Distribution of Sr and Ba between natural feldspar and igneous melt

Korringa, Marjorie K.; Noble, Donald C.

doi:10.1016/0012-821x(71)90157-9

Cited by 39 publications

(4 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Strontium increases with SiO 2 content in the pyroxene-bearing rocks from the Atazaico Andesite to compositions of about 62 wt percent SiO 2 , and then decreases slightly from 62 to 71 wt percent SiO 2 in the San Jose Ignimbrite and the late Coriwachay Dacite. Barium increases with increasing SiO 2 content, consistent with its generally incompatible behavior in magmas (Korringa and Noble, 1971;Blundy and Wood, 1991).…”

Section: Trace-element Compositionssupporting

confidence: 62%

Evolution of Calc-Alkaline Volcanism and Associated Hydrothermal Gold Deposits at Yanacocha, Peru

Longo¹,

Dilles²,

Grunder³

et al. 2010

Economic Geology

View full text Add to dashboard Cite

Clusters of high-sulfidation epithermal deposits containing more than 50 Moz of gold are hosted by advanced argillic-altered Miocene volcanic rocks in the Yanacocha district, northern Peru (lat. 6°59'30" S, long. 78°30'45" W). We describe the nature of the volcanism and its relation to the gold ores on the basis of new district-scale geologic mapping, 69 40 Ar/ 39 Ar ages on igneous rocks and hydrothermal alunite, and petrologic and geochemical investigations. Volcanic rocks of the Calipuy Group are the oldest Cenozoic rocks at Yanacocha, and include the Huambo Cancha andesite, andesitic lahars of Tual and Chaupiloma (19.5-15.9 Ma), and the dacitic Cerro Fraile pyroclastics (15.5-15.1 Ma). The younger Yanacocha Volcanics (14.5-8.4 Ma) form a cogenetic series of lavas and pyroclastic rocks with a cumulative volume of ~88 km 3 that represents eruption from a moderate-size volcanic center. Early pyroxene>hornblende-bearing lavas of the Atazaico Andesite (14.5-13.3 Ma) erupted from small stratovolcanoes progressively younger from southwest to northeast. Dacitic dikes followed that are spatially associated with gold deposits at Quilish and Cerro Negro (~7 Moz Au) and stage 1 alunite (13.6-12.6 Ma). The Colorado Pyroclastics erupted in the center of the district and include the hornblende-and biotite-bearing andesitic to dacitic Cori Coshpa (12.6 Ma) and Maqui Maqui (12.5-12.4 Ma) ignimbrites. The Colorado Pyroclastics are overlain by hornblende>pyroxene-bearing andesitic to dacitic lavas, flow-domes, and minor pyroclastic rocks of the Azufre Andesite (12.1-11.6 Ma). Widespread stage 2 alunite (11.5 Ma) and minor gold deposition (~0.5 Moz) closely follow. The San Jose Ignimbrite (11.5-11.2 Ma) overlies the Azufre Andesite and stage 2 alunite and includes three members of hornblende-pyroxene (biotite) dacite and andesite that erupted in the center of the district and flowed southward. Mineralogically similar domes were emplaced into the inferred vents. The Coriwachay Dacite (10.8-8.4 Ma) forms the youngest and most silica rich igneous rocks in the district, and includes intrusions and flow domes of dacite to rhyolite at Corimayo (10.8 Ma), Cerro Yanacocha (9.9 Ma), and Yanacocha Lake (8.4 Ma). Most of the gold (>47 Moz) was deposited at Yanacocha during intrusion of the late Coriwachay Dacite. These late dacites are volumetrically smallest (~2% of the total volume of erupted magma) and are temporally associated with stage 3 to 5 alunites. Stage 3 alunite (11.0-10.7 Ma) developed along a northeast trend for 9 km that includes the gold deposits of Corimayo, San Jose, Carachugo, and Maqui Maqui. The deeper Kupfertal Cu-Au porphyry has an age of 10.7 Ma on hydrothermal biotite and underlies zones of stage 4 and 5 quartz-alunite alternation that are 0.8 and 1.5 m.y. younger, respectively. Stage 4 alunite ranges in age from 10.2 to 10.3 Ma at the Tapado and Chaquicocha Sur gold deposits to Cerro Sugares east of the Maqui Maqui deposit. Stage 4 also includes a younger alunite age of 9.9 Ma from the San Jose gold deposit. Stage...

show abstract

Section: Trace-element Compositionssupporting

confidence: 62%

Evolution of Calc-Alkaline Volcanism and Associated Hydrothermal Gold Deposits at Yanacocha, Peru

Longo¹,

Dilles²,

Grunder³

et al. 2010

Economic Geology

View full text Add to dashboard Cite

show abstract

“…Distribution coefficients are from Arth (1976), Willemant el al. (1981, Pearce & Norry (1979), Mahood (1981), Korringa & Noble (1971) and Drexler, Burnhorst & Noble (1983). R 2 = is the sum of the residues squared; the residues are the differences between the F, calculated for each element and the mean value of F,.…”

Section: A2 Fractional Crystallizationmentioning

confidence: 99%

Geology, geochronology and chemical evolution of the island of Pantelleria

Civetta

Cornette

Crisci³

et al. 1984

Geol. Mag.

