The East African Rift System in the Light of KRISP 90
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Tectonic Imbrication and Foredeep Development in the Penokean
Tectonic Imbrication and Foredeep Development in the Penokean Orogen, East-Central Minnesota An Interpretation Based on Regional Geophysics and the Results of Test-Drilling The Penokean Orogeny in Minnesota and Upper Michigan A Comparison of Structural Geology U.S. GEOLOGICAL SURVEY BULLETIN 1904-C, D AVAILABILITY OF BOOKS AND MAPS OF THE U.S. GEOLOGICAL SURVEY Instructions on ordering publications of the U.S. Geological Survey, along with prices of the last offerings, are given in the cur rent-year issues of the monthly catalog "New Publications of the U.S. Geological Survey." Prices of available U.S. Geological Sur vey publications released prior to the current year are listed in the most recent annual "Price and Availability List." Publications that are listed in various U.S. Geological Survey catalogs (see back inside cover) but not listed in the most recent annual "Price and Availability List" are no longer available. Prices of reports released to the open files are given in the listing "U.S. Geological Survey Open-File Reports," updated month ly, which is for sale in microfiche from the U.S. Geological Survey, Books and Open-File Reports Section, Federal Center, Box 25425, Denver, CO 80225. Reports released through the NTIS may be obtained by writing to the National Technical Information Service, U.S. Department of Commerce, Springfield, VA 22161; please include NTIS report number with inquiry. Order U.S. Geological Survey publications by mail or over the counter from the offices given below. BY MAIL OVER THE COUNTER Books Books Professional Papers, Bulletins, Water-Supply Papers, Techniques of Water-Resources Investigations, Circulars, publications of general in Books of the U.S. -
PROFILES of ATTRACTION SITES-ELGEYO MARAKWET. Tourist Attractions in Elgeyo Marakwet County Include Sports Tourism, Rivers, a Na
PROFILES OF ATTRACTION SITES-ELGEYO MARAKWET. Tourist attractions in Elgeyo Marakwet County include Sports Tourism, Rivers, A national reserve, waterfalls and the hills and escarpments. Rimoi National Reserve The National Reserve is a protected area in the kerio valley along the escarpment of the Great Rift Valley. The 66 square kilometers (25sq mi) reserve was created in 1983 and is managed by the Kenya Wildlife Service. The isolated Kerio Valley lies between the Cherangani Hills and the Tugen Hills with the Elgeyo Escarpment rising more than 1,830 meters (6,000ft) above the valley in places. The valley is 4,000 feet (1,200m) deep. It has semi-tropical vegetation on the slopes, while the floor of the valley is covered by dry thorn bush. The most comfortable time of the year is in July and August when the rains have ended and the temperatures are not excessive. The reserve is on the west side of the Kerio River, while the Lake Kamnarok National Reserve is on the east side. The reserve has beautiful scenery, prolific birdlife and camping site in the bush beside Lake Kamnarok. Gazzement of the conservation area was done to protect wildlife from rampant poaching which was going on at the time. A fence was also put up to address human wildlife conflicts. It provides unique geological scenery & biodiversity and is one of the few protected areas within the spectacular Kerio Valley. The main attraction is the groups of elephants, Culture and scenery of the Kerio valley. The Reserve has earth and gravel road network which make for an adventurous outing. -
Potential Capacity for Geologic Carbon Sequestration in the Midcontinent Rift System in Minnesota
