Petrogenesis and Tectonic Implications of the Early Triassic Nianzi Adakitic Granite Unit in the Yanshan Fold and Thrust Belt:New Constraints from U-Pb Geochronology and Sr-Nd-Hf Isotopes

The Nianzi granite unit,which includes the Nianzi,Xiaolianghou and Xiawopu granitic intrusions,is a significant component of the northern part of the North China Craton(NCC)and is situated in the Yanshan fold and thrust belt(YFTB).However,there is still debate regarding the tectonic evolutionary history of the YFTB during the late Permian to Triassic period,specifically regarding the timing of subduction and collision between the NCC and the Paleo-Asian Ocean.The Nianzi granite unit exhibits unique petrological,geochronological and geochemical signatures that shed light on the tectonic evolutionary history of the YFTB.This study presents detailed petrology,whole-rock geochemistry,together with Sr-Nd isotopic,zircon U-Pb dating and Lu-Hf isotopic data of the granites within the Nianzi granite unit.Our findings demonstrate that the granites primarily consist of subhedral K-feldspar,plagioclase,quartz,minor biotite and hornblende,with accessory titanite,apatite,magnetite and zircon.Zircon U-Pb dating indicates that the Xiaolianghou granite was emplaced at 247.5±0.62 Ma.Additionally,the adakitic characteristics of the Nianzi,Xiawopu and Xiaolianghou granitic intrusions,such as high Sr and Ba contents and high ratios of Sr/Y and(La/Yb)N,combined with negative Sr-Nd and Lu-Hf isotopes(87Sr/86Sr)i=0.705681–0.7057433,εNd(t)=−21.98 to−20.97,zirconεHf(t)=−20.26 to−9.92,as well as the I-type granite features of high SiO_(2),Na_(2)O and K_(2)O/Na_(2)O ratios,enriched Rb,K,Sr and Ba,along with depleted Th,U,Nb,Ta,P and Ti,suggest that the Nianzi granitic unit was mainly derived from the partial melting of a thickened lower crust containing hydrous,calc-alkaline to high-K calc-alkaline,mafic to intermediate metamorphic rocks.In light of these parameters,we further integrate our data with previous studies and conclude that the Nianzi granitic unit was generated in a post-collisional extensional environment during the Early Triassic.

Inversion of the Main Mineral Compositions and Subdivision of Tectonic Units on Lunar LQ-4 based on Chang'e Data

Spectra are sensitive in detecting main minerals on the lunar surface from visible light to infrared light. Since spectral characteristics of minerals are closely related to their compositions and the maturity level of soil on the Moon, studying the compositions and distribution of elements and minerals on the lunar surface can help to understand the evolution of the Moon through remote sensing technology. The correlation between the spectral characteristics of Chang＇e-1 interference imaging spectrometry（IIM） reflectance images and the mineral contents of LSCC（Lunar Soil Characterization Consortium） lunar surface mineral samples was discussed and the spatial distributions of Fe O and Al_2O_3 contained in both pyroxene and plagioclase on LQ-4 were studied using the improved angle parameter method, MNF, and band ratio statistics. A comparison of the mapping results of the optical models by Lucey, Shkuractov and other researchers on Clementine and the gamma ray spectrometry data shows that the content error is within 0.6% for lunar mare areas and close to 1% for the highland areas. The tectonic framework on the lunar surface was also investigated. And based on integrated analysis of previous findings on topography of the lunar surface, Chang＇e LAM, CCD and LOLA images and the gravity anomalies data（Clementine GLGM-2）, the tectonic unit subdivision was established for LQ-4, the idea of subdividing the lunar tectonic units was proposed, and this will provide a good foundation for studying the lunar tectonic evolution.

The mapping methods and division of tectonic units of the regional tectonic map in the eastern China seas and adjacent regions

