松潘-甘孜地块地壳性质再研究

松潘-甘孜地块的基底构造性质对于探讨青藏高原的形成至关重要,备受国内外学者的关注。然而,由于松潘-甘孜地块被广泛分布的三叠纪复理石沉积所覆盖,关于松潘-甘孜地块基底属性的研究并不多见,它属于洋壳还是陆壳,至今仍在争论之中。本文利用跨越松潘-甘孜地块的深地震反射剖面、深地震测深剖面、区域航磁异常和花岗岩同位素地球化学等资料,通过综合分析研究其地球物理与地球化学特征,发现松潘-甘孜地块的下地壳存在元古代变质基底,该基底具有亲扬子地块的性质。     

Evaluation of tectonic structure of İskenderun Basin (Turkey) using steerable filters

In this paper, we demonstrate the effectiveness of steerable filters as a method of delineating the boundaries of subsurface geological structures. Steerable filters, generally used for edge detection on 2-D images, have the properties of band pass filters with certain directions and are applied to many image processing problems. We first tested the method on synthetic data and then applied it to the aeromagnetic data of İskenderun Basin and adjacent areas.İskenderun Basin is located in the Northeastern Mediterranean where African–Arabian and Anatolian plates are actively interacting. The basin fill records a complex tectonic evolution since the Early Miocene, involving ophiolite emplacement, diachronous collision of Eurasian and Arabian plates and subsequent tectonic escape related structures and associated basin formation. Geophysical investigations of the tectonic framework of İskenderun Basin of Turkey provide important insights on the regional tectonics of the Eastern Mediterranean and Middle East. In this study we show geological structures, which are responsible for the magnetic anomalies in İskenderun Basin and enlighten the structural setting of the Northeastern Mediterranean triple junction using steerable filters. We obtained a magnetic anomaly map of the region from the General Directorate of Mineral Research and Exploration as raw data and then evaluated this by steerable filters. We determined the magnetic anomaly boundaries for İskenderun Basin by using various types of steerable filters and correlated these to drilling data and seismic profiles from the Turkish Petroleum Corporation. The result of the steerable filter analysis was a clarified aeromagnetic anomaly map of İskenderun Basin. The tectonic structure of İskenderun Basin is divided into regions by an N–S trending oblique-slip fault defined by the steerable filter outputs. We propose a new tectonic structure model of İskenderun Basin and modify the direction of the East Anatolian Fault Zone. In our model, East Anatolian Fault Zone cross-cuts the basin as a narrow fault zone and continues towards the Cyprus arc.     

Magnetic characterization of a retroarc extensional basin: The Loncopué Trough

The Loncopué Trough is a Pliocene to Quaternary extensional basin developed over the hinterland area of the Southern Central Andes. This basin is bounded by two neotectonic extensional fault systems delimiting a narrow topographic low. Previous studies have mostly focused on structural and geochemical aspects of this feature. However, geophysical surveys, aimed to unravel deep structure beneath a thick-younger than 5 My volcanic coverage, are scarce and based their interpretations on low resolution data sets. In this study, we collected new aeromagnetic data with the objective of characterizing the magnetic properties of the crust in the Loncopué Through and nearby zones. Additionally, we analyze the spatial relation between geological structures, volcanic fields and magnetic data. In order to highlight the boundaries of the magnetic sources and calculate the basement depth, we applied derivative techniques and the source parameter imaging. Also, we estimated an effective susceptibility model using the Magnetization Vector Inversion method, which takes into account the combined effects of remanence and induced magnetization. To determine the thermal structure of the area, we calculated the Curie depth points through the spectral analysis technique. From the analysis of magnetic data we were able to characterize the main structures and lineaments associated with this retroarc extensional trough. Notably, only the Loncopué eastern fault system seems to be a crustal-scale tectonic feature, while E-W-, ENE- and ESE-trending lineaments are interpreted as relatively minor structures segmenting the basement. Finally, our susceptibility model, together with the analysis of the Curie point, revealed potential magmatic/hydrothermal reservoirs in the Copahue volcano, and the Codihue and Cajón de Almanza regions that could be connected at depth forming a regional magmatic body.     

