DOCSLIB.ORG

Low-Temperature Thermal History and Landscape Development of the Eastern Adirondack Mountains, New York: Constraints from Apatit

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Low-Temperature Thermal History and Landscape Development of the Eastern Adirondack Mountains, New York: Constraints from Apatit Downloaded from gsabulletin.gsapubs.org on January 23, 2015 Low-temperature thermal history and landscape development of the eastern Adirondack Mountains, New York: Constraints from apatite fi ssion-track thermochronology and apatite (U-Th)/He dating Joshua P. Taylor† and Paul G. Fitzgerald Department of Earth Sciences, 204 Heroy Geology Laboratory, Syracuse University, Syracuse, New York 13244, USA ABSTRACT chronological data suggest that the present The Adirondack Mountains of northern New relief developed during the Late Cretaceous– York State form an oval outlier of late Precam- The Adirondack Mountains in northern Cenozoic through plateau dissection during brian age rocks connected to the greater Gren- New York State form an elongate, domal periodic base-level changes. ville Province of the Canadian Shield through exposure of mainly high-grade metamor- the Frontenac Arch. Mountainous terrain (~1 km phic tectonites in a mountainous setting with INTRODUCTION of relief) characterizes the eastern Adirondack topographic relief of ~1 km. The origin of the Mountains, where it exposes mainly ortho- Adirondack Mountains and this relief has The Adirondack Mountains of New York gneisses and granulite-grade metamorphic rocks. long been enigmatic, since the Adirondacks State constitute a region of moderate relief In this paper, we present results of AFT ther- presently lie within an intracratonic setting, along the tectonically stable eastern margin of mochronology and apatite (U-Th)/He (AHe) inboard of the North American passive mar- North America. The timing and mechanism(s) dating from a number of key localities to con- gin and far from any active plate boundaries. behind the formation of these mountains remain strain the post-Triassic low-temperature thermal Through the application of apatite fi ssion- enigmatic, as indeed does the development of history and the timing of relief development in track (AFT) thermochronology and apatite mountainous topography inland of many pas- the eastern Adirondack Mountains (Fig. 1). In (U-Th)/He (AHe) dating within the eastern sive margins (e.g., Gilchrist and Summerfi eld, particular, we explore the effects of passage Adirondack Mountains, this study provides 1990). The Adirondack Mountains also repre- over the Great Meteor hotspot ca. 130–95 Ma, constraints on both the thermal and ero- sent one of a few regions in the United States, the resultant cooling/erosional history, and sub- sional effects of Mesozoic passage near a hot- another being the Ozarks of Arkansas-Missouri sequent relief development. While our study spot and the timing of relief development. (Brown and Marshak, 2004; Marshak et al., builds on earlier, more regional low-temperature AFT thermochronology and AHe dating 2005), where intraplate mountains expose crys- thermochronology studies by Roden-Tice et al. record relatively stable thermal conditions talline Precambrian metamorphic terrains. The (2000) and Roden-Tice and Tice (2005), our within the eastern Adirondacks from the purpose of our work is to further constrain the more focused sampling strategy permits signifi - Middle Jurassic into the Early Cretaceous. Mesozoic to Holocene history of the Adiron- cant advances in the understanding of the ther- During the Early Cretaceous (ca. 130– dacks. Our results, combined with previous mal and tectonic evolution of the Adirondacks. 120 Ma), the region underwent heating as- work, indicate that the low-temperature thermal sociated with progressive movement near history of the eastern Adirondacks coincides GEOLOGIC BACKGROUND the Great Meteor hotspot, resulting in the with passage near a hotspot during the Creta- temporary establishment of an elevated geo- ceous. Moreover, the regional distribution of The Adirondack Mountains record a pro- thermal gradient. Following regional heat- apatite fi ssion-track (AFT) ages across the range tracted geologic history that spans Grenvillian ing, cooling rates increased considerably sheds insight on the age of relief. Though our orogenesis to Pleistocene glaciation. The high- (ca. 105–95 Ma), likely due to both thermal results have direct implications on the thermal grade mineral assemblages and deformation doming, producing an increase in erosion history and landscape development of northern fabrics of the majority of rocks found within the rate, and the relaxation of isotherms after New York, they also outline the particular use- eastern Adirondacks formed during the Gren- passage near the hotspot. fulness of low-temperature thermochronology ville orogenic cycle (ca. 1350–1020 Ma; e.g., The regional distribution of AFT ages in recording the thermal and topographic effects McLelland et al., 1996; Wasteneys et al., 1999; across the eastern Adirondacks reveals no of passage near a hotspot (e.g., Crough, 1981; Heumann et al., 2006). By the Late Proterozoic– systematic age gradient from core to periph- Eby, 1984; Cobbold et al., 2001; Roden-Tice Early Cambrian, regional