Abstract: Two-Stages of Cenozoic Tectonic Deformation in the California Borderland

AAPG Bulletin ◽  
1998 ◽  
Vol 82 (1998) ◽  
Author(s):  
HOWELL, S. M., I. SACRAMENTOGRILO,
Keyword(s):  
Tectonic Deformation ◽  
California Borderland ◽  
Two Stages

Archaean precious-metal hydrothermal systems, Dome Mine, Abitibi Greenstone Belt. I. Patterns of alteration and metal distribution

1979 ◽  
Vol 16 (3) ◽  
pp. 421-439 ◽  
Author(s):  
B. J. Fryer ◽  
R. Kerrich ◽  
R. W. Hutchinson ◽  
M. G. Peirce ◽  
D. S. Rogers
Keyword(s):  
Greenstone Belt ◽  
Precious Metals ◽  
Hydrothermal Systems ◽  
Tectonic Deformation ◽  
Hydrothermal Quartz ◽  
Abitibi Greenstone Belt ◽  
Two Stages ◽  
Host Rocks ◽  
Chemical Sediments ◽  
Gold Bearing

The Porcupine District, Abitibi Greenstone Belt is one of the most extensive areas of Archaean auriferous mineralization. At least two stages of lode gold emplacement may be recognized. The first involves gold-bearing ferroan dolomite layers with subordinate chert, sulphides, and graphite deposited as laterally extensive chemical sediments at interflow horizons within the mafic volcanic sequence. The second stage is represented by major gold-bearing hydrothermal quartz–albite–dravite veins which transect diverse host rocks including the carbonate chemical sediments. Differences between gold-bearing chemical sediment and auriferous hydrothermal veins, in terms of texture, mineralogy, and nature of inclusions, together with considerations of chemistry are not compatible with local derivation of veins from enveloping chemical sediments or adjacent host rocks. The chemical sediments display slump structures and predate all tectonic deformation. In general, auriferous hydrothermal quartz veins transect bedding and/or schistosity, and are at a low state of internal strain. They appear to have been emplaced late during the second regional fold episode.Au, Ag, and Pd average 10, 2, and 0.1 ppm respectively in ore types at the Dome mine; representing concentration factors of 10 000,40, and 10 times background values in unmineralized metabasalt, and primary igneous rocks worldwide. Au and Ag are inhomogeneously distributed.Mineralized metabasic rocks adjacent to vein stockworks have Ti/Zr and Ti/Al2O3 ratios comparable to tholeiitic basalts, but display variable enrichment or depletion of silica, systematic depletion in Na2O, and where intensely altered significant extraction of calcium. The low Ni and Cr contents of the carbonate layers, together with low Ti/Zr ratios (43–78) of the carbonates and their enveloping mafic schists, are not consistent with the hypothesis that these auriferous rocks are carbonated ultramafics. Massive banded quartz–fuchsite–dravite veins have Cr and Ni abundances averaging 350 ppm, implying hydrothermal transport of these elements. Ti/Zr ratios of 120, together with high Mg, Cr, and Ni abundances in magnesite–dolomite–quartz– chlorite schists which host the banded veins are compatible with a primary komatiitic composition. Mineralized metabasic rocks are reduced (Fe2+/ΣFe = 0.9) relative to rocks with primary background abundances of precious metals (Fe2+/ΣFe = 0.7). This change of oxidation state implies that large volumes of reducing hydrothermal solutions were involved in vein mineralization.

scholarly journals Neotectonics, drainage pattern and geomorphology of the orogen-parallel Upper Enns Valley (Eastern Alps)

2011 ◽  
Vol 62 (3) ◽  
pp. 279-295 ◽  
Author(s):  
Melanie Keil ◽  
Franz Neubauer
Keyword(s):  
Late Pleistocene ◽  
Source Region ◽  
Eastern Alps ◽  
Tectonic Deformation ◽  
Provenance Analysis ◽  
Drainage Pattern ◽  
Surface Uplift ◽  
Basement Rocks ◽  
Two Stages ◽  
Analytical Limit