The geological-geophysical map series of the eastern China seas and adjacent region （1：1 000 000） will be published in the late half year of 2009. The regional tectonic map is one of the main professional maps. The Mapping methods, the division method of geological tectonic units and the main geological tectonic units are mainly discussed. The strata from Pliocene to Holocene are peeled off so as to display the Pre-Pliocene structures. In basins, isopaches are drawn for the Cenozoic deposits. The plate tectonic theory and present tectonic pattern are adopted as the priorities in tectonic division. As to the division of intraplate tectonic units, it is a revision, complement and improvement of previous dividing systems, and the nomenclature for each tectonic unit follows the current system in China. The first-order tectonic unit is plate （Pacific Plate, Eurasian Plate and Philippine Sea Plate）. The second-order tectonic unit is tectonic domain （East Asian continental tectonic domain,East Asian continental margin tectonic domain and west Pacific tectonic domain）. The Philippine Sea Plate and the west part of the Pacific Plate are called the West Pacific tectonic domain. The part of the Eurasian Plate involved in this study area can be further divided into East Asian continental tectonic domain and East Asian continental margin tectonic domain. The East Asian continental margin domain is composed of the Ryukyu island arc, the Okinawa Trough back-arc basin and the back-arc basin of Sea of Japan. The East Asian continental tectonic domain in this study area is composed of the Sino-Korea Massif, the Changjiang River （Yangtze） Massif and South China Massif. In turn, these massifs consist of basins, folded belts or uplift zones. The basins,the folded belts or the uplift zones are further divided into uplifts and depressions made up of sags and swells.

Tectonic Related Lithium Deposits Another Major Region Found North East Tanzania—A New Area with Close Association to the Dominant Areas: The Fourth of Four

The current “mega” interest in Lithium resources was spurred by the development of Lithium-Ion batteries to aid in restructuring the world’s reliance on carbon spewing power petroleum reserves. Current resources of lithium recovery have fallen into two main categories—Pegmatite, found worldwide associated with felsic intrusions and Brine Related, and now with development in the Southwest United States of America (SWUS), a third category— Tertiary Volcanic clays, are specifically associated with Tertiary volcanics and major Tectonic Plate interactions. “Active” Plate tectonics is important as both the SWUS, the Lithium Triangle of South America (LTSA) and the Tibetan Plateau of China (TPC) producing tertiary (Miocene) volcanism that is important to the development of Lithium resources. The Tanzanian part of the East Africa Rift System (EARS) has features of both the SWUS, tertiary volcanic related “playas” and Continental rifting, the LTSA, tertiary volcanic related “Brines” and a major Tectonic plate event (subduction of an Oceanic Plate beneath the Continental South American Plate) and the TPC, tertiary volcanics (?) and major tectonic plate event (subduction of the Indian Continental Plate under the Eurasian Continental Plate). As well as the association of peralkaline and metaluminous felsic volcanics with Lithium playas of the SWUS and the EARS (Tanzania) “playas”. These similarities led to an analysis of a volcanic rock in Northeast Tanzania. When it returned 1.76% Lithium, a one-kilometer spaced soil sampling program returned, in consecutive samples over 0.20% Lithium (several samples over 1.0% lithium and a high of 2.24% lithium). It is proposed that these four regions with very similar past and present geologic characteristics, occur nowhere else in the world. That three of them have produced Lithium operations and two of them have identified resources of Lithium clay and “highly” anomalous Lithium clays should be regarded as more than “coincidental”.

Tectonic unit divisions based on block tectonics theory in the South China Sea and its adjacent areas

Identifying distinct tectonic units is key to understanding the geotectonic framework and distribution law of oil and gas resources.The South China Sea and its adjacent areas have undergone complex tectonic evolution processes,and the division of tectonic units is controversial.Guided by block tectonics theory,this study divide the South China Sea and its adjacent areas into several distinguished tectonic units relying on known boundary markers such as sutures(ophiolite belts),subduction-collision zones,orogenic belts,and deep faults.This work suggests that the study area is occupied by nine stable blocks(West Burma Block,Sibumasu Block,LanpingSimao Block,Indochina Block,Yangtze Block,Cathaysian Block,Qiongnan Block,Nansha Block,and Northwest Sulu Block),two suture zones(Majiang suture zone and Southeast Yangtze suture zone),two accretionary zones(Sarawak-Sulu accretionary zone and East Sulawesi accretionary zone),one subduction-collision zone(RakhineJava-Timor subduction-collision zone),one ramp zone(Philippine islands ramp zone),and six small oceanic marginal sea basins(South China Sea Basin,Sulu Sea Basin,Sulawesi Sea Basin,Banda Sea Basin,Makassar Basin,and Andaman Sea Basin).This division reflects the tectonic activities,crustal structural properties,and evolutionary records of each evaluated tectonic unit.It is of great theoretical and practical importance to understand the tectonic framework to support the exploration of oil and gas resources in the South China Sea and its adjacent areas.

