选取2012-2022年青藏高原东北缘山丹等7个观测台地磁垂直(Z)分量数据,基于2021年5月22日青海玛多M_(S)7.4地震等4个地震事件,利用重标极差法(R/S,Rescaled Range Analysis)与最小二乘法(LSM,Least Square Method)计算地磁Z分量赫斯特指...选取2012-2022年青藏高原东北缘山丹等7个观测台地磁垂直(Z)分量数据,基于2021年5月22日青海玛多M_(S)7.4地震等4个地震事件,利用重标极差法(R/S,Rescaled Range Analysis)与最小二乘法(LSM,Least Square Method)计算地磁Z分量赫斯特指数(Hurst Exponent,H)值,分析H值的时序变化与地震活动关系。结果表明:①7个观测台地磁Z分量11年时间序列H值的分布范围均为0.5<H<1.0,具有长程相关性与持久性,可对未来趋势做出预测。②7个观测台的地磁Z分量H值在4个地震事件前1~3个月迅速下降,直至H<0.5,背离地磁场正常(0.5<H<1.0)变化规律,出现震磁异常现象。震级越大、震中距越小,震磁效应越明显。③H值的反持续性可能与青藏高原东北缘壳-幔深部物质流的运移有关。青藏高原二级块体(如松潘-甘孜地块)深部热流的上涌和侧向迁移导致地壳内部应力场改变,从而引起地磁场扰动,进而出现H值异常。基于赫斯特指数的数据分析,进一步补充震例研究,捕捉与解译震磁异常,研究地磁时序变化与地震活动对应关系,为探索青藏高原东北缘块体内部及边缘的震磁机制提供参考。展开更多
依据236口井共2706组的静温数据以及25口井的系统测温数据，分析计算了渤海盆地地温梯度及大地热流；建立地壳分层结构模型，利用回剥法计算现今地幔热流、深部温度以及岩石圈厚度；在此基础上，利用地球动力学方法恢复本区热流演化史...依据236口井共2706组的静温数据以及25口井的系统测温数据，分析计算了渤海盆地地温梯度及大地热流；建立地壳分层结构模型，利用回剥法计算现今地幔热流、深部温度以及岩石圈厚度；在此基础上，利用地球动力学方法恢复本区热流演化史。结果表明：渤海盆地背景地温梯度为32.2℃/km，热流值为64.8 mW/m2；盆地现今热岩石圈厚度在61～69 km 之间，地幔热流占地表热流的比例在60％左右，属于“热幔冷壳”型岩石圈热结构，盆地地壳底部或莫霍面温度变动在548～749℃之间；热流演化的特征与盆地的构造演化背景吻合，新生代以来盆地经历了3期岩石圈减薄并加热的过程，在东营组沉积末期热流达到最高（70～83 mW/m2），这期间盆地内产出多期碱性玄武岩，表明盆地经历了波及地幔的裂谷过程，随后进入热沉降期，热流逐渐降低，盆地向坳陷型转变。展开更多
The Huangtuliang gold deposit is characterized by its wide and large ore belt,stable extension and closely spaced orebodies.Unfortunately,no orebody was found by deep drilling.As a result,ore prospecting in this regio...The Huangtuliang gold deposit is characterized by its wide and large ore belt,stable extension and closely spaced orebodies.Unfortunately,no orebody was found by deep drilling.As a result,ore prospecting in this region was once put into dilemma.Detailed analysis of ore-forming and ore-controlling structures in the mining district by the authors has revealed that the ore-forming and ore-controlling structure in this mining district is a steeply dipping(85°-110°/∠70°-85° N-NNE),spade-shaped ductile shear zone,and the ore-controlling structures are a series of nearly erected second-ordered faults which are developed in the upper part of the ductile shear zone,intersecting with the ductile shear zone.Deep cutting of the ductile shear zone made it possible the ascending of ore fluids from the mantle plume at depth and these ore fluids would migrate upwards along the ductile shear zone under certain temperature and pressure conditions.Along their ascending path,the ore fluids would extract ore-forming elements from the country rocks and the extracted ore-forming elements would be deposited as ores in the hanging-wall second-ordered faults.The reason why no orebody was found in early prospecting at depth is that northward-dipping drilling in the southern part of the shear zone extended so deeply as to be beneath the shear zone.Only shallow-level orebodies could be found by southward-dipping drilling practice in the northern part of the shear zone.The location where deep-seated orebodies occurred shifted northwards and the orebodies occurred at greater depth.Therefore,it is natural that no orebody could be found when drill core passed through the shear zone.After the ore-forming and ore-controlling structures were well understood,the focus of ore prospecting was placed on the deep-level,northward-penetrating veins.In this way a number of new blind orebodies of great thickness have been found.On the basis of research development in the mining district,a prospecting plan has been made for ore prospecting in the periphery of eastern mining district.Prospecting practice has shown that there occur generally continuous engineering orebodies at large intervals.So,the Huangtuliang gold deposit has turned at one stroke from a medium sized to a large-sized,even a super-large gold deposit between prospecting lines 30-98.展开更多
This work deals with the characteristics of mantle branch structure in western Shandong Province, China, with respect to the distribution characteristics and ages of the regional strata, the development of ring-like a...This work deals with the characteristics of mantle branch structure in western Shandong Province, China, with respect to the distribution characteristics and ages of the regional strata, the development of ring-like and radial faults, the development of gently inclined detachment-slip structures in the axial part, mantle-source magmatic activities, regional petrology, petrochemistry and isotope geology. The study indicated that the N-W sharply plunged ductile shear zone in the region of western Shandong cuts through the mantle rocks detached from the deep-seated North China mantle sub-plume, hence leading to unloading in response to depressurization and thereafter the formation of anatexis magma. The intense and complete magmatic evolution series not only manifests a variation trend of alkalinity of magma from high to low and its intrusive depth from deep to shallow, but also reflects that the wall-rock alteration shows a general evolution trend from strong to weak. The evolution of mantle structure played an important role in controlling endo-mineralogenesis, accompanied with the rise of the country rocks. As a result, typical mantle branch structures were formed as observed in western Shandong. At the top of the mantle branch structure was developed an obvious detachment-tilt fault block, and some endogenic ores, at the same time, were uplifted onto the shallow levels.展开更多
