台风路径多模式集成预报技术研究

利用NCEP、ECMWF、日本数值、英国数值、上海台风模式和广州模式包含全球模式和区域在内的6家数值模式资料,利用近似SEAV方法,设计台风路径多模式集成预报方法(SHME),并用2014—2016年的台风客观预报数据进行多模式集成预报的效果检验,且与ECMWF模式进行比较,通过比较发现,SHME方法较ECMWF在12～48 h预报上有明显改进,在72～120 h预报2014年尤其突出,2015—2016年均与ECMWF预报效果相当。     

Meso-Cenozoic tectonic evolution of the Talas-Fergana region of the Kyrgyz Tien Shan revealed by low-temperature basement and detrital thermochronology

This study provides new low-temperature thermochronometric data, mainly apatite fission track data on the basement rocks in and adjacent to the Talas-Fergana Fault, in the Kyrgyz Tien Shan in the first place.In the second place, we also present new detrital apatite fission track data on the Meso-Cenozoic sediments from fault related basins and surrounding intramontane basins. Our results confirm multistaged Meso-Cenozoic tectonic activity, possibly induced by the accretion of the so-called Cimmerian blocks to the Eurasian margin. New evidence for this multi-staged thermo-tectonic activity is found in the data of both basement and Meso-Cenozoic sediment samples in or close to the Talas-Fergana Fault.Zircon(U-Th)/He and apatite fission track data constrain rapid Late TriassiceE arly Jurassic and Late JurassiceE arly Cretaceous basement cooling in the Kyrgyz Tien Shan around 200 Ma and 130 -100 Ma respectively. Detrital apatite fission track results indicate a different burial history on both sides of the Talas-Fergana Fault. The apatite fission track system of the Jurassic sediments in the Middle Tien Shan unit east of the Talas-Fergana Fault is not reset, while the Jurassic sediments in the Fergana Basin and Yarkand-Fergana Basin, west of the fault zone, are partially and in some cases even totally reset. The totally reset samples exhibit Oligocene and Miocene ages and evidence the Cenozoic reactivation of the western Kyrgyz Tien Shan as a consequence of the India-Eurasia convergence.     

Linking uplift and mineralisation at the Mount Novit Zn-Pb-Ag Deposit,Northern Australia: Evidence from geology,U–Pb geochronology and sphalerite geochemistry

The subeconomic Mount Novit Zn-Pb-Ag deposit is located approximately 20 km south of Mount Isa, Queensland. In contrast to the nearby Mount Isa, Hilton and George Fisher Zn-Pb-Ag deposits, mineralisation at Mount Novit is situated to the west of the regional-scale Mount Isa Fault and is hosted in the Moondarra Siltstone as opposed to the Urquhart Shale. Lower-grade (<4 wt.% Zn + Pb) Zn-Pb-Ag mineralisation primarily replaces pre-existing carbonate alteration and veining and consists of pyrrhotite, pyrite and sphalerite with lesser galena. Higher-grade (>10 wt.% Zn + Pb) mineralisation occurs as a matrix supported breccia dominated by sphalerite and pyrrhotite with galena, pyrite, and magnetite. In-situ U–Pb geochronology was completed on apatite and two textural varieties of monazite. Fine-grained (<50 µm) subhedral to anhedral monazite is located within highly foliated biotite alteration directly adjacent Zn-Pb-Ag mineralisation and yields a mean weighted ²⁰⁷Pb/²⁰⁶Pb age of 1527 ± 18 Ma (MSWD = 1.06). This age is consistent with the formation of highly foliated biotite alteration during D₃ deformation of the Isan Orogeny. Apatite from the same fabric yields a lower intercept age of 1443 ± 29 Ma (MSWD = 1.30). Consistent with previous studies, this age is interpreted to represent the age of a major thrusting event along the Mount Isa Fault that resulted in the cooling of the Mount Novit area below ～375 °C. Coarse-grained monazite is coeval with Zn-Pb-Ag mineralisation and yields a mean weighted ²⁰⁷Pb/²⁰⁶Pb age of 1457 ± 11 Ma (MSWD = 0.28). Sphalerite from Mount Novit has low concentrations (<1 ppm) of Ge and Ga and a relatively high concentration of In (5 to >10 ppm), possibly reflecting the leaching of the metals from an underlying basement unit. The GGIMFis geothermometer (Frenzel et al., 2016) produced a mean formation temperature of 345 ± 52 °C. The timing and temperature of Zn-Pb-Ag mineralisation is consistent with the age and cooling temperature of apatite presented in this study. Based on these correlations, we suggest that Zn-Pb-Ag mineralisation at Mount Novit was emplaced during an episode of major thrusting along the Mount Isa Fault, with the precipitation of Zn-Pb-Ag mineralisation driven by the cooling of the Mount Novit area below ～375 °C. A key implication of this study is a new model for synorogenic Zn-Pb-Ag mineralisation to the south of Mount Isa, which contrasts with the widely accepted regional-scale syngenetic metallogenic model.     

