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1.
The salt tectonics of the Glueckstadt Graben has been investigated in relation to major tectonic events within the basin. The lithologic features of salt sections from Rotliegend, Zechstein and Keuper show that almost pure salt is prominent in the Zechstein, dominating diapiric movements that have influenced the regional evolution of the Glueckstadt Graben. Three main phases of growth of the salt structures have been identified from the analysis of the seismic pattern. The strongest salt movements occurred at the beginning of the Keuper when the area was affected by extension. This activation of salt tectonics was followed by a Jurassic extensional event in the Pompeckj Block and Lower Saxony Basin and possibly in the Glueckstadt Graben. The Paleogene–Neogene tectonic event caused significant growth and amplification of the salt structures mainly at the margins of the basin. This event was extensional with a possible horizontal component of the tectonic movements. 3D modelling shows that the distribution of the initial thickness of the Permian salt controls the structural style of the basin, regionally. Where salt was thick, salt diapirs and walls formed and where salt was relatively thin, simple salt pillows and shallow anticlines developed.  相似文献   

2.
The Glueckstadt Graben is one of the deepest post-Permian structures within the Central European Basin system and is located right at its “heart” at the transition from the North Sea to the Baltic Sea and from the Lower Saxony Basin to the Rynkoebing–Fyn High.The Mesozoic to recent evolution is investigated by use of selected seismic lines, seismic flattening and a 3D structural model. A major tectonic event in the latest Middle–Late Triassic (Keuper) was accompanied by strong salt tectonics within the Glueckstadt Graben. At that time, a rapid subsidence took place within the central part, which provides the “core” of the Glueckstadt Graben. The post-Triassic tectonic evolution of the area does not follow the typical scheme of thermal subsidence. In contrast, it seems that there is a slow progressive activation of salt movements triggered by the initial Triassic event. Starting with the Jurassic, the subsidence centre partitioned into two parts located adjacent to the Triassic “core.” In comparison with other areas of the Central European Basin system, the Glueckstadt Graben was not strongly affected by additional Jurassic and Cretaceous events. During the late Jurassic to Early Cretaceous, the area around the Glueckstadt Graben was affected by relative uplift with regional erosion of the elevated relief. However, subsidence was reactivated and accelerated during the Cenozoic when a strong subsidence centre developed in the North Sea. During Paleogene and Quaternary–Neogene, the two centres of sedimentation moved gradually towards the flanks of the basin.The data indeed point toward a control of post-Permian evolution by gradual withdrawal of salt triggered by the initial exhaustion along the Triassic subsidence centre. In this sense, the Glueckstadt Graben was formed at least partially as “basin scale rim syncline” during post-Permian times. The present day Hamburger, East and Westholstein Troughs are the actual final state of this long-term process which still may continue and may play a role in terms of young processes and, e.g., for coastal protection.  相似文献   

3.
Gravity signals from the lithosphere in the Central European Basin System   总被引：1，自引：0，他引：1  
We study the gravity signals from different depth levels in the lithosphere of the Central European Basin System (CEBS). The major elements of the CEBS are the Northern and Southern Permian Basins which include the Norwegian–Danish Basin (NDB), the North-German Basin (NGB) and the Polish Trough (PT). An up to 10 km thick sedimentary cover of Mesozoic–Cenozoic sediments, hides the gravity signal from below the basin and masks the heterogeneous structure of the consolidated crust, which is assumed to be composed of domains that were accreted during the Paleozoic amalgamation of Europe. We performed a three-dimensional (3D) gravity backstripping to investigate the structure of the lithosphere below the CEBS.Residual anomalies are derived by removing the effect of sediments down to the base of Permian from the observed field. In order to correct for the influence of large salt structures, lateral density variations are incorporated. These sediment-free anomalies are interpreted to reflect Moho relief and density heterogeneities in the crystalline crust and uppermost mantle. The gravity effect of the Moho relief compensates to a large extent the effect of the sediments in the CEBS and in the North Sea. Removal of the effects of large-scale crustal inhomogeneities shows a clear expression of the Variscan arc system at the southern part of the study area and the old crust of Baltica further north–east. The remaining residual anomalies (after stripping off the effects of sediments, Moho topography and large-scale crustal heterogeneities) reveal long wavelength anomalies, which are caused mainly by density variations in the upper mantle, though gravity influence from the lower crust cannot be ruled out. They indicate that the three main subbasins of the CEBS originated on different lithospheric domains. The PT originated on a thick, strong and dense lithosphere of the Baltica type. The NDB was formed on a weakened Baltica low-density lithosphere formed during the Sveco-Norwegian orogeny. The major part of the NGB is characterized by high-density lithosphere, which includes a high-velocity lower crust (relict of Baltica passive margin) overthrusted by the Avalonian terrane. The short wavelength pattern of the final residuals shows several north–west trending gravity highs between the Tornquist Zone and the Elbe Fault System. The NDB is separated by a gravity low at the Ringkøbing–Fyn high from a chain of positive anomalies in the NGB and the PT. In the NGB these anomalies correspond to the Prignitz (Rheinsberg anomaly), the Glueckstadt and Horn Graben, and they continue further west into the Central Graben, to join with the gravity high of the Central North Sea.  相似文献   

