Abstract:

Abstract:The Songpan- Ganze orogenic belt is a super- enrichment zone of lithium- beryllium- tantalum rare elements. In view of the bottleneck of the upstream development of lithium mineral resources, we are launching a 3000 m scientific drilling project of lithium deposit in western Sichuan. The drill hole will penetrate granite and pegmatite, as well as metamorphic rocks, in order to establish a multi- disciplinary crustal “lithium column”. Key scientific issues include: “tectonic origin of granite- pegmatite- type lithium deposits”, “genetic types and properties of the granites related to the lithium deposits”, “relationship between granite and pegmatite and their differentiation processes”, “the source- migration- accumulation process of rare metals”, “the orogenic process of deformation- metamorphism- magmatism- mineralization: from heat dissipation to lithium enrichment” and “the specificity and diversity of microorganisms under rare- element- bearing extreme conditions and their relationships with depth”. The project will be able to offer the tectonic background, the restriction factor, the reference data and the scientific basis for the lithium ore exploration breakthrough, to provide the scientific symbol for the prospecting prediction target area, and to establish the innovative lithium deposit genesis theory, which has the important scientific significance and the practical value.

Abstract:The Mesozoic Yanshan orogenic belt in the North China is typical of intracontinental orogeny, but there are divergent views on the dynamic mechanism of its orogeny. In this article an attempt is made to explore the key factors in the intracontinental orogeny by comprehensively investigating the structures at different depths of the lithosphere to discover the main characteristics of the Mesozoic tectonic movement in the Yanshan belt. At first, with the JiningChengde basement lithospheric fault belt as an example, activation of the preexisting weak structure belts is studied in terms of geological actions at different depth levels: (1) the surface faulted basins and their volcanicsedimentary formations, (2) the different swells of block structures, (3) the rheological deformation and thermal activity, (4) the mantlederived or crustmantle miscible volcanism. Secondly, weakening of the lithosphere is investigated through the mantle- derived fusionfluid metasomatism. Finally, by taking into account the tomographic imaging of the lithospheric structures, it can be concluded that (1) the upwelling of mantle diapir is the most important background of Mesozoic intracontinental orogeny in the North China Craton, and (2) that the effects of interaction between adjacent plates should not be excluded. Finally, from comparison with other typical intracontinental orogenic beltsabroad, it is further recognized that deep mantle material upwelling and isostatic adjustment of upper lithosphere materialsare essential differences of the intracontinental orogeny from the continental margin orogeny.

Abstract:The zircons of alkali- feldspar granite in Nuominhe area, Northern Da Hing’an Mountains are self- shaped—semi- self- shaped short column—plate- like, with a well- structured oscillation growth zone and a high Th/U ratio (1.10～2.18). It is a typical magma- forming zircon. The LA- ICP- MS U- Pb geochronology study showed that the rock was formed in the Early Carboniferous Duinian period (352.9 ± 3.3 Ma). Rock geochemical studies show that the rock belongs to quasi- aluminum- weak aluminous high- potassium- calcium- alkaline rock, rich in silicon (SiO 2 =73.25%～77.01%), alkali- rich (Na 2 O+K 2 O=7. 72% ～9.48%), rich Iron (Fe 2 O 3 =2.06%～2.97%, Fe 2 O 3 + FeO=2.32%～3.33%), magnesium deficiency (MgO=0.08%～0.26%). Strongly depleted Sr, Eu, Ba, Ti, P and other elements, the REE distribution curve is right- winged seagull type and obvious Eu negative anomaly ( δ Eu=0.26～0.31), and the rock is judged to be A- type granite. Lu- Hf isotope analysis based on zircon U- Pb isotopic dating.The sample 176 Yb/ 177 Hf value was 0.03778～0.133612, the 176 Lu/ 177 Hf value was 0.001095～0.004155, and the 176 Hf/ 177 Hf value was 0. 282824～0.282863. The corresponding zircon U- Pb age calculated zircon ε Hf ( t )=8. 9 ～10.6, the first- stage Hf mode age was t DM1 =560～658 Ma, and the two- stage Hf mode age t DM2 =815～974 Ma, indicating that it originated from Partial melting of the Neoproterozoic source rocks. Our study and the development of the Early Carboniferous A- type granite in the Erguna block indicate that the closure of the Paleo- Asian ocean basin in the northeastern part of the Xingmeng orogenic belt occurred in the Early Carboniferous. Combined with the closure of the Paleo- Asian Ocean basin in the central part of Inner Mongolia, it is the Late Carboniferous, indicating that the closure of the ancient Asian ocean basin is a “scissor- like” development process in the east, west and west.

Abstract:The middle Paleoproterozoic (2. 1～2. 2 Ga) magma in the eastern orogenic belt of the north China craton recorded important crustal evolution information in the early stage of the orogenic belt, which is of great significance for understanding the Paleoproterozoic geological evolution in the Liaoning- Jilin orogenic belt. In this paper, we have studied petrology, geochemistry, zircon U- Pb chronology and Hf isotope characteristics of Paleoproterozoic alkali feldspar granite in the Heigou area, eastern Liaoning province. The zircon U- Pb dating result of the granite by LA- ICP- MS was 2186. 5±6. 5 Ma, and the formation age was Paleoproterozoic. The rocks belong to the alkaline and weakly peraluminous A- type granites. The rocks are high in Si and rich in alkali, poor in Ca, Mg and Al, extremely rich in sodium and poor in potassium. They are also rich in the HFSEs (such as Hf, Zr, Nb, Y), deficient in the LILEs (such as Rb, K, Ba), have high (K 2O+Na 2O)/Al 2O 3, FeOT/MgO, Ga/Al ratios, and negative Eu anomaly. The rare earth elements distribution curve shows the right- leaning seagull pattern. The saturation temperature of zircon ranges is between 857 ℃ and 884 ℃, and has a very low Sr and high Yb characteristic, indicating that the rock was formed in the extensional tectonic background of low pressure and high temperature. ε Hf ( t ) values of zircons in the granites range from -0. 96~+4. 58, and two- stage Hf model ages ( t DM 2 ) are 2476～2821 Ma, which are significantly older than the zircon U- Pb ages of the granites. Combined with lithogeochemical characteristics, it indicates that the Paleoproterozoic granites were derived from partial melting of Archean TTG gneisses under an extensional environment at shallow crustal level. Based on the data of petrology, geochemistry and isotopic characteristics, the Liaoning- Jilin region was likely to be in the tectonic environment of continental back- arc basin in the early Paleoproterozoic, and the Heigou alkali feldspar granite is the product of the extensional environment of back- arc basin.

