A new species,Scarburgia baiyanghensis sp.nov. was reported from the Middle Jurassic Xishanyao Formation of Baiyanghe, the Junggar Basin in Xinjiang,northwestern China. The new species is characterized by fertile appendages (megasporophylls) arranged helically,each composed of a short stalk expanding into a pointed ovate scale,stalk attached to axis at a wide angle, curved up near the apex,a single rounded or ovate seed borne on upper surface of scale and partly covered by scale tissue. The characters show the new species is different from other known species of Scarburgia. It is known that very limited species of Scarburgia are reported in China and most of them are collected in the Early Cretaceous deposits. Therefore, the discovery of the present new species provides new fossil record in the Middle Jurassic age.

Taking the mudstone cap rocks in the 2nd and 3rd Members of Qingshankou Formation in Hada Mountain of Songliao Basin as an example, the authors studied the major elements and trace elements of rare earths in mudstone samples by combining the petrological and geochemical methods. The results show that: ①Mudstone has high amount of rare earth elements (104.99×10^-6～281.88×10^-6), high ∑ LREE/HREE ratio(6.50～9.96),and REE distribution patterns show enrichment in light rare earth elements and depletion in heavy rare earth element, with negative Eu anomaly(0.88～1.16); ②Source rock types are mainly sedimentary rocks and intermediate-basic volcanic rocks, the origin of potassium metasomatism of source rocks is likely related to the conversion of clay minerals from mixed-layer illite/smectite to authigenic illite; ③The revised CIA value(44.75~72.24)of provenance mudstone is low, suggesting that the provenance experienced weak weathering, and Sr/Cu value indicates that provenance was controlled by dry and hot climate for a long time.

The volcanic rocks in Manitu Formation of Suolun area are composed of andesite, trachy-andesite and dacite petrographically,but they are mainly basaltic andesite or trachy-andesite with minor rhyolite based on chemical composition. Zircon U-Pb dating results show that they formed in Early Cretaceous from 130 to 132 Ma. These volcanic rocks belong to high-K calc-alkaline series. They are high in total rare earth elements (∑REE=95.19×10^-6～198.38×10^-6), with high LREE/HREE(6.38～10.59) and negative Eu anomalies (δEu=0.68～1.01). The volcanic rocks are enriched in LILE(K, Rb, Th)and LREE, but depleted in HFSE(Nb, Ta, P, Ti). Trace elements are characterized by high Sr (>499×10^-6), low Yb (the maximum is 2.83×10^-6, <3.6×10^-6) and Y (majority <29.9×10^-6), and high ratio of Sr/Y and low ratio of Rb/Sr, indicating the characteristic of arc volcanic rocks. The volcanic rocks have positive values of ε_Hf(t) (7.3～13.7), and the initial ¹⁷⁶Hf/¹⁷⁷Hf ratios for magmatic zircons is 0.282 964, suggesting that the andesitic magma of Manitu Formation was derived from the lithosphere mantle and partial melting of newly accreted lower crust, and is affected by the subduction fluid. Volcanic rocks of Manitu Formation formed in the island arc tectonic environment caused by the subductions of the Paleo-Pacific Plate beneath the Eurasian continent.

Huzhong volcanic rock belt lies in the northern part of Greater Khingan Range. Tamulangou Formation, which is one of the earlier phases of the eruption, is mainly composed of intermediate-basic volcanic rock. Zircon U-Pb dating shows that the Huzhong volcanic rock formed in the Late Jurassic (154±1 Ma). SiO₂ content of Huzhong volcanic rock is 49.80%~55.96%, Al₂O₃ is 16.70%~18.93%, Na₂O+K₂O is 6.35%~9.11%, belonging to intermediate-basic high alumina alkaline rocks. The volcanic rocks are enriched in large ion lithophile elements Ba, and depleted in Nb, Ta, with Nb/Ta=12.44~15.58. The changes of Huzhong volcanic rock element contents and their ratios indicate that the basaltic magma of Tamulangou Formation is influenced by crust-derived material during fractional crystallization process. The formation was formed in the plate margin arc orogen environment related to the subduction of Paleo Asian Ocean plate and (or) Mongolia-Okhotsk Ocean plate.