Identification and evolution of tectonic units in the Philippine Sea Plate

The Philippine Sea Plate is located at the convergence zone of the Eurasian Plate,the Pacific Plate,and the Indo-Australian Plate.This paper divides the Philippine Sea Plate into two second-order tectonic units and eight third-order tectonic units by summarizing the marine geological,geophysical,and submarine geomorphological data of the Philippine Sea Plate collected for years and referring to the seafloor spreading theory and the trench-arc-basin system.The two second-order tectonic units are the West Philippine Sea block and the Izu-Bonin-Mariana arc-basin system.The former includes the West Philippine Basin,the Huatung Basin,the Daito Basin,and the Palau Basin,while the latter consists of the Kyushu-Palau Ridge,the Shikoku-Parece Vela Basin,the Izu-Bonin Arc,and the Mariana Arc.Furthermore,this study concludes that the Philippine Sea Plate has undergone three stages of tectonic evolution,namely the early stage of the evolution of marginal basins with Cretaceous basement(Early Cretaceous),the middle stage of the spreading of the West Philippine Basin(Eocene),and the late stage of the subduction of the Izu-Bonin-Mariana arc-basin system(Oligocene-present).The Kyushu-Palau Ridge is a window to discover the tectonic evolution of the Philippine Sea Plate due to its unique geographical location.

A new pattern of the tectonic units and metallogenic belts in Africa continent in terms of lithosphere

Based on the comprehensive study of geology and geophysics in African continent,three types of lithosphere(craton-type,orogenic-type and rift-type)can be identified.Considering lithosphere discontinuities as the boundary,two first-order tectonic units(mainly cratonic-type in the west and rift-type in the east)are proposed.Different types of lithosphere can be divided into secondary-order and third-order structural units,and the blocks within lithosphere can be further divided into fourth-order structural units.The geological history,the formation process and significance of different types of lithosphere in African continent are briefly discussed.

Tectonic evolution of the West Kunlun Orogenic Belt along the northern margin of the Tibetan Plateau:Implications for the assembly of the Tarim terrane to Gondwana

The West Kunlun orogenic belt(WKOB) along the northern margin of the Tibetan Plateau is important for understanding the evolution of the Proto-and Paleo-Tethys oceans. Previous investigations have focused on the igneous rocks and ophiolites distributed mostly along the Xinjiang-Tibet road and the China-Pakistan road, and have constructed a preliminary tectonic model for this orogenic belt. However, few studies have focused on the so-called Precambrian basement in this area. As a result, the tectonic affinity of the individual terranes of the WKOB and their detailed evolution process are uncertain. Here we report new field observations, zircon and monazite U-Pb ages of the "Precambrian basement" of the South Kunlun terrane(SKT) and the Tianshuihai terrane(TSHT), two major terranes in the WKOB. Based on new zircon U-Pb age data, the amphibolite-facies metamorphosed volcanosedimentary sequence within SKT was deposited during the late Neoproterozoic to Cambrian(600-500 Ma), and the flysch-affinity Tianshuihai Group, as the basement of the TSHT, was deposited during the late Neoproterozoic rather than Mesoproterozoic. The rock association of the volcano-sedimentary sequence within SKT suggests a large early Paleozoic accretionary wedge formed by the long-term lowangle southward subduction of the Proto-Tethys Ocean between Tarim and TSHT. The amphibolitefacies metamorphism in SKT occurred at ca. 440 Ma. This ca. 440 Ma metamorphism is genetically related to the closure of the Proto-Tethys Ocean between Tarim and the Tianshuihai terrane, which led to the assembly of Tarim to Eastern Gondwana and the final formation of the Gondwana. Since the late Paleozoic to early Mesozoic, the northward subduction of the Paleo-Tethys Ocean along the HongshihuQiaoertianshan belt produced the voluminous early Mesozoic arc-signature granites along the southern part of NKT-TSHT. The Paleo-Tethys ocean between TSHT and Karakorum closed at ca. 200 Ma, as demonstrated by the monazite age of the paragneiss in the Kangxiwa Group. Our study does not favor the existence of a Precambrian basement in SKT.