Abstract:The Duerji tectonic melange is composed of “matrix” and “blocks”. Based on petrological and geochemical studies, the “matrix” is considered to be a set of marine debris rocks formed in the tectonic environment of active continental margins. The “blocks” include pyroxene amphibolite, amphibolite, basalt, diabase, diorite. Basalt and diabase are Na- rich and K- poor rock system with low Ti, high Mg and Al. They have the dual tectonic properties of MORB and IAT, and are allochthonous blocks that formed in the tectonic forearc when the ocean began to initially subduct. Diorite is the Mg diorite (MA) which has the characteristic of SiO2 (53. 41%), MgO (5. 57%), Mg＃ (51), FeO/MgO (1. 08). Compared with basalt and anthracite, diorite has the characteristic of high Ti, Ta and low Nb, and is an autochthonous block formed in the tectonic environment of active continental margins with subduction. The conclusion of the study on the material composition and tectonic properties of the Duerji tectonic melange is that it may reflect the process of late Carboniferous Ocean Subduction- Early Permian Ocean Land Subduction- MiddlePermianoceanBasin Closing.

Abstract:The Alxa Block is located between the Central Asian Orogenic Belt to the north and the Qilian Orogenic Belt to the southwest. However, the Early Paleozoic tectonic setting of its southwestern margin has long been debated. Researchers who studied the Early Paleozoic plutons in the eastern Beidashan believe that the subduction of Paleo- AsianOcean had reached the southwestern Alxa Block. Others have proposed the post- collision extensional setting for this area based on the Early Paleozoic magmatic rocks in the eastern Longshoushan. It is noteworthy that there is no large fault between the eastern Beidashan and Longshoushan, and the distances between the western Longshoushan and the two orogenic belts are the same as those for the eastern Beidashan and Longshoushan, indicating same tectonic setting. In order to discuss the Early Paleozoic tectonic setting of the western Longshoushan, the Dafosi alkali- feldspar granite, the Wuba biotite granite and the Zhangjiayao granodiorite were sampled for LA- ICP- MS zircon U- Pb dating and element and isotope geochemical analyses. The results indicate that the Dafosi alkali- feldspar granite was formed during Late Silusian (426±2 Ma), and its major elements are characterized by high SiO2 (78. 03%) and total alkali (7. 96%), low CaO (0. 60%) and MgO (0. 13%), with prominent V- type rare earth element pattern and negative Ba, Sr, and Eu anomalies, belonging to aluminous A2- type granite. The Wuba biotite granite and the Zhangjiayao granodiorite were formed during the Late Silurian (421±2 Ma) and the Early Devonian (406±4 Ma), respectively, and both are high K calc- alkaline I- type granites. They have enriched LREEs (La/YbN=10. 69~13. 79), depleted Eu (δEu=0. 56~0. 77), and simultaneously exhibit apparently negative Nb- Ta anomalies and positive Zr- Hf anomalies.Moreover, all the three plutons have enriched Sr- Nd isotopic features and Mesoproterozoic two- stage Nd model ages. Therefore, they may have originated from the partial melting of Mesoproterozoic crust and indicate post- collisional tectonic setting. According to the statistical analysis and regional comparison, the tectonic evolution of southwestern Alxa Block could be divided into the subduction stage of Middle Ordovician- Early Silurian (ca.461~441 Ma) and the post- collision stage of Middle Silurian- Early Devonian (ca. 432~397 Ma). This process is comparable with the evolution of Qilian Orogenic Belt indicating a genetic relationship.

Abstract:The article mainly focusses on the petrology, geochemistry, zircon chronology and Lu- Hf isotope analysis of the quartz diorite that is exposed in the Bashikourgan rock group in the Munabulake area on the west side of the South Altyn Tagh. Whole rock geochemical research indicates that the quartz diorite has SiO2 content of 55. 94%~57. 38%, exhibits the characteristics of high ratio of Na2O/K2O=1. 19~1. 60 and quasi- aluminium (A/CNK=0. 92~0. 95). On the REE partition diagram, all samples show weak or no obvious Eu anomaly, enriched LREE pattern and defected HREE pattern. On the primitive mantle- normalized spider diagram, samples are relatively enriched in large ion lithophile elements (LILE), such as Rb, Th and K, and depleted in high field strength elements (HFSE), such as Nb, Ta, Sr, P and Ti, showing the characteristics of quasi- aluminous I- type granites of crustal high- K calc- alkaline to calc- alkaline series. The zircon crystals in the quartz diorite are euhedral and mostly show long columnar shape with clear oscillatory zones. Zircon U- Pb dating by LA- ICP- MS obtains the age of 455. 5±1. 3 Ma, which is inferred to represent the formation age of quartz diorite based on the internal structure of CL image of zircon. This age is identical to the high- pressure granulite facies retrograde metamorphic age of HP/UHP rocks from the South Altyn Tagh, and is also identical to the third stage of the magmatism (460~451 Ma) in early Paleozoic in the South AltynTagh. All spots of zircons have ε Hf( t )=-6. 29~-1. 35 and T DM C=1512~1823 Ma, which is similar to early Paleozoic granite of the Southern AltynTagh ( T DM C=1331~1789 Ma, ε Hf( t )=-8. 8~-0. 4), suggesting that they were derived from the consistent source rock, which was accreted in Middle Mesoproterozoic- Paleoproterozoic. According to the geochemical characteristics, the quartz diorite was inferred to have formed by partial melting of the basalt in the lower crust, with mantle magma mixed in during the formation process. Based on the results of our studies we conclude that the quartz diorite from the Munabulake area in the South AltynTagh was produced when the metamorphic basalt partially melted and mixed with mantle due to the loss of the pressure, followed by intrusion and crystallization into the crust during the subduction when the continental crust turns back.