The zircon LA-ICP-MS U-Pb isotopic dating of sandstones in Buyant Group in Holingola area of Inner Mongolia has been presented. The results from 112 sampling points show that the main peaks of yield ages are 257 Ma, 283 Ma, 313 Ma and some older ages(>1 700 Ma). The zircons with a peak age of 257 Ma indicate that the depositional age of the sedimentary rocks was Early Triassic, which means that Buyant Group should be assigned into Lower Triassic, rather than Lower Proterozoic. The provenance of the sandstones are mainly the volcanic rocks of Dashizhai Formation, the Sunidzuoqi-Xilinhot-southern Xi Ujimqin volcanic arc and the metamorphic basement of the adjacent block, and partly from the northern margin of the North China Plate. It is indicated that the collision between the northern margin of North China Plate and the blocks to the north began in Early Triassic.

Based on the study of Jifanggou rock group,the authors confirmed that it is a set of structure strata which is composed of tectonic slices. By collecting two samples (Pm001-6-2, Pm001-7-4) in the behind the Xiawazi of Shanghewan in Jiutai County, which is the original Jifanggou rock group metamorphic acid-intermediate acidic volcanic rocks, the authors obtained the zircon LA-ICP-MS U-Pb age of(389.4±3.0)Ma and(388.3±3.9)Ma, determining that there exists volcanic rock formation of Givet Period of Middle Devonian in Jilin Province. Integrating the correlation with volcanic rock formations in Inner Mongolia, Heilongjiang and Songnen massif, it is concluded that in the southern margin of Jia-Meng massif from Laotudingzi-Baoquan-Xiawazi-Fang-niugou through Songnen Basin to Mandula, there exists a volcanic rock belt in late Early Devonian- early Late Devonian.

Petrography, geochemistry and LA-ICP-MS U-Pb dating of Beigou granites have been obtained in central Jilin of the northern margin of North China plate. LA-ICP-MS zircon U-Pb dating indicate that the granites from Beigou pluton formed during the later period of Middle Permian(~263 Ma). Beigou granites belong to calc-alkaline, metaluminous I-type granites with high K₂O content. They show strong enrichment in LREEs and LILEs (Cs,Ba,K and Sr), depletions in HREEs and HFSEs (Nb, Ta and Ti), with geochemical characteristics of adakite. The primary magma for Beigou pluton could be mainly derived from partial melting of the thickening mafic lower crust. The emplacement of Beigou pluton indicated that the initial collision in central Jilin between the north-eastern margin of the North China Plate and the Songnen terrain occurred during the later period of Middle Permian.

LA-ICP-MS zircon U-Pb dating and geochemical data of Simuke porphyritic syenogranite have been studied.The results indicate that the diagenetic age of porphyritic syenogranite is (144±0.85)Ma,belonging to Late Jurassic.The geochemical study shows that the porphyritic syenogranite belongs to high-K calc-alkaline series and high aluminum rocks. The rare earth elements are characterized by rich light rare earth elements and significant fractionation of LREE and HREE[(La/Yb)_N=3.15～6.63].The REE distribution patterns are right deviated, with weak negative europium anomalies(δEu=0.54～0.66). For trace elements, the porphyritic syenogranites are enriched in Rb and K,but depleted in Nb,Ta,P and Ti.The porphyritic granite in Simuke area is high differentiation I type granite,derived from partial melting of basic volcanic rocks in the crust.Based on Nb-Y tectonic environment discrimination diagram and tectonic environment,combined with the characteristic of I type granite,the porphyritic granite in Simuke area should be the product of extensional tectonic system and it is formed in post-orogenic extensional tectonic environment.

The authors analyzed zircon geochronological data and geochemical data of Zhushan metagabbro from Yilan, eastern Heilongjiang to determine their age, petrogenesis and tectonic setting. Zircons from metagabbro are euhedral-subhedral in shape with typical striation absorption features and high Th/U ratios (0.20~0.86), implying their magmatic origin. LA-ICP-MS zircon U-Pb dating shows that Zhushan metagabbro from Yilan formed during Late Permian with age of (256±3)Ma. The geochemical characteristics show that these metagabbros are low in silicon and high in magnesium, iron, aluminum and calcium. The rocks are enriched in LREEs and LILEs (Rb, Ba), and depleted in HREEs and HFSEs (Nb, Ta, Zr, Hf and Ti). Combined with the regional geological data, it is proposed that Zhushan metagabbro was derived from a mantle wedge that had been metasomatized by subducted slab-derived fluids. Its formation was probably related to the subduction of a paleo-oceanic plate, which implies that the collision between the Jiamusi Massif and the Songnen Massif may have not happened before Late Permian.

