DOCSLIB.ORG

Islands, Reefs and a Hotspot

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Islands, Reefs and a Hotspot Northwestern Hawaiian Islands Exploration Islands, Reefs and a Hotspot Focus Mantle Formation of the Hawaiian archipelago Asthenosphere Convection current Grade Level Faults 5-6 Earth Science Magma Basalt Focus Question Subduction What geological processes produced the different Eruption physical forms seen among the Hawaiian Islands? Crater Summit Learning Objectives Caldera Students will be able to describe eight stages in the formation of islands in the Hawaiian archipelago. There are no formal signs in American Sign Language for any of these words listed as key Students will be able to describe the movement of words and many are difficult to lipread. Having tectonic plates in the Hawaiian archipelago region. the vocabulary list on the board as a reference during the lesson will be extremely helpful. It may Students will be able to describe how a combina- also be helpful to have a list of the key words as a tion of hotspot activity and tectonic plate move- handout for the students. ment could produce the arrangement of seamounts observed in the Hawaiian archipelago. Convection currents are explained in the Background Information. A brief demonstration of Additional Information for Teachers of Deaf Students a convection current can be conducted by adding In addition to the words listed as key words, the fol- food coloring to a heated container of water. This lowing words should be part of the vocabulary list. will be helpful to demonstrate the concept. It would Atoll also be helpful to make an overhead transparency Nautical in addition to the handout of the “Location and SCUBA Age of Some Islands in the Hawaii Archipelago” Exploration listed in Step 2. The activity should be conducted ROV as a group rather than individually. Corals Archipelago The eight stages of growth and erosion in the Tectonic plate islands of the Hawaiian Archipelago are listed in the Lithosphere Background Information and discussed in Step 4 of Crust the Learning Procedure. This should be copied and 1 Northwestern Hawaiian Islands Exploration — Grades 5-6 Formation of the Hawaiian Archipelago oceanexplorer.noaa.gov given as a handout to the students to assist during Key Words the activity. It can also be reviewed as homework Archipelago after the first day. Depending on the level of your Tectonic plate students, you may prefer using the second part of the Mantle activity. Asthenosphere Lithosphere Substitute the following for Step 5 in the Learning Magma Procedure: Select several islands from the Rift Northwestern Hawaiian Islands group, and provide Subduction a brief description of these islands. Construct a Hotspots model or diagram of the appropriate development Caldera stage and provide an explanation for their clas- sification. Background Information Nearly 70% of all coral reefs in U.S. waters are Materials found around the Northwestern Hawaiian Islands, Copies of the “Central Pacific Map Grid” and a chain of small islands and atolls that stretches “Location and Age of Some Islands in the Hawaii for more than 1,000 nautical miles (nm) northwest Archipelago,” one for each student group (or an of the main Hawaiian Islands. While scientists overhead transparency of the latter data sheet). have studied shallow portions of the area for many Diagram of “The Hawaiian Archipelago” years, almost nothing is known about deeper ocean (Download from http://www.soest.hawaii.edu/GG/HCV/ habitats below the range of SCUBA divers. Only a few explorations have been made with deep-div- haw_formation.html) ing submersibles and remotely-operated vehicles Materials for constructing island models OR draw- (ROVs), but these have found new species and ing materials OR student Internet access, depend- species previously unreported in Hawaiian waters. ing upon option chosen for Learning Procedure These islands are regularly visited by Hawaiian Step #4 monk seals, one of only two species of monk seals Brief description of selected islands (see Learning remaining in the world (the Caribbean monk seal Procedure step #5; http://www.bishopmuseum.org/ was declared extinct in 1994). Waters around the research/nwhi/geograph.html is a useful source for this Northwestern Hawaiian Islands may be an impor- information) tant feeding area for the seals, which appear to feed on fishes that find shelter among colonies of Audio/Visual Materials deep-water corals. These corals are also of inter- None, unless an overhead transparency is used est, because they include several species that are instead of individual handouts of “Location and commercially valuable for jewelry. The possibility Age of Some Islands in the Hawaii Archipelago” of discovering new species also has commercial importance as well as scientific interest, since some Teaching Time of these species may produce materials of impor- One or two 45-minute class periods tance to