Neotectonics, drainage pattern and geomorphology of the orogen-parallel Upper Enns Valley (Eastern Alps)The geomorphology and neotectonics of the Upper Enns Valley (Austria) in the Eastern Alps reveal the formation of a fault-controlled orogen-parallel valley. In the study area, the Eastern Alps have been under surface uplift since Early Miocene times. Quaternary processes such as uplift and cyclic glaciations likely interfere with neotectonic activity as the Upper Enns Valley follows the Salzach-Enns-Mariazell-Puchberg (SEMP) fault. The geomorphologically different landscapes comprise three main tectonic units: (1) the Austroalpine crystalline basement exposed in the Niedere Tauern, (2) the Austroalpine Paleozoic units (Greywacke Zone) and (3) the Dachstein Plateau dominated by Triassic carbonate successions. The Upper Pleistocene Ramsau Conglomerate overlying the Greywacke Zone on the northern slope of the Upper Enns Valley is a crucial element to reconstruct the evolution of the valley. A new14C date (uncalibrated) indicates an age older than 53,300 years, outside of the analytical limit of the methods. Provenance analysis of the Ramsau Conglomerate shows the Niedere Tauern as a source region and consequently a post-early Late Pleistocene dissection of the landscape by the Upper Enns Valley. Paleosurfaces at elevations of about 1100 m on the northern and southern slopes of the Upper Enns Valley allow us to estimate surface uplift/incision of about 2.5 mm/yr. Regularly oriented outcrop-scale faults and joints of the Ramsau Conglomerate document Pleistocene to Holocene tectonic deformation, which is consistent with ongoing seismicity. Paleostress tensors deduced from slickensides and striae of pre-Cenozoic basement rocks indicate two stages of Late Cretaceous to Paleogene deformation independent of the SEMP fault; the Oligocene-Neogene evolution comprises NW-SE strike-slip compression followed by E-W compression and Late Pleistocene ca. E-W extension, the latter recorded in the Ramsau Conglomerate.

Altered Fine Structure of B Lymphocytes Correlated with Defective Terminal Differentiation

1973 ◽  
Vol 31 ◽  
pp. 386-387
Author(s):  
Dale E. Bockman ◽  
L. Y. Frank Wu ◽  
Alexander R. Lawton ◽  
Max D. Cooper
Keyword(s):  
Immune Deficiency ◽  
B Lymphocytes ◽  
Plasma Cells ◽  
Present Report ◽  
Specific Antigen ◽  
Terminal Differentiation ◽  
Second Stage ◽  
Two Stages ◽  
Deficiency Diseases ◽  
Cell Line Generation

B-lymphocytes normally synthesize small amounts of immunoglobulin, some of which is incorporated into the cell membrane where it serves as receptor of antigen. These cells, on contact with specific antigen, proliferate and differentiate to plasma cells which synthesize and secrete large quantities of immunoglobulin. The two stages of differentiation of this cell line (generation of B-lymphocytes and antigen-driven maturation to plasma cells) are clearly separable during ontogeny and in some immune deficiency diseases. The present report describes morphologic aberrations of B-lymphocytes in two diseases in which second stage differentiation is defective.

Formation of Dislocation Channels in Neutron Irradiated Molybdenum

1972 ◽  
Vol 30 ◽  
pp. 672-673
Author(s):  
S. Mahajan
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Ambient Temperature ◽  
Room Temperature ◽  
Channel Formation ◽  
Early Stages ◽  
Transmission Electron ◽  
Three Stages ◽  
Two Stages ◽  
Polycrystalline Molybdenum

The evolution of dislocation channels in irradiated metals during deformation can be envisaged to occur in three stages: (i) formation of embryonic cluster free regions, (ii) growth of these regions into microscopically observable channels and (iii) termination of their growth due to the accumulation of dislocation damage. The first two stages are particularly intriguing, and we have attempted to follow the early stages of channel formation in polycrystalline molybdenum, irradiated to 5×1019 n. cm−2 (E > 1 Mev) at the reactor ambient temperature (∼ 60°C), using transmission electron microscopy. The irradiated samples were strained, at room temperature, up to the macroscopic yield point.Figure 1 illustrates the early stages of channel formation. The observations suggest that the cluster free regions, such as A, B and C, form in isolated packets, which could subsequently link-up to evolve a channel.