LA-ICPMS zircon U-Pb dating and geochemical data of meta-basic volcanics of Baiyinnuoer region from Wenduermiao area in central Inner Mongolia were studied. The results indicate that the meta-basic volcanics formed in (254.8±6.2)Ma, belonging to Late Permian. Meanwhile, geochemical studies show that the meta-basic volcanics belongs to sub-alkaline tholeiitic series. The rocks were obviously depleted in (LILE) Ba, Rb, Sr and rich in (HFSE) Nb and Zr, with positive anomalies of Eu. Geochemistry analysis shows that meta-basic volcanics are very similar to E-MORB, and the magma was derived from enriched lithospheric mantle. Combining with the geology features the rocks should belong to the ophiolite component, which indicates that Paleo-Asian Ocean has not been closed in the Late Permian and the closing time of Paleo-Asian Ocean should be later than the Early Triassic.

Based on the study of petrography, zircon U-Pb chronology and geochemical data, the authors determined the formation age, petrogenesis and tectonic setting for the basic-ultrabasic complex from Gushanzi. The complex is mainly composed of pyroxenite and hornblende pyroxenite. The geochemical analysis results show that the complex is enriched in MgO (4.54%~13.25%), low in SiO₂ (34.28%~49.22%), and K₂O>Na₂O, which belong to alkaline series. Chondrite-normalized rare-earth element pattern shows that the rocks are enriched in light rare-earth element, the ratio of (La/Yb)_N=8.14～36.19, with light Eu anomalies. These rocks are characterized by enrichment in LILE (Rb, Ba,K)and LREE(La, Ce), relatively depletion in HFSE(Nb, Ta, Ti)and HREE. The ratios of Nb/U, Ce/Pb and La/Sm indicate that the complex experienced limited crustal contamination. LA-ICP-MS U-Pb dating results of zircons from Gushanzi complex can be separated into three groups. The first group is with U-Pb age of(1 392±10)Ma, which is detrital zircons captured during the emplacement of ultrabasic intrusion. The second group is with U-Pb age of (274.5±2.1)Ma, representing the formation age of ultrabasic rocks. The third group is with U-Pb age of (53.02±1.1)Ma, which are typical hydrothermal zircons. These rocks are derived from partial melting of depleted mantle wedge modified by subduction-related fluids from the subduction of Paleo-Asian Ocean crust during Paleozoic and crustal contamination. Combined with the research of regional tectonic evolution, the authors conclude that the complex was formed after the closure of the Paleo-Asian Ocean in a tectonic setting of transition from compression to extension.

Panzhihua Permian volcanic rocks consist of basal and alkaline ends of basalt and trachyte, and the intermediate transitional types are absent. SiO₂ content in the basalt ranges from 45.65% to 49.32%, while SiO₂ content in the trachyte ranges from 64.39% to 69.17%, which constitute the classic “bimodal” volcanic assemblages. Both basalt and trachyte are enriched in Na and light rare earth elements, but depleted in K, with obvious light and heavy rare earth fractionation. In addition, the variation in typical trace elements ratios of Nb/Ta, Th/Ta, and Th/U is relatively small, the ratios in the basalt are 15.16, 2.70 and 4.13, and that in the trachyte are 15.40, 2.55 and 4.12, respectively, indicating that they have similar geochemical properties. Trace element characteristics show that, except minor high field elements like Ti and Y that are not consistent, changes of most trace elements in the basalt and trachyte are similar, and characteristics of Rb, Ce, Y, Nb, Hf and Ta is consistent with that of Ocean Island basalt (OIB), which indicate that the Panzhihua volcanic rocks are with magma property from mantle column structure system, and magma stemmed from partial melting of garnet lherzolite lithosphere mantle. Combined with the previous studies, the determination of the Permian bimodal volcanic rocks in Panzhihua not only implies that the magma was formed in the extensional rift tectonic environment, but also supports that the origin of the Permian Emeishan igneous province in southwest China is related to mantle plume.

