Guo, F. et al. (2007) Generation of Palaeocene Adakitic Andesites by Magma Mixing, Yanji area, NE China., Journal of Petrology, 48, 661-692, doi: 10.1093/petrology/egl077. < 20100403101827779.admin > pub

Map on Earth or stone. Places and analyses are shown.

  • abstract:

    Palaeocene (c. 55–58 Ma) adakitic andesites from the Yanji area, NE China, are typically clinopyroxene-bearing sodic andesites containing 60.9–62.2% SiO2 and 4.02–4.36% MgO, with high Mg-number [100 Mg/(Mg + ΣFe) atomic ratio] from 65.5 to 70.1. Whole-rock geochemical features include high Cr (128–161 ppm) and Ni (86–117 ppm) concentrations, extremely high Sr (2013–2282 ppm), low Y (10–11 ppm) and heavy rare earth elements (HREE; e.g. Yb = 0.79–1.01 ppm), and mid-ocean ridge basalt (MORB)-like Sr–Nd–Pb isotopic compositions [e.g. 87Sr/ 86Sr(i) = 0.70298–0.70316, εNd(t) = +3.8 to +6.3 and 206Pb/ 204Pb = 17.98 – 18.06], analogous to high-Mg adakites occurring in modern subduction zones. However, mineralogical evidence from clinopyroxene phenocrysts and microcrystalline plagioclase clearly points to magma mixing during magma evolution. Iron-rich clinopyroxene (augite) cores with low Sr, high Y and heavy REE contents, slightly fractionated REE patterns and large negative Eu anomalies probably crystallized along with low-Ca plagioclase from a lower crustal felsic magma. In contrast, high Mg-number clinopyroxene (diopside and endiopside) mantles and rims have higher Sr and lower HREE and Y concentrations, highly fractionated REE patterns (high La/Yb) and negligible Eu anomalies, similar to those found in adakites from subduction zones. The Yanji adakitic andesites can be interpreted as a mixture between a crust-derived magma having low Mg-number and Sr, and high Y and HREE, and a mantle-derived high Mg-number adakite having high Sr and low Y and HREE concentrations. During storage and/or ascent, the mixed magma experienced further crustal contamination to capture zircons, of a range of ages, from the wall rocks. The absence of coeval arc magmatism and an extensional tectonic regime in the Yanji area and surrounding regions suggest that these Palaeocene adakitic andesites were formed during post-subduction extension that followed the late Cretaceous Izanagi–Farallon ridge subduction. Generation of these adakitic andesites does not require contemporaneous subduction of a young, hot oceanic ridge or delamination of eclogitic lower crust as suggested by previous models.

