Structural relationships between the Neoproterozoic rock complexes of a continental massif， island arc and back- arc basin geodynamic affinities are described and considered in this work based on field observations within the northeastern segment of the Central Taimyr tectonic zone distinguished in the late Hercynian fold- thrust belt of Taimyr Peninsula． As is established for the first time，rock complexes of the continental massif with the early Late Ｒiphean (Tonian- Cryogenian) volcanogenic- sedimentary cover occur in the study region as the allochthonous syn-and post- sedimentary thrust sheets buried in or thrust over deposits of a back- arc basin， which accumulated in the terminal Late Ｒiphean (Cryogenian)- -initial Vendian (Ediacaran)． These and other results of the large- scale structural observations elucidate important details of the region tectonic development in the Late Precambrian，when two lateral ensembles of the Neoproterozoic structures originated in the region． In the first half of the Neoproterozoic，the regional tectonic ensemble included the oceanic plate abut on the conti- nental massif with a primitive volcano- plutonic belt． The subsequent system of an island arc and marginal back- arc basin originated in the second half of the Neoproterozoic and existed approximately till the mid- Vendian (Ediacaran) phase of the intense formation of thrust sheets in the region．

Zircon LA- ICP- MS U- Pb age，geochemical and Nd isotopic data are presented for a newly recognized high- Mg dioritic dike from Haicheng，Liaodong Peninsula，NE China，to constrain its petrogenesis． The zircons from the high- Mg diorite exhibit striped absorption and oscillatory growth zoning in the cathodoluminescence (CL) images，and have high Th/U ratios (0. 05- - 0. 9)，indicating a magma origin． Zircon LA- ICP- MS U- Pb dating indicates that 206 Pb/ 238 U ages of 12 spots of zircons are between 167 Ma and 178 Ma，yielding a weighted mean 206 Pb/ 238 U age of 172 ±2 Ma (MSWD =4. 1)，which represents the forming age of the high- Mg dioritic dike，i. e. Middle Jurassic． Geochemically，the samples have SiO 2 = 55. 4- -60. 6 wt. %，Na 2 O = 2. 2- -2. 76 wt. %，K 2 O =1. 32- - 2. 02 wt. % and (Na 2 O + K 2 O) =3. 82- - 4. 47 wt. %，belonging to sub- alkaline series and displaying a calc- alkaline evolutionary trend． They are characterized by high MgO(4. 75- - 6. 85 wt. %)，Mg# (55- - 61)，Cr(130- - 262 ppm)，Ni(63- - 130 ppm)，Sr(568- - 857 ppm)，and Ba(484- - 1 130 ppm) contents， with geochemical features analogous to those of high- Mg adakites． They show variable ε Nd (t) values ( －1. 3 to －3. 9)，with a weighted value of －2. 7，which plot intermediately between the field of the ancient continental crust and the depleted mantle source，indicating that both the lower crust and mantle source are necessary for the generation of the parent magma of the Haicheng high- Mg diorites． The Haicheng high- Mg dioritic dike in the Liaodong Peninsula and the Jurassic magmatism in the eastern North China Craton formed under a continental crustal thickening setting that may be related to subduction of the Paleo- Pacific oceanic plate．

Based on X- ray diffraction，optical microscopy and scanning electron microscopy analysis of the Dachang gold ore，it is showed that the sulfide of ore is the main carrier minerals of gold． A majority of gold is embedded in pyrite and tetrahedrite as the form of inclusion and a small amount intergrowth with pyrite and gangue mineral， occasionally the presence is in form of monomer natural gold． The main factors which influence the recovery rate are sulfide mineral particle size，and the fine grained sulfide is beneficial for the dissociation and flotation of gold bearing minerals． The monomer dissociation degree of gold bearing minerals can reach 91. 3%，when the grinding fineness is less than 0． 074 mm and grain level accounts as 80%． It is not condu- cive to the flotation of sulfide if the grinding fineness is low or high． It is difficult to completely dissociate the monomer if there is a small amount of pyrite and arsenopyrite in the ore． Therefore，before leaching the gold， it must conduct pretreatment to reach the ideal recovery rate of the gold，like roasting oxidation，pressure oxida- tion and biological oxidation． The fine microscopic gold has little influence on the gold recovery rate．

Based on introducing geological structure of Tanggu area，the authors analyzed the sedimentary envi- ronment of Paleogene Dongying Formation，and further analyzed its geothermal occurrence． The studied area spans two grade Ⅳ tectonic units which are Beitang depression and Banqiao depression． The studied area is mainly located in the Tanggu nose- like structure which is the secondary structure of Beitang depression． Its ex- istence affects the sedimentary distribution of the part strata of Paleogene． The depositions of Dongying Ⅲ (SQEd 3 ) and DongyingⅡ (SQEd 2 ) are mainly delta front facies and lake sand bars which are propitious to the geothermal fluid enrichment． The favorable enrichment region of geothermal fluid is located in south Hetou- Tanggu． Most of DongyingⅠ (SQEd 1 ) changes into swamp plain deposition， only the northeast part of this area is the distributary riverway facies with developed sand layers． There is the favorable enrichment region of geo- thermal fluid． The hydraulic connection is weak among the geothermal reservoirs of Dongying Formation and its overlying Guantao and Minghuazhen formations． The underlying Shahejie Formation geothermal reservoir pro- vides a steady stream of fluid supply and ground pressure protection for Dongying Formation geothermal reser- voir．

The excavation for the municipal tunnel will disturb the soil around the tunnel，and the deformation and subsidence of the earth surface always take place，which may lead to instability and even collapse for the building above the tunnel． At the same time the deformation and subsidence of the earth surface affect the nor- mal use of underground municipal pipelines，and may cause the road sudden collapse，leading to significantly traffic accidents． The authors did a research by simulating for the excavation of municipal tunnel and designed the related supporting plan，and put forward some suggestions and measures for the design and construction of urban tunnel．

According to the elements of hydrogeological conditions， lithology，stratigraphic thermal physical pa- rameters，construction technology and economic rational elements，the evaluation system of ground source heat pump (GSHP) were established in Baotou plain． The factor weights were determined by using analytic hierar- chy process， and the comprehensive element method was selected to evaluate the region suitability of GSHP sys- tem． The results show that the suitable area is 559． 63 km 2 for utilizing GSHP in the studied area，accounting for 62． 58% of the total area; while the unsuitable area is 334． 60 km 2 ， accounting for 37． 42%． The evaluating results can provide not only a scientific basis for development and utilization rationally of shallow geothermal heat in Baotou，but also offer an important reference to the other areas．

According to the chemical and mineral composition characteristics of the fly ash，alumina can be ex- tracted from fly ash through the calcining method by using sodium carbonate and calcium carbonate additives． The effects on leaching rate of alumina have been investigated． The results showed that the fly ash can be acti- vated effectively and the leaching rate of alumina can be improved to more than 92% through this method． The best process parameters were the ratio of raw materials，i． e． the material weight ratio of fly ash，calcium car- bonate and sodium carbonate was 1． 0∶1． 2∶0． 9． The activating temperature was 850℃- 900℃，activating time was 3 h． This process has a potential application prospect and improves the value of comprehensive utilization of fly ash．