MINNESOTA GEOLOGICAL SURVEY Harvey Thorleifson, Director POTENTIAL CAPACITY FOR GEOLOGIC CARBON SEQUESTRATION IN THE MIDCONTINENT RIFT SYSTEM IN MINNESOTA L. Harvey Thorleifson, Minnesota Geological Survey, Editor A report prepared in fulfillment of the requirements of Minnesota Legislative Session 85 Bill S. F. 2096 Minnesota Geological Survey Open File Report OFR-08-01 University of Minnesota Saint Paul – 2008 Cover figure credit: Iowa Geological Survey 2 POTENTIAL CAPACITY FOR GEOLOGIC CARBON SEQUESTRATION IN THE MIDCONTINENT RIFT SYSTEM IN MINNESOTA 3 This open file is accessible from the web site of the Minnesota Geological Survey (http://www.geo.umn.edu/mgs/) as a PDF file readable with Acrobat Reader. Date of release: 24 January 2008 Recommended citation Thorleifson, L. H., ed., 2008, Potential capacity for geologic carbon sequestration in the Midcontinent Rift System in Minnesota, Minnesota Geological Survey Open File Report OFR-08-01, 138 p Minnesota Geological Survey 2642 University Ave West Saint Paul, Minnesota 55114-1057 Telephone: 612-627-4780 Fax: 612-627-4778 Email address: [email protected] Web site: http://www.geo.umn.edu/mgs/ ©2008 by the Regents of the University of Minnesota All rights reserved The University of Minnesota is committed to the policy that all persons shall have equal access to its programs, facilities, and employment without regard to race, color, creed, religion, national origin, sex, age, marital status, disability, public assistance status, veteran status, or sexual orientation. 4 CONTENTS EXECUTIVE SUMMARY L. H. Thorleifson . 7 INTRODUCTION L. H. Thorleifson . 11 CLIMATE CHANGE L. H. Thorleifson . 11 Introduction . 11 Intergovernmental Panel on Climate Change (IPCC) . -
U–Pb Zircon (SHRIMP) Ages for the Lebombo Rhyolites, South Africa
Journal of the Geological Society, London, Vol. 161, 2004, pp. 547–550. Printed in Great Britain. 2000) and the ages corroborate and further strengthen the SPECIAL chronology of the Lebombo stratigraphy. The rapid eruption of the Karoo succession is thought to have been responsible for trigger- U–Pb zircon (SHRIMP) ing the early Toarcian extinction event (Hesselbo et al. 2000). Geological setting. The Karoo Supergroup succession along the ages for the Lebombo Lebombo monocline is highlighted in Figure 1. The oldest phase of Karoo volcanism is marked by the Mashikiri nephelinites, rhyolites, South Africa: which unconformably overlie Jurassic Clarens Formation sand- stones (Fig. 2). The nephelinites have been dated at 182.1 Æ refining the duration of 1.6 Ma (40Ar/39Ar plateau age; Duncan et al. 1997) and form a lava succession up to 170 m thick (Bristow 1984). These rocks Karoo volcanism are confined to the northern part of the Lebombo rift and are absent along the central and southern sections. The nephelinites T. R. RILEY1,I.L.MILLAR2, are conformably overlain by picrites and picritic basalts of the 3 1 Letaba Formation, although in the southern Lebombo the picrites M. K. WATKEYS ,M.L.CURTIS, directly overlie the Clarens Formation. The picrites overlap in 1 3 P. T. LEAT , M. B. KLAUSEN & age (182.7 Æ 0.8 Ma; Duncan et al. 1997) with the Mashikiri C. M. FANNING4 nephelinites and are believed to form a succession up to 4 km in thickness. 1British Antarctic Survey, High Cross, Madingley Road, The Letaba Formation picrites are in turn overlain by a major Cambridge, CB3 0ET, UK (e-mail: [email protected]) succession (4–5 km thick) of low-MgO basalts, termed the Sabie 2British Antarctic Survey c/o NERC Isotope Geosciences River Basalt Formation (Cleverly & Bristow 1979). -
Insights from the P Wave Travel Time Tomography in the Upper Mantle Beneath the Central Philippines
remote sensing Article Insights from the P Wave Travel Time Tomography in the Upper Mantle Beneath the Central Philippines Huiyan Shi 1 , Tonglin Li 1,*, Rui Sun 2, Gongbo Zhang 3, Rongzhe Zhang 1 and Xinze Kang 1 1 College of Geo-Exploration Science and Technology, Jilin University, No.938 Xi Min Zhu Street, Changchun 130026, China; [email protected] (H.S.); [email protected] (R.Z.); [email protected] (X.K.) 2 CNOOC Research Institute Co., Ltd., Beijing 100028, China; [email protected] 3 State Key Laboratory of Geodesy and Earth’s Dynamics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, China; [email protected] * Correspondence: [email protected] Abstract: In this paper, we present a high resolution 3-D tomographic model of the upper mantle obtained from a large number of teleseismic travel time data from the ISC in the central Philippines. There are 2921 teleseismic events and 32,224 useful relative travel time residuals picked to compute the velocity structure in the upper mantle, which was recorded by 87 receivers and satisfied the requirements of teleseismic tomography. Crustal correction was conducted to these data before inversion. The fast-marching method (FMM) and a subspace method were adopted in the forward step and inversion step, respectively. The present tomographic model clearly images steeply subduct- ing high velocity anomalies along the Manila trench in the South China Sea (SCS), which reveals a gradual changing of the subduction angle and a gradual shallowing of the subduction depth from the north to the south. -