medicine or industry. Seating Arrangement The islands of the Hawaiian archipelago were Groups of four students formed by a series of volcanic eruptions that began more than 80 million years ago. Volcanoes are Maximum Number of Students often associated with movement of the tectonic 32 plates that make up the Earth’s crust. The outer 2 Northwestern Hawaiian Islands Exploration — Grades 5-6 oceanexplorer.noaa.gov Formation of the Hawaiian Archipelago shell of the Earth (called the lithosphere) consists of The Pacific tectonic plate is presently moving over about a dozen large plates of rock (called tectonic the asthenosphere toward the northwest at a rate plates) that move several centimeters per year rela- of 5 to 10 cm per year. As the plate moves over tive to each other. These plates consist of a crust the Hawaiian hotspot, magma periodically erupts about 5 km thick, and the upper 60 - 75 km of the to form volcanoes that become islands. The old- Earth’s mantle. The plates that make up the litho- est island is Kure at the northwestern end of the sphere move on a hot flowing mantle layer called archipelago. The youngest is the Big Island of the asthenosphere, which is several hundred kilo- Hawaii at the southeastern end. Loihi, east of the meters thick. Heat within the asthenosphere creates Big Island, is the newest volcano in the chain and convection currents (similar to the currents that can may eventually form another island. As the Pacific be seen if food coloring is added to a heated con- plate moves to the northwest, islands are carried tainer of water). These convection currents cause farther away from the hot spot, and the crust cools the tectonic plates to move. Plates may slide hori- and subsides. At the same time, erosion gradu- zontally past each other at transform plate bound- ally shrinks the islands, and unless there is further aries. The motion of the plates rubbing against volcanic activity (or a drop in sea level) the island each other sets up huge stresses that can cause eventually submerges below the ocean surface. To portions of the rock to break, resulting in earth- the northwest of Kure, the Emperor Seamounts are quakes. Places where these breaks occur are called the submerged remains of former islands that are faults. A well-known example of a transform plate even older than Kure. boundary is the San Andreas fault in California. Scientists recognize eight stages of growth and ero- Where tectonic plates move apart (for example, sion in the islands of the Hawaiian archipelago: along the mid-ocean ridge in the middle of the 1. The deep submarine stage begins with Atlantic Ocean) a rift is formed, which allows submarine eruptions, which eventually reach magma (molten rock) to escape from deep within the ocean surface (Loihi is in this stage); the Earth and harden into solid rock known as 2. The shallow submarine stage features basalt. Where tectonic plates come together, one an above-water crater, which spouts lava from plate may descend beneath the other in a process rifts on the side of the cone; called subduction, which generates high tempera- 3. The subaerial shield-building stage tures and pressures that can lead to explosive begins with collapse of the highest point (sum- volcanic eruptions (such as the Mount St. Helens mit) on the volcanic cone to form a caldera. eruption which resulted from subduction of the Juan The volcano continues to emit lava from the de Fuca tectonic plate beneath the North American summit and from rifts in the side of the cone tectonic plate). Volcanoes can also be formed at (Mauna Loa and Kilauea are in this stage); hotspots, which are thought to be natural pipelines 4. The post-caldera stage, in which lava fills to reservoirs of magma in the upper portion of and overflows the caldera to form a rounded the Earth’s mantle. The Hawaiian islands are the summit. While overall volcanic activity may result of volcanic activity associated with a hotspot slow down, significant lava flow still contin- that appears to deeply penetrate the mantle to ues (the Kohala Mountains, Mauna Kea, and the boundary between the mantle and the Earth’s Hualalai are in this stage; Haleakala is also metallic core. The Hawaiian hotspot is presently in this stage, even though the caldera is not located beneath the Big Island of Hawaii at the filled and still has a crater shape); southeastern end of the archipelago. 5. The erosional stage, in which lava is no longer being added, and the volcanic cone is attacked by erosion from the ocean and 3 Northwestern Hawaiian Islands Exploration — Grades 5-6 Formation of the Hawaiian Archipelago oceanexplorer.noaa.gov rainfall. A sea bluff, deep valleys and sharp Grid” and “Location and Age of Some Islands ridges are characteristic features of this stage in the Hawaii Archipelago” to each group (or (Kauai, Oahu, and portions of all the major display an overhead projection of the latter Hawaiian Islands are in this stage); data sheet).