新疆且末县迪木那里克一带1∶5万航磁异常查证新进展

新疆若羌县祁漫塔格—且末县迪木那里克一带1∶5万航磁异常查证工作重点是对阿尔金南缘深大断裂带之南侧迪木那里克铁矿东西两侧的航磁异常进行查证。通过查证工作证实,新C-2008-2200、C-2008-2201、C-2008-2202、C-2008-2220、C-2008-2221与迪木那里克铁矿所在的新C-2206、C-2207、C-2008异常均在阿尔金深大断裂带南侧的"长沙沟构造蛇绿混杂岩带"之中的复理石岩片千枚岩中,可确定迪木那里克铁矿带已控制长度达50 km。其中,在新C-2200、C-2201、C-2202异常区,新发现且末县玉岭铁矿;在新C-2008-2220、C-2008-2221异常区,新发现若羌县河肃铁矿。并确定新C-2008-C-2196、C-2008-C-2198、C-2008-C-2199、C-2008-C-2230、C-2008-C-2280航磁异常有进一步工作价值。     

四川盆地及其西部边缘震区基底磁性界面与地震的研究

在对四川盆地及其西部边缘震区航磁资料进行分析研究的基础上，依据频率域磁性单界面反演方法对航磁异常进行了数据处理，求取了基底磁性界面的定量埋深，结合区域构造特征，地热分布及板块运动对地震的孕育环境进行了综合研究和讨论。     

柴达木盆地中部深部构造和地震活动

用航磁资料研究了青海柴达木盆地中部的深部构造环境。结果表明：该地区存在由东西向、北西向和北东向各两条断裂组成的构造系统；地震主要分布在由两条东西向断裂和两条北东向断裂交截形成的顺扭平形四边形的角区；构造应力场主压应力方向大致为近南北方向，在其作用下，北东向和东西向断裂都是该地区主要的发震构造。     

1505年10月9日63／4级地震震中的再考证

１５０５年发生在南黄海的地震至今已有１２次震中定位。由于该震中位置的确定直接影响到一些重大工程的地震安全性评价工作，因此，本文通过收集大量影响场的历史资料，参考了国内ＩＸ度地震等震线资料，采用与地球物理场和构造条件相结合的方法，重新考证了该震震中位置。     

东北地区1:100万航磁图匹配滤波及地质解释

本文概括地叙述了匹配滤波提取区域磁场的原理、方法,并将东北地区的匹配滤波结果与向上延拓结果作了比较,说明了两个结果的异同点。着重分析了匹配滤波所得的东北地区区域磁场特征及它所反映的区域地质构造,指出华北地台北缘隆起带东延、华北地台北部存在西拉木伦褶皱系、松辽盆地内部的构造分区和东北东西向断裂的等间距性等。     

准噶尔地区磁场解释及区域构造特征

根据准噶尔盆地及周围山区航空磁测结果,发现了5个沉积盖层厚度大于12km的拗陷,其中3个的盖层厚度可达18km,从而提高了盆地的油气远景评价。盆地内为隆拗相间的格局。 盆地内有一范围比盆地略小的以前寒武系为基底的稳定地块--准噶尔地块,它以断裂为边界。 盆地中部的北西西向长条状正异常,推断是由发育在下古生代裂陷槽中以基性为主的基性超基性杂岩体引起的。     

松辽盆地北部徐家围子断陷火山岩分布及天然气富集规律

提出一个新的带通滤波器——延拓回返垂直二次导数,该滤波器可通过调节延拓回返高度及次数来达到调频目的,以突出勘探目标层段的信息.利用该技术对松辽盆地深层勘探程度最高的徐家围子断陷的航磁资料进行目标处理,与钻井资料对比表明,经处理后的航磁资料可以较好地反映火山岩的分布特征.以航磁资料为主结合钻井、地震资料预测了徐家围子三套火山岩的平面分布.指出航磁异常梯度带是火山岩储层的发育区带,近烃源岩或沟通烃源岩的航磁异常梯度带是火山岩天然气的富集区带.该认识对今后松辽盆地的勘探部署有着十分重要的指导意义,对我国其他地区的火山岩勘探也具有借鉴意义.