4.
Thermal maturity information has been compiled for one of the deepest parts of the Central European Basin system, the Schleswig-Holstein area in northern Germany. New vitrinite reflectance data were obtained and old data were evaluated from a total of 31 wells. Furthermore, numerical 1D basin modelling was performed in order to interpolate/extrapolate vitrinite reflectance data to base Zechstein and base Keuper. For these two horizons, maturity maps were finally compiled revealing large differences in present-day thermal maturity within the basin. For example, vitrinite reflectance at base Zechstein ranges from greater than 4.5% in the Glueckstadt Graben to less than 1% in the northern part of the study area. Highest thermal maturity of base Keuper occurs in the West Holstein Trough and in the northern part of the Glueckstadt Graben. The timing of maturation is greatly affected by the complex tectonic evolution of the area. For six key wells distributed over the entire study area, burial and temperature histories as well as evolution of maturity were evaluated using 1D basin modelling. Deepest burial and maximum temperatures occurred either during Jurassic, Upper Cretaceous or Neogene times in these wells. Only some parts of the sedimentary package in Schleswig-Holstein show a significant increase in maturity during the Tertiary leading to additional hydrocarbon generation and entrapment.  相似文献   

5.
基于GPU的任意三维复杂形体重磁异常快速计算   总被引：3，自引：0，他引：3  
提出了基于图形处理单元的任意三维复杂形体的重磁异常快速正演计算方法。将地下半空间剖分为大小相等规则排列的一组长方体单元,任意三维复杂形体可以表示成很多不同体积和密度(磁性)的长方体的近似组合。用解析方法计算出所有这些长方体在计算点的重力(磁力)异常,并累加求和,就可以得到整个模型体在计算点引起的重(磁)异常值。为了提高近似程度,需将地下半空间剖分得很细,用传统的CPU串行程序计算相当耗时。GPU在处理能力和存储器带宽上相对CPU有明显优势,采用GPU并行算法,可大大提高计算速度。相关试验结果表明,用GPU实现的正演快速算法计算结果正确,效率明显提高,为重磁异常三维物性反演提供了基础。  相似文献   

6.
With this paper, we assess the present-day conductive thermal field of the Glueckstadt Graben in NW Germany that is characterized by large salt walls and diapirs structuring the graben fill. We use a finite element method to calculate the 3D steady-state conductive thermal field based on a lithosphere-scale 3D structural model that resolves the first-order structural characteristics of the graben and its underlying lithosphere. Model predictions are validated against measured temperatures in six deep wells. Our investigations show that the interaction of thickness distributions and thermal rock properties of the different geological layers is of major importance for the distribution of temperatures in the deep subsurface of the Glueckstadt Graben. However, the local temperatures may result from the superposed effects of different controlling factors. Especially, the upper sedimentary part of the model exhibits huge lateral temperature variations, which correlate spatially with the shape of the thermally highly conductive Permian salt layer. Variations in thickness and geometry of the salt cause two major effects, which provoke considerable lateral temperature variations for a given depth. (1) The “chimney effect” causes more efficient heat transport within salt diapirs. As a consequence positive thermal anomalies develop in the upper part and above salt structures, where the latter are covered by much less conductive sediments. In contrast, negative thermal anomalies are noticeable underneath salt structures. (2) The “thermal blanketing effect” is caused by thermally low conductive sediments that provoke the local storage of heat where these insulating sediments are present. The latter effect leads to both local and regional thermal anomalies. Locally, this translates to higher temperatures where salt margin synclines are filled with thick insulating clastic sediments. For the regional anomalies the cumulative insulating effects of the entire sediment fill results in a long-wavelength variation of temperatures in response to heat refraction effects caused by the contrast between insulating sediments and highly conductive crystalline crust. Finally, the longest wavelength of temperature variations is caused by the depth position of the isothermal lithosphere–asthenosphere boundary defining the regional variations of the overall geothermal gradient. We find that a conductive thermal model predicts observed temperatures reasonably well for five of the six available wells, whereas the steady-state conductive approach appears not to be valid for the sixth well.  相似文献   

