Evidence for Differential Unroofing in the Adirondack Mountains, New York State, Determined by Apatite Fission-Track Thermochronology

Apatite fission-track ages of 168-83 Ma for 39 samples of Proterozoic crystalline rocks, three samples of Cambrian Potsdam sandstone, and one Cretaceous lamprophyre dike from the Adirondack Mountains in New York State indicate that unroofing in this region occurred from Late Jurassic through Early Cretaceous. Samples from the High Peaks section of the Adirondack massif yielded the oldest apatite fission-track ages (168-135 Ma), indicating that it was exhumed first. Unroofing along the northern, northwestern, and southwestern margins of the Adirondacks began slightly later, as shown by younger apatite fission-track ages (146-114 Ma) determined for these rocks. This delay in exhumation may have resulted from burial of the peripheral regions by sediment shed from the High Peaks. Apatite fission-track ages for samples from the southeastern Adirondacks are distinctly younger (112-83 Ma) than those determined for the rest of the Adirondack region. These younger apatite fission-track ages are from a section of the Adirondacks dissected by shear zones and post-Ordovician north-northeast-trending normal faults. Differential unroofing may have been accommodated by reactivation of the faults in a reverse sense of motion with maximum compressive stress, sigma1, oriented west-northwest. A change in the orientation of the post-Early Cretaceous paleostress field is supported by a change in the trend of Cretaceous lamprophyre dikes from east-west to west-northwest.     

洋中脊处矿床的形成

２０年前,科学家乘“阿尔文”号深潜器沿东太平洋海隆２１°Ｎ洋中脊下潜,通过舷窗看到一个惊人景象:翻腾的云团状黑色“烟雾”从高高的岩石质“火山囱”顶部快速上升。由黑色、细粒颗粒组成的烟雾悬浮在热液卷流中,火山囱由富金属矿物组成。“阿尔文号”用特制流体瓶子和...     

澳大利亚的航空物探

澳大利亚的官方航空物探机构及其技术发展 澳大利亚地调局于1951年开始航磁测量工作,是将一台磁通门磁力仪安装在DC3(VH-BUR)固定翼飞机上.第二年在同一架飞机上安装了闪烁晶体探测器,进行了300m测线间距的航放测量.在当时这是全国仅有的一家航空物探机构,到1955年发展到拥有60多人4架测量飞机的航空磁/放测量队伍.1963年在装有闪烁晶体探测器的CESSNA180(VHGEO)飞机上安装了质子旋进磁力仪.     

澳大利的航空物探

澳大利亚的官方航空物探机构及其技术发展澳大利亚地调局于1951年开始航磁测量工作,是将一台磁通门磁力仪安装在DC3(VH-BUR)固定翼飞机上.第二年在同一架飞机上安装了闪烁晶体探测器,进行了300m测线间距的航放测量.在当时这是全国仅有的一家航空物探机构,到1955年发展到拥有60多人4架测量飞机的航空磁/放测量队伍.1963年在装有闪烁晶体探测器的CESSNA180(VH-     

在计算合成震波图中震源和接收器井孔效果的组合

由于震源移入不同的地层及由于井孔环境的变化，井孔震源的辐射图形有很大变化，同样，地震检波器也有能够影响记录波形的接收图形。我们用两种方式将这些振幅和相位以合成震波图中。首先，由３－Ｄ有限并分的直接解为相对较小的地球模型提供精确的全波形解。对于震源／接收器大间距的模拟，我们将震源辐射的静止相位解与射线追踪的接收图形相结合。有限差分震波图与从均匀试验介质中计算出射线追踪结果的比较表明：根据射线计算出的     

利用初至时距进行相位改正的波动方程析射线法

我们利用初至时距改正非线性波动方程反演方法中的相位畸变问题，从而改善了大变量速度层析射线重精度，并帮助解决了波动方程反演的不适当问题，当速度分布变化较大时，普通的非线性波动方程反演严重不适定，对于这样严重的非线性问题，不能获得正确的反结果。     

Cloning and sequence analysis of the self-fertilizing fish Rivulus marmoratus immediate early gene c-fos

We have cloned the proto-oncogene c-fos from a self-fertilizing fish Rivulus marmoratus (Cyprinodontiformes, Rivulidae) after screening of R. marmoratus lambdaGEM-11 genomic DNA library, and sequenced over 12 kb including all exons, introns and the promoter region. The R. marmoratus c-fos gene consisted of one noncoding exon and four exons with high similarity to those of fugu and mammals. We sequenced approximately 7 kb of the R. marmoratus c-fos gene promoter region to gain a better understanding of the molecular anatomy of the immediate response of this gene upon cellular damage. In the promoter region, R. marmoratus c-fos gene has seven xenobiotic response elements (XREs) and eight metal response elements (MREs) as well as two estradiol (E2), 4 NFkappaB, 2 CarG, 2 prolactin (PRL) motifs and one pit1 site, while the 3'-UTR of this gene contains the estrogen response element (ERE). The seven XRE and eight MRE motifs raise the possibility of its regulation by exposure to environmental pollutants. In this paper, we discuss the gene structure of R. marmoratus c-fos gene and compare its promoter region with those of other organisms' c-fos genes. We propose its potential use in ecotoxicology.     

Female infanticide and child neglect as possible reasons for low sex ratio in the Punjab, 1881-1931

"The social and cultural practices prevalent in various parts of [India] resulted in the neglect of the female child...[in general, and] probably more so in the Punjab. Moreover, female mortality significantly exceeded male mortality in years of epidemics and famines. This paper tries to examine the socio-cultural and economic factors, namely, the system of land holdings and inheritance strategies, structured customs in different parts of the province, and notions of honour and status which probably have been at the back of neglect of the girl child. Among certain caste groups even female infanticide might not have been uncommon."