In 2005, the members of the laboratory had undertaken 30 scientific and researching projects sponsored by the Ministry of Science and Technology, National Natural Science Foundation of China, Chinese Academy Sciences.

1. Complete list of important scientific and research projects

 

* First leaders of projects are from outside the laboratory, second leader of projects are listed in the remark column

 

2. The progress of major research projects

   The project, keep continental subductions, has been successfully concluded

The project had been approved to be set up in December, 1999, and passed the appraisal in September, 2005. Chief scientists, such as Ye Kai, Guo Jinghui and Zhu Rixiang are presiding respectively at the following subprojects: physical changes of the lithioplate in deep continental subductions, chemical changes of plank during the deep continental subduction and its reforming effects on the mantle wedges, and effect of the relationship between the deep continental subduction and the Creatceous magnetostaitc belts on the geophysical fields. Mr. Zhang Hongfu, one of the researchers, has accomplished majority of the study on effect of the relationship between the deep continental subduction and the Creatceous magnetostaitc belts on the geophysical fields. The whole projects, including the above-mentioned subprojects, were all labeled excellent by the expert group in the appraisal.

Members of our laboratory have achieved in the study of keep Continental Subduction on the following six aspects:      

 

 monstrate that the massive continental crust had experienced the deep continental subduction. With the help of the laser-micro-Raman spectra, we detected in zircon form gneiss in ultra-high pressure metamorphic belt in Dabie-Sulu(Jiangsu and Shangdong provinces) many high and ultra high pressure mineral inclusions, such as fine coesite, aragonite, acmite or chalchewete, lepidomorphite, and etc., proving that these gneiss had undergone metamorphism under high and ultra-high pressure and that the ultra-high pressure metamorphic belt in Dabie-Sulu area had went through deep subduction, thus basically solved the dispute over the gneiss and eclogitic being of n-situ oreign rigins.

 cognize the mylonite formed in ultra-high pressure inside the Dabie-Sulu orogenic zone, and illustrating under this understanding the characteristics of shear deformation of the blocks under ultra-high pressure during the early inversion. Study on the shear zone of high and ultra-high pressure in Yangkou, Shangdong Province, reveals that dislocation creep is the main deformation mechanism working on deformation of the continental crust, and the stress inside the deep subduction zone is at least over several MPa, much higher than the value predicted by foreign scholars.

 monstrate that there were intensive melted fluid activities during the deep continental subduction and inversion and reveal its petrologic mechanism through the study of metamorphic petrology and metamorphic mineralogy. The detailed study of petrology indicates that   some minerals, such as chlorite, amphibole, and natron onkosin, in low-pressure fluid were dehydrated, resolved, and precipitated during the continental subduction some anhydrous minerals (such as chalchevete, acmite, rutile, and garnet) of ultra-high pressure contain certain amount of inherent moisture, which can be released during the inversion of metamorphic rock under ultra-high pressure  solid evidence of early dehydration and melting of lepidomorphite and epidote in ultra-high pressure eclogite during inversion had been found, the idea that the dehydration and melting of these rocks induces the melting of ultra-high metamorphic terrain was testified. All these studies reveal that continental crust can bring large amount of fluid into the deep of the mantle during the subduction and cause mantle alteration  evidence concerning the mantle alteration by melted fluid during deep continental subduction is also found in the hyperbasite of Sulu areas.

The crust-mantle interaction during the continental crust subduction and inversion revealed in the above researches is a very special mechanism and process between the crust and mantle, different from the that caused by ocean plate subduction, with which we have been quite familiar.

 establish the deep continental subduction between the evolution of lithospheric mantle in southern craton margin of North China and the Yangtze Plate, discover and prove that the Daibie-Sulu and its adjacent areas, which is the source area of the basic magmatic rock, feature in geochemical behavior of II-type enriched mantle, showing that the lithospheric mantle went through  widely enrichment reformation, proving the process of silicone-rich and carbonate-rich  fused bodies alterating the lithospheric mantle in North China, proposing that the mantle alteration caused by the deep subduction of Yangtze Plate and the interaction of peridotite and fused mass being one of the reasons of the inhomogeneity in the Mesozoic lithosphere in North China, confirming the enrichment features of this lithospheirc mantle showing the  spatial change pattern of south-north direction along the Daibie/Sulu-North China, observing for the first time the end members of lower crust of South China subduction (high Th and Pb and low Sr) and EM-II enriching lithospheric mantle in North China(low Th and Pb and high Sr) in augite and gabbro source areas after the Dabeishan collision.

