摘要：Igneous and detrital zircons have six major U/Pb isotopic age peaks in common (2700 Ma,1875 Ma,1045 Ma,625 Ma,265 Ma and 90 Ma).For igneous rocks,each age peak is comprised of subpeaks with distinct geographic distributions and a subpeak age range per age peak ≤100 Myr.There are eight major LIP age peaks (found on ≥ 10 crustal provinces) of which only four are in common to major detrital zircon age peaks (2715 Ma,1875 Ma,825 Ma,90 Ma).Of the whole-rock Re depletion ages,58％ have corresponding detrital zircon age peaks and 55％ have corresponding LIP age peaks.Ten age peaks are found in common to igneous zircon,detrital zircon,LIP,and Re depletion age time series (3225 Ma,2875 Ma,2145 Ma,2085 Ma,1985 Ma,1785 Ma,1455 Ma,1175 Ma,825 Ma,and 90 Ma),and these are very robust peaks on a global scale as recorded in both crustal and mantle rocks.About 50％ of the age peaks in each of these time series correspond to predicted peaks in a 94-Myr mantle cycle,including four of the ten peaks in common to all four time series (2875 Ma,1785 Ma,825 Ma and 90 Ma).Age peak widths and subpeak ranges per age peak suggest that mantle events responsible for age peaks are ＜100 Myr and many ＜ 50 Myr in duration,Age peak geographic distributions show three populations (≤ 1000 Ma,2500 -1000 Ma,≥2500 Ma),with the number of new provinces in which age peaks are represented decreasing with time within each population.The breaks between the populations (at 2.5 Ga and 1 Ga) fall near the onsets of two transitions in Earth history.The First Transition may represent a change from stagnant-lid tectonics into plate tectonics and the Second Transition,the onset of subduction of continental crust.The major factor controlling geographic distribution of age peaks is the changing locations of orogeny.Before ～ 2 Ga,age subpeaks and peaks are housed in orogens within or around the edges of crustal provinces,mostly in accretionary orogens,but beginning at 1.9 Ga,collisional orogens become more important.The coincidence in duration between magmatic flare-ups in Phanerozoic arcs and duration of age subpeaks (10-30 Myr) is consistent with subpeaks representing periods of enhanced arcrelated magmatism,probably caused by increased subduction flux.The correlation of isotopic age peaks between time series supports a cause and effect relationship between mantle plume activity,continental magma production at convergent margins,and crustal deformation.Correlation of over half of the detrital zircon age peaks (and six of the nine major peaks) with Re depletion age peaks supports an interpretation of the zircon peaks as crustal growth rather than selective preservation peaks.