On Palaeozoic Tectonics in the Alxa Region, Inner Mongolia, China

Abstract: Two ophiolitic mélange belts in the Late Carboniferous formations have been discovered recently in the Alxa region. One is in the Engger Us fault and possesses properties of oceanic crust. The other is in the Badain Jaran fault and shows properties of a back-arc basin. These two faults, together with the Yagan fault, constitute the important boundaries of tectonic units in the Alax region. The four tectonic units delimited by these faults are different in rock assemblages, metamorphism and geochemistry. They reflect the nature of tectonic environments in which they are found. The tectonic units may be traced and correlated to the eastern and western neighbouring areas. The formation and evolution process of the units and their interaction in the Alxa region may be described in terms of the evolution of the Palaeo-Mongolian Ocean and its continental margins.

Geotectonic evolution of lunar LQ-4 region based on multisource data

The Sinus Iridum region, the first choice for China＇s＂Lunar Exploration Project＂is located at the center of the lunar LQ-4 area and is the site of Chang＇e-3 （CE-3）＇s soft landing. To make the scientific exploration of Chang＇e-3 more targeted and scientific, and to obtain a better macro-level understanding of the geotectonic environment of the Sinus Iridum region, the tectonic elements in LQ-4 region have been studied and the typical structures were analyzed statistically using data from CE-1, Clementine, LRO and Lunar Prospector missions. Also, the mineral components and periods of mare basalt activities in the study area have been ascertained. The present study divides the tectonic units and establishes the major tectonic events and sequence of evolution in the study area based on morphology, mineral constituents, and tectonic element distribution.

西准噶尔构造带包古图地层小区上泥盆统红山梁组的建立及地质意义

西准噶尔构造带包古图地层小区白碱滩北红山梁剖面上新发现一套晚泥盆世红色“硅质岩、粉砂质硅质岩、凝灰质硅质岩”海相沉积组合,与上覆包古图组深灰色—灰黑色含碳粉砂岩呈整合接触。经区域对比确认,该套地层显著有别于研究区乃至整个西准噶尔构造带地层分区已发现的全部上泥盆统各组岩石地层,符合“野外可识别、界面可区别、区域可对比、图面可表达”的原则,据此新建红山梁组。本次于红山梁组枕状玄武岩、玄武岩、安山岩中分别获得365.9±5.0Ma、370.6±7.4Ma和374.6±3.6Ma的LA-ICP-MS锆石U-Pb年龄,佐证其时代为晚泥盆世。红山梁组与包古图组连续沉积之确认,消除了包古图组老于希贝库拉斯组这一存疑,建立了完整的下石统地层序列,新增了包古图地层小区泥盆纪的沉积记录,为区域沉积与构造演化研究提供了新资料。

东北地区大地构造演化与成矿制约

东北地区处于华北板块、西伯利亚板块与西太平洋板块交汇部位,是研究华北克拉通、古亚洲洋构造域、古太平洋构造域复合造山与成矿作用的重要地区.东北地区成矿地质条件优越,是我国战略性矿产资源找矿的重点片区之一.2011年以来,为保障我国资源能源可持续发展和重大基础地质问题的解决,国家逐渐加强了东北地区基础地质调查和研究工作,在东北地区主要成矿带、盆-山结合带及资源基地开展了大量1∶5万区域地质矿产调查、成矿地质背景及综合研究等工作,取得了一大批基础性和原创性地质成果,填补了东北地区中大比例尺地质调查空白.本文以“东北地区区域地质志”项目为依托,对2011年以来开展的基础地质调查项目取得的新数据和成果进行了系统梳理,总结了东北地区取得的主要基础地质研究成果或进展.在此基础上,进一步分解了华北克拉通、兴-蒙造山带等大地构造单元,恢复了古亚洲洋、鄂霍次克洋、古太平洋构造演化历史,完善了东北地区大地构造格架,并探讨了其对区域成矿作用的制约,为新一轮找矿突破战略实施提供基础地质支持.