Load more

Recommended publications
  • Hot Spots and Plate Movement Exercise
    Name(s) Hot Spots and Plate Movement exercise Two good examples of present-day hot spot volcanism, as derived from mantle plumes beneath crustal plates, are Kilauea, Hawaii (on the Pacific oceanic plate) and Yellowstone (on the continental North American plate). These hot spots have produced a chain of inactive volcanic islands or seamounts on the Pacific plate (Fig. 1) and volcanic calderas or fields on the North American plate (Fig. 2) – see the figures below. Figure 1. Chain of islands and seamounts produced by the Hawaiian hot spot. Figure 2. Chain of volcanic fields produced by the Yellowstone hot spot. The purposes of this exercise are to use locations, ages, and displacements for each of these hot spot chains to determine 1. Absolute movement directions, and 2. Movement rates for both the Pacific and western North American plates, and then to use this information to determine 3. Whether the rates and directions of the movement of these two plates have been the same or different over the past 16 million years. This exercise uses the Pangaea Breakup animation, which is a KML file that runs in the standalone Google Earth application. To download the Pangaea Breakup KML file, go here: http://csmgeo.csm.jmu.edu/Geollab/Whitmeyer/geode/pangaeaBreakup /PangaeaBreakup.kml To download Google Earth for your computer, go here: https://www.google.com/earth/download/ge/agree.html Part 1. Hawaiian Island Chain Load the PangaeaBreakup.kml file in Google Earth. Make sure the time period in the upper right of the screen says “0 Ma” and then select “Hot Spot Volcanos” under “Features” in the Places menu on the left of the screen.
    [Show full text]
  • Life in Mauna Kea's Alpine Desert
    Life in Mauna Kea’s by Mike Richardson Alpine Desert Lycosa wolf spiders, a centipede that preys on moribund insects that are blown to the summit, and the unique, flightless wekiu bug. A candidate for federal listing as an endangered species, the wekiu bug was first discovered in 1979 by entomologists on Pu‘u Wekiu, the summit cinder cone. “Wekiu” is Hawaiian for “topmost” or “summit.” The wekiu bug belongs to the family Lygaeidae within the order of insects known as Heteroptera (true bugs). Most of the 26 endemic Hawaiian Nysius species use a tube-like beak to feed on native plant seed heads, but the wekiu bug uses its beak to suck the hemolymph (blood) from other insects. High above the sunny beaches, rocky coastline, Excluding its close relative Nysius a‘a on the nearby Mauna Loa, the wekiu bug and lush, tropical forests of the Big Island of Hawai‘i differs from all the world’s 106 Nysius lies a unique environment unknown even to many species in its predatory habits and unusual physical characteristics. The bug residents. The harsh, barren, cold alpine desert is so possesses nearly microscopically small hostile that it may appear devoid of life. However, a wings and has the longest, thinnest legs few species existing nowhere else have formed a pre- and the most elongated head of any Lygaeid bug in the world. carious ecosystem-in-miniature of insects, spiders, The wekiu bug, about the size of a other arthropods, and simple plants and lichens. Wel­ grain of rice, is most often found under rocks and cinders where it preys diur­ come to the summit of Mauna Kea! nally (during daylight) on insects and Rising 13,796 feet (4,205 meters) dependent) community of arthropods even birds that are blown up from lower above sea level, Mauna Kea is the was uncovered at the summit.
    [Show full text]
  • Determining the Depths of Magma Chambers Beneath Hawaiian Volcanoes
    Determining the Depths of Magma Chambers beneath Hawaiian Volcanoes using Petrological Methods Senior Thesis Submitted in partial fulfillment of the requirements for the Bachelor of Science Degree At The Ohio State University By Andrew Thompson The Ohio State University 2014 Approved by Michael Barton, Advisor School of Earth Sciences Table of Contents Abstract .................................................................................................... 3 Acknowledgements ......................................................................................4 Introduction ............................................................................................... 5 Geologic Setting .......................................................................................... 6 Methods Filtering ............................................................................................ 9 CIPW Normalization ............................................................................. 11 Classification .................................................................................... 12 Results Kilauea ............................................................................................ 14 Mauna Kea ........................................................................................ 18 Mauna Loa ........................................................................................ 20 Loihi ............................................................................ ................... 23 Discussion ................................................................................................