Sandaowanzi gold deposit is a typical gold telluride minerals deposit, located at the northern edge of the Xiao Xing'an range, NE China. In order to reveal the ore-forming geological setting, the authors recently conducted studies on geochronology and geochemistry of volcanic rocks hosting the deposit. The results show that the zircon U-Pb ages of the trachydacite porphyry from the syn ore-forming geological bady and basaltic trachyandesite porphyry from ore-forming rock are (124.2±0.9)Ma (MSWD=0.5, n=18) and (118.9±2.3) Ma(MSWD=0.5, n=6); Volcanic rocks from the basaltic trachyandesite and trachydacite porphyry are high in SiO₂ (52.75%～62.30%), and the K₂O and Na₂O are 2.02%～2.85% and 3.96%～4.24%, respectively; Rittman index (δ) is between 0.85 and 3.67, which belongs to the high-K calc-alkaline to calc-alkaline series; the dike of basaltic trachyandesite porphyry formed after mineralization is with SiO₂ of 51.53%～52.32%, K₂O of 2.30%～2.36%, Na₂O of 3.78%～4.14%, and Rittman index (δ) is between 4.05 and 4.86; these rocks are characterized by enrichment in large ion lithophile elements (LILEs, such as Cs, K, Rb, Ba, and LREEs) and depletion in high field strength elements (HFSEs, such as Nb, Ta, Zr, Hf, and HREEs), especially the features of strong positive Th, U, Nb, and Ta, which is similar to the calc-alkaline island arc basalt. It is concluded that the Sandaowanzi gold deposit formed in the Early Cretaceous (124～119 Ma) or Late Mesozoic post-collision extensional setting. The source may be the oceanic lithosphere mantle, which was mixed with crustal material in magma evolution, and the mineralization is closely related to the Early Cretaceous subalkalic volcanic-rocks.

LA-ICP-MS U-Pb zircon geochronology of Huoluotai granodiorite of Daxing'anling area in Heillongjiang Province shows that Huoluotai granodiorite (145 Ma) results from magmatic intrusion of Early Cretaceous. The composition of elementary geochemistry indicates that it is a set of adakitic rocks characterized by high-K calc-alkaline series, with a high content of SiO₂ (65.64%~66.00%) and K₂O (3.67%~3.77%), low MgO (0.09%~1.21%), high content of Sr (814.00×10^-6~893.00×10^-6), low Yb (0.194×10^-6 to 0.536×10^-6) and Y (6.38×10^-6 to 7.73×10^-6), and obvious differentiation of light and heavy rare earth elements (10.1~14). The characteristics of La/Yb (92.54~245.88), Th/La (0.17~0.2), Th/U (4.01~4.84) and Mg^# (26.70~29.22) show that the Huoluotai granodiorite was formed by partially melting of the thickened lower crust. Combined with regional tectonic evolution, it is concluded that the Huoluotai granodiorite originated from the transition process of crustal thickening compression to extension under the influence of Mongolia-Okhotsk tectonic system.

A series of strike-slip thrust faults were found in Yehe of Siping, exhibiting features of flat and steep-dipping fault planes with strikes ranging from NNE15°~35° and distributing in an echelon pattern. These faults form the branch faults between the two major boundary faults of Jiamusi-Yitong. The branch faults intersect the major faults with striking of NE 45° at an acute angle, indicating that the boundary faults have a dextral strip slip characteristic. The discovery of the strike-slip thrust fault zone in Yehe provides a new evidence for the strike-slip thrust event during late-end Late Cretaceous in the Jiamusi-Yitong fault. Yehe branch fault zone is the southern extension of the Shiling branch fault zone. Intersecting same strata, possessing identical structural characteristic and tectonic attribute and belonging to one strike-slip thrust system, the two fault zones are produced in the same geodynamic background in the late-end Late Cretaceous.