7.
Gravity and magnetic anomalies have previously been interpreted to indicate strongly magnetic Permian or even Tertiary intrusive bodies beneath the Skagerrak waterway (such as the ‘Skagerrak volcano’) and beneath Silkeborg in Denmark. Our combined modelling of the magnetic and gravity anomalies over these rock bodies indicates that a steep upward magnetisation is required to explain the magnetic anomalies at the surface, reminiscent of the magnetic direction in the Sveconorwegian rocks of the Rogaland Igneous Province in southern Norway. The younger rocks of the Permian Oslo Rift region have intermediate and flat magnetisation that is inadequate to explain the observed magnetic field. The positive part of the Skagerrak aeromagnetic anomaly is continuous with the induced anomalies associated with the eastward extension of the Rogaland Igneous Province. This relation also suggests that rocks of the Rogaland Igneous Province and its offshore extension are responsible for the Skagerrak anomalies. Both the negative, remanence-dominated aeromagnetic anomaly and the positive gravity anomaly can be modelled using constraints from seismic reflection lines and available density data and rock-magnetic properties. A 7 km thick complex of ultramafic/mafic intrusions is located below a southward dipping 1–4 km thick section of Mesozoic sediments and 1–2 km of Palaeozoic sediments. The enormous body of dense, ultramafic/mafic rocks implied by the modelling could be the residue of the parental magma that produced the voluminous Rogaland anorthosites. The application of similar petrophysical properties in the forward modelling of the Silkeborg source body provides an improved explanation of the observed gravity and magnetic anomalies compared with earlier studies. The new model is constrained by magnetic depth estimates (from the Located Euler method) ranging between 6 and 8 km. Forward modelling shows that a model with a reverse magnetic body (anorthosite?) situated above a dense, mafic/ultramafic body may account for the Silkeborg anomalies. The anorthosites may have formed by differentiation of the underlying mafic intrusion, similar to the intrusive relations in the Rogaland Igneous Province. We conclude that there is strong evidence for a Sveconorwegian age for both the Skagerrak and the Silkeborg anomalous rock bodies.  相似文献   

8.
Up to now subsurface information permitted the delineation of the top of the Triassic salt, all throughout the Cantabro–Navarro domain, although little was known on the location and geometry of its base and thus on the estimation of the total salt thickness. A 3D-gravity inversion scheme combined with a 3D analytic method has been conducted to map out the geometry of the main salt structures of the basin. The gravity modeling results have been constrained by well log information and available geological and reflection seismic data. The combined 3D scheme integrated with available geological and geophysical data has allowed us to obtain the geometry of the main diapirs that characterize the central and marginal regions of the basin.From our interpretation, the Salinas de Añana diapir has almost vertical flanks and can be divided into two different parts, one of them forming a lateral overhang of the main body.The Salinas de Oro diapir has near vertical flanks and a main axis in the N–S direction. Also, the anomaly is rather more extensive than the outcrop of the diapir, which implies an important expansion of non-outcropping salt in this area. Like the Hoz-Sobrón diapir, the Salinas de Ollo diapir is long and narrow. stretching in the NW–SE direction, which includes three important highs, plus an intense zone of salt migration.The Estella and Alloz diapirs crop out individually in spite of being connected at depth. Also two non-outcropping salt domes have been detected to the south of Atauri that, like the Estella diapir, are related to the thrust front. We point out the gravity signature of the Murguia diapir, which shows an intense gravity high probably due to the presence of high-density rocks in the cap rock or more probably due to the existence of Triassic volcanites of ophitic texture pinched-off into the diapir.  相似文献   