    [Show full text]
  • Cenozoic Changes in Pacific Absolute Plate Motion A
    CENOZOIC CHANGES IN PACIFIC ABSOLUTE PLATE MOTION A THESIS SUBMITTED TO THE GRADUATE DIVISION OF THE UNIVERSITY OF HAWAI`I IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE IN GEOLOGY AND GEOPHYSICS DECEMBER 2003 By Nile Akel Kevis Sterling Thesis Committee: Paul Wessel, Chairperson Loren Kroenke Fred Duennebier We certify that we have read this thesis and that, in our opinion, it is satisfactory in scope and quality as a thesis for the degree of Master of Science in Geology and Geophysics. THESIS COMMITTEE Chairperson ii Abstract Using the polygonal finite rotation method (PFRM) in conjunction with the hotspot- ting technique, a model of Pacific absolute plate motion (APM) from 65 Ma to the present has been created. This model is based primarily on the Hawaiian-Emperor and Louisville hotspot trails but also incorporates the Cobb, Bowie, Kodiak, Foundation, Caroline, Mar- quesas and Pitcairn hotspot trails. Using this model, distinct changes in Pacific APM have been identified at 48, 27, 23, 18, 12 and 6 Ma. These changes are reflected as kinks in the linear trends of Pacific hotspot trails. The sense of motion and timing of a number of circum-Pacific tectonic events appear to be correlated with these changes in Pacific APM. With the model and discussion presented here it is suggested that Pacific hotpots are fixed with respect to one another and with respect to the mantle. If they are moving as some paleomagnetic results suggest, they must be moving coherently in response to large-scale mantle flow. iii List of Tables 4.1 Initial hotspot locations .
    [Show full text]
  • Mauna Loa Reconnaissance 2003
    “Giant of the Pacific” Mauna Loa Reconnaissance 2003 Plan of encampment on Mauna Loa summit illustrated by C. Wilkes, Engraved by N. Gimbrede (Wilkes 1845; vol. IV:155) Prepared by Dennis Dougherty B.A., Project Director Edited by J. Moniz-Nakamura, Ph. D. Principal Investigator Pacific Island Cluster Publications in Anthropology #4 National Park Service Hawai‘i Volcanoes National Park Department of the Interior 2004 “Giant of the Pacific” Mauna Loa Reconnaissance 2003 Prepared by Dennis Dougherty, B.A. Edited by J. Moniz-Nakamura, Ph.D. National Park Service Hawai‘i Volcanoes National Park P.O. Box 52 Hawaii National Park, HI 96718 November, 2004 Mauna Loa Reconnaissance 2003 Executive Summary and Acknowledgements The Mauna Loa Reconnaissance project was designed to generate archival and inventory/survey level recordation for previously known and unknown cultural resources within the high elevation zones (montane, sub-alpine, and alpine) of Mauna Loa. Field survey efforts included collecting GPS data at sites, preparing detailed site plan maps and feature descriptions, providing site assessment and National Register eligibility, and integrating the collected data into existing site data bases within the CRM Division at Hawaii Volcanoes National Park (HAVO). Project implementation included both pedestrian transects and aerial transects to accomplish field survey components and included both NPS and Research Corporation University of Hawaii (RCUH) personnel. Reconnaissance of remote alpine areas was needed to increase existing data on historic and archeological sites on Mauna Loa to allow park managers to better plan for future projects. The reconnaissance report includes a project introduction; background sections including physical descriptions, cultural setting overview, and previous archeological studies; fieldwork sections describing methods, results, and feature and site summaries; and a section on conclusions and findings that provide site significance assessments and recommendations.