Abstract:Ilvaite, a common calcium silicate mineral in skarn- type deposit, which is associated with the Pb- Zn mineralization closely. In this study, the optical property, mineral association and chemical composition of ilvaite in Niukutou deposit are discussed. There are three ilvaite- bearing association in the Niukutou deposit: (1) Ilvaite+garnet+magnetite mineral assemblage; (2) Ilvaite+mangan- hedenbergite (Mn- Hd)+johannsenite (Jo)+galena+magnetite mineral assemblage; (3) Ilvaite+calcite+quartz+sulfide (pyrite, pyrrhotite and other sulfide) mineral assemblage, and formed a garnet- magnetite+ilvaite+ johannsenite skarn zonation outward from the skarn- related pluton. These three mineral associations are corresponding to three mineralization phases, respectively. Stage Ⅰ, the prograde garnet was replaced by the ilvaite. Stage Ⅱ, the mangan- hedenbergite (Mn- Hd) or johannsenite (Jo) were replaced by the manganilvaite. Stage Ⅲ，similar to quartz sulfide stage, the further breakdown of ilvaite produced magnetite, calcite and quartz. The mineral chemical composition by EPMA showed that the molecular formula of the Niukutou ilvaiteis Ca 0. 94- 0. 98 (Fe 1. 22- 1. 92 Mn 0. 10- 0. 75 Mg 0. 01- 0. 03 ) 2+ (2. 00- 2. 05) (Fe 0. 83- 0. 93 Al 0. 01- 0. 07) 3+ (0. 82- 1. 03) \[Si 2. 00- 2. 07 O7\]O(OH). The in situ LA- ICP- MS trace element analysis showed that the REE patterns of ilvaites are similar to the prograde garnet- pyroxene, which is an evidence for their inheritance in the hydrothermal process. Together with the mineral assemblage, we suggest that ilvaite originated from the continuous alteration and replacement of the early skarn silicates. The skarn zonation in Niukutou deposit is indicative of evolution of the hydrothermal process from reducing (Fe 2+ , Mn 2+ ) during the formation of the primary skarns, to hydrated and more oxidizing (with Fe 2+ , Mn 2+ +Fe 3+ , and then Fe 3+ ) during the overlapping retrograde alterations and deposition of the ore minerals.

Abstract:Several world class ore- forming belts (deposits) such as the Pontides, the Sahand- Bazman, the Chagai, the Yulong and the Gangdeseoccur in the Tethyanmetallogenic domain, referred to as one of the three giant metallogenic domains. In order to further understand the genesis and mineralization of Miocene porphyry copper deposits in the Tethyan domain, the geological, geochemical and Sr- Nd- Pb isotopic data of ore- bearing porphyries from typical porphyry Cu deposits in the Sahand- Bazman, the Chagai and the Gangdese belts have been analyzed and compared, their petrogenesis, source and tectonic environment have been discussed, and their tectonic evolution and metallogenic process have been deduced and summarized in this paper. The geochemical results suggest that the Miocene porphyries in these three belts show the characteristics of calc- alkaline I- type granite, with adakite magmatic affinity. Compared with the lithogeochemical features of porphyries in the Gangdese belt, the ones in the Sahand- Bazman and the Chagai belts show the transitioning characteristics from arc magmatic suites to adakites, which might be caused by the partial melting of MORB- derived amphibole eclogite or eclogite occurred in the magma source with a greater degree. The Sr- Nd- Pb isotopic data suggests that these ore- bearing porphyries might have been sourced from a mixture of crust and mantle controlled by magma, showing DUPAL anomaly. After comprehensively analyzing the geological, geochemical and isotopic characteristics of these porphyry deposits, it is believed that these ore- bearing porphyries were formed in the island arc setting of collision- orogenic belt, serving as the partial melting products of thickened lower crust during the subduction of oceanic crust and the continental collision.

Abstract:The Longshan Au- Sb deposit is a typical Au- Sb ore deposit in central Hunan. Analysis and comparison of S, Pb and Sr isotopic composition of different ores, wall rocks and regional strata from the Longshan deposit have been carried out in this study. The δ 34 S values of ores vary from -3. 0‰ to 5. 1‰ with an average of 2. 3‰ and the δ 34 S values of wall rocks vary from 4. 0‰ to 5. 9‰ with an average of 5. 2‰, and the δ 34 S value of the regional strata from 9. 3 ‰ to 13. 3‰ with the average of 11. 3‰. The sulfur isotopic compositions of ores differ from the wall rocks and the regional strata, and show magmatic character. The 206 Pb/ 204 Pb, 207 Pb/ 204 Pb and 208 Pb/ 204 Pb ratios of ores are 16. 992~18. 457, 15. 392~15. 722 and 37. 586~38. 960, respectively; the 206 Pb/ 204 Pb, 207 Pb/ 204 Pb and 208 Pb/ 204 Pb ratios of wall rocks are 17. 630~17. 993, 15. 522~15. 644, 38. 981~38. 366, respectively; and the 206 Pb/ 204 Pb, 207 Pb/ 204 Pb and 208 Pb/ 204 Pb ratios of regional strata are 17. 566~18. 092, 15. 430~15. 630 and 37. 988~38. 710, respectively. The Pb isotopic compositions of ores vary greatly, and the sources are complicated, where the strata, Indosinian magma and upper mantle are all possible lead providers. The ( 87 Sr/ 86 Sr)i range of fluid inclusions in quartz is 0. 71540～0. 72309, the ( 87 Sr/ 86 Sr)i range of wall rocks is 0. 71844～0. 72153; the ( 87 Sr/ 86 Sr)i range of regional strata is 0. 71792～0. 71939. The initial Sr values of ore rocks, wall rocks and regional strata are all relatively high, suggesting that they might mainly have come from the crust, with some contribution of Sr from ore- bearing strata and the Indosinian magma. The ore- forming materials in the Longshan deposits show characteristics of crust- mantle mixture, in which the ore- forming sulfur originated from magma while the other ore- forming material are partially from the regional strata of the Jiangkou Formation, and partially from the Indosinian magma.