Yangbishan iron deposit in Heilongjiang is located in the middle of Jiamusi Massif. The iron formation belongs mainly to the first segment of Dapandao Formation of Xingdong Group. The iron formation is composed of garnet-mica-quartz schist, sillimanite-biotite-quartz schist and gneiss, indicating that it can be classified as the khondalite series. The protolith of khondalite series reflect its neritic shelf sedimentary setting. The magnetite is the main metal mineral in ore, of which a minor amount was replaced by late pyrite. Quartz and sillimanite are the main nonmetallic minerals and both are in orientational arrangement. The iron ores in the Yangbishan deposit is predominantly banded, with minor massive. According to ore-forming geological condition and deposit characteristics, the Yangbishan ore deposit can be defined as Superior-type BIF. LA-ICP-MS U-Pb dating has been carried for detrital zircon grains from the ore-hosting sillimanite-biotite-quartz schist. The dating results can be listed as four groups, 1 006~1 212 Ma, 1 238~1 480 Ma, 1 521~1 742 Ma and > 1 800 Ma, respectively. The age of 1 006~1 212 Ma, the minimum age group, determines the sedimentary age of iron formation in Yangbishan iron deposit. The major age group (1 238~1 480 Ma) reflects the main rocks in erosion area are Mesoproterozoic magmatic rocks. While the two oldest zircons (2 672 Ma, 2 711 Ma) hold the conclusion that there developed the Archean crystalline basement in Jiamusi Massif. Combined with the previous research results of Mashan Group, it is concluded that the Xiongdong Group is the underlying strata of the Mashan Group in Jiamusi area.

The ore-hosting intrusion of Guzhonggonglu molybdenum deposit is the fragmented silication gneissic monzogranite, and the alterations are distributed in belt. The metallogenic process can be divided into K-feldspar+quartz, quartz+molybdenite and quartz+pyrite stages. The Re-Os isotope model age of two molybdenite samples are (142.4±2.9)Ma and (142.3±2.0)Ma, respectively, indicating that the deposit was caused by the Early Cretaceous tectonic-magmatic activities. The content of Re in the molybdenite are 11.894×10^-6 and 11.584×10^-6, respectively, suggesting that the ore-forming materials are mainly derived from the crust, and probably affected by the mantle. The preliminary study of fluid inclusions demonstrates that the fluid inclusions in the quartz are mainly gas-liquid two phase inclusions, secondly gas-liquid-solid three phase inclusions, minor CO₂-bearing three phase inclusions. The homogenization temperature of all type of inclusions are of 196.3~>450℃, while the salinities can be divided into two groups: 0.18%~12.62% and 45.33%~>53.26%. Thus, the ore-forming fluid belongs to the medium-high temperature, and high salinity NaCl-H₂O-CO₂ fluid system, and the fluid boiling might occur during the ore-forming stage and be the major metallogenic mechanism. Combined with the characteristics of ore-forming conditions, ore deposit geology and fluid inclusions, the study indicate that the Guzhonggonglu molybdenum deposit is of porphyry type, and formed under a regional extension tectonic settings.

In order to determine the prospecting potential of Kaoshantun silver-lead polymetallic deposit in Inner Mongolia, the authors extracted the geology, aeromagnetic excitation and geochemical prospecting information. The results show that the Kaoshantun silver-lead polymetallic deposit is a medium scale of deposit which mainly contain silver accompanied by lead and zinc, which occurs in both of moyite in Early Cretaceous and tuff in Late Jurassic. The alteration and mineralization characteristics show that the genetic type of the deposit is medium hydrothermal vein type. The volcanic rocks in Upper Jurassic Manitu Formation are rich in Pb and Ag, and are favourable ore hosting rocks. The faults near the volcanic rocks and rock contact belts are favorable ore controlling structures, and the phyllic alteration and silicification are closely related to the alteration of surrounding rocks. The diverse uplift occured after mineralization, the mineralization in the middle and northeast of the exploration area is mainly galena and associated silver minerals, and the deposit was well-preserved as alteration belt Ⅱand alteration belt Ⅲ. The southwest of exploration area is mainly sphalerite (chalcopyrite), with high degree of denudation, for example alteration beltⅠ, which is characterized by medium-high polarization, low or high resistance, low-high magnetic anomaly. The anomalies are good identity of concentration for Pb, Zn, and Ag elements, with large abnormal area of Pb and Ag. The KHt4-11 distribution with high abnormal intensity has a good preservation condition and prospect. The Zn anomaly area is large, and the abnormal distribution of Pb and Ag anomaly in the outside of the KHt1 and KHt3 distribution area is large with poor prospecting potential.