exhumation exposed ery, which would be expected under con- and Tice, 2005; Pik et al., 2008; Roden-Tice this Grenville basement at the surface, where ditions of persistent high relief during the et al., 2009) and may contribute to the greater it was covered by the Potsdam Sandstone and decay of a crustal root over many tens to hun- understanding of the formation and/or preserva- younger stratigraphic units during rifting and dreds of millions of years. Instead, thermo- tion of relief inland of tectonically stable passive formation of a passive margin along the Iapetus margins (e.g., Braun and van der Beek, 2004; Ocean (e.g., Bird and Dewey, 1970; Cawood et Spotila et al., 2004; Persano et al., 2005). al., 2001). Many of the NE-striking faults now †E-mail: [email protected] GSA Bulletin; March/April 2011; v. 123; no. 3/4; p. 412–426; doi: 10.1130/B30138.1; 10 fi gures; 2 tables. 412 For permission to copy, contact [email protected] © 2011 Geological Society of America Downloaded from gsabulletin.gsapubs.org on January 23, 2015 Low-temperature thermal history and landscape development of the eastern Adirondack Mountains, New York found throughout New York State may have burial. K-feldspar thermal models (Heizler and resulting in regional magmatism and landscape originated as normal faults during this Late Pro- Harrison, 1998) and analysis of fl uid inclusions modifi cation (Fig. 2; e.g., Crough, 1981). The terozoic extension (e.g., Jacobi, 2002). and clay digenesis in sedimentary rocks that Great Meteor hotspot is named for the Great During the Middle Ordovician, both loading fl ank the Adirondack Mountains (Sarwar and Meteor Seamount now located off the west coast and subsidence, due to overthrusting of Lau- Friedman, 1994) also suggest that sedimenta- of Africa. Through a number of seamounts, in- rentia by the Taconic allochthon, resulted in the tion continued throughout the Mississippian and cluding the Corner, Nashville, Gosnold, and creation and/or reactivation of normal faults and Pennsylvanian. The late Pennsylvanian to Perm- Bear, its hotspot track can be traced to offshore burial of much of the eastern Adirondacks and ian Alleghanian orogeny marks the fi nal event Massachusetts (Duncan, 1984; Sleep 1990). The the Mohawk Valley of New York (Bradley and in the Appalachian orogenic cycle and was the hotspot track is mainly traced through the North Kidd, 1991). The Devonian to Permian tectonic last collisional orogeny to affect the Adirondack American continent via the age progression of history of the Adirondack region is not as well region (e.g., Hatcher, 2002). K-feldspar thermal kimberlite dikes in Canada (Heaman and Kjars- constrained. On the basis of temperature-time modeling suggests that the Alleghanian orogeny gaard, 2000) and intrusions in Montréal and (T-t) histories produced by 40Ar/39Ar multidif- produced slow uplift and exhumation in the east- New England (Foland and Faul, 1977; McHone fusion domain (MDD) K-feldspar models of ern Adirondacks (Heizler and Harrison, 1998). and Butler, 1984; Foland et al., 1986). On the ba- samples from the Adirondacks (Heizler and Har- The effect of Mesozoic continental rifting on the sis of 40Ar/39Ar ages for plutonic rocks collected rison, 1998), and constraints from isopach maps Adirondack region is not well constrained, but it from the Monteregian Hills magmatic complex of Middle and Late Devonian strata to the south likely resulted in prolonged regional exhumation in Quebec (ca. 125 Ma; Foland et al., 1986) and of the Adirondacks (Faill, 1985), the main effects (Heizler and Harrison, 1998). for volcanic rocks collected from New England of the Acadian orogeny on the eastern portion Northern New York and New England passed Seamounts (<100 Ma; Duncan, 1984), the Ad- of the Adirondack region were subsidence and over the Great Meteor hotspot in the Cretaceous, irondack and New England regions passed over the hotspot between ca. 125 and 100 Ma (Fig. 2). During the Cenozoic, the Adirondacks under- 80°W 75°W went Pleistocene glaciation followed by possible recent surface uplift. Isachsen and colleagues Canada A (Isachsen, 1975, 1981; Isachsen and Kelly, 1992) proposed that the Adirondack Mountains Grenville Province are currently experiencing surface uplift at a rate Central-eastern 44°N Adirondacks Atlantic Adirondacks of ~1 mm/yr from the center outward due to USA Ocean Eastern Adirondack Mountains C Modified from Baird and MacDonald, 2004 thermal doming caused by a Cenozoic hotspot. Southeastern Adirondacks However, this hypothesis remains controversial. B The MDD feldspar thermal models of Heizler and Harrison (1998) suggest that the rocks now exposed at the surface within the eastern Adiron- dacks were at a temperature of ~200–150 °C in the Early Jurassic, just above the temperature 42°N sensitivity range of the AFT system (~110– 60 °C). Previous AFT thermochronology and AHe dating (Miller and Lakatos, 1983; Roden- Tice et al., 2000; Roden-Tice and Tice, 2005) have revealed important general cooling trends and exhumation patterns in the Adirondacks. We 100 km build upon this work using a different sampling strategy that focused on the collection of two vertical profi les in two key regions, the south- B C eastern and central-eastern Adirondacks (Fig.