Assessment of Questions and Questionaries

1971 ◽  
Vol 10 (04) ◽  
pp. 222-228 ◽  
Author(s):  
D. W. YOUNG
Keyword(s):  
Two Stages ◽  
The Way

A method is presented for the evaluation of. both individual questions and whole questionaries. The method involves two stages, administering the questions and later an interview at which the questions are reasked and the answers checked. It is suggested that questions can be described by means of nine properties and that questionaries can be described by means of these same nine properties plus two others. A set of indices representing these properties is derived from the evaluation of a particular set of questions. The way certain indices are selected for different purposes is discussed.

Interference mitigation in point to point wireless sensor networks using LSP protocol and time division multiplexing approach

2020 ◽  
Vol 39 (4) ◽  
pp. 5449-5458
Author(s):  
A. Arokiaraj Jovith ◽  
S.V. Kasmir Raja ◽  
A. Razia Sulthana
Keyword(s):  
Energy Consumption ◽  
Large Scale ◽  
Control Parameter ◽  
Interference Mitigation ◽  
Wireless Sensor ◽  
Point To Point ◽  
A Minor ◽  
Two Stages ◽  
Time Division ◽  
And Control

Interference in Wireless Sensor Network (WSN) predominantly affects the performance of the WSN. Energy consumption in WSN is one of the greatest concerns in the current generation. This work presents an approach for interference measurement and interference mitigation in point to point network. The nodes are distributed in the network and interference is measured by grouping the nodes in the region of a specific diameter. Hence this approach is scalable and isextended to large scale WSN. Interference is measured in two stages. In the first stage, interference is overcome by allocating time slots to the node stations in Time Division Multiple Access (TDMA) fashion. The node area is split into larger regions and smaller regions. The time slots are allocated to smaller regions in TDMA fashion. A TDMA based time slot allocation algorithm is proposed in this paper to enable reuse of timeslots with minimal interference between smaller regions. In the second stage, the network density and control parameter is introduced to reduce interference in a minor level within smaller node regions. The algorithm issimulated and the system is tested with varying control parameter. The node-level interference and the energy dissipation at nodes are captured by varying the node density of the network. The results indicate that the proposed approach measures the interference and mitigates with minimal energy consumption at nodes and with less overhead transmission.

Distributed Entropy Energy-Efficient Clustering algorithm for cluster head selection (DEEEC)

2020 ◽  
Vol 39 (6) ◽  
pp. 8139-8147
Author(s):  
Ranganathan Arun ◽  
Rangaswamy Balamurugan
Keyword(s):  
Energy Efficient ◽  
Clustering Algorithm ◽  
Cluster Head ◽  
Residual Energy ◽  
Energy Utilization ◽  
Sensor Nodes ◽  
Second Stage ◽  
Energy Efficient Clustering ◽  
Two Stages ◽  
Ch Selection

In Wireless Sensor Networks (WSN) the energy of Sensor nodes is not certainly sufficient. In order to optimize the endurance of WSN, it is essential to minimize the utilization of energy. Head of group or Cluster Head (CH) is an eminent method to develop the endurance of WSN that aggregates the WSN with higher energy. CH for intra-cluster and inter-cluster communication becomes dependent. For complete, in WSN, the Energy level of CH extends its life of cluster. While evolving cluster algorithms, the complicated job is to identify the energy utilization amount of heterogeneous WSNs. Based on Chaotic Firefly Algorithm CH (CFACH) selection, the formulated work is named “Novel Distributed Entropy Energy-Efficient Clustering Algorithm”, in short, DEEEC for HWSNs. The formulated DEEEC Algorithm, which is a CH, has two main stages. In the first stage, the identification of temporary CHs along with its entropy value is found using the correlative measure of residual and original energy. Along with this, in the clustering algorithm, the rotating epoch and its entropy value must be predicted automatically by its sensor nodes. In the second stage, if any member in the cluster having larger residual energy, shall modify the temporary CHs in the direction of the deciding set. The target of the nodes with large energy has the probability to be CHs which is determined by the above two stages meant for CH selection. The MATLAB is required to simulate the DEEEC Algorithm. The simulated results of the formulated DEEEC Algorithm produce good results with respect to the energy and increased lifetime when it is correlated with the current traditional clustering protocols being used in the Heterogeneous WSNs.