Abstract:The Zhilingtou deposit has a “three- story” mode: the upper part (volcanic rock caprock) is dominated by lead- zinc deposits and sulfur deposits, the middle section (metamorphic rock basement) by gold- silver and lead- zinc deposits, and the deep part (intrusive rock) by porphyry molybdenum deposits. Based on the previous studies, this paper determined the ore- forming age of the Zhilingtou deposit by molybdenite Re- Os isotope dating. The model age of the six molybdenite samples was 113. 7~114. 6 Ma, with a weighted average age of 114. 03±1. 78 Ma, indicating that the mineralization of the Zhilingtou Mo polymetallic deposit occurred in the late stages of the Early Cretaceous. The Re content of the molybdenum sample in this deposit changed from 16. 05×10 -6 to 66. 29×10 -6 , indicating that its ore- forming material has the characteristics of crust- mantle mixed source. The sulfur composition of sulphide has a narrow range of changes (-2. 1‰~2. 6‰), which reaches the equilibrium of isotope fractionation and may be derived mainly from the deep magma of the upper mantle or the lower crust. It has a relatively uniform source of sulfur, but may also be affected by the continental crust. The range of lead isotope composition of the ore minerals from the Zhilingtou Mo- Pb- Zn- Au polymetallic deposit is relatively small. The values of 208 Pb/204 Pb , 207 Pb/ 204 Pb, and 206 Pb/ 204 Pb are 38. 765~39. 137, 15. 523~15. 751, 18. 450~18. 667, respectively, indicate crust- mantle mixing characteristics. The determination of the ore- forming age of the Zhilingtou Mo polymetallic deposit provides an important clue for the prospecting of contemporary porphyry ore- forming systems in the region, and provides new information for further studying the petrogensis and metallogeny of the southeast coastal metallogenic belt.

Abstract:The Maerkang rare metal orefield located in the eastern of Songpan- Ganzi orogenic belt is presently the largest pegmatite- type rare metal orefield in China. There are several medium to large scale spodumene pegmatite deposits, including Guanyinqiao, Yelong, Lijiagou, Dangba etc. Due to the limited surface bedrock outcrops and deep topographical incision by the rivers, it is more difficult to find hidden ore veins until now, thus slowing down the prospecting progress. In this paper, we consider the new development of ore- prospecting in the Jiada area as an example, and discuss the application of metallogenic theories and prospecting methods. The main contents are as follows: based on the original outcrop of spodumene pegmatite and the eluvial- slope gravel belts delineated by geological mapping, the trend of hidden pegmatite vein is deduced. The tendency of pegmatite is also inferred by combining the hidden high resistivity anomaly zone delineated by multi- electrode electrical measurement. Finally, the position of drilling hole is arranged, and the hidden lodes are controlled. Those prospecting methods are of great use in determining the existence of hidden lodes and their continuity between the outcrops of pegmatite. It is also effective in describing the conformity between the high resistance abnormal zone and the outcrop of spodumene pegmatite or the eluvial- slope gravel belts. Finally, the prospecting strategy for the eastern Maerkangorefield is determined.

Abstract:The depositional age of the Dingqinghu Formation in the Lunpola Basin is of great relevance in studying the paleo- elevation and climate of the central Tibetan Plateau. Due to a lack of absolute age of the Dingqinghu Formation in the Lunpola Basin, it is still controversial if the uppermost part of the Formation contains Miocene deposits. Two tuff layers were found in the Lower to Middle Dingqinghu Formation during the geological survey in the Ejiazu area of the Lunpola Basin. The LA- ICP- MS zircon U- Pb dating of the tuffs from Middle and Upper part of the Ejiazu profile yielded ages of 24. 05±0. 24 Ma (MSWD=1. 07, n=24) and 22. 64±0. 33 Ma (MSWD=0. 45, n=17) respectively, indicating a depositional age of Late Oligocene and Early Miocene respectively. According to the new zircon U- Pb age and previous research, the clasticrockstrata in the Ejiazu profile was the Dingqinghu Formation rather than the Niubao Formation, and the depositional age of the Dingqinghu Formation is Oligocene to Middle Miocene. Using sedimentation rate and sediment thickness of the Dingqinghu Formation, the deposition of the whole Dingqinghu Formation was estimated to have lasted about 21 to 23 Ma, and the top of the Dingqinghu Formation was extrapolated to 11~13 Ma. Therefore, the clastic strata were deposited continually until at least the Middle Miocene, which was much later than the previously estimated paleo- elevation and climate of the central Tibetan Plateau since the Late Eocene to Oligocene. The recent discovery of fossil mammals, climbing perch, and palm plants and advanced palynological paleoaltimetry collectively demonstrate that the paleo- elevation of the Lunpola Basin was lower than ~2500~3000m. The warm and humid climate that prevailed in this area during the Late Oligocene to Middle Miocene was probably influenced by the airflow from the India Ocean penetrating into the central Tibetan Plateau.We conclude that the Indian monsoon prevailed in the Lunpola Basin at the latest in the Middle Miocene, which led to the diversity of organisms in the Tibetan Plateau.