不同构造单元页岩孔隙结构差异及其油气地质意义——以四川盆地泸州地区深层页岩为例

不同构造单元页岩储层品质、含气性差异明显,构造改造作用对页岩气勘探开发具有控制作用,但关于深层页岩气的构造控制作用机理研究较少,相关认识尚不明确,制约了深层页岩气的勘探开发。为此,通过“岩心—薄片—扫描电镜”多尺度观察、全岩矿物X射线衍射分析、核磁共振等技术手段,对比分析了四川盆地南部泸州地区不同构造单元上奥陶统五峰组—下志留统龙马溪组深层页岩孔隙结构和储层特征的差异,探讨了不同构造单元页岩孔隙结构差异与储层品质的耦合关系,明确了页岩气产量差异的内在地质原因,落实了构造改造作用下的页岩气勘探开发有利区。研究结果表明:①向斜区页岩主要以有机质孔隙、非构造裂缝为主,孔径大;背斜区页岩孔隙结构被强烈改造,以矿物粒间孔、构造裂缝为主,矿物粒间孔狭长且定向排列,孔径小。②向斜区构造相对稳定,有机质孔隙、矿物粒间孔以及成岩裂缝保存较好,宏孔占比高,储集性能好,含气量和产量高;背斜区页岩储层发育大量构造裂缝与断层,孔隙和成岩裂缝被压实,孔径减小,储集性能变差,含气量和产量低。③距盆缘剥蚀区越远,构造越稳定的单元,保存条件越好,该类构造单元页岩储层越发育,含气量和产量越高,页岩气勘探开发潜力越大。结论认为,构造运动对于压力系统的影响是形成不同构造单元深层页岩孔隙结构特征差异的重要因素,并控制了页岩储层的含气性与产量;向斜区深层保存条件好,远离剥蚀区,为勘探开发的最有利区,该认识可为深层页岩气勘探开发提供技术支撑。

基于CSAMT测量的川井坳陷构造单元及砂体特征

为了助力国家“双碳”目标的达成,实现生态环境的协调发展,核能正在发挥越来越重要的作用。铀资源为核能发展的基础,能否通过铀矿找矿工作保障天然铀供应,是关系到核能是否能可持续发展的重大问题。川井坳陷落实了铀矿产地,成矿条件优越,但物探工作程度薄弱,研究各次级构造单元的分布及砂体特征对铀矿找矿具有重要意义。地震勘探在划分构造单元和砂体的分布特征方面应用最为广泛、效果最好,但成本较高。

中祁连元古代皋兰岩群的解体:古元古代变质事件与早-中寒武世大陆裂谷作用

中祁连东段元古代皋兰岩群是一套变质程度极不均一的变质岩系,本次工作根据变质程度将其重新划分为北部的低绿片岩相与南部的高绿片岩相(局部低角闪岩相)两个岩石单元。两者分别具有不同的岩相学、锆石U-Pb年代学和岩石地球化学特征,并以韧性剪切带相隔。低绿片岩相岩石单元中玄武岩和流纹岩的成岩年龄为502.5±3Ma、500.8±3Ma和507.8±4Ma,表明其形成时代为早-中寒武世;高绿片岩相(局部低角闪岩相)岩石单元中的斜长角闪岩变质锆石的U-Pb年龄为1873±10Ma,暗示其形成于古元古代中-晚期中祁连地块基底形成阶段,该岩石单元是中祁连地块对哥伦比亚超大陆聚合事件的物质记录。结合年代学、岩石组合以及区域资料,将低绿片岩相岩石单元从皋兰岩群中解体出来,划归北祁连寒武纪黑茨沟组。岩石地球化学分析显示,新解体出来的黑茨沟组双峰式火山岩形成于大陆裂谷环境,其中玄武质岩浆可能来自软流圈地幔,在上涌过程中受到轻微的地壳混染;流纹岩主要由玄武质岩浆结晶分异而来,并且有少量地壳物质的加入。综合分析祁连山地区原特提斯洋开启时限研究成果,认为新元古代晚期至早古生代早期北祁连地区的裂解作用乃至大洋化过程并非同步进行,而是呈现出西早东晚的特征。

准噶尔盆地东南缘柴窝堡地区构造特征及勘探方向

准噶尔盆地东南缘柴窝堡地区形成过程中受博格达山和伊林黑比尔根山双向挤压,形成逆冲推覆叠加构造,断裂和裂缝非常发育,二叠系芦草沟组沉积期位于生烃凹陷中心,油气源充足,成藏条件非常有利。研究区内8口井都见到丰富油气显示,达1、柴参1地两口井获低产,勘探潜力非常大。但由于构造特征复杂,且勘探研究程度较低,导致构造地质模型及圈闭发育规律认识不清,制约了该区有利勘探区带及目标的优选。通过对柴窝堡地区大量野外露头和地震资料综合分析.

