Comments
Dear Editor
Thank you very much for considering me as a reviewer Geological Journal. Please find below remarks on the article entitled “Geochemistry, zircon U–Pb geochronology and Lu–Hf isotopes of the Late Jurassic granitoids from the Shuangyuangou deposit, South Qinling, China: Implications for petrogenesis and porphyry Cu metallogeny”.
This manuscript presents systematic study involving whole rock geochemistry, zircon U-Pb geochronology and Lu-Hf isotope on suite of quartz diorite porphyry, lamprophyre and granite porphyry from the Shuangyuangou porphyry Cu deposit in Qinling. The results are crucial in raveling the age and source of porphyry magmatism, petrogenesis, and evaluating the factors favorable for porphyry Cu mineralization. The data are high quality and the manuscript is organized very well. Overall, I suggest the manuscript is suitable for publication in GJ after minor revision. Here are some comments and suggestions:
L27: which deposit
L31-32: ‘in’ should be ‘of’
L72: shape and size of magma chamber, efficiency of fluid focusing into small volume etc, are also favorable factors for porphyry mineralization
L130: space between 'Formation' and 'and'
L153: The sentence is overlapped with the description in L148-149.
L245-254: The description of whole rock compositions are long and boring, decrease and only keep some useful elements
L317: delete ‘in the range of’
L320-324: there should be more references that have dated the intrusions, the available data should give a more reliable age range
L358-360: why the higher Zr/Sm ratio higher than PM can suggest source rock of garnet amphibolite? what is the relationship or logic? The garnet amphibolite can be juvenile lower crust.
L402: 'indicate that the samples are I-type granites' should be 'show I-type affinity'
L412: The magma of copper fertile porphyry
L448: add necessary references after the age
L451: Yanshanian period should be changed to Late Jurassic to Early Cretaceous
L451-452: delete 'thrust......erosion' as this information are not related to the discussion
L469: delete possible
L498-501: The last sentence is confusing, how you know it is mafic magma that has been injected to the bottom of the crust. The bottom of the crust means lower crust? but the latter is considered as a potential magma source through partial melting.
Figure 1: Siluric should be Silurian; Mineral deposit should be Porphyry-skarn Cu (-Mo) deposit
Figure 4: The figure contains some mistakes
Figure 7: 2.0 Ga crust
Figure 8: I-type granitoids
Figures 9: The x and y axis also contains mistakes, w is not necessary, wt.% versus %, ppm versus 10-6, some unnecessary bracket
Figure 10: spell mistake of fractionation, add wt.% in a, °C in d
Figure 11: why and where is the high-Mg diorites?