Abstract:Baogutu porphyry copper deposit, the largest porphyry type deposit of the area, is located in the west Junngar, Xinjiang. The ore- forming processes are closely associated with the late Carboniferous in termidate- acidic intrusions. The intrusion III- 2, located in the south of the mine, with the characteris tics of wholly mineralized and low grade, is an ideal sample for investigation of the nature of the ore- forming magma. In thispaper, oxygen fugacity of ore- forming magma was disscussed on the basis of petrology and mineral compositions of amphibole and zircon, by comparison with typical porphyry copper deposits. The results show that the Baogutu intrusion III- 2 is mainly composed of quartz diorite (porphyry) and diorite, with a small amount of pyroxene diorite. Plagioclase, amphibole, biotite, quartz and potassium feldspar are the major ore- forming minerals, with minor ilmenite, sphene and apatite. Early stage euhedrae amphiboles from quartz diorite are classified as calcic amphibole with high Mg# (0. 72~1. 00). The oxygen barometer based on amphibole compositions provides log f O2 values ranging from △NNO+1. 4 to △NNO+2. 6, which is in the variation range of ore- bearing intrusions from porphyry copper deposits worldwide. Zircons from quartz diorite are characterized by high REE content (338×10-6~ 959×10-6). With depleted LREE and enriched HREE, these zircons display left- leaning REE patterns and strongly positive Ce and negtive Eu anomalies. The moderate Ce4+/Ce3+(29. 55~89. 50) and Eu/Eu* ratios (0. 32~0. 47) are in the overlapping portion of ore- bearing and ore- barren intrusions from porphyry copper deposits. These data indicate that the oxygen fugacity of the ore- forming magma of the Baogutu intrusion III- 2 are relatively high, which is beneficial for the dissolution and migration of metal elements, and also facilitates the formation of poyphyry copper deposits.

Abstract:The Nixiong Iron Mine, a large magnetite deposit in the central Gangdese belt, was mainly formed in the Early Cretaceous. This paper will discuss the metallogenic background of Early Cretaceous Nixiong magnetite deposit that can be divided into the Skarn type and the hydrothermal vein type. Gabbro dyke in mining area yielded the UPb age of 120. 1±1. 7 Ma which limits the mineralization era of the hydrothermal vein magnetite to about 120 Ma and is fully consistent with the determined mineralization era of Skarn magnetite deposit, indicating that a similar tectonic setting controlled both types magnetite deposits. Clastic rocks, as the wall rock of the Nixionggranitoid from the Upper Permian Dibucuo Formation, yielded a detrital zircon UPb age of 130~120 Ma with the youngest peak age of 131.25 Ma which was prior to the emplacement age of the Nixiong rock (~120 Ma) suggesting that the Upper Permian Dibucuo Formation should be renamed to be the Lower Cretaceous. Combined with the new regional stratigraphic and magmatic data, we propose that an Early Cretaceous volcanicintrusive complex system consisted of volcanic rocks from the Zenong Group and emplacing granitoid in the Zenong Group in the Central Gangdese belt. This Early Cretaceous metallogenic magmatic system is closely related to the Early Cretaceous Nixiong magnetite deposit. Both geochemical characteristics of the Early Cretaceous igneous rocks and the shallow surface structure show an extensional tectonic setting in the Central Gangdese belt in the Early Cretaceous. Based on the new understanding of the tectonic background in Nixiong area, a metallogenic geological model of the Early Cretaceous Nixiong magnetite deposit was established.

Abstract:The Songpan- Ganzi orogenic belt is an important part of the northeastern Qinghai- Tibet Plateau. It is the major convergent region of the North China, the Yangtze and the Qiangtang blocks. The orogenic belt consists of Mesozoic low- grade metamorphic strata and a series of magmatic rocks, and has recorded convergent events of the three blocks since the Indosinian Period. Yajiang remnant basin within the orogenic belt, in which an extremely thick sedimentary series and widespread magmatic rocks occur, is an ideal region for research on the tectonic evolution of the Songpan- Ganzi orogenic belt. This study undertakes detrital zircon LA- ICP- MA U- Pb geochronology. The results show that the zircon U- Pb age values focus on four peaks, 231~281 Ma, 424~502 Ma, 707~983 Ma, 1539~1850 Ma, respectively, indicating that the west margin of the Yangtze craton and the Songpan- Ganzi orogenic belt have been subjected to at least four stages of intensive tectonic- magmatic events that were recorded in the Triassic strata in this area. The zircons with ages 231~281 Ma are most probably from the arc granites of the east Kunlun Mountains, formed during subduction of the Permian Songpan- Ganzi Ocean downward to the North China block. The zircons with ages 424~502 Ma were derived from the Yangtze block, representing a splicing event of the south Qinling, the north Qinling and the North China blocks. The zircons with ages 722~983 Ma are from the Yangtze block, and most probably from the granites of south Qinling formed during the subduction of the Neoproterozoic extensional upper Yangtze craton basin below the North China block. The granites are the products of crustal growth event in the Jinning period. The ages 1539~1850 Ma correspond to that of basement of the North China block, when the eastern and the western parts of the North China craton collided in the central area and the North China paleo- continent was in the process of further solidification and extension. The Archean material and newly generated igneous and sedimentary rocks were inherited, and a great many of these detrital materials were carried into the Songpan- Ganzi basin through an east- west directed transport system during the closure and collisional orogeny of the south Qinling Ocean in Middle- Late Triassic Epoch. Our results suggest that the origin of the Triassic Xinduqiao Formation in the Songpan- Ganzi flysch basin was mainly the material from the east Kunlun Mountains, the North China block and the Qinling orogenic belt. The youngest detrital zircons can limit the oldest depositional age. The weighted average age of four youngest zircons is 241. 8±4. 5 Ma, temporally constraining the deposition event of sedimentary rocks.