文摘依据236口井共2706组的静温数据以及25口井的系统测温数据，分析计算了渤海盆地地温梯度及大地热流；建立地壳分层结构模型，利用回剥法计算现今地幔热流、深部温度以及岩石圈厚度；在此基础上，利用地球动力学方法恢复本区热流演化史。结果表明：渤海盆地背景地温梯度为32.2℃/km，热流值为64.8 mW/m2；盆地现今热岩石圈厚度在61～69 km 之间，地幔热流占地表热流的比例在60％左右，属于“热幔冷壳”型岩石圈热结构，盆地地壳底部或莫霍面温度变动在548～749℃之间；热流演化的特征与盆地的构造演化背景吻合，新生代以来盆地经历了3期岩石圈减薄并加热的过程，在东营组沉积末期热流达到最高（70～83 mW/m2），这期间盆地内产出多期碱性玄武岩，表明盆地经历了波及地幔的裂谷过程，随后进入热沉降期，热流逐渐降低，盆地向坳陷型转变。
基金supported jointly by the Natural Science Foundation of Hebei Province(Grant No.D2007000751)the exploration projects of Hebei Province Resources Department(2006122,the Large-scale Geological Survey in China)(No.121201631106).
文摘The Huangtuliang gold deposit is characterized by its wide and large ore belt,stable extension and closely spaced orebodies.Unfortunately,no orebody was found by deep drilling.As a result,ore prospecting in this region was once put into dilemma.Detailed analysis of ore-forming and ore-controlling structures in the mining district by the authors has revealed that the ore-forming and ore-controlling structure in this mining district is a steeply dipping(85°-110°/∠70°-85° N-NNE),spade-shaped ductile shear zone,and the ore-controlling structures are a series of nearly erected second-ordered faults which are developed in the upper part of the ductile shear zone,intersecting with the ductile shear zone.Deep cutting of the ductile shear zone made it possible the ascending of ore fluids from the mantle plume at depth and these ore fluids would migrate upwards along the ductile shear zone under certain temperature and pressure conditions.Along their ascending path,the ore fluids would extract ore-forming elements from the country rocks and the extracted ore-forming elements would be deposited as ores in the hanging-wall second-ordered faults.The reason why no orebody was found in early prospecting at depth is that northward-dipping drilling in the southern part of the shear zone extended so deeply as to be beneath the shear zone.Only shallow-level orebodies could be found by southward-dipping drilling practice in the northern part of the shear zone.The location where deep-seated orebodies occurred shifted northwards and the orebodies occurred at greater depth.Therefore,it is natural that no orebody could be found when drill core passed through the shear zone.After the ore-forming and ore-controlling structures were well understood,the focus of ore prospecting was placed on the deep-level,northward-penetrating veins.In this way a number of new blind orebodies of great thickness have been found.On the basis of research development in the mining district,a prospecting plan has been made for ore prospecting in the periphery of eastern mining district.Prospecting practice has shown that there occur generally continuous engineering orebodies at large intervals.So,the Huangtuliang gold deposit has turned at one stroke from a medium sized to a large-sized,even a super-large gold deposit between prospecting lines 30-98.
基金This research project was financially supported jointly by the NationaNatural Science Foundation of China (Grant No. 40272088), theLarge-scale Geological Survey in China (No. 2000110100038) and theCentral Mining Funds (2003-20).
文摘This work deals with the characteristics of mantle branch structure in western Shandong Province, China, with respect to the distribution characteristics and ages of the regional strata, the development of ring-like and radial faults, the development of gently inclined detachment-slip structures in the axial part, mantle-source magmatic activities, regional petrology, petrochemistry and isotope geology. The study indicated that the N-W sharply plunged ductile shear zone in the region of western Shandong cuts through the mantle rocks detached from the deep-seated North China mantle sub-plume, hence leading to unloading in response to depressurization and thereafter the formation of anatexis magma. The intense and complete magmatic evolution series not only manifests a variation trend of alkalinity of magma from high to low and its intrusive depth from deep to shallow, but also reflects that the wall-rock alteration shows a general evolution trend from strong to weak. The evolution of mantle structure played an important role in controlling endo-mineralogenesis, accompanied with the rise of the country rocks. As a result, typical mantle branch structures were formed as observed in western Shandong. At the top of the mantle branch structure was developed an obvious detachment-tilt fault block, and some endogenic ores, at the same time, were uplifted onto the shallow levels.
