The SHRIMP zircon U-Pb dating was carried out and yielded 287±5 Ma (MSWD = 0.34) and 274±3 Ma (MSWD = 1.35) for the Kalatongke No. 1 and Huangshan- dong Cu-Ni-bearing mafic-ultramafic complexes. These ages a...The SHRIMP zircon U-Pb dating was carried out and yielded 287±5 Ma (MSWD = 0.34) and 274±3 Ma (MSWD = 1.35) for the Kalatongke No. 1 and Huangshan- dong Cu-Ni-bearing mafic-ultramafic complexes. These ages are much more precise than pre-existing rock-mineral Rb-Sr, Sm-Nd and Re-Os isochron ages for the two complexes and constrain the timing of not only the complexes but also the magmatic Cu-Ni sulfide deposits more reliably. It is neces- sary to carefully reevaluate the previous chronological data for the complexes. The Cu-Ni-bearing mafic-ultramafic com- plexes have the ages similar to those of postcollisional A-type granites in the same area, implying that they could be related to the delamination of lithospheric mantle and upwelling and partial melting of asthenospheric mantle in postcollisional setting. Therefore, the Cu-Ni-bearing mafic-ultramafic com- plexes are a direct indicator of vertical growth of the conti- nental crustal in the Central Asian Orogenic Belt.展开更多
北山柳园地区分布大量的花岗岩类岩石,岩石类型有花岗闪长岩、二长花岗岩、钾长花岗岩和斑状花岗岩。锆石SHRIMP U—Pb 定年分析结果为:花岗闪长岩的侵位年代为423±8Ma 辉铜山以东(HT-)钾长花岗岩和二长花岗岩的侵位分别为436±...北山柳园地区分布大量的花岗岩类岩石,岩石类型有花岗闪长岩、二长花岗岩、钾长花岗岩和斑状花岗岩。锆石SHRIMP U—Pb 定年分析结果为:花岗闪长岩的侵位年代为423±8Ma 辉铜山以东(HT-)钾长花岗岩和二长花岗岩的侵位分别为436±9Ma 和397±7Ma。该区花岗质岩石都具有大离子亲石元素和轻稀土元素相对富集,K、Ni、Ta、P 和 Ti 负异常的特征,属于准铝质到过铝质的高 K 花岗岩。花岗闪长岩无 Sr 和 Eu负异常的特征,ε_(Nd)(t)=-2.5～-0.8,其岩浆源于岩石圈地幔或是软流圈与岩石圈地幔相混合的岩浆熔融,并受到了含有火山弧组分的年轻地壳的混染。钾长花岗岩和二长花岗岩具有 Sr 和 Eu 负异常的特征,ε_(Nd)(t)值分别为+1.4、-4.0～-2.0和-2.7～-0.3。HT-钾长花岗岩岩浆主要源于由于岩石圈地幔岩浆作用而导致上覆年轻地壳物质的部分熔融;花牛山附近(HN-)钾长花岗岩岩浆主要源于软流圈地幔部分熔融,可能受到了部分年轻地壳物质的混染;二长花岗岩岩浆主要源于年轻地壳的部分熔融。柳园地区4类花岗岩类岩石都是后碰撞构造背景下的岩浆产物,岩浆形成可能与俯冲板片断离有关。展开更多
文摘The SHRIMP zircon U-Pb dating was carried out and yielded 287±5 Ma (MSWD = 0.34) and 274±3 Ma (MSWD = 1.35) for the Kalatongke No. 1 and Huangshan- dong Cu-Ni-bearing mafic-ultramafic complexes. These ages are much more precise than pre-existing rock-mineral Rb-Sr, Sm-Nd and Re-Os isochron ages for the two complexes and constrain the timing of not only the complexes but also the magmatic Cu-Ni sulfide deposits more reliably. It is neces- sary to carefully reevaluate the previous chronological data for the complexes. The Cu-Ni-bearing mafic-ultramafic com- plexes have the ages similar to those of postcollisional A-type granites in the same area, implying that they could be related to the delamination of lithospheric mantle and upwelling and partial melting of asthenospheric mantle in postcollisional setting. Therefore, the Cu-Ni-bearing mafic-ultramafic com- plexes are a direct indicator of vertical growth of the conti- nental crustal in the Central Asian Orogenic Belt.
文摘北山柳园地区分布大量的花岗岩类岩石,岩石类型有花岗闪长岩、二长花岗岩、钾长花岗岩和斑状花岗岩。锆石SHRIMP U—Pb 定年分析结果为:花岗闪长岩的侵位年代为423±8Ma 辉铜山以东(HT-)钾长花岗岩和二长花岗岩的侵位分别为436±9Ma 和397±7Ma。该区花岗质岩石都具有大离子亲石元素和轻稀土元素相对富集,K、Ni、Ta、P 和 Ti 负异常的特征,属于准铝质到过铝质的高 K 花岗岩。花岗闪长岩无 Sr 和 Eu负异常的特征,ε_(Nd)(t)=-2.5～-0.8,其岩浆源于岩石圈地幔或是软流圈与岩石圈地幔相混合的岩浆熔融,并受到了含有火山弧组分的年轻地壳的混染。钾长花岗岩和二长花岗岩具有 Sr 和 Eu 负异常的特征,ε_(Nd)(t)值分别为+1.4、-4.0～-2.0和-2.7～-0.3。HT-钾长花岗岩岩浆主要源于由于岩石圈地幔岩浆作用而导致上覆年轻地壳物质的部分熔融;花牛山附近(HN-)钾长花岗岩岩浆主要源于软流圈地幔部分熔融,可能受到了部分年轻地壳物质的混染;二长花岗岩岩浆主要源于年轻地壳的部分熔融。柳园地区4类花岗岩类岩石都是后碰撞构造背景下的岩浆产物,岩浆形成可能与俯冲板片断离有关。
