A Tale of Two Plutons: Geochemical Evidence Bearing on the Origin and Differentiation of the Red Lake and Eagle Peak Plutons, Central Sierra Nevada, California

Noyes, H. J.; Frey, Frederick A.; Wones, David R.

doi:10.1086/628801

Cited by 84 publications

(28 citation statements)

References 51 publications

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“…Hence most of the trace elements transfer and deplete in the Shihu gold deposit. The same as Rb, Ba and K, Co, Ni and Fe have the same geochemical natural during the alteration (Fourcade and Allegre, 1981;Noyes et al, 1983). That is why the elements of the two groups have the same characteristic of depletion or enrichment.…”

Section: Discussionmentioning

confidence: 98%

The Behavior of the Elements During the Alteration in the Shihu Gold Deposit, Taihang Mountains Belt, Eastern China

Wang

Yü

et al. 2014

Acta Geologica Sinica (Eng)

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Section: Discussionmentioning

confidence: 98%

The Behavior of the Elements During the Alteration in the Shihu Gold Deposit, Taihang Mountains Belt, Eastern China

Wang

Yü

et al. 2014

Acta Geologica Sinica (Eng)

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“…This is consistent with the generally higher ε Nd values of enclaves than host rocks, and with the similar zircon U-Pb ages (127-130 Ma [18,19] ) of the two rock units. Therefore, apparently the origin of enclaves cannot be explained by models of cognate fragments of cumulates [1,2] , or refractory "restites" [3] . Our petrological and geochemical data suggest that the mafic enclaves were formed by complicated interaction between basaltic and crust-derived granitic magmas, including magma mixing of the two magmas in depth (before injection) and the local mechanical and chemical exchange at the contact of the two magmas after injection of enclaves.…”

Section: Discussionmentioning

confidence: 99%

“…Models for the origin of mafic enclaves include: (1) mafic enclaves are formed as cognate fragments of cumulate minerals from a mafic magma [1,2] , (2) mafic enclaves represent recrystallized, refractory and residual phase assemblage derived from a granite source [2,3] , and (3) mafic enclaves are formed through hybridization between mafic and felsic magmas [4][5][6][7][8][9][10] .…”

mentioning

confidence: 99%

Petrogenesis of mafic enclaves from the north Taihang Yanshanian intermediate to felsic plutons: Evidence from petrological, geochemical, and zircon Hf-O isotopic data

Chen

2009

Sci. China Ser. D-Earth Sci.

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We report the zircon Hf-O isotopic data for mafic enclaves from the Taihang Yanshanian intermediate to felsic plutons, and use them, along with the petrological, whole-rock chemical and Nd-Sr isotopic data, to reveal the petrogenesis of mafic enclaves. Mafic enclaves show magmatic textures and are finer-grained than host rocks. In places they are highly elongated due to stretching within the partially crystallized, convective felsic magma, but show no solid-state deformation. These data suggest that mafic enclaves and host rocks were co-existing, but compositionally distinct magmas. The mafic enclaves contain abundant hydrous minerals such as hornblende and biotite, with pyroxene relict being surrounded by hornblende reaction rim. Plagioclase xenocrysts from mafic enclaves show a complicated compositional and textural disequilibrium. Comparison between mafic enclaves and the immediate host rocks suggests that the two rock units are compositionally correlated. The ε Nd values of mafic enclaves are generally higher than the host rocks, though the Sr isotopic ratios of the two rock units are indistinguishable. Zircons from a single enclave sample show a significant variation in Hf isotopic compositions, with ε Hf = −10-−22, suggesting an origin through magma mixing between mafic and felsic magmas. This is supported by the relatively large variation of zircon O isotopic ratios (δ 18 O = 5.5‰-7.8‰) of the mafic enclaves. The petrogenesis of mafic enclaves could be described as below. Evolved basaltic magma (via fractionation of olivine and pyroxene) first mixed with crustally derived granitic melts in depths, forming a hybrid magma; then the hybrid magma broke up into discrete lumps upon entering the above felsic magma. Subsequently, the enclave-forming magma experienced a double mechanical transfer of plagioclase, and inward chemical transfer of fluid and Na, P, Y, Nb and Pb at the contacts with host felsic magmas. mafic enclaves, compositional zoning, Nd-Sr isotopes, zircon Hf-O isotopes, magma mixingThe petrogenesis of mafic enclaves has been an issue of controversy for long. Models for the origin of mafic enclaves include: (1) mafic enclaves are formed as cognate fragments of cumulate minerals from a mafic magma [1,2] , (2) mafic enclaves represent recrystallized, refractory and residual phase assemblage derived from a granite source [2,3] , and (3) mafic enclaves are formed through hybridization between mafic and felsic magmas [4][5][6][7][8][9][10] .More and more studies suggest that most enclaves are formed by magma mixing between mantle-and crustle-derived melts. However, the mechanisms of magma

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“…With the exception of alkali granites (Drysdall et al, 1984), the total rare-earth element amount generally decreases in the more differentiated members of the silicic granitoid suites (Cullers and Graf, 1984). Aplites often have considerably a lower total REE amount than the associated granites (Mittlefehldf and Miller, 1983;Noyes et al, 1983). Particularly, the light REE and Eu are depleted in the aplites whereas the abundances of the heavy REEs may be similar to or even higher than in the associated granites.…”

Section: Introductionmentioning

confidence: 99%

“…The more siliceous rocks typically have higher contents of elements such as Rb, Y, Nb, HREE, Th and U (and often Na), and lower contents of, for example, Mg, P, Ca, Ti, V, Mn, Fe, Sr, Zr, Ba, LREE and Eu (and sometimes K). Most studies of granite-aplite systems, however, favor a fractional crystallization model (Miller and Mittlefehldt, 1984), and detailed studies emphasize that fractionation of LREE-rich accessory minerals, such as monazite and allanite, is necessary to explain the changing REE patterns (Noyes et al, 1983). In the study of three areas with molybdenite mineralized aplites in Eastern Desert of Egypt, significant differences in REE patterns between the aplites and the associated granites were found in one area analyzed for REE.…”

Section: Introductionmentioning

confidence: 99%

Geology and rare-earth element geochemistry of highly evolved, molybdenite-bearing granitic plutons, Southeastern Desert, Egypt

Saleh

2007

Chin. J. of Geochem.

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The field relations, mineralogy, and major and trace elements (including REE analyses of whole-rock samples and minerals) of granites and their associated molybdenite + uranium mineralized aplites in Southeastern Desert, Egypt, have been studied. The granites are leucocratic and mostly peraluminous in nature with muscovite increasing at the expense of biotite. The chemical and mineralogical characteristics of the granitic rocks indicate that their melts originated from the LILE-enriched mantle wedge by partial melting and are contaminated by crustal melts, followed by thermogravitational processes. Leucogranites with higher Na 2 O/K 2 O ratios from Um Dargag and Um Maiat crystallized under H 2 O-saturated equilibrium conditions in which the exsolved vapor continuously migrated away. The REE patterns of the granites studied are characterized by LREE enrichments and negative Eu anomalies. In comparison, the potassic aplites and the more sodic leucogranites are depleted in LREE, enriched in HREE and show more remarkable negative Eu anomalies. Allanite and monazite are the most important REE carriers in the granites. These minerals are strongly enriched in LREE, whereas fluorite and xenotime, which are more abundant in the aplites, are enriched in HREE. The average Lu/Ce ratio represents the fractionation trend with respect to HREE. It is 0.71 for radioactive fluorite, and it increases to 1.22 for non-radioactive fluorite. The high REE contents of molybdenite represent re-deposition of the mobilized Mo and REE. Due to the strong control of accessory minerals, the REEs are of limited use in petrogenetic modelling of highly evolved granitic systems.

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A Tale of Two Plutons: Geochemical Evidence Bearing on the Origin and Differentiation of the Red Lake and Eagle Peak Plutons, Central Sierra Nevada, California

Cited by 84 publications

References 51 publications

The Behavior of the Elements During the Alteration in the Shihu Gold Deposit, Taihang Mountains Belt, Eastern China

The Behavior of the Elements During the Alteration in the Shihu Gold Deposit, Taihang Mountains Belt, Eastern China

Petrogenesis of mafic enclaves from the north Taihang Yanshanian intermediate to felsic plutons: Evidence from petrological, geochemical, and zircon Hf-O isotopic data

Geology and rare-earth element geochemistry of highly evolved, molybdenite-bearing granitic plutons, Southeastern Desert, Egypt

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