柴达木盆地东部燕山期剥蚀量恢复:来自地球物理和低温热年代学的证据

依据地面地质调查分析了柴达木盆地东部主要不整合面的接触关系和发育特征,并利用古温标(镜质体反射率(R_o)、磷灰石裂变径迹)反演和地震地层趋势延伸法对柴达木盆地东部燕山期剥蚀量进行了恢复。结果表明,研究区东部旺尕秀、牦牛山一带晚燕山期剥蚀量为500~2 300 m,研究区南缘格尔木、大干沟、纳赤台一带剥蚀厚度最高达2 000 m,研究区北缘绿梁山、大柴旦一带增大到平均1 750 m,至柴东欧南凹陷、霍布逊凹陷逐渐减小到平均700 m。该区剥蚀厚度表现出由周缘老山向坳陷中心逐步减小的趋势,并呈现出“东西分块、南北分带”的特征。柴达木盆地东部燕山运动发生的时间为87~62 Ma,该时期研究区整体处于SE-NW向弱挤压的环境,与早白垩世末冈底斯—念青唐古拉地块群和欧亚大陆拼合有关,导致柴达木盆地东部差异隆升,形成现今欧龙布鲁克隆起带的雏形,并进一步控制该区油气的富集,一方面是造成局部地区地层剥蚀严重,油气散失;另一方面是因构造挤压,在覆盖区挤压拗陷,主力烃源岩进一步深埋,该区侏罗系烃源岩进一步成熟生烃,下伏石炭系烃源岩经历二次生烃;同时在挤压环境下形成一系列的近EW向的圈闭,有利油气的调整、聚集。     

哀牢山—红河剪切带新生代热史演化及其构造意义

笔者等通过对哀牢山—红河剪切带5件砂岩磷灰石样品裂变径迹分析,获得测试分析样品的表观年龄,对所有样品利用模拟退火法进行了热史模拟,取得其热演化史;得出哀牢山—红河剪切带在新生代发生了相似的构造演化过程,其经历了2次快速冷却剥露事件,分别发生在37～14 Ma和5.1～0 Ma,平均冷却速率分别为3.98℃/Ma和11.15℃/Ma;在发生快速冷却的时间上,存在自东向西逐渐变晚的趋势,说明哀牢山—红河剪切带在新生代可能为自东向西的幕式隆升。     

Thermochronology of the Longmen Shan seismic fault and its implications for faulting activities.SCIEI北大核心CSCD

中生代和新生代多期次的新老构造活动叠加造成了龙门山现今地震频发和复杂的构造格局。沿2008年汶川地震断裂带出露有多种断裂岩组合,为直接开展断裂带热年代学研究提供了重要素材。本研究首次尝试针对映秀-北川断裂带出露的假玄武玻璃开展^(40)Ar/^(39)Ar年龄的多重扩散域(MDD)模拟研究。与钾长石相似的阶梯状上升的年龄谱图表明假玄武玻璃同样具有开展MDD模拟的应用潜力。模拟结果显示,映秀-北川断裂带分别经历了~230Ma和~180Ma起始的构造热事件,对应青藏高原东缘中-晚三叠世统一的挤压造山运动和造山后的伸展垮塌。断裂带内新获得的断层角砾岩磷灰石裂变径迹(AFT)结果与上、下盘已有结果共同组成了较为完整的年龄-高程剖面,揭示出年龄拐点出现在~13Ma,位于~1100m的海拔高度,与热历史反演结果一致,对应映秀-北川断裂带的出露位置,直接证实断裂活动在中中新世以来龙门山的隆升过程中发挥了重要作用。进入中中新世以来,龙门山断裂带的快速剥蚀和地温梯度的显著降低很可能暗示了构造活动机制上的重要转变。     