    [Show full text]
  • Hawaiian Volcanoes: from Source to Surface Site Waikolao, Hawaii 20 - 24 August 2012
    AGU Chapman Conference on Hawaiian Volcanoes: From Source to Surface Site Waikolao, Hawaii 20 - 24 August 2012 Conveners Michael Poland, USGS – Hawaiian Volcano Observatory, USA Paul Okubo, USGS – Hawaiian Volcano Observatory, USA Ken Hon, University of Hawai'i at Hilo, USA Program Committee Rebecca Carey, University of California, Berkeley, USA Simon Carn, Michigan Technological University, USA Valerie Cayol, Obs. de Physique du Globe de Clermont-Ferrand Helge Gonnermann, Rice University, USA Scott Rowland, SOEST, University of Hawai'i at M noa, USA Financial Support 2 AGU Chapman Conference on Hawaiian Volcanoes: From Source to Surface Site Meeting At A Glance Sunday, 19 August 2012 1600h – 1700h Welcome Reception 1700h – 1800h Introduction and Highlights of Kilauea’s Recent Eruption Activity Monday, 20 August 2012 0830h – 0900h Welcome and Logistics 0900h – 0945h Introduction – Hawaiian Volcano Observatory: Its First 100 Years of Advancing Volcanism 0945h – 1215h Magma Origin and Ascent I 1030h – 1045h Coffee Break 1215h – 1330h Lunch on Your Own 1330h – 1430h Magma Origin and Ascent II 1430h – 1445h Coffee Break 1445h – 1600h Magma Origin and Ascent Breakout Sessions I, II, III, IV, and V 1600h – 1645h Magma Origin and Ascent III 1645h – 1900h Poster Session Tuesday, 21 August 2012 0900h – 1215h Magma Storage and Island Evolution I 1215h – 1330h Lunch on Your Own 1330h – 1445h Magma Storage and Island Evolution II 1445h – 1600h Magma Storage and Island Evolution Breakout Sessions I, II, III, IV, and V 1600h – 1645h Magma Storage
    [Show full text]
  • HAWAII National Park HAWAIIAN ISLANDS
    HAWAII National Park HAWAIIAN ISLANDS UNITED STATES RAILROAD ADMINISTRATION N AT IONAL PAR.K. SERIES n A 5 o The world-famed volcano of Kilauea, eight miles in circumference An Appreciation of the Hawaii National Park By E. M. NEWMAN, Traveler and Lecturer Written Especially for the United States Railroad Administration §HE FIRES of a visible inferno burning in the midst of an earthly paradise is a striking con­ trast, afforded only in the Hawaii National Park. It is a combination of all that is terrify­ ing and all that is beautiful, a blending of the awful with the magnificent. Lava-flows of centuries are piled high about a living volcano, which is set like a ruby in an emer­ ald bower of tropical grandeur. Picture a perfect May day, when glorious sunshine and smiling nature combine to make the heart glad; then multiply that day by three hundred and sixty-five and the result is the climate of Hawaii. Add to this the sweet odors, the luscious fruits, the luxuriant verdure, the flowers and colorful beauty of the tropics, and the Hawaii National Park becomes a dreamland that lingers in one's memory as long as memory survives. Pa ae three To the American People: Uncle Sam asks you to be his guest. He has prepared for you the choice places of this continent—places of grandeur, beauty and of wonder. He has built roads through the deep-cut canyons and beside happy streams, which will carry you into these places in comfort, and has provided lodgings and food in the most distant and inaccessible places that you might enjoy yourself and realize as little as possible the rigors of the pioneer traveler's life.
    [Show full text]
  • I COPV of HAWAI R SYSTEM FEB 2 3 2018
    David LaS5ner UNIVERSITY President 1 I COPV of HAWAI r SYSTEM FEB 2 3 2018 February 12, 2018 ~..., . Mr. Scott Glenn, Director o 0 (X) c::o - ;o Office of Environmental Quality Control l> ...,, r .,., m Department of Health -rri rr, --i :z CD 0 State of Hawai'i -< < ,n 235 South Beretania Street, Room 702 r. :::i -N Oo Honolulu, Hawai'i 96813 :Z :;r.: -i:, < --i7::.,:;=;:-, rn -vi ·"":) Subject: Environmental Impact Statement Preparation Notice for Lancr' := 0 Authorizations for Long-Term Continuation of Astronomy on Maunakea Dear Director Glenn: The University of Hawai'i (UH) has determined at the outset that it will prepare an Environmental Impact Statement (EIS) for its proposed new land authorizations for the continuation of astronomy on Maunakea. UH will prepare the EIS in accordance with the provisions and requirements of Hawai'i Revised Statutes (HRS) Chapter 343. Pursuant to HRS Chapter 343-S(c), an Agency Publication Form and Environmental Impact Statement Preparation Notice (EISPN) are attached. The EISPN includes a description of the requested land authorization and a brief discussion of the kinds of potential environmental impacts which will be analyzed in the forthcoming EIS. In accordance with Hawai'i Administrative Rules Chapter 11-200, we respectfully request that you publish this notice in the next available edition of The Environmental Notice for the public to submit comments to UH during the statutory 30-day public consultation period. If you have any further questions about this letter or its attachments, please contact Stephanie Nagata, Director, Office of Mauna Kea Management, at (808) 933-0734.