The Geothermal Activity of the East African Rift
Presented at Short Course IV on Exploration for Geothermal Resources, organized by UNU-GTP, KenGen and GDC, at Lake Naivasha, Kenya, November 1-22, 2009. Kenya Electricity Generating Co., Ltd. GEOTHERMAL TRAINING PROGRAMME Geothermal Development Company THE GEOTHERMAL ACTIVITY OF THE EAST AFRICAN RIFT Peter A. Omenda Geothermal Development Company P. O. Box 100746, Nairobi 00101 KENYA [email protected] ABSTRACT The East Africa Rift System is a classical continental rift system associated with the world-wide mid ocean rift systems. The rift extends from the Red Sea – Afar triple junction through Ethiopian highlands, Kenya, Tanzania and Malawi to Mozambique in the south. The western branch passes through Uganda, DRC and Rwanda while the nascent south-western branch runs through Luangwa and Kariba rifts in Zambia into Botswana. The volcanic and tectonic activity in the rift started about 30 million years ago and in the eastern branch the activity involved faulting and eruption of large volumes of mafic and silicic lavas and pyroclastics. The western branch, typified by paucity of volcanism, is younger and dominated by faulting that has created deep basins currently filled with lakes and sediments. Geothermal activity in the rift is manifested by the occurrences of Quaternary volcanoes, hotsprings, fumaroles, boiling pools, hot and steaming grounds, geysers and sulphur deposits. The manifestations are abundant and stronger in the eastern branch that encompasses Afar, Ethiopian and Kenya rifts while in the western branch, the activity is subdued and occurs largely as hotsprings and fumaroles. Detailed and reconnaissance studies of geothermal potential in Eastern Africa indicates that the region has potential of 2,500MWe to 6,500MWe. -
Midcontinent Rift
VOL. 97 NO. 18 15 SEP 2016 NORTH AMERICA’S MIDCONTINENT RIFT Augmented Reality for Earth Science Quirky Geoscience Tunes Future of AGU Meetings NEW in Fall 2016 GeoHealth will foster the intersection of Earth science disciplines (Earth processes, climate change, atmospheric and ocean sciences, hydrology, among others), with those of the health sciences, defined broadly (environmental and ecosystem health and services, human and agricultural health, geomedicine, and the impact of natural hazards). Now Accepting Applications for Two Editors in Chief of GeoHealth AGU is launching GeoHealth under Founding Editor Rita R. Colwell. We are seeking applications for two dynamic, well-organized scientists with high editorial standards and strong leadership skills to serve 4-year terms as the editors in chief (EICs) to lead this exciting journal starting in 2017 and beyond. One editor’s main area of focus will be on the geosciences, while the other editor’s main area of focus will be on health. This is an important opportunity to help shape and lead this increasingly important, cross-cutting discipline. The EICs will be the principal architects of the scientific content of the journal. They are active scientists, well-known and well-regarded in their respective discipline. The EICs must be active in soliciting the best science from the best scientists to be published in the journal. Working with the other editors and AGU staff, EICs are the arbiter of the content of the journal. Among other functions, EICs will be responsible for: • Acting as an ambassador to the author/editor/reviewer/scientist community. • Setting the strategy for the journal. -
1843 KMS Kenya Past and Present Issue 43