  • doi: 10.1093/petrology/egl077
  • modified at 16 h ago


(a) TIMS on TIMS Thermo-Fisher MAT262


(a) XRF and LOI on XRF Rigaku RIX300
(b) ICPMS on ICPMS
Tixhr719893402 thumb 04YJ-9A < 20180222110613-428706 >pub
  • classification: volcanic:andesitic
  • physical-form: on mount
  • status: (unknown)
  • description: sample was collected from the largest outcrop of Cpx-andesites about 10 km NW of Longjing town
  • modified at 2020-05-11
Tixhr939815304 thumb 04YJ-7A < 20180222110156-835282 >pub
  • classification: volcanic:andesitic
  • physical-form: on mount
  • status: (unknown)
  • description: sample were collected from the largest outcrop of Cpx-andesites about 10 km NW of Longjing town
  • modified at 2020-05-11
Tixhr862752745 thumb 04YJ-2A < 20180221104529-592891 >pub
  • classification: volcanic:andesitic
  • physical-form: on mount
  • status: (unknown)
  • description: sample were collected from the largest outcrop of Cpx-andesites about 10 km NW of Longjing town
  • modified at 2020-05-11
Tixhr 60621870 thumb 04YJ-5A < 20180221104631-895414 >pub
  • classification: volcanic:andesitic
  • physical-form: on mount
  • status: (unknown)
  • description: sample were collected from the largest outcrop of Cpx-andesites about 10 km NW of Longjing town
  • modified at 2020-05-11
name box-type global-id
binder of Generation of Palaeocene Adakitic Andesites by Magma Mixing, Yanji area, NE China pub container 20191101153302-914071
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04YJ-9 pub ICPMS 30 20191031153616-313994
04YJ-9 pub XRF Rigaku RIX300 12 20191031153602-601379
04YJ-9 pub TIMS Thermo-Fisher MAT262 22 20191101094629-453491
04YJ-7 pub XRF Rigaku RIX300 12 20191031153602-964216
04YJ-7 pub TIMS Thermo-Fisher MAT262 22 20191101094628-347893
04YJ-7 pub ICPMS 30 20191031153615-931971
04YJ-2 pub XRF Rigaku RIX300 12 20191031153601-869498
04YJ-2 pub TIMS Thermo-Fisher MAT262 22 20191101094626-114789
04YJ-2 pub ICPMS 30 20191031153613-087430
04YJ-5 pub TIMS Thermo-Fisher MAT262 22 20191101094627-861275
04YJ-5 pub XRF Rigaku RIX300 12 20191031153601-141345
04YJ-5 pub ICPMS 30 20191031153614-716655
04YJ-2_Pl@3 pub EPMA 12 20191031141012-468608
04YJ-2_Pl@4 pub EPMA 12 20191031141013-588285
04YJ-5_Pl@8 pub EPMA 12 20191031141015-505444
04YJ-5_Pl@5 pub EPMA 12 20191031141014-831015
04YJ-2_Pl@1 pub EPMA 12 20191031141011-968844
04YJ-9_Pl@14 pub EPMA 12 20191031141018-542677
04YJ-7_Pl@11 pub EPMA 12 20191031141016-509898
04YJ-7_Pl@9 pub EPMA 12 20191031141015-010636
04YJ-5_Pl@7 pub EPMA 12 20191031141014-338892
04YJ-2_Pl@2 pub EPMA 12 20191031141012-215371
04YJ-9_Pl@16 pub EPMA 12 20191031141019-739647
04YJ-7_Pl@10 pub EPMA 12 20191031141016-410184
04YJ-5_Pl@6 pub EPMA 12 20191031141014-725644
04YJ-9_Pl@15 pub EPMA 12 20191031141018-067848
04YJ-9_Pl@13 pub EPMA 12 20191031141017-335232
04YJ-7_Pl@12 pub EPMA 12 20191031141016-784422
04YJ-2_Cpx@4 pub EPMA 15 20191024150738-979910
04YJ-5_Cpx@2 pub EPMA 15 20191024150746-947036
04YJ-7A_Cpx@1 pub EPMA 15 20191024150735-105678
04YJ-7A_Cpx@2 pub EPMA 15 20191024150736-609986
04YJ-5_Cpx@4 pub EPMA 15 20191024150750-498676
04YJ-2_Cpx@6 pub EPMA 15 20191024150739-675798
04YJ-7A_Cpx@3 pub EPMA 15 20191024150736-632145
04YJ-2_Cpx1@2 pub EPMA 15 20191024150740-051034