Abstract:Weibei Sag was a strike- slip pull- apart basin, which formed by the strike- slip actives of the Tan- lu fault, and the strike- slip actives played an important role on the evolution of fault system, the formation of the traps, and the hydrocarbon accumulation in Weibei Sag. During the sedimentation of Kongdian formation, Weibei Sag successively experienced sinistral strike- slip and right- lateral strike- slip, the characteristics and development of the fault in different tectonic evolution stage showed significant difference, and the multi- strike- slip activities caused the formation of three weak strike- slip belts in the east part of Weibei sag. Meanwhile, the the multi- strike- slip activities also leaded to the formation and evolution of massive traps of different types, so the oil&gas could accumulated in them. In addition, the activities of Tan- lu fault controlled the hydrocarbon accumulation in Weibei Sag. Macroscopic view, oil&gas migrated to the southeast and accumulated in the Zaohu nose structure belt, which was uplifted according to the strike- slip activities. In microscopic scales, due to the strike- slip rotation- shearing actions, the oil and gas migrated from west to east along the tensile fault in east- west direction, and sealed by the strike- slip fault in south- north direction. Corresponding to the three weak strike- slip fault belts, the planar distribution of oil and gas in Kongdian formation showed characteristics of “extend in east- west direction” and “zonal distribution in south- north direction”. The middle & north part of the middle weak strike- slip fault belt is the key exploration direction for Weibei Sag at present, and the west weak strike- slip fault belt could to be the study area for tight stone reservoirs and shale oil and gas.

Abstract:The different extension and strike- slip mechanism was built to understand the mechanisms responsible for differences in hydrocarbon enrichment in Wenchang B sag, based on fault distribution and formation periods, structural styles and combination, the difference in tectonic evolution and fault activity. The results indicate that the Sub- sag 19 was in extension and strong- strike- slip setting, Sub- sag 14 in extension and medium- strike- slip setting, and Sub- sag 30 in extension and medium- strike- slip setting. The different extension and strike- slip not only provided source channels and reformed reservoirs but also controlled the distribution and expelling direction of source rocks, the carrier system types and migration dynamic, the trap types and mechanical properties. Moreover, based on the pre- existing fault form, dextral evolution of extensional stress field and strain difference, a recognition method of strike- slip stress- increased traps was built and divided into 3 types: such as S- shaped stress- increased traps: dextral left- step stress- increased traps; and skew- shaped stress- increased traps. In conclusion, the hydrocarbon enrichment in Wenchang B sag was controlled by the extension and strike- slip setting and source- migration configuration, Sub- sag 19 and 14 were hydrocarbon enrichment region owing to strong- medium strike- slip setting and excellent source rocks in semi- deep lacustrine facies. Finally, the study has promoted several exploration discoveries in the Wenchang sag.

Abstract:The comprehensive studies of sedimentology, micropaleontology and chronology of borehole LZK06 at 40m depth and combined with the data of boreholes LZK02- 04 in the Dalinghe estuary area revealed that the study area experienced two transgression- regressions since the Late Middle Pleistocene, and the Late Middle Pleistocene lacustrine/fluvial Late Pleistocene marine lacustrine/fluvial Holocene marine fluvial stratums were sequentially formed. In the Early and Middle Holocene, due to the lower source supply, the study area was in a 10 ka long phase of starving deposition environment with an average sedimentary rate of 0. 02~0. 05 cm/a. In the Late Holocene, about 1500 years ago, due to the human activities leading to soil erosion and increased sediment transport in the river, the study area began a rapid accretion process with an average sedimentary rate of 0. 9~1. 2 cm/a, and the lower Liaohe plain was quickly filled. Compared with the tempo- spatial pattern of global sea level change, it is speculated that the marine bed II was formed in MIS 5- early MIS 3 and marine bed I was formed in MIS 1. Frequent sea level change is the main controlling factor for stratigraphic and environmental evolution in the muddy coast of Liaodong Bay since the Late Pleistocene.

Abstract:A large number of coarse clastic rock deposits were developed in the Lower Cretaceous Xiguayuan Formation in the Luanping Basin. Using 3D digital model as well as manual photography of typical outcrops, combined with fluid transportation mechanism, microfacies identification, the debris deposits in fault depressed lacustrine basin were studied in detail. The results show that the northern part of Luanping Basin in the Xiguayuan Formation was affected by the boundary fault activity, and the nearshore subaqueous fan deposition system of the typical fault basin was developed. According to outcrop observation and research, three sub- facies including root fan, mid fan and fan end can be identified. Among them, the root fan sub- facies are characterized by the fact that the detrital clasts directly enters the lake, the lithology is coarse, the sorting is extremely poor with no rounding. The mid fan adopt the division method of “subaqueous channel micro- facies” and “marginal micro- facies”. The micro- facies of the subaqueous channel sediments were controlled by two different fluid properties of debris flow and turbidity flow that developed simultaneously. The boundary is clear and slightly scoured, the lateral continuity is relatively stable, the gravel has a certain orientation, the rounding is poor, and it is best developed in the mid fan.The marginal facies are relatively mixed, the boulders are more common, and the obvious plate is visible. Interlaced bedding, poor lateral continuity, indicating diversion or marginal deposition by rivers, and no development of erosion- filling structures. The fan end sub- facies are characterized by thin- interbedded sandstone or thick layer of fine sandstone, showing bioturbation structures and fine gravel layers. The microfacies division method has a causal basis. The research results provide a new idea for the identification of nearshore subaqueous fans in similar basins. The underground research and will be conducive to oil and gas exploration and development.