Analisis Kebutuhan Petunjuk Praktikum Berbasis Keterampilan Proses Sains untuk Mencapai Kemampuan Merancang Eksperimen

2019 ◽  
Vol 2 (2) ◽  
Author(s):  
Fitriah Khoirunnisa ◽  
Friska Septiani Silitonga ◽  
Veri Firmansyah
Keyword(s):  
Core Competence ◽  
Process Skills ◽  
Learning Materials ◽  
Science Process Skills ◽  
Second Stage ◽  
The Core ◽  
The Core Competence ◽  
Two Stages ◽  
Practical Instruction ◽  
Design Experiments

Penelitian ini bertujuan menganalisis kebutuhan petunjuk praktikum berbasis Keterampilan Proses Sains (KPS) untuk mencapai kemampuan merancang eksperimen pada materi kalor reaksi kalorimetri. Penelitian dilakukan terhadap peserta didik kelas XI SMA Negeri 2 Kota Tanjungpinang. Variabel penelitian mencakup analisis kebutuhan bahan ajar dan analisis kesesuaian Kompetensi Inti (KI) dan Kompetensi Dasar (KD). Jenis penelitian yang dilakukan adalah penelitian deskriptif kualitatif. Tahapan pertama dalam penelitian ini adalah menganalisis kebutuhan bahan ajar dengan cara membandingkan dua petunjuk praktikum yang selama ini telah digunakan di sekolah tersebut, ditinjau dari aspek struktur format penulisan, aspek kreativitas, dan aspek keterampilan proses sains yang terdapat dalam petunjuk praktikum. Sehingga didapatkan kesimpulan bahwa petunjuk praktikum yang selama ini digunakan tidak memberikan kesempatan kepada peserta didiknya untuk merancang eksperimen yang telah ditentukan. Tahapan kedua yaitu menganalisis kesesuaian kompetensi inti dan kompetensi dasar, yang bertujuan untuk menentukan indikator pencapaian kompetensi (IPK) yang akan menjadi acuan dalam mengembangkan petunjuk praktikum berbasis keterampilan proses sains. Dari kedua tahapan yang telah dilakukan maka dapat disimpulkan bahwa peserta didik memerlukan petunjuk praktikum yang mampu mengonstruksi pikiran dan mengaktifkan kinerja mereka, sehingga pendekatan Keterampilan Proses Sains menjadi pilihan dalam mengembangkan petunjuk praktikum yang sesuai dengan karakteristik kurikulum 2013.   This research aims to analyze the needs of Science Process Skills based Practical Instruction to achieve the ability to design experiments on the calor of reaction. This research was done to the students of class XI SMA Negeri 2 Tanjungpinang City. Research Variable includes the analysis of the needs of the learning materials and analysis of the suitability of the Core Competence (KI) and Basic Competence (KD). The type of research conducted is descriptive qualitative research. The first stages in this research is to analyze the needs of learning materials by comparing two practical instructions that had been implementing in the school, from the aspects of the structure of writing format, creativity, and science process skills embedded in practical instructions. The conclusion of this research that current practical instructions does not give an opportunity to the participants to design determined experiments. The second stage, namely analyzing the suitability of core competence and basic competence, which aims to determine the indicators of achievement of the competencies (GPA) which will be a reference in developing process skills-based teaching instructions science. Of the two stages that has been done then it can be concluded that learners need practical instructions to construct  thinking and and their performance, so the Science Process Skills approach is an option in developing practical instruction suitable for the characteristics of the curriculum of 2013.

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