Kenya Past and Present Issue 43 Kenya Past and Present Editor Peta Meyer Editorial Board Marla Stone Patricia Jentz Kathy Vaughan Kenya Past and Present is a publication of the Kenya Museum Society, a not-for-profit organisation founded in 1971 to support and raise funds for the National Museums of Kenya. Correspondence should be addressed to: Kenya Museum Society, PO Box 40658, Nairobi 00100, Kenya. Email: [email protected] Website: www.KenyaMuseumSociety.org Statements of fact and opinion appearing in Kenya Past and Present are made on the responsibility of the author alone and do not imply the endorsement of the editor or publishers. Reproduction of the contents is permitted with acknowledgement given to its source. We encourage the contribution of articles, which may be sent to the editor at [email protected]. No category exists for subscription to Kenya Past and Present; it is a benefit of membership in the Kenya Museum Society. Available back issues are for sale at the Society’s offices in the Nairobi National Museum. Any organisation wishing to exchange journals should write to the Resource Centre Manager, National Museums of Kenya, PO Box 40658, Nairobi 00100, Kenya, or send an email to [email protected] Designed by Tara Consultants Ltd ©Kenya Museum Society Nairobi, April 2016 Kenya Past and Present Issue 43, 2016 Contents KMS highlights 2015 ..................................................................................... 3 Patricia Jentz To conserve Kenya’s natural and cultural heritage ........................................ 9 Marla Stone Museum highlights 2015 ............................................................................. 11 Juliana Jebet and Hellen Njagi Beauty and the bead: Ostrich eggshell beads through prehistory .................................................. 17 Angela W. -
2009 Trip Report KENYA
KENYA and TANZANIA TRIP REPORT Sept 25-Oct 23, 2009 PART 1 - Classic Kenya text and photos by Adrian Binns Sept 25 / Day 1: Blue Post Thika; Castle Forest We began the morning with an unexpected Little Sparrowhawk followed by a Great Sparrowhawk, both in the skies across the main road from the Blue Post Hotel in Thika. The lush grounds of the Blue Post are bordered by the twin waterfalls of the Chania and Thika, both rivers originating from the nearby Aberdare Mountain Range. It is a good place to get aquatinted with some of the more common birds, especially as most can be seen in close proximity and very well. Eastern Black-headed Oriole, Cinnamon-chested Bee- eater, Little Bee-eater, White-eyed Slaty Flycatcher, Collared Sunbird, Bronzed Mannikin, Speckled Mousebird and Yellow-rumped Tinkerbird were easily found. Looking down along the river course and around the thundering waterfall we found a pair of Giant Kingfishers as well as Great Cormorant, Grey Heron and Common Sandpiper, and two Nile Monitors slipped behind large boulders. A fruiting tree provided a feast for Yellow-rumped Seedeaters, Violet-backed Starlings, Spot-flanked Barbet (right), White-headed Barbet as a Grey-headed Kingfisher, an open woodland bird, made sorties from a nearby perch. www.wildsidenaturetours.com www.eastafricanwildlifesafaris.com © Adrian Binns Page 1 It was a gorgeous afternoon at the Castle Forest Lodge set deep in forested foothills of the southern slope of Mt. Kenya. While having lunch on the verandah, overlooking a fabulous valley below, we had circling Long-crested Eagle (above right), a distant Mountain Buzzard and African Harrier Hawk. -
Africa-Arabia-Eurasia Plate Interactions and Implications for the Dynamics of Mediterranean Subduction and Red Sea Rifting
This page added by the GeoPRISMS office. Africa-Arabia-Eurasia plate interactions and implications for the dynamics of Mediterranean subduction and Red Sea rifting Authors: R. Reilinger, B. Hager, L. Royden, C. Burchfiel, R. Van der Hilst Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA USA, [email protected], Tel: (617)253 -7860 This page added by the GeoPRISMS office. Our proposed GeoPRISMS Initiative is based on the premise that understanding the mechanics of plate motions (i.e., the force balance on the plates) is necessary to develop realistic models for plate interactions, including processes at subduction and extensional (rifting) plate boundaries. Important advances are being made with new geologic and geophysical techniques and observations that are providing fundamental insights into the dynamics of these plate tectonic processes. Our proposed research addresses directly the following questions identified in the GeoPRISMS SCD Draft Science Plan: 4.2 (How does deformation across the subduction plate boundary evolve in space