    [Show full text]
  • THE HAWAIIAN-EMPEROR VOLCANIC CHAIN Part I Geologic Evolution
    VOLCANISM IN HAWAII Chapter 1 - .-............,. THE HAWAIIAN-EMPEROR VOLCANIC CHAIN Part I Geologic Evolution By David A. Clague and G. Brent Dalrymple ABSTRACT chain, the near-fixity of the hot spot, the chemistry and timing of The Hawaiian-Emperor volcanic chain stretches nearly the eruptions from individual volcanoes, and the detailed geom­ 6,000 km across the North Pacific Ocean and consists of at least etry of volcanism. None of the geophysical hypotheses pro­ t 07 individual volcanoes with a total volume of about 1 million posed to date are fully satisfactory. However, the existence of km3• The chain is age progressive with still-active volcanoes at the Hawaiian ewell suggests that hot spots are indeed hot. In the southeast end and 80-75-Ma volcanoes at the northwest addition, both geophysical and geochemical hypotheses suggest end. The bend between the Hawaiian and .Emperor Chains that primitive undegassed mantle material ascends beneath reflects a major change in Pacific plate motion at 43.1 ± 1.4 Ma Hawaii. Petrologic models suggest that this primitive material and probably was caused by collision of the Indian subcontinent reacts with the ocean lithosphere to produce the compositional into Eurasia and the resulting reorganization of oceanic spread­ range of Hawaiian lava. ing centers and initiation of subduction zones in the western Pacific. The volcanoes of the chain were erupted onto the floor of the Pacific Ocean without regard for the age or preexisting INTRODUCTION structure of the ocean crust. Hawaiian volcanoes erupt lava of distinct chemical com­ The Hawaiian Islands; the seamounts, hanks, and islands of positions during four major stages in their evolution and the Hawaiian Ridge; and the chain of Emperor Seamounts form an growth.
    [Show full text]
  • Hawaiian Hotspot
    V51B-0546 (AGU Fall Meeting) High precision Pb, Sr, and Nd isotope geochemistry of alkalic early Kilauea magmas from the submarine Hilina bench region, and the nature of the Hilina/Kea mantle component J-I Kimura*, TW Sisson**, N Nakano*, ML Coombs**, PW Lipman** *Department of Geoscience, Shimane University **Volcano Hazard Team, USGS JAMSTEC Shinkai 6500 81 65 Emperor Seamounts 56 42 38 27 20 12 5 0 Ma Hawaii Islands Ready to go! Hawaiian Hotspot N ' 0 3 ° 9 Haleakala 1 Kea trend Kohala Loa 5t0r6 end Mauna Kea te eii 95 ol Hualalai Th l 504 na io sit Mauna Loa Kilauea an 509 Tr Papau 208 Hilina Seamont Loihi lic ka 209 Al 505 N 98 ' 207 0 0 508 ° 93 91 9 1 98 KAIKO 99 SHINKAI 02 KAIKO Loa-type tholeiite basalt 209 Transitional basalt 95 504 208 Alkalic basalt 91 508 0 50 km 155°00'W 154°30'W Fig. 1: Samples obtained by Shinkai 6500 and Kaiko dives in 1998-2002 10 T-Alk Mauna Kea 8 Kilauea Basanite Mauna Loa -K M Hilina (low-Si tholeiite) 6 Hilina (transitional) Hilina (alkali) Kea Hilina (basanite) 4 Loa Hilina (nephelinite) Papau (Loa type tholeiite) primary 2 Nep Basaltic Basalt andesite (a) 0 35 40 45 50 55 60 SiO2 Fig. 2: TAS classification and comparison of the early Kilauea lavas to representative lavas from Hawaii Big Island. Kea-type tholeiite through transitional, alkali, basanite to nephelinite lavas were collected from Hilina bench. Loa-type tholeiite from Papau seamount 100 (a) (b) (c) OIB OIB OIB M P / e l p 10 m a S E-MORB E-MORB E-MORB Loa type tholeiite Low Si tholeiite Transitional 1 f f r r r r r r r f d y r r d b b