河南舞阳赵案庄铁矿床成因:来自磁铁矿和磷灰石的矿物学证据

河南舞阳赵案庄铁矿位于华北克拉通南缘,赋存于新早古元古界太华杂岩赵案庄组中,是舞阳铁矿的一部分。赵案庄铁矿在时空上与变质的超基性岩关系密切,矿石中的脉石矿物与其寄主岩石的主矿物一致,指示其成因方面的亲缘性。赵案庄铁矿石具有典型的海绵陨铁结构,其中的磁铁矿具有高V(1458×10-6~2524×10-6)、稍高Mg(2502×10-6~4674×10-6)和低Ti(395×10-6~3186×10-6)、Cr(3.30×10-6~66.1×10-6)、Ni(93.0×10-6~176×10-6)、Mn(259×10-6~937×10-6)的特征。磷灰石以粗粒(0.3~1.5mm)、等粒状分散在磁铁矿的粒间,具有高REE总量(4983×10-6~7038×10-6)、高F(2.69%~3.52%)、高F/Cl比值(21.5~78.8)和低Sr(215×10-6~241×10-6)的特征。磁铁矿和磷灰石的化学组成均指示岩浆成因,并携带热液信息。利用磷灰石的微量元素含量反演成矿岩浆的微量元素组成,表明成矿岩浆受到了地层物质的混染。橄榄石低Cr、Ni高Mg的特征也指示岩浆中富挥发分的特征。此外,矿石中大量的碳酸盐矿物指示岩浆中有来自地层的CO2加入,导致岩浆的氧逸度升高,促进了磁铁矿的结晶,并抑制了钛铁矿结晶,是磁铁矿低Ti的一个原因。此外,源区低Ti也是导致磁铁矿低Ti的原因。因此,本文认为赵案庄铁矿属与超基性岩有关的岩浆矿床但受到富CO2流体的影响。     

Apatite fission‐track analysis of Cretaceous alkaline rocks of Ponta Grossa and Alto Paranaíba Arches,Brazil

This work presents fission‐track ages and thermal history modelling of apatite samples from two Brazilian alkaline formations: Alto Paranaíba and Ponta Grossa Arches. The apatite fission‐track ages obtained for Alto Paranaíba Arch agree with those determined by other radiometric dating methods presenting higher closure temperatures. The ages given by the fission‐track thermochronometer suggest that no strong tectonic event has occurred after Alto Paranaíba Formation during Upper Cretaceous. This event is also supported by thermal history modelling of this arch, which is characterized by fast cooling followed by residence at lower temperatures. On the other hand, apatite fission‐track ages from Ponta Grossa Arch are systematically lower than other radiometric ages, suggesting that at least one tectonic event occurred after Ponta Grossa Formation, around 130 Ma. Copyright © 2015 John Wiley & Sons, Ltd.     

基于历史数据的中国台风灾害孕灾环境敏感性分析

根据台风路径数据,通过计算评价单元内不同强度台风灾害发生频数和路径长度,综合表征台风孕灾环境敏感性的大小。结果表明:1)在四个强度台风条件下,敏感性最高的区域位于海南省、广东省沿海、福建省和浙江省沿海,随着台风灾害强度增强,影响范围呈现向北、向内陆延伸、扩展的趋势;2)台风灾害强度达到中度时,高敏感性的区域减少,低敏感性的区域面积大幅度增加,同时,台风路径东移明显,福建所受影响加重,海南和广东影响有所减小。