9.
This paper combines geological knowledge and geophysical imagery at the crustal scale to model the 3D geometry of a segment of the Hercynian suture zone of western Europe in the Champtoceaux area (Brittany, France). The Champtoceaux complex consists of a stack of metamorphic nappes of gneisses and micaschists, with eclogite-bearing units. The exhumation of the complex, during early Carboniferous times, was accompanied by deformation during regional dextral strike–slip associated with a major Hercynian shear zone (the South Armorican Shear Zone, SASZ). Dextral shearing produced a km-scale antiformal structure with a steeply dipping axial plane and a steeply eastward plunging axis. Armor 2 deep seismic profile shows that the regional structure was cut by a set of faults with northward thrusting components. Based on the seismic constraint, direct 2D crustal-scale modelling was performed throughout the Champtoceaux fold on seven radial gravity profiles, also using geological data, and density measurements from field and drill-hole samples. The 3D integration of the cross-sections, the digitised geological map, and the structural information (foliation dips) insure the geometrical and topological consistency of all sources of data. The 2D information is interpolated to the whole 3D space using a geostatistical analysis. Finally, the 3D gravity contribution of the resulting model is computed taking into account densities for each modelled geological body and compared to the Bouguer anomaly. The final 3D model is thus compatible with the seismic and gravity data, as well as with geological data. Main geological results derived from the modelling are (i) the overall 3D geometry of the south dipping thrust system interpreted on the seismic profile emphasises northward thrusting and folding of the Champtoceaux complex which was coeval with strike–slip along the South Armorican Shear Zone; (ii) the gravity modelling suggests the presence of a relatively dense body below the Champtoceaux complex that could be interpreted as a result of relative uplift of midcrustal material during thrusting along the E–W trending wrench–thrust system; (iii) the northern limb of the Champtoceaux anticline is a relatively shallow feature; and (iv) Vigneux synkinematic granitic body is a laccolith sheared and rooted along the southern branch of the SASZ and spreads away from the strike–slip zone within weak country-rocks.  相似文献   

10.
三维地质填图为我国启动的新一轮地质调查项目,为提高重磁资料在三维地质填图中的应用效果,笔者提出重磁资料2.5D/3D相互约束重磁反演技术方案:利用重磁资料2.5D剖面反演结果、3D物性反演结果作为彼此反演约束条件,并通过了理论模型试验。试验结果表明,该技术方案使反演结果中物性参数、空间位置更接近理论模型体。通过对本溪—临江地区思山岭铁矿磁异常及酸性岩体重力异常进行反演实践——估算磁异常铁矿资源量、研究酸性侵入岩深部展布形态的效果良好,可为大面积三维填图提供有效途径。  相似文献   

11.
The key for understanding the dynamics of the Northeast German basin is the knowledge of its present-day structures. Our studies are focused on the complex geometry and evolution of this basin by the aid of numerical models. To support this task, it was necessary to consider and integrate all available geoscientific information. Based on borehole data, depth maps and on results of isostatic modelling we derived a 3D model of the basin structure. A smoothed map of the regional gravity field (after Grosse and Conrad, 1990) completed the data base. By means of 3D gravity modelling, the initial model structure was modified to fit in the geophysical data set.An important characteristic of the Northeast German Basin is the presence of Upper Permian Zechstein salt. The salt domes and walls related to the postdepositional mobilisation of the salt layer cause pronounced negative gravity anomalies. This effect is considered as a central problem in this study. In order to investigate possible causes of gravimetric anomalies, we studied the influence of different crustal depth levels. We applied a 3D gravity stripping approach to eliminate the gravimetric effects caused by sedimentary fill of the basin and to separate density anomalies within the sedimentary fill from the influence of deeper levels in the crystalline crust. Complementary, we calculated the downward continuation of the gravimetric field to the basin floor and compared the outcome with the results obtained by 3D stripping. The good fit between the calculated gravity anomalies and the measured anomalies confirms the applicability of the approach. Additionally, we interpreted the Bouguer anomalies in terms of crustal density distribution and discuss the model concerning its consistency with other geophysical data considering the first results of the seismic reflection experiment DEKORP BASIN96.  相似文献   

12.
S.B. Lyngsie  H. Thybo   《Tectonophysics》2007,429(3-4):201-227
We present a new model for the lithospheric structure of the transitions between Laurentia, Avalonia and Baltica in the North Sea, northwestern Europe based on 2¾D potential field modelling of MONA LISA profile 3 across the Central Graben, with constraints from seismic P-wave velocity models and the crustal normal incidence reflection section along the profile. The model shows evidence for the presence of upper-and lower Palaeozoic sedimentary rocks as well as differences in crustal structure between the palaeo-continents Laurentia, Avalonia and Baltica. Our new model, together with previous results from transformations of the gravity and magnetic fields, demonstrates correlation between crustal magnetic domains along the profile and the terrane affinity of the crust. This integrated interpretation indicates that a 150 km wide zone, characterized by low-grade metamorphosis and oblique thrusting of Avalonia crust over Baltica lower crust, is characteristic for the central North Sea area. The magnetic susceptibility and the density across the Coffee Soil Fault range from almost zero and 2715 kg/m3 in Avalonia crust to 0.05 SI and 2775 kg/m3 in Baltica crust. The model of MONA LISA profile 3 indicates that the transition between Avalonia and Baltica is located beneath the Central Graben with a ramp–flat–ramp geometry. Our results indicate that the initial rifting of the Central Graben and the Viking Graben was controlled by the location of the Caledonian collisional suture, located at the Coffee Soil Fault, and that the deep crustal part of Baltica extends further to the west than hitherto believed.  相似文献   