Based on the survey of 1:50 000 regional mineral survey in Xiaoshan area from 2010 to 2014, the authors systematically summarized the metallogenic conditions and geological characteristics of the study area. Combined with the regional geology, geophysical exploration, geochemical exploration and remote sensing,using analogy theory, comprehensive metallogenic information and metallogenic model theory,the authors established a comprehensive information prospecting model. According to the prospecting model, six prospecting targets were designated, of which two are in grade A, two are in grade B and two are in grade C.

Reservoir space types and controlling factors of alteration of Yingcheng Formation volcanic rocks in Xujiaweizi depression were studied by core data, thin sections and scanning electric microscope. Based on chemical alteration index (CIA), clay mineral test and rock mineral characteristics, the intensity of alteration is divided into three types: weak alteration(CIA<50), moderate alteration(50< CIA< 60)and strong alteration(CIA>60). The types of diagenesis related to alteration include: devitrification, dissolution and filling. It is indicated from this research that more secondary pores were developed with the increasing of alteration intensity, devitrification of matrix and clay mineralization of rocks. Devitrification and dissolution can also improve the reservoir properties. Although cavity filling apparently reduced the reservoir properties, there are intergranular micropores in the infilling of clay minerals, which still has a certain reservoir performance.

The rock slides of Chengzihe and Muling formations in Jixi Basin were studied under the microscope, and samples with a great number of fluid inclusions were chosen to make inclusion slides. The homogenization temperature test of fluid inclusion was subsequently performed on the freezing and heating stage.By analyzing the testing temperature data in combination with the burial history and thermal history of Jixi Basin, the oil and gas migration periods and accumulation stages of Chengzihe and Muling formations in Jixi Basin were discussed.The results showed that two stages and four episodes of hydrocarbon migration and accumulation occurred in the study area, which could be divided into two periods of 80~77 Ma and 45~38 Ma.There were three episodes of oil and gas migration in Chengzihe Formation,the filling time was 80 Ma, 45 Ma and 38 Ma, respectively, and there was one episode of oil and gas filling in Muling Formation in 77 Ma.The results of this study are consistent with two tectonic movements in the Jixi Basin:①Kula plate activity, in a period of 120~65 Ma, which had shaped China's mainland margin;②the earlier Himalayan movement in about 40 Ma in Eocene and Oligocene, both of which were accompanied by the migration and accumulation of oil and gas.

Tilt-depth method is a new inversion method for fast estimation of the top depths of magnetic bodies. Two- and three-dimensional model tests show that the inversion error of tilt-depth method is related to the top depth, thickness and horizontal scale of geological body. In addition, superimposed anomaly also has an effect on the inversion results. Tilt-depth method is applied to the aeromagnetic data over Xiazhuang ore field in Guangdong, and the authors find that two near EW-trending anomaly zones on tilt map are produced from deep ultrabasic diabase. Tilt-depth method is used to invert top depths of 11 inversion points on the two high magnetic anomaly zones in the tilt map. Based on the inversion results, the authors found that the depth of magnetic body located in the north of the Xiazhuang ore field is relatively shallow and is getting deeper from south to north, whereas the magnetic body in the south of the Xiazhuang ore field is relatively deeper and with larger scale. This important information is very useful for the deep mineral exploration.

Seismic signal denoising can effectively improve the signal-to-noise ratio and the resolution of the signal. The second-generation wavelet transform can denoise signal in different scales and resolutions and realize local analysis in which the window width can be adjusted adaptively. However, in the process of denoising, wavelet threshold method exhibits pseudo gibbs effect for discontinuous signal. This problem can be solved by the translation invariant threshold denoising method via translation-denoising-average. Therefore, based on the existing results on the second-generation wavelet transform and threshold denoising, translation invariant will be applied to the second-generation wavelet transform to denoise signal fast and effectively, and achieve good denoising result in the simulated data trial and real data trial.

In order to avoid the pseudo-frequency in the process of eliminating multiples and extracting velocity difference of hyperbolic Radon transform, which caused certain impacts on seismic data processing, the authors studied the curvature parameters and iteration numbers of least square hyperbolic Radon transform in time domain and figured out the optimum range of the parameter of 30 to 40 for curvature sampling and 6 to 10 for the iteration numbers. Synthetic model and real data tests show that proper setting of parameters could ensure the accuracy and reduce the computing time, which is beneficial for the application of hyperbolic Radon transform.