04YJ-5_Cpx@6 pub EPMA 15 20191024150751-159989
04YJ-5_Cpx@1 pub EPMA 15 20191024150746-941640
04YJ-7A_Cpx1@7 pub EPMA 15 20191024150745-820723
04YJ-2_Cpx@2 pub EPMA 15 20191024150737-027552
04YJ-2_Cpx1@4 pub EPMA 15 20191024150741-481389
04YJ-7A_Cpx@4 pub EPMA 15 20191024150736-721719
04YJ-5_Cpx@3 pub EPMA 15 20191024150749-747078
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04YJ-2_Cpx@5 pub EPMA 15 20191024150739-741714
04YJ-5_Cpx@5 pub EPMA 15 20191024150751-978616
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04YJ-7A_Cpx@1 pub SIMS Cameca ims-5f 17 20191024152907-746285
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04YJ-2_Cpx1@1 pub SIMS Cameca ims-5f 17 20191024152911-487486
04YJ-5_Cpx@2 pub SIMS Cameca ims-5f 17 20191024152916-742948
04YJ-7A_Cpx1@2 pub SIMS Cameca ims-5f 17 20191024152913-538115
04YJ-7A_Cpx1@4 pub SIMS Cameca ims-5f 17 20191024152914-713401
04YJ-2_Cpx1@3 pub SIMS Cameca ims-5f 17 20191024152912-029195
04YJ-5_Cpx@3 pub SIMS Cameca ims-5f 17 20191024152916-340457
04YJ-7A_Cpx1@6 pub SIMS Cameca ims-5f 17 20191024152915-559485
04YJ-5_Cpx@4 pub SIMS Cameca ims-5f 17 20191024152917-704901
04YJ-2_Cpx@4 pub SIMS Cameca ims-5f 17 20191024152910-176434
04YJ-5_Cpx@5 pub SIMS Cameca ims-5f 17 20191024152917-577559
04YJ-2_Cpx@2 pub SIMS Cameca ims-5f 17 20191024152909-607289
04YJ-7A_Cpx1@1 pub SIMS Cameca ims-5f 17 20191024152913-518866
04YJ-5_Cpx@6 pub SIMS Cameca ims-5f 17 20191024152918-218874
04YJ-7A_Cpx1@3 pub SIMS Cameca ims-5f 17 20191024152914-230375
04YJ-2_Cpx@6 pub SIMS Cameca ims-5f 17 20191024152911-098315
04YJ-7A_Cpx1@5 pub SIMS Cameca ims-5f 17 20191024152915-585394
04YJ-5_Cpx@7 pub SIMS Cameca ims-5f 17 20191024152918-144131
04YJ-2_Opx@5 pub EPMA 15 20191031135112-146261
04YJ-5_Cpx1@1 pub SIMS Cameca ims-5f 17 20191024152918-230673
04YJ-7A_Cpx1@7 pub SIMS Cameca ims-5f 17 20191024152915-092955
04YJ-5_Cpx1@2 pub SIMS Cameca ims-5f 17 20191024152919-189797
04YJ-5_Cpx1@3 pub SIMS Cameca ims-5f 17 20191024152919-111741
04YJ-2_Opx@4 pub EPMA 15 20191031135111-337845
04YJ-5_Cpx1@4 pub SIMS Cameca ims-5f 17 20191024152919-957846
04YJ-5_Cpx1@5 pub SIMS Cameca ims-5f 17 20191024152920-413993
04YJ-5_Cpx1@6 pub SIMS Cameca ims-5f 17 20191024152920-884245
04YJ-5_Cpx1@7 pub SIMS Cameca ims-5f 17 20191024152921-566103
04YJ-5_Opx@1 pub EPMA 15 20191031135110-171260
04YJ-5_Opx@2 pub EPMA 15 20191031135110-950753
04YJ-5_Opx@3 pub EPMA 15 20191031135111-567177
name spots global-id
caption ID assembly stone
Table 3: Representative electron microprobe analyses of plagioclase pub 20191031142545-457338 major_Pl (Guo et al., 2007) 16
Table 9: Sr-Nd-Pb isotopic compositions of the Palaeocene Yanji adakitic andesites pub 20191101095216-390377 Sr-Nd-Pb-isotopes (Guo et al., 2007) 4
Table 8: Major and trace element compositions of the Palaeocene Yanji adakitic andesites pub 20191031154054-057232 major-trace (Guo et al., 2007) 4
Table 1: Representative electron microprobe and ion microprobe data for clinopyroxene phenocrysts pub 20191024151003-251137 major-trace_Cpx (Guo et al., 2007) 35
Table 2: Representative electron microprobe analyses of orthopyroxene pub 20191031142434-717413 major_Opx (Guo et al., 2007) 5
manual
  • name
  • Guo, F.
  • Nakamura, E.
  • Fan, W.
  • Kobayashi, Katsura
  • Li, C.