166

View full text Add to dashboard Cite

Potassium-argon dating, field relations, geochemical and strontium-isotope compositions are reported for the island of Pantelleria (Strait of Sicily, Italy). These data support the following model for the genesis and evolution through time of the volcanic system: the peralkaline rocks originated from mantle-derived parental magmas; the trachytic magma differentiated in a low pressure magma chamber by crystal-liquid fractionation. This process led to a chemically zoned magma chamber tapped at different levels by successive eruptions. During low-pressure differentiation the 87 Sr/ 86 Sr ratios of some of the most evolved Sr-poor rhyolitic magmas increased from 0.703 up to 0.708 by contamination with crustal material.The chemical variation displayed by the products of each of the defined eruptive cycles in the last 50000 years suggests an open system behaviour of the magma chamber which is episodically refilled by more mafic parent magma, differentiated at high rate and episodically erupted.

show abstract

“…The fact that K p s can be used to approximate variations in chemical potential of trace species in crystals has been exploited in studies of diffusion chronometry to provide information on the chemical gradient and distribution of a trace species across a zoned crystal in partial equilibrium with the host melt (for example, Zellmer and others, 1999;Costa and others, 2003;Druitt and others, 2012). In the case of plagioclase solid solutions it has been apparent for some time that K p s for most trace elements are sensitive to the anorthite (An) content of the host crystal (for example, Korringa and Noble, 1971;Blundy and Wood 1991). Consequently, if a crystal of plagioclase is zoned in terms of An (as most volcanic plagioclases are) a mobile trace element will, with time, diffuse through the crystal to form an "equilibrium" distribution that is not homogeneous, but will vary with An across the crystal in much the same way as K p varies with An.…”

mentioning

confidence: 99%

A predictive thermodynamic model for element partitioning between plagioclase and melt as a function of pressure, temperature and composition

Dohmen

Blundy

2014

American Journal of Science

View full text Add to dashboard Cite

One-atmosphere experiments in the system diopside-albite-anorthite (Di-Ab-An) have been used to explore the controls on plagioclase-melt partitioning of trace elements (Li, K, Rb, Cs, Mg, Zn, Sr, Ba, La, Sm, Y). By performing experiments along isotherms it was possible to isolate compositional controls from those of temperature. The lattice strain model accounts for variations in partition coefficients (K p(i) ) for isovalent series of cations (i n؉ ) and the experimental data are used to optimize the lattice strain parameters so that partition coefficients for n ‫؍‬ 1 to 3 can be derived from K p(Na) , K p(Ca) , and K p(La) , respectively, at the conditions of interest. The optimized lattice strain parameters have magnitudes and compositional and thermal dependences that are consistent with elastic data for plagioclases. Kp(La) is parameterized via an exchange reaction involving CaAl 2 Si 2 O 8 and the La-feldspar component La 0.5 Na 0.5 Al 2 Si 2 O 8 . The free energy change of this reaction is small, but well constrained by the data, such that for a given P-T-X K p(La) can be derived from a combination of K p(Na) and K p(Ca) . In the case where K p(Na) and K p(Ca) are independently constrained, the models reproduce the experimental values of 749 K p s for Li, Mg, K, Rb, Sr, Y, Cs, Ba, and REE (obtained from 91 individual experiments varying over five orders of magnitude) within a factor of 1.5 for 53 percent of the data and a factor of 2 for 74 percent of the data. The isothermal experimental data reveal that additional compositional effects, arising from non-ideal mixing in plagioclase and in melt, also influence K p(i) . A thermodynamic model based on the free energy of fusion of albite (NaAlSi 3 O 8 ) and anorthite (CaAl 2 Si 2 O 8 ), and taking into account plagioclase and melt non-ideality in Di-Ab-An, is developed to express K p(Na) , K p(Ca) as functions of pressure (P ), temperature (T ) and composition (X). The thermodynamic models are extended to a wider compositional range by means of an empirical parameterization of 919 K p(Na) and 920 K p(Ca) from a database of 991 published experiments. These models are able to reproduce 919 measured partitioning values for Li, Na, Mg, Ca, K, Rb, Sr, Y, Cs, Ba, and REE (from 91 experiments) with 47 percent of the model values within a factor of 1.5 of the measured values and 69 percent within a factor of 2 for any P-T-X condition. The models can also be used to constrain the dependence of the chemical potential of trace cations in plagioclase solid solutions ( i pl ) for use in diffusion chronometry where the fully equilibrated trace element concentration profile must be known in order to calculate timescales. It is shown that i pl is not adequately described by existing empirical models used to predict K p as a function of anorthite because of the conflating effects of T and X in the polythermal experimental datasets from which those models were derived.

show abstract

Distribution of Sr and Ba between natural feldspar and igneous melt

Cited by 39 publications

References 18 publications

Evolution of Calc-Alkaline Volcanism and Associated Hydrothermal Gold Deposits at Yanacocha, Peru

Evolution of Calc-Alkaline Volcanism and Associated Hydrothermal Gold Deposits at Yanacocha, Peru

Geology, geochronology and chemical evolution of the island of Pantelleria

A predictive thermodynamic model for element partitioning between plagioclase and melt as a function of pressure, temperature and composition

Contact Info

Product

Resources

About