Full waveform inversion (FWI) is a highly non-linear optimization problem. When there is a lack of low-frequency components in the seismic data and the initial velocity is far from the true velocity, it is easily trapped into local minima. The authors propose a new objective function that combines the normalized cross-correlation of modeled and observed data with the least squares criterion. Cross-correlation emphasizes on phase matching and behaves in a more linear way, thus can mitigate the cycle-skipping issue. By setting a weighting factor, the authors use the cross-correlation norm to update the low-wave number components of the velocity model at the early stage of the inversion, while using the least squares criterion to update high-wave number details of the model. Numerical examples show that FWI based on the new objective function converges quickly toward global minima and does not rely on accurate initial velocity model as well as low-frequency information, it can improve the robustness of the inversion and generate more accurate inversion results than the conventional approach.

The ghost notches limited the frequency bandwidth and resolution of seismic records in variable-depth streamer data, which increase the difficulties of inversion and interpretation of seismic data. By suppressing the ghost, high-resolution broadband data can be obtained. Based on the de-ghosting method of flat-streamer in Radon domain, combining the characteristics of the ghost varied with offset, the authors derive the inverse transform operator for primary wave and ghost wave in frequency-Radon domain and build the new relationship between the total wavefield at the cable and the up-going wavefield at the sea surface. The up-going wavefield at the sea surface can be calculated by the least squares inversion method, and can be extrapolated to obtain the deghosted data at the cable. By considering the influence of emerging angle and offset on the ghost delay time, the error in the ghost delay time estimation is compensated. This method does not need to perform inverse iteration to obtain the optimal ghost delay time, which improves the computational efficiency. Test results on synthetic and field data show that the proposed approach can remove ghost better and broaden the bandwidth of seismic data.

Through the study of cross-correlation imaging conditions between wavefield decomposition and source-receiver bi-directional illumination, the authors combine the imaging advantages of two methods in the noise elimination and amplitude distortion compensation to increase the imaging resolution and improve the existing imaging conditions. The main procedures include separating source and receiver wave fields into one-way wave components and adopting bi-directional illumination compensation cross-correlation imaging condition to image the wavefields. Model trial validates that the imaging conditions proposed can effectively suppress noise and compensate imaging amplitude.

Shot separation process will inevitably lose some useful information, in order to solve this problem, the authors set up model experiments, which transformed blended acquisition data into frequency domain common offset gathers for F-K filter pre-processing, and suppressed most blended noises in the process of preserving seismic event. The authors then transformed the data to time domain common offset gathers for small window median filter, and designed iteration formula to undertake Curvelet threshold iteration denoising for common receiver point gathers. Separation results were finally obtained by constant iterations. Both simulated synthetic and field data certify that the deblended single shot record processed by this method is clear, and has good practical application value.

In order to estimate the nearshore suspended sediment concentration and the concentration of chlorophyll-a in South China Sea, the authors determined their sensitive wave bands and built the experience models based on Landsat-8 data. The results showed that Band 1, Band 2 and Band 4 in Landsat-8 data were sensitive to suspended sediment, and Band 1, Band 2 and Band 3 were sensitive to chlorophyll-a. However, the single-band model was not accurate enough to retrieve the concentration of suspended sediment or chlorophyll-a, therefore, a combination estimation model was established. The correlation coefficient, average relative error and inversion accuracy of suspended sediment concentration inversion model using Band 1, Band 2 and Band 4 were 0.904, 10.24% and 89.76%, respectively. The correlation coefficient, average relative error and inversion accuracy of chlorophyll-a concentration inversion model using Band 1, Band 2 and Band 3 were 0.886, 11.27% and 88.73%, respectively.

The Landsat 8 OLI data was used to extract hydrothermal alteration information of Changbai Mountain area by the ratio method and principal component analysis method. The extraction precision verified by the field investigation was 83.3%. Isometric partitioned weighted superposition analysis of statistical methods was used to achieve the quantitative analysis of the spatial relations between the distribution of hydrothermal alteration and the main fault zone. The results show a negative correlation between the intensity of the hydrothermal alteration and the distance from the fault, and the high intensity hydrothermal alteration occurred near the newly formed fault and intersecting zone of faults.