Abstract:Based on a comprehensive research on several sections of the Hongguleleng Formation in western Junggar, the boundary between the Hongguleleng and Heishantou Formations was proposed at the disappearance of calcareous clastic rocks and the appearance of dark finegrained volcanoclastic rocks. The uppermost part of the Hongguleleng Formation is a suite of clastic rocks (calcareous siltstones with ‘ Lingula ’, tuffaceous sandstones, granule conglomerates, or sandy conglomerates with shellsdeposited in the backshore environment, and is named the “Yangzhuang Sandstone”. The boundary between the two formations can be easily identified and correlated in many stratal sections. Nine genera (or subgenera) and 14 species of trilobites were collected from the upper part of the Hongguleleng Formation and the lower part of the Heishantou Formationincluding Omegopssp. Pudoproetussp. Linguaphillipsia sp. Belgibole sp. B.abruptirhachis Philliboloides sp. , Winterbergia（W. ） sp. , W.（Eowinterbergia） ? sp. , Weberiphillipsia sp. , Conophillipsia sp. 1, C . sp. 2, C . ? sp. 3, C . ? paucicostata , and C . ? morganensis . According to the biostratigraphy of trilobitesthe DevonianCarboniferous boundary was established in western Junggar and is placed between the disappearance level of Omegops and the appearance level of the BelgiboleConophillpsia assemblage zone. The DevonianCarboniferous boundary is in accordance with the boundary between the Hongguleleng and Heishantou Formations. The “Yangzhuang Sandstone” resulted from a sealevel fall event that happened at the end of Devonian in the islandarc context, and is also the embodiment of the Hangenberg event during the DevonianCarboniferous transition in western Junggar.

Abstract:The cuticular features are important for identification and classification of fossil plants, and also helpful in reconstructing palaeoclimate during geological history. It is important to choose the appropriate experimental technology for obtaining better characteristics of cuticle features for the fossil plants with cuticles. In this paper three different methods namely Aqua regia and NaClO maceration method, NaClO maceration method, and HNO3 maceration method were used to obtain cuticles from fossil plants of different geological ages. The results show that the Aqua regia and NaClO maceration method is suitable for the fossil plants in sandy mudstone. The NaClO maceration method is suitable for the fossil plants in mudstone of coal bed or coal- accumulating period, and the HNO3 maceration method is suitable for the fossil plants in gray- white or diatomite mudstone. The three kinds of maceration methods used in this paper can either be selected according to the specific conditions of fossil materials in the study of plant cuticles or all three methods can be tried at the same time to obtain the best experimental results. This study summarizes the effect of three methods on fossil plant cuticles in different geological ages, and aims to provide an effective experimental approach to studying the cuticular features of fossil plants.

Abstract:In order to explore the joint inversion effect of GPS and cross- fault crustal deformation data, this paper takes the Xianshuihe fault as the research object. The study analyzed and contrasted the difference between joint inversion result and GPS inversion result and the deformation characteristics and seismic hazard of the Xianshuihe fault zone. The horizontal velocity data of GPS in China from 1999~2007, 2009~2013 and 2013~2017 were used, and the Bayesian inversion procedure was applied to estimate the movement rate of the Xianshuihe fault by using the cross- fault data as a priori condition. We compared individual GPS data inversion results with joint inversion results. It was found that the difference between near- field and far- field rates in the inversion image is more significant after the cross- fault data is added. The rate of fault activity varies significantly in different periods, especially during the deformation adjustment process after the Wenchuan earthquake. However, the effect of this method for pre- seismic is not obvious, especially the reverse strike- slip characteristics of part of cross- fault sites before the Wenchuan earthquake are difficult to show, and it is difficult to play a dominant role in earthquake prediction. But in general the analysis of fusion inversion analysis can be more intuitive to reflect the difference in velocity between the fault in the near and far fields. Finally, according to the above research method, after the Wenchuan earthquake, the left- lateral strike- slip rate has basically recovered to the pre- earthquake state by years of stress adjustment, and the southern section of the Xianshuihe fault continues to stretch. The clockwise rotation of the Sichuan- Yunnan block continues to strengthen. In addition, the Daofu section and the Moxi section of the Xianshuihe fault are at a certain slip- rate loss. It is necessary to pay attention to the seismic hazard and the correlation of earthquake risk in these two areas.

Abstract:An MS5. 0 earthquake occurred in Jinkouhe in 2015. In order to reveal the internal relationship and dynamic background between the earthquake and the in- situ stress, the in- situ stress measurement data of hydraulic fracturing in two boreholes about 12km away from the epicenter were analyzed and studied, the stability of faults in the northern Ebian- Jinyang fault zone is analyzed by using by Byeerly’s criterion and stress Mohr’s circle, and the dynamic background of the occurrence of the Jinkouhe earthquake is discussed in combination with the value of seismicity parameter b. The results show that, within the depth of 94.90 to 722.10 meters, the maximum horizontal principal stress is 5.89 MPa to14.50 MPa, and the minimum horizontal principal stress is 3.79 to 10.30 MPa; that the maximum horizontal principal stress direction is N50° W to N68° W, which tends to be Northwest to West direction, consistent with the regional tectonic stress field; that the relative magnitude of the triaxial principal stress of YJP- 1 borehole is favorable for the activities of reverse fault and strike- slip fault, while the relative magnitude of the triaxial principal stress of DPS- 1 borehole is favorable for the activities of normal fault; that the average value of μm (ratio of maximum shear stress to average stress) under the effective stress condition of DPS- 1 borehole is 0.46, which is close to the lower limit of fault friction sliding threshold of 0.51, and is favorable for normal fault sliding, and that the stress locking concentrated area in the bending structure of Emei- Yanfeng fault is the main reason for the weak horizontal structure near the borehole. The research results are of great significance for revealing the dynamic background before the Jinkouhe MS 5. 0 earthquake.