中国新疆-中亚大地构造单元划分及演化简述

中国新疆-中亚地处特提斯构造域和古亚洲构造域交汇部位,跨全球最重要三大构造(成矿)域中的2个,对认识全球构造演化和资源环境效应具有重要意义,前人对该区域开展了大量研究,提出了不同的大地构造单元和成矿区(带)划分方案,然而不同学派之间存在诸多争议。笔者结合“多岛弧盆系”构造理论,遵循将今论古的比较构造地质学研究原则,以大地构造相的时空结构分析为主线,以对接带、造山系和陆块区3类一级大地构造单元,依据优势大地构造相将研究区划分为12个一级构造单元、32个二级构造单元和74个三级构造单元,并针对二级构造单元的构造环境和岩石建造组合进行描述、总结,以建立研究区总体构造格架和演化历史。在此基础上,依据两大构造域时空演化特征,追溯古亚洲洋和特提斯构造域的构造演化历史。通过对研究区构造单元划分和构造演化的重新厘定,以期为区域基础地质研究和资源能源勘查提供基础依据。

基于瓦斯地质单元划分的瓦斯赋存规律分析

搞清井田瓦斯赋存规律是瓦斯治理的基础,是矿井实现“一矿一策,一区一策”瓦斯治理措施的保障。以古汉山井田为例,运用瓦斯赋存构造逐级控制理论,在分析区域构造演化及控制的基础上,探讨了古汉山井田瓦斯赋存规律及主控因素。研究结果表明,石炭-二叠系含煤地层沉积之后经历的多期构造运动造就了焦作煤田现今的构造格局及瓦斯赋存特征。以团相断层及其NE向延伸方向断层为界,将古汉山井田划分为3个瓦斯地质单元。马坊泉断层与团相断层间形成的地堑是造成瓦斯地质单元1上覆基岩厚度为井田最厚的原因,同等埋深条件下瓦斯地质单元1上覆基岩厚度厚是造成该区瓦斯含量高的主要原因;赤庄断层形成的煤层隐伏露头和上覆基岩厚度薄是瓦斯地质单元2瓦斯含量井田最低的主要原因;上覆基岩厚度相同情况下瓦斯地质单元1和3瓦斯含量相差不大。

基于卫星重力异常的渤海盆地秦南凹陷及邻区构造格局研究

渤海盆地是我国目前发现海上油气田最多的地区,秦南凹陷作为渤海盆地中的潜在富油气凹陷,具有较高的勘探潜力,对凹陷及邻区的构造格局研究具有重要意义和应用价值。本文利用卫星重力异常,通过校正陆域地形和海水的影响得到布格重力异常,采用归一化总水平导数垂向导数(NVDR-THDR)、欧拉反褶积、最小曲率位场分离和双界面模型重力场快速反演等方法得到了断裂的平面分布和视深度、新生界厚度以及构造单元边界;结合地质及地球物理资料,分析了研究区内主要断裂和构造单元的分布特征及地球物理特征。研究表明秦南凹陷及邻区的断裂主要呈NE向、NEE向和NW向展布,断裂视深度以1~10 km为主,在控坳断裂的部分位置及众多断裂交汇处达到了15~25 km;新生界厚度在0~11 km,构造单元呈NE向和NEE向交替分布,其边界大多受断裂控制;通过进一步研究,将秦南凹陷西侧的洼陷划归为乐亭凹陷,对其他构造单元的边界也进行了调整。本次断裂分布和构造单元分布特征的研究结果能为秦南凹陷的油气勘探提供一定的地球物理支撑。

Aegir脊及邻区重磁异常及构造特征

为研究北极地区挪威海内Aegir脊及邻区断裂构造特征,为北极地区油气勘探提供方向,在斯克里普斯海洋研究所发布的研究区重力数据(网格数据)基础上填充最新船测数据,对已有重磁资料进行异常分离、滑动平均和重磁场边界识别。目前,研究区的特征断裂和构造单元划分尚不清楚。根据异常极值带、异常带走向、异常梯度带变化程度等,对研究区进行了断裂识别和构造单元划分。研究表明:重磁异常特征呈NNE-NW-NE向展布,重力异常呈现高低分带,反映出该区基底隆坳相间的格架。根据重磁异常与断裂对应关系,识别出4个构造走向和7条主要断裂,划分出Mohns脊、扬马延微陆块、东扬马延断裂带、西扬马延断裂带、Aegir脊、东扬马延深海盆地和挪威深海盆地等7个构造单元。