福建东山变质岩LA-ICP-MS同位素年龄及其地质意义

LA-ICPMS锆石U-Pb法测得东山地区变质岩的年龄为176.8 Ma、203 Ma、230 Ma、1320 Ma、1810 Ma等,其中176.8 Ma为火山-沉积岩中的岩浆锆石,代表着地层形成的年龄;203 Ma、230 Ma为继承岩浆碎屑锆石,代表了晚三叠世源区火成岩的物源年龄;1810 Ma、1320 Ma为变质岩继承锆石,代表了基底物源年龄。地球化学分析结果表明:岩石具贫硅、高铝、铁,富钾,Co、Ni、V含量低,Ba、Rb、Zr、Hf、U、Th及La含量高,具壳源特征;稀土元素总量较高,轻稀土略富集,轻、重稀土元素分异不明显,无明显的负铕异常,表明变质岩的部分物质与地幔有关。福建东山地区亲营山组可能属早侏罗世晚期华夏陆块边缘进入裂陷期海陆交互相火山-沉积的产物。     

Kinetic and chemical equilibrium of the Universe and gravitino production

Flat directions in generic supersymmetric theories can change the thermal history of the Universe. A novel scenario was proposed earlier where the vacuum expectation value of the flat directions induces large masses for all the gauge bosons and gauginos. This delays the thermalization of the Universe after inflation and solves the gravitino problem. In this article we perform a detailed calculation of the above scenario. We include the appropriate initial state particle distribution functions, consider the conditions for the feasibility of the non-thermal scenario, and investigate phase space suppression of gravitino production in the context of heavy gauge bosons and gauginos in the final state. We find that the total gravitino abundance generated is consistent with cosmological constraints.     

The kinematic characteristics of magnetic O‐type stars

Although magnetic fields have been discovered in ten massive O‐type stars during the last years, the origin of their magnetic fields remains unknown. Among the magnetic O‐type stars, two stars, HD 36879 and HD 57682, were identified as candidate runaway stars in the past, and θ¹ Ori C was reported to move rapidly away from its host cluster. We search for an explanation for the occurrence of magnetic fields in O‐type stars by examining the assumption of their runaway status. We use the currently best available astrometric, spectroscopic, and photometric data to calculate the kinematical status of seven magnetic O‐type stars with previously unknown space velocities. The results of the calculations of space velocities suggest that five out of the seven magnetic O‐type stars can be considered as candidate runaway stars. Only two stars, HD 155806 and HD 164794, with the lowest space velocities, are likely members of Sco OB4 and NGC 6530, respectively. However, the non‐thermal radio emitter HD 164794 is a binary system with colliding winds, for which the detected magnetic field has probably a different origin in comparison to other magnetic O‐type stars (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

基于支持向量机的2021年2月13日日本福岛近海Mj7.3级地震震级估算

2021年2月13日日本福岛县近海发生M_j7.3级地震,触发了日本气象厅地震预警系统,系统在首台触发后5.6s发出震级为M_j6.3级的预警第1报,首台触发后10s对公众发布警报、预警震级为M_j6.4级。基于多类型特征参数输入的机器学习支持向量机震级估算模型（SVM-M）,利用2021年2月13日日本福岛县近海M_j7.3级地震获取的日本K-net强震动观测数据,分析SVM-M模型在该次地震中首台触发初期（首台触发后1~10s）的震级估算效能。结果表明:SVM-M震级估算模型,在首台触发后1s即可给出M_j6.3级的震级估算结果,与日本气象厅在首台触发后5.6s发布的预警第1报震级相同;随着时间窗的增加,首台触发后5s和10s,SVM-M模型的震级估算结果分别是M_j6.7级和M_j6.6级,均大于日本气象厅首台触发后10s对公众发布警报的预警震级。该次地震的离线模拟结果表明:SVM-M模型可在地震发生初期有效提高地震预警震级确定的准确性和时效性。     

2021年2月13日日本福岛Mj7.3级地震潜在破坏区快速估计

基于2021年2月13日日本福岛M_j7.3级地震加速度记录,离线模拟了阈值预警方法在此次地震中快速估计潜在破坏区的表现。结果显示,该方法能够在台站P波触发后3s就快速对台站及其周边区域进行地震破坏性判断,同时估计的潜在破坏区域也基本与美国地质调查局（USGS） ShakeMap震后实测VII度以上区域吻合,展示了该方法在此次地震中运用的可行性;然而该方法没有对处在震后实测VII度以上区域内的宫城县南部沿海以及福岛县小部分东北区域给出准确的潜在破坏区判断,这一估计偏差为该方法的适应性研究以及下一步优化提供了参考。     

Geologic age of the lower Josoji Formation,Shimane Peninsula,Southwest Honshu,Japan: Implications for an abrupt change to deep-water during the earlier opening stage of the Japan Sea