Abstract:This work aims to study the factors influencing dynamical changes in karst springs using Jinan area as an example. The study calculated the fractal dimension values and stability index of longterm multivariate data using time series fractal method. The database included the monitoring data of spring water level, rainfall, groundwater exploitation and artificial recharge in the Baotu and Heihu springs since the closure of groundwater supply source in 2003. The results show that the fractal dimension values of spring water level on a tenday scale are larger than that of the spring water level on a monthly scale. The fractal dimension of precipitation at rainfall stations in Ordovician limestone distribution area is smaller, but better precipitation infiltration and recharge conditions result in a closer relationship to spring water level fluctuation. Among the factors influencing the spring water level, the stability of recharge factor is the worst as it is highly vulnerable to the interference from external factors. The grey correlation degree was used to validate and analyze the degree of association between rainfall, artificial exploitation, artificial recharge with water level of the Baotu spring, which are 0. 858, 0. 647 and 0. 667 respectively, and the degree of association with water level of the Heihu spring are 0. 859, 0. 646 and 0. 668 respectively. The overall order of correlation degree is rainfall>artificial recharge>artificial exploitation, indicating that the atmospheric precipitation, not artificial exploitation, is the primary factor affecting spring water level dynamics since 2003. Based on the analysis of the evolution of spring resources, the regression analysis of fractal dimension and dynamic dimension of spring water level shows that the Ordovician limestone area is more suitable for artificial recharge of spring water. The results provide a reference for the protection of the Jinan karst spring.

Abstract:Thermal- infrared spectroscopy (6~4 μm) is a new environmental- friendly technology for ore exploration. It aids mineral mapping and ore exploration through the analysis of spectral characteristics of minerals. Compared with the short- wave infrared (SWIR) technology at wavelength of 11~25 μm, it was more sensitive for minerals such as quartz, feldspar, garnet, olivine, pyroxene, carbonate minerals, biotite, amphibole, apatite etc. However, little research on the thermal- infrared spectroscopy of minerals and its application in ore exploration has been conducted. Components of minerals was the main factor for spectral variation, which was the foundation for mineral identification and mapping. In this paper, spectra of typical minerals at thermal- infrared wavelength were obtained from different spectral libraries and literature, and the diagnostic and identifiable characteristics of these minerals were summarized. Then thermal- infrared technology were divided into two categories (field thermal- infrared spectroscopy and air- borne thermal- infrared image), and recent developments in their application in geological ore exploration were analyzed. Field thermal- infrared spectroscopy was based on spectra analysis of huge field outcrop samples or drill hole samples, which guided mineral mapping and ore exploration. Air- borne thermal- infrared technology was mainly based on the processing of thermal- infrared images, which generated the mineral mapping results. Finally, the challenges and exciting areas in the development of thermal- infrared technology were predicted, which include development of thermal- infrared instruments with higher precision, identification technology ofminerals from thermal- infrared spectra, optimization of mineral information extraction algorithms based on thermal- infrared images.

Abstract:Carbonate oil and gas reservoirs occupy an important position in the world's oil and gas reservoirs. The quantity of oil and gas in the carbonate reservoir accounts for about 70% of the total quantity of oil and gas in the world. The characteristics of carbonate reservoir are deep burial, strong heterogeneity and complex structure. It is an urgent issue to obtain the exact location and structural characteristics of carbonate reservoir in oil and gas exploration. Accurate seismic wave theory is applied in prestack reverse time migration, which can image any complex structure in high precision theoretically. To address the difficulty of carbonate reservoir imaging, the anisotropic prestack reverse time migration is studied and applied to the exploration of carbonate reservoir in this paper. First, the pure qP wave equation in anisotropic media is derived by using the accurate dispersion relation. The pure qP wave in anisotropic media is then simulated by using the high- precision finite difference method, and the pure qP wave is imaged using the anisotropic prestack reverse time migration method. Based on the actual geological conditions of typical carbonate reservoirs, a geophysical model of carbonate rock is established, which is close to the real geological conditions. The numerical results of the above model show that the anisotropic prestack reverse time migration is an effective exploration technique for carbonate reservoirs. The field data results further verify the important role of the anisotropic prestack reverse time migration in carbonate reservoir exploration.

Abstract:The sea- land transition zone is a complex and intersecting geographical unit, and is the area with the most superior resources and environment conditions. It is of great significance to integrate airborne gravity and ground gravity to form continuous gravity field data for resources and environment assessment of sea- land transition zone. In this paper, Rizhao- Lianyungang sea- land transition was selected as the demonstration areato carry out the research on the fusion of airborne gravity data and ground gravity data.Through data sorting and comparative analysis,the determination method of system difference between data is summarized, and anevaluationmethod of consistency and difference between airborne gravity and ground gravity is put forward, and the consistency and difference between data are quantitatively evaluated in two forms of section and plane respectively;Base on the quantitative evaluation of data, plane root mean square error method is used to evaluate the blend method and suture method respectively, which provides a quantitative basis for the selection of data fusion methods.The research results show that the airborne and groundgravity data in Rizhao- Lianyungang area have good consistency. The consistency coefficient range is 0.81~0.99 in profile, and the consistency coefficient is 0.95 on the surface.The comparative test shows that the seam method is better for the air ground gravity data fusion in the sea land transition area, and the gravity number after seam fusion is adopted. The standard deviation between the fusion data and the original airborne gravity data is 2.63×10 -5 m/s 2 ,and standard deviation between the fusion data and the original ground gravity data is 0.98×10 -5 m/s 2 ,which achieves good good fusion effect. The airborne gravity and ground gravity data fusion in Rizhao- Lianyungang sea land transition area provides a reference for similar areas to carry out multi- source gravity data fusion.