determine The Age Of A Diamond.
- ;
- Club Atlético Tucumán - Fixtures by date | Transfermarkt?
- History of Changes for Study: NCT.
Annual asthma exacerbation rate [Time Frame: Immediately following the first administration of study drug through Study Week To assess the effect of benralizumab on asthma symptoms and other asthma control metrics as per the ePRO Endpoints: - Asthma symptom score total,daytime and night time - Rescue medication use - Home lung function morning and evening PEF - Nights with awakening due to asthma - ACQ-6 [Time Frame: Immediately following the first administration of study drug through Study Week To assess the effect of benralizumab on emergency room visits and hospitalizations due to asthma Annual rate of asthma exacerbations that are associated with an emergency room visit or a hospitalization [Time Frame: Immediately following the first administration of study drug through Study Week Scroll up to access the controls Scroll to the Study top.
July 31, None earliest Version on record 2.