    [Show full text]
  • Geology, Geochemistry and Earthquake History of Lō`Ihi Seamount, Hawai`I
    INVITED REVIEW Geology, Geochemistry and Earthquake History of Lō`ihi Seamount, Hawai`i Michael O. Garcia1*, Jackie Caplan-Auerbach2, Eric H. De Carlo3, M.D. Kurz4 and N. Becker1 1Department of Geology and Geophysics, University of Hawai`i, Honolulu, HI, USA 2U.S.G.S., Alaska Volcano Observatory, Anchorage, AK, USA 3Department of Oceanography, University of Hawai`i, Honolulu, HI, USA 4Department of Chemistry, Woods Hole Oceanographic Institution, Woods Hole, MA, USA *Corresponding author: Tel.: 001-808-956-6641, FAX: 001-808-956-5521; email: [email protected] Key words: Loihi, seamount, Hawaii, petrology, geochemistry, earthquakes Abstract A half century of investigations are summarized here on the youngest Hawaiian volcano, Lō`ihi Seamount. It was discovered in 1952 following an earthquake swarm. Surveying in 1954 determined it has an elongate shape, which is the meaning of its Hawaiian name. Lō`ihi was mostly forgotten until two earthquake swarms in the 1970’s led to a dredging expedition in 1978, which recovered young lavas. This led to numerous expeditions to investigate the geology, geophysics, and geochemistry of this active volcano. Geophysical monitoring, including a real- time submarine observatory that continuously monitored Lō`ihi’s seismic activity for three months, captured some of the volcano’s earthquake swarms. The 1996 swarm, the largest recorded in Hawai`i, was preceded by at least one eruption and accompanied by the formation of a ~300-m deep pit crater, renewing interest in this submarine volcano. Seismic and petrologic data indicate that magma was stored in a ~8-9 km deep reservoir prior to the 1996 eruption.
    [Show full text]
  • The Plate Tectonics of Cenozoic SE Asia and the Distribution of Land and Sea
    Cenozoic plate tectonics of SE Asia 99 The plate tectonics of Cenozoic SE Asia and the distribution of land and sea Robert Hall SE Asia Research Group, Department of Geology, Royal Holloway University of London, Egham, Surrey TW20 0EX, UK Email: robert*hall@gl*rhbnc*ac*uk Key words: SE Asia, SW Pacific, plate tectonics, Cenozoic Abstract Introduction A plate tectonic model for the development of SE Asia and For the geologist, SE Asia is one of the most the SW Pacific during the Cenozoic is based on palaeomag- intriguing areas of the Earth$ The mountains of netic data, spreading histories of marginal basins deduced the Alpine-Himalayan belt turn southwards into from ocean floor magnetic anomalies, and interpretation of geological data from the region There are three important Indochina and terminate in a region of continen- periods in regional development: at about 45 Ma, 25 Ma and tal archipelagos, island arcs and small ocean ba- 5 Ma At these times plate boundaries and motions changed, sins$ To the south, west and east the region is probably as a result of major collision events surrounded by island arcs where lithosphere of In the Eocene the collision of India with Asia caused an the Indian and Pacific oceans is being influx of Gondwana plants and animals into Asia Mountain building resulting from the collision led to major changes in subducted at high rates, accompanied by in- habitats, climate, and drainage systems, and promoted dis- tense seismicity and spectacular volcanic activ- persal from Gondwana via India into SE Asia as well
    [Show full text]