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]
  • Related Magmatism in the Upper Wind River Basin, Wyoming (USA), GEOSPHERE; V
    Research Paper THEMED ISSUE: Cenozoic Tectonics, Magmatism, and Stratigraphy of the Snake River Plain–Yellowstone Region and Adjacent Areas GEOSPHERE The leading wisps of Yellowstone: Post–ca. 5 Ma extension- related magmatism in the upper Wind River Basin, Wyoming (USA), GEOSPHERE; v. 14, no. 1 associated with the Yellowstone hotspot tectonic parabola doi:10.1130/GES01553.1 Matthew E. Brueseke1, Anna C. Downey1, Zachary C. Dodd1, William K. Hart2, Dave C. Adams3, and Jeff A. Benowitz4 12 figures; 2 tables; 1 supplemental file 1Department of Geology, Kansas State University, 108 Thompson Hall, Manhattan, Kansas 66506, USA 2Department of Geology and Environmental Earth Science, Miami University, 118C Shideler Hall, Oxford, Ohio 45056, USA 3Box 155, Teton Village, Wyoming 83025, USA CORRESPONDENCE: brueseke@ ksu .edu 4Geophysical Institute and Geochronology Laboratory, University of Alaska Fairbanks, Fairbanks, Alaska 99775, USA CITATION: Brueseke, M.E., Downey, A.C., Dodd, Z.C., Hart, W.K., Adams, D.C., and Benowitz, J.A., 2018, The leading wisps of Yellowstone: Post–ca. 5 Ma ABSTRACT the issue of linking volcanic events to a specific driving mechanism (Fouch, extension-related magmatism in the upper Wind River 2012; Kuehn et al., 2015). Complicating matters, magmatism often continues Basin, Wyoming (USA), associated with the Yellow- The upper Wind River Basin in northwest Wyoming (USA) is located ~80– long after (e.g., millions of years) the upper plate has been translated away stone hotspot tectonic parabola: Geosphere, v. 14, no. 1, p. 74–94, doi:10.1130/GES01553.1. 100 km southeast of the Yellowstone Plateau volcanic field. While the upper from an upwelling plume (Bercovici and Mahoney, 1994; Sleep, 2003; Shervais Wind River Basin is a manifestation of primarily Cretaceous to Eocene Lara- and Hanan, 2008; Jean et al., 2014).
    [Show full text]
  • The Track of the Yellowstone Hot Spot: Volcanism, Faulting, and Uplift
    Geological Society of America Memoir 179 1992 Chapter 1 The track of the Yellowstone hot spot: Volcanism, faulting, and uplift Kenneth L. Pierce and Lisa A. Morgan US. Geological Survey, MS 913, Box 25046, Federal Center, Denver, Colorado 80225 ABSTRACT The track of the Yellowstone hot spot is represented by a systematic northeast-trending linear belt of silicic, caldera-forming volcanism that arrived at Yel- lowstone 2 Ma, was near American Falls, Idaho about 10 Ma, and started about 16 Ma near the Nevada-Oregon-Idaho border. From 16 to 10 Ma, particularly 16 to 14 Ma, volcanism was widely dispersed around the inferred hot-spot track in a region that now forms a moderately high volcanic plateau. From 10 to 2 Ma, silicic volcanism migrated N54OE toward Yellowstone at about 3 cm/year, leaving in its wake the topographic and structural depression of the eastern Snake River Plain (SRP). This <lo-Ma hot-spot track has the same rate and direction as that predicted by motion of the North American plate over a thermal plume fixed in the mantle. The eastern SRP is a linear, mountain- bounded, 90-km-wide trench almost entirely(?) floored by calderas that are thinly cov- ered by basalt flows. The current hot-spot position at Yellowstone is spatially related to active faulting and uplift. Basin-and-range faults in the Yellowstone-SRP region are classified into six types based on both recency of offset and height of the associated bedrock escarpment. The distribution of these fault types permits definition of three adjoining belts of faults and a pattern of waxing, culminating, and waning fault activity.
    [Show full text]
  • Discovery of Two New Super-Eruptions from the Yellowstone Hotspot Track (USA): Is the Yellowstone Hotspot Waning? Thomas R
    https://doi.org/10.1130/G47384.1 Manuscript received 13 January 2020 Revised manuscript received 16 April 2020 Manuscript accepted 16 April 2020 © 2020 The Authors. Gold Open Access: This paper is published under the terms of the CC-BY license. Published online 1 June 2020 Discovery of two new super-eruptions from the Yellowstone hotspot track (USA): Is the Yellowstone hotspot waning? Thomas R. Knott1, Michael J. Branney1, Marc K. Reichow1, David R. Finn1, Simon Tapster2 and Robert S. Coe3 1 School of Geography, Geology and the Environment, University of Leicester, Leicester LE1 7RH, UK 2 British Geological Survey, Nottingham NG12 5GG, UK 3 Earth and Planetary Science Department, University of California–Santa Cruz, Santa Cruz, California 95064, USA ABSTRACT Super-Eruption Recognition Super-eruptions are amongst the most extreme events to affect Earth’s surface, but too few Recognizing a super-eruption requires quan- examples are known to assess their global role in crustