Source and tectonic implications of tonalite-trondhjemite magmatism in the Klamath Mountains

Barnes, Calvin G.; Petersen, Scott W.; Kistler, Ronald W.; Murray, Robert B.; Kays, M. A.

doi:10.1007/s004100050142

Cited by 93 publications

(48 citation statements)

References 49 publications

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“…2(B), 2(C) and 3(D)), weak negative Sr anomalies, and very low Sr/Ba (<0.30) (Fig. 7(B)) are consistent with residual plagioclase persisting in the source as well (Arth and Hanson, 1975;Barnes et al, 1996;Martin, 1999). In the (La/Yb) c -(La/Sr) c diagrams (Fig.…”

Section: and Clearly Higher Than The Experimental Melts Of Metabasasupporting

confidence: 56%

“…The moderate and high K/Rb (355-1060) and lack of concavity of the middle REE are inconsistent with the persistence of hornblende as a major residual phase in the source (Fig. 7(B)) (Arth and Hanson, 1975;Gromet and Silver, 1987;Barnes et al, 1996). In the (La/ Yb) c -(La/Sr) c diagrams (Fig.…”

Section: For Reference Tertiary Andean Magmas Of 28°-33°s Are Transimentioning

confidence: 93%

“…The lack of Eu anomalies, unusually high Sr contents (positive Sr anomalies) and high Sr/Ba (1.1-4.5) preclude significant residual plagioclase in the source (Fig. 7(B)) (Arth and Hanson, 1975;Barnes et al, 1996;Martin, 1999). The moderate and high K/Rb (355-1060) and lack of concavity of the middle REE are inconsistent with the persistence of hornblende as a major residual phase in the source (Fig.…”

Section: For Reference Tertiary Andean Magmas Of 28°-33°s Are Transimentioning

confidence: 95%

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Cretaceous high-potassium intrusive rocks in the Yueshan-Hongzhen area of east China: Adakites in an extensional tectonic regime within a continent

et al. 2004

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Adakites are generally associated with subduction zones (i.e., at convergent plate margins). This paper reports geochemical and isotopic data for early Cretaceous high-potassium adakitic intrusive rocks in the Yueshan-Hongzhen area of east China, which occur in an extensional tectonic regime within a continent. Based on petrology and geochemistry, these adakitic intrusive rocks are classified into two groups. One group (the Hongzhen adakitic granites) is characterized by high SiO 2 (69-75%) contents and K 2 O/Na 2 O (>1.0), low MgO (or Mg # ) values, Ni and V concentrations, low ε Nd (t) (-17.01~-18.13), and high ( 87 Sr/ 86 Sr) i (0.7071~0.7072). The other group (the Yueshan and Zongpu adakitic rocks) is characterized by relatively low SiO 2 (58-67%) contents and K 2 O/Na 2 O (<1.0), high MgO (Mg # ) values, Ni and V concentrations, as well as relatively high ε Nd (t) (-6.63~-9.62) and low ( 87 Sr/ 86 Sr) i (0.7064~0.7069). Both groups are associated with the contemporary Dongling metamorphic core complex, A-type granites, and some per-alkaline igneous rocks that are formed only in an extensional setting. The tectonic setting and chemical compositions suggest that: (1) the adakitic intrusive rocks in the Yueshan-Hongzhen area were formed in an extensional tectonic regime within a continental plate; (2) the Hongzhen adakitic granites were most likely derived directly from partial melting of mafic material with high potassium contents at the base of the continental crust at pressures of ~1.2 GPa, leaving residual garnet ± hornblende ± plagioclase in the source; (3) the Yueshan and Zongpu adakitic rocks were most probably derived from dehydration melting of basaltic materials delaminated into underlying mantle at pressures >1.2 GPa, leaving residual garnet + pyroxene in their sources. Both groups of adakitic rocks have high La/Yb and Sr/Y, indicating that the crustal thickness in the YueshanHongzhen area exceeded 40 km when the adakitic magmas were generated in the early Cretaceous. The present thickness of the crust in the Yueshan-Hongzhen area is only ~31 km, and therefore the crust appears to have been thinned by at least 10 km since the early Cretaceous. The relatively high MgO, Ni, and V values of the Yueshan and Zongpu adakitic rocks suggest that adakitic magmas interacted with mantle rocks, possibly concurrently with delamination of the lower crust.Keywords: adakite, delamination, lower crust, high potassium, east China geochemical similarity Drummond and Defant, 1990;Martin, 1999). However, some rocks with adakitic compositional features have been argued to be alternative origins, e.g., partial melting of mafic lower crust (Atherton and Petford, 1993;Muir et al., 1995;Petford and Atherton, 1996;Johnson et al., 1997), assimilation and fractional crystallization (AFC) processes involving basaltic magmas (Feeley and Hacker, 1995;Wareham et al., 1997;Castillo et al., 1999). Experimental studies (e.g., Rapp et al., 1991Rapp et al., , 1999Sen and Dunn, 1994;Rapp, 1995; Rapp and Waston, 1995;Springer and Seck, 19...

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Section: and Clearly Higher Than The Experimental Melts Of Metabasasupporting

confidence: 56%

Section: For Reference Tertiary Andean Magmas Of 28°-33°s Are Transimentioning

confidence: 93%

Section: For Reference Tertiary Andean Magmas Of 28°-33°s Are Transimentioning

confidence: 95%

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Cretaceous high-potassium intrusive rocks in the Yueshan-Hongzhen area of east China: Adakites in an extensional tectonic regime within a continent

et al. 2004

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“…Consequently, Atherton and Petford (1993) and Petfort and Atherton (1996) suggested that these rocks were produced by melting of basaltic lower crust. Adakite-like rocks from the South Island, New Zealand (Muir et al, 1995), the Klamath Mountains of California and Oregon (Barnes et al, 1996), the Antarctic Peninsula (Wareham et al, 1997), and the eastern China (Zhang, Q. et al, 2001) were subsequently interpreted as the products of partial melting of mafic lower crust, formed in response to crustal thickening achieved through underplating of mantle-derived mafic magmas. The Zhantang adakite-like andesites are also considered as the products of partial melting of mafic lower crust, though they require a compositionally peculiar basaltic protolith.…”

Section: Petrogenetic Model For the Zhantang Adakite-like Andesitic Mmentioning

confidence: 99%

Extremely high-Na adakite-like magmas derived from alkali-rich basaltic underplate: The Late Cretaceous Zhantang andesites in the Huichang Basin, SE China.

Xiong

et al. 2003

Geochem. J.

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The Zhantang andesites, which erupted in the Late Cretaceous Huichang Basin of SE China interior, were associated with the Late Mesozoic lithospheric extension and basaltic underplating. They are highNa (6.59-8.46 wt% Na 2 O), high-Al trondhjemitic rocks with high Sr and Ba, low Y and HREE, and high Sr/Y and La/Yb ratios, similar to modern adakites. However, they are much higher in Na 2 O but lower in CaO than adakites. Their εNd(T) values of -2.3 to -3.8 and initial 87 Sr/ 86 Sr ratios of 0.707 to 0.708 are also significantly different from those of adakites with MORB-like isotopic compositions. These chemical and isotopic features, along with the tectonic setting, suggest that they were not produced by partial melting of subducting slab.The Zhantang adakite-like magmas may be derived from underplated basaltic lower crust, but require a compositionally peculiar basaltic protolith to account for their extremely high-Na and low-Ca feature. They are compositionally comparable to the experimentally produced partial melts of alkali-rich basalt. We therefore interpret them as the products of melting of an alkali-rich basaltic rock.

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“…Beard and Lofgren, 1991;Rapp and Watson, 1995). This situation may be reached either in a subducted slab Drummond and Defant, 1990;Peacock et al, 1994;Drummond et al, 1996) or in the lower crust (Barnes et al, 1996), producing asymmetrically or concentrically zoned batholiths, respectively. In the Verkhisetsk batholith, the existence of marked magmatic W-E polarity as well as the close spatial relationship to the Serov-Mauk suture clearly favour the idea that the protolith was a subducted slab of oceanic lithosphere.…”

Section: Older Rocksmentioning

confidence: 99%

Generation and evolution of subduction-related batholiths from the central Urals: constraints on the P-T history of the Uralian orogen

et al. 1997

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Batholiths from the accreted terranes in the Urals were generated by repeated episodes of melting and intrusion. Verkhisetsk, the largest and one of the most complex subduction-related batholiths from the Urals, comprises an outer envelope of older tonalites, trondhjemites and granodiorites dated at 315-320 Ma and equilibrated at 6 kbar, intruded by an inner core of younger granodiorites, adamellites and granites dated at 275-290 Ma and equilibrated at 4 kbar. Older rocks have a high-A1 "VI'D/adakite chemistry, _320Ma/~r.~x ~ 2--5, and initial 87Sr/86Sr ~,~ 0.7043, with pronounced lateral ~chur ~I~U) zoning marked by the increase of LREE/HREE, Cr, Ni, and Mg eastwards. They were originated by melting of metabasalts in a subducted slab of young hot oceanic lithosphere with a temperature/depth trajectory that intersected the garnet-in univariant at ~1050°C and 13 kbar, thus causing the lateral zoning. We believe that such a 'warm' trajectory can be attributed to the oblique subduction of a young lithosphere. Younger rocks range from Na-rich metaluminous granodiorites to K-rich peraluminous two-mica granites with relict epidote crystals, and have almost the same isotopic signature as older rocks, from which they were generated by anatexis as a consequence of a melting event that occurred throughout the Urals at 275-290 Ma and produced most of the huge continental-type batholiths on the eastern side. This melting event is tentatively supposed to be the result of underplating by mafic magmas, which also caused the growth of the Urals crust from the Moho downwards until it reached the increased thickness revealed by seismological studies.

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Source and tectonic implications of tonalite-trondhjemite magmatism in the Klamath Mountains

Cited by 93 publications

References 49 publications

Cretaceous high-potassium intrusive rocks in the Yueshan-Hongzhen area of east China: Adakites in an extensional tectonic regime within a continent

Cretaceous high-potassium intrusive rocks in the Yueshan-Hongzhen area of east China: Adakites in an extensional tectonic regime within a continent

Extremely high-Na adakite-like magmas derived from alkali-rich basaltic underplate: The Late Cretaceous Zhantang andesites in the Huichang Basin, SE China.

Generation and evolution of subduction-related batholiths from the central Urals: constraints on the P-T history of the Uralian orogen

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