These achievements successfully connected the evolution of lithospheric mantle in the southern margin of North China and the deep continental subduction.

 veal the ultra-high pressure syn-collision in northern Sulu and the magnetic activity after the collision. The research confirms that three phases of syn-collision and magmatism after collision: intrusion of olivine latite series from the late Triassic to 210Ma. Original magma came from the enriched mantle and its formation indicates the breaking and aparting effect of continental plate during deep subduction formation of calc-alkalic series of granide during the Later Jurassic (160-140Ma), a product of partially melted Yangtze plate under high pressure, indicating a delamination of the thickening lower crust of Sulu orogenic zone; intrusion of calc-alkalic series with high content of K, a product of lithospheric thinning in eastern China, proving that Yangtze plate matters are prevalent in the lower crust in the Jiaodong and Xuhuai areas and providing important evidence for further understanding the structure before collision and collision process.

scover the negative correlation between the geomagnetic poloarity reversal frequency and terrestrial magnetic field intensity before the occurrence of the Cretaceous Normal Superchron. The research proposes the standards and new experimental methods for rock magnetism measurements for volcanic rocks thus enhancing the return ratio and dependability of terrestrial magnetic field intensity measurements, achieving a batch of high quality data concerning the Cretaceous Normal Superchron and the terrestrial magnetic field intensity, discovering the negative correlation between the the geomagnetic poloarity reversal frequency and terrestrial magnetic field intensity before the occurrence of the Cretaceous Normal Superchron, blaring out new path for the study of the effect of processes in deep Earth on the evolution of the lithosphere.

 

Major progress had been made in the Mesozoic mantle derived rock and its inclusion in eastern China and their constraints over the lithosphere thinning ponsored by the youth found of the National Development and Reform Commission

  The project the Mesozoic mantle derived rock and its inclusion in eastern China and their constraints over the lithosphere thinning  undertaken by Zhang Hongfu had passed the mid-term evaluation in 2005. Among the 13 theses concerning the project that had been published, ten had been accepted by SCI(among them, 6 are foreign SCI), and another six SCI theses are still in the stage of amendment and appraisal. Following achievements had been made by the research fellows:

 

  research indicates that the Mesozoic lithospheric mantle in North China is different either from the Palaeozic craton lithospheric mantle or the Cenozoic  Ζcean ithospheric mantle, i.e. enriched lithospheric mantle, and evidence of time and space evolution divergences are found in different block bodies, inferring the thinning and enriching of the Mesozoic lithosphere in North China is connected with the continuous subduction and collision at northern and southern sides since the Eopaleozoic. One thesis that elucidates the issue had been quoted more than 40 times and ranked as the 1%  op Journal Retrieval  by SCI.

  discovery of mantle olivine and augite chadacryst with clear atoll texture, especially the accidental inclusion in mantle olivine, proves that the interaction of peridotite-fused mass be possible in the lithospheric mantle and it be an important way of component change. The discovery and study of compound mantle peridotite inclusion, pyroxenite inclusion and fused mass inclusion infer that these fused mass came from the subducted Yangtze continental crust.  The fused mass containes alkali, silicone, and volatile components. These fused masses migrated inside the lithospheric mantle and transformed the Palaeozoic magnesium-rich peridotite into the Late Cretaceous iron-rich peridotite and pyroxenite.This conclusion has been highly regarded by the experts of the domain, thus helping obtaining the  ransforming process of the Mesozoic lithospheric mantle in eastern China: interaction of peridotite and fused mass , a key project of continental kinetics sponsored by the National Nature science and foundation of China.

 ansforming process of the Mesozoic lithospheric mantle in eastern China: interaction of peridotite and fused mass , a key project of continental kinetics sponsored by the National Nature science and foundation of China, has already started.  Mantle peridotite inclusions formed by the interaction between peridotite and fused masses has been located in several places.

  first batch of Hf isotopic measurement data of basaltic had been acquired and the research approaches to the basic magmatic origin had been expanded. Achievements had been made in the advanced research of Li isotope. By applying the Li isotope in the research of the Cenozoic mantle peridotite inclusions in our country, it is suggested that Li isotope is an important means  in the research of mantle alteration and the interaction between peidotite and fused masses. After measurements by using C and N isotopic ion probes on the diamond of juvenile orgin in our country, dimonds with the lowest N isotope had been discovered, further proving that the formation of diamonds is anatetic origin and can be traced back to very ancient times. The project is still in the process of researching.

The results of these studies were made as the special reports on The Origin, Evolution and Present State of Subcontinental Lithosphere (IUGS-SECE) international symposium on the special report  ransformation of sub-continental lithospheric mantle through melt-peridotite interaction: implication from mantle xenocrysts and xenoliths  , and the representative paper (Zhang H.-F. 2005. Transformation of lithospheric mantle through peridotite-me 60m reaction: a case of Korean Craton. Earth and Planeta ry Science Letters 237: 768-780. ) had been published.

Brief introduction on the above-mentioned theses of representativeness:

The rarely found olivine with clear atoll texture is discovered in the Early Cretaceous basalt in Fangcheng. These olivine have the same components in its central part with that of the olivine found in peridotite inclusion carried by the Cenozoic basalt in North China, while the make-up of the marginal area of the olivine is similar to that  phaerocyst olivine in basalt. The characteristics of the chemical components of the olivine together with its perfectly round shape of the crystal body and smaller size rove that these olivines are all mantle mineral inclusions, i.e, the disintegrated minerals from mantle peridotite. Its central part can represent the components of mantle peridotite. Its atoll texture is caused by the rapid reaction between the olivine inclusion and host basalt. This reaction is prevalent in the Mexozoic lithospheric mantle (an important displacement of the lithospheric mantle),causing the high magnesium peridotite with high concentration elements defected transformed into low magnesium peridotite with isotopes of high concentration elements and isotopes enriched during the Palaeozoic and the later Mesozoic, resulting in the disappearance of the ancient litheospheric mantle.