13.
局部重磁场源全方位成像理论概要   总被引：5，自引：5，他引：0  
安玉林 《物探与化探》2000,24(6):401-411
本文概要阐述了复杂条件下局部重磁场源全方位成像理论体系的实用价值与学术意义、球坐标系内三度体重磁场球谐级数正演通式、三度体重磁场全方位延拓和全方位反演等。  相似文献   

14.
Detailed gravity data integrated with geological data and mining well data are analysed to constrain the shape of the Triassic evaporitic body at Jebel El Mourra (northern Tunisian Atlas) and the mechanism of its emplacement at the surface. The gravity data analysis included the construction of a gravity anomaly maps, and synthetic and forward 2.5D gravity models. The complete Bouguer and residual gravity anomaly maps indicate a positive amplitude gravity anomaly over the Triassic evaporitic outcrops and prominent NE–SW‐trending features associated with the boundary of the Triassic rocks and surrounded layers. A NW–SE‐trending gravity model that crosses the Triassic evaporitic outcrop at Jebel El Mourra shows that the positive gravity anomaly can be explained by a deep‐rooted salt diapir. Conventional models of salt dome formation suggest that they produce negative gravity anomalies; however, this study shows that this model is not universal. The studied area is an example of a diapir expressed by positive gravity anomaly and this result is supported by synthetic gravity models at different stages of salt piercing.  相似文献   

15.
In this study a 2D basin model has been built along a transect crossing the Horn Graben in WNW-ESE direction. The aim of the investigation was to improve the understanding of the thermal evolution of the basin and its influence on possible petroleum systems. The 2D model of the subsurface is based on one seismic line and data from two exploration wells. Both wells TD’ed in Triassic sediments. The updoming of the Ringkøbing-Fyn High began during Late Carboniferous–Early Permian. At the end of the Permian the Horn Graben became active due to regional extension. The subsequent sedimentation history from Triassic to date is well recorded by well reports. A matter of debate has been whether or not significant amounts of Pre-Permian sediments exist in this area of the North Sea. Since organic material rich Paleozoic sediments serve as source rocks in widespread areas of North Germany and the southern North Sea it would be of great importance to know whether the same deposits exist in the Horn Graben. Nielsen et al. (Bull Geol Soc Denmark Copenhagen 45:1–10, 1998) introduced a model, which shows Paleozoic sediments covering the basement at a maximum depth of 6.5 km. Assuming, Paleozoic sediments are underlying the Permian salt deposits there should be an active petroleum system present. The 2D model includes the Paleozoic source rock and tries to explain why two exploration wells have not found petroleum.  相似文献   

16.
In the Goiás Alkaline Province, in central Brazil, some mafic–ultramafic alkaline bodies crop out, such as Morro do Engenho Complex (ME), whereas other intrusive bodies are completely covered by Quaternary sediments, such as A2 body, and can only be defined by their magnetic and gravity responses. The bodies give rise to strong gravity and magnetic anomalies. We inverted the gravity and magnetic data to estimate 3D density and magnetic intensity contrasts. The gravity inversion reveals that ME and A2 intrusions, totally emplaced in the upper crust, have maximum depths of about 10 and 6 km, respectively. The estimated density contrast distribution indicates a NE–SW preferential direction for ME intrusive body. Since the remnant magnetization is very important in the area, we inverted the magnetic data, testing two hypotheses: only induced field and induced plus remnant magnetizations. The results of the inversion using only induced field could not explain the observed magnetic field, which was about 1000 nT larger than the calculated one. Induced plus remnant field inferred from wandering polar path fitted the observations. 3D magnetic inversions when remnant magnetization was included recover deeper and thinner bodies compared with gravity inversion. The inverted bodies have spherical shapes which are more consistent with the model of magmatic chambers instead of plug intrusions.  相似文献   