and time, through the seismic cycle and beyond?), 4.6 (What are the physical and chemical conditions that control subduction zone initiation and the development of mature arc systems?), and 4.7 (What are the critical feedbacks between surface processes and subduction zone mechanics and dynamics?). It has long been recognized that the Greater Mediterranean region provides a natural laboratory to study a wide range of geodynamic processes (Figure 1) including ocean subduction and continent- continent collision (Hellenic arc, Arabia-Eurasia collision), lithospheric delamination (E Turkey High Plateau, Alboran Sea/High Atlas), back-arc extension (Mediterranean basins, including Alboran, Central Mediterranean, Aegean), “escape” tectonics and associated continental transform faulting (Anatolia, North and East Anatolian faults), and active continental and ocean rifting (East African and northern Red Sea rifting, central Red Sea and Gulf of Aden young ocean rifting). -
Full-Text PDF (Final Published Version)
Pritchard, M. E., de Silva, S. L., Michelfelder, G., Zandt, G., McNutt, S. R., Gottsmann, J., West, M. E., Blundy, J., Christensen, D. H., Finnegan, N. J., Minaya, E., Sparks, R. S. J., Sunagua, M., Unsworth, M. J., Alvizuri, C., Comeau, M. J., del Potro, R., Díaz, D., Diez, M., ... Ward, K. M. (2018). Synthesis: PLUTONS: Investigating the relationship between pluton growth and volcanism in the Central Andes. Geosphere, 14(3), 954-982. https://doi.org/10.1130/GES01578.1 Publisher's PDF, also known as Version of record License (if available): CC BY-NC Link to published version (if available): 10.1130/GES01578.1 Link to publication record in Explore Bristol Research PDF-document This is the final published version of the article (version of record). It first appeared online via Geo Science World at https://doi.org/10.1130/GES01578.1 . Please refer to any applicable terms of use of the publisher. University of Bristol - Explore Bristol Research General rights This document is made available in accordance with publisher policies. Please cite only the published version using the reference above. Full terms of use are available: http://www.bristol.ac.uk/red/research-policy/pure/user-guides/ebr-terms/ Research Paper THEMED ISSUE: PLUTONS: Investigating the Relationship between Pluton Growth and Volcanism in the Central Andes GEOSPHERE Synthesis: PLUTONS: Investigating the relationship between pluton growth and volcanism in the Central Andes GEOSPHERE; v. 14, no. 3 M.E. Pritchard1,2, S.L. de Silva3, G. Michelfelder4, G. Zandt5, S.R. McNutt6, J. Gottsmann2, M.E. West7, J. Blundy2, D.H. -
The Science Behind Volcanoes
The Science Behind Volcanoes A volcano is an opening, or rupture, in a planet's surface or crust, which allows hot magma, volcanic ash and gases to escape from the magma chamber below the surface. Volcanoes are generally found where tectonic plates are diverging or converging. A mid-oceanic ridge, for example the Mid-Atlantic Ridge, has examples of volcanoes caused by divergent tectonic plates pulling apart; the Pacific Ring of Fire has examples of volcanoes caused by convergent tectonic plates coming together. By contrast, volcanoes are usually not created where two tectonic plates slide past one another. Volcanoes can also form where there is stretching and thinning of the Earth's crust in the interiors of plates, e.g., in the East African Rift, the Wells Gray-Clearwater volcanic field and the Rio Grande Rift in North America. This type of volcanism falls under the umbrella of "Plate hypothesis" volcanism. Volcanism away from plate boundaries has also been explained as mantle plumes. These so- called "hotspots", for example Hawaii, are postulated to arise from upwelling diapirs with magma from the core–mantle boundary, 3,000 km deep in the Earth. Erupting volcanoes can pose many hazards, not only in the immediate vicinity of the eruption. Volcanic ash can be a threat to aircraft, in particular those with jet engines where ash particles can be melted by the high operating temperature. Large eruptions can affect temperature as ash and droplets of sulfuric acid obscure the sun and cool the Earth's lower atmosphere or troposphere; however, they also absorb heat radiated up from the Earth, thereby warming the stratosphere.