The lower part of the Josoji Formation, Shimane Peninsula, contains clues for figuring out changes in deep-water characteristics during the opening of the Japan Sea. The foraminiferal assemblage includes early to middle Miocene biostratigraphic index taxa such as planktonic foraminiferal Globorotalia zealandica and Globorotaloides suteri. The occurrence of these two species, together with the absence of praeorbulinids, suggests that the lower part of the Josoji Formation is assigned to the top of planktonic foraminiferal Zone N7/M4 (16.39 Ma). The benthic foraminiferal assemblage, which is characterized by Cyclammina cancellata and Martinottiella communis, clearly suggests that the lower Josoji Formation was deposited at bathyal depths, and that it developed in association with the abrupt appearance of deep-sea calcareous forms. Such bathyal taxa are the main constituents of the Spirosigmoilinella compressa–Globobulimina auriculata Zone of the Josoji Formation and also of the Gyrodina–Gyroidinoides Zone at Ocean Drilling Program Site 797 in the Japan Sea. The base of these benthic foraminiferal zones can be correlated with the base of the nannofossil Sphenolithus heteromorphus Base Zone (= CNM6/CN3); thus, its estimated age is 17.65 Ma. This biostratigraphic information suggests that the lower Josoji Formation was deposited from shortly before 17.65–16.39 Ma in upper limit age. Evidence that fresh to brackish and shallow-water basins formed in the rifting interval of 20–18 Ma in the Japan Sea borderland suggests that the abrupt appearance of deep-sea calcareous foraminifera occurred about 1 my earlier in this area than in other sedimentary basins and suggests that a significant paleoceanographic change occurred in the proto-Japan Sea at 17.65 Ma.     

Charge exchange in massive star‐forming regions

As a result of feedback from massive stars, via their intense winds and/or supernova explosions, massive star‐forming regions are entirely filled with hot, X‐ray emitting plasmas, which escape into the ambient ISM. As shown recently by Townsley et al. for several “extreme” cases (Carina, M17, NGC 3576, NGC 3603, 30 Dor), by way of large Chandra ACIS mosaics, extra, non‐thermal emission lines are present on top of the standard lines emitted by hot plasmas. Some of them are very close to lines characteristic of charge‐exchange reactions between the hot plasma and the cold surrounding material, suggesting that this mechanism operates on large spatial scales (several 10 pc) in star‐forming regions in general. The connection with starburst galaxies is briefly mentioned, and it is pointed out that supernovae interacting with molecular clouds may also provide a good environment to look for charge exchange processes (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

重庆市地质灾害监测预警信息系统建设与应用

文章从系统建设需求、系统构架、功能组成及数据集成建设、系统展示与应用六个方面介绍了重庆市地质灾害监测预警系统建设与应用。系统研发过程中利用了计算机网络、通信和3S技术,按照统一的标准和规范要求建设,旨在搭建一个重庆市地质灾害防治信息与监测预警平台,实现地质灾害防治网络化运作模式,提升地质灾害防治日常管理、监测预警、决策支持和应急处置能力,为重庆地质灾害防治提供信息服务及决策服务。     

张衡地动仪的诞生

地动仪的诞生有着深厚的历史背景,本文旨在探讨张衡科学思想的形成过程和物质基础.张衡生活在东汉文化发展的顶峰时期,“观察异象、辨别凶吉”的朴素愿望是研制地动仪的原始动力.作者追溯了当时的历史背景、张衡的学术历程、地动仪的问世过程,分析了东汉早期的地震活动、古代的地震观念和灵台科学活动的特点.指出地动仪的研制起步于公元128年,张衡基于感性认识升华出两个地震概念——地震的位置可按方位判断、地震和地裂必须加以区别,这使地动仪的研制有了明确的技术追求.仪器制作上,张衡崇尚“制器尚象”的原则.地动仪的测震原理模仿了悬挂物(即天然验震器)对地震的反应,技术实现上借鉴了门闩类的触发机构,还通过龙首吐丸的方式留下了发生地震的物质证据,这3个关键问题的解决成就了公元132年地动仪的问世和134年的成功验震,构成他科技创新的完整内容.地动仪的发明深化了人类对自然规律的认识,对当时的东汉及其后世界文化的发展具有积极意义.     

ENERGY SOURCES FOR EVAPORATION ON TROPICAL ISLANDS

The sources of energy for evaporation on tropical islands were explored by studying 49 lowland sites in the Hawaiian Islands with concurrent pan evaporation and solar radiation measurements. The Priestley-Taylor (1972) method was used to quantify the contribution of solar radiation in evaporation and the residual term between estimated and measured evaporation was attributed to heat advection. Pearson correlation coefficients between monthly measured and estimated evaporation (using solar radiation data) were greater than 0.95 at 26 of the sites, 0.90 for 37 sites, and 0.80 at 46 of the 49 sites used in the study. As expected, solar radiation supplies the bulk of the energy absorbed by evaporation at low elevations in Hawaii. However, a pattern of negative advection in summer and positive advection in winter from the surrounding ocean modifies the monthly evaporation values. For the 20 sites showing the greatest oceanic influence, departures ranged, on average, from +0.84 mm/day in November to -0.71 mm/day in June. This onshore advection corresponds to the seasonal lag in sea surface temperatures. At inland and wet lee sites, the effect of advection from oceanic sources diminishes. At dry lee sites, strong positive advection is evident in summer and autumn, enhancing evaporation by up to 2.8 mm/day. [Key words: evaporation, energy, tropical islands, radiation, advection]