17.
Numerical studies of ductile deformations induced by salt movements have, until now, been restricted to two-dimensional (2D) modelling of diapirism. This paper suggests a numerical approach to model the evolution of three-dimensional (3D) salt structures toward increasing maturity. This approach is also used here to restore the evolution of salt structures through successive earlier stages. The numerical methodology is applied to study several model examples. We analyse a model of salt diapirs that develop from an initial random perturbation of the interface between salt and its overburden and restore the evolved salt diapirs to their initial stages. We show that the average restoration errors are less than 1%. An evolutionary model of a 2D salt wall loaded by a 2D pile of sediments predicts a decomposition of the salt wall into 3D diapiric structures when the overburden of salt is supplied by 3D synkinematic wedge of sediments. We model salt extrusion feeding a gravity current over the depositional surface and estimate an average rate of extrusion and horizontal velocity of salt spreading. Faulting of the overburden to salt overhangs initiates new secondary diapirs, and we analyse the growth of these secondary diapirs. We also study how lateral flow effects the evolution of salt diapirs. The shape of a salt diapir can be very different if the rate of horizontal flow is much greater than the initial rate of diapiric growth solely due to gravity. We discuss the applicability of the results of the models to the evolution of Late Permian salt structures in the Pricaspian basin (Russia and Kazakhstan). These structures are distinguishable into a variety of styles representing different stages of growth: salt pillows, diapirs, giant salt massifs, 2D diapiric walls and 3D stocks complicated by large overhangs. The different sizes, shapes and maturities of salt structures in different parts of the Pricaspian basin reflect areal differences in salt thickness and loading history. Our results suggest that the numerical methodology can be employed to analyse the evolution of all salt structures that have upbuilt through younger ductile overburdens.  相似文献   

18.
A 3D geological model of the area east of Basel on the southeastern border of the Upper Rhine Graben, consisting of 47 faults and six stratigraphic horizons relevant for groundwater flow, was developed using borehole data, geological maps, geological cross sections, and outcrop data. This model provides new insight into the discussions about the kinematics of the area between the southeastern border of the Upper Rhine Graben and the Tabular Jura east of Basel. A 3D analysis showed that both thin-skinned and thick-skinned tectonic elements occur in the modeled area and that the Anticline and a series of narrow graben structures developed simultaneously during an extensional stress-field varying from E–W to SSE–NNW, which lasted from the Middle Eocene to Late Oligocene. In a new approach the faults and horizons of the 3D geological model were transferred into discrete elements with distributed hydrogeological properties in order to simulate the 3D groundwater flow regime within the modeled aquifers. A three-layer approach with a horizontal regularly spaced grid combined with an irregular property distribution of transmissivity in depth permitted the piezometric head of the steady-state model to be automatically calibrated to corresponding measurements using more than 200 piezometers. Groundwater modeling results demonstrated that large-scale industrial pumping affected the groundwater flow field in the Upper Muschelkalk aquifer at distances of up to 2 km to the south. The results of this research will act as the basis for further model developments, including salt dissolution and solute transport in the area, and may ultimately help to provide predictions for widespread land subsidence risks.  相似文献   

19.
钟云川  蒋丛林 《云南地质》2009,28(2):185-190
潞西地区航磁有三个异常带：第一异常带为同源重磁异常,反映高密度磁源体,由基性～超基性岩引起;第二异常带区域不同源重磁异常,反映低密度磁源体为混合片麻岩、混合岩等低密度地层,局部可能反映团坡厂和轩岗乡与黄铁矿相类似的矿床（点）;第三异常带,重磁异常也不同源,反映寒武系一第四系的新地层,局部与花岗岩接触带及与断裂破碎有关的矽卡岩型铅锌多金属矿。依据区内航磁异常及地球物理特征,提出在潞西地区的找矿思路和方向。  相似文献   

20.
简要介绍了接触交代—热液型铁矿床和沉积变质铁矿床形成的地质环境、控制条件,矿体形态特点和经济利用价值,通过平台磁异常Za-Ha双分量参量图研究,拟合反演,提出平台磁异常可能对应陡立接触带形态的磁性体。在重磁相关分析中,由相关系数的大小判断出平台磁异常重磁不同源,说明平台磁异常主体部分对应的磁性体不是沉积变质铁矿床。在CSAMT测深法探测结果分析中,提出平台磁异常深部可能存在岩浆岩侵入活动的物探证据。从而说明平台磁异常区具备形成接触交代—热液型铁矿床的可能性和几个必要条件,综合地质、物探资料推测平台磁异常成矿类型可能是接触交代—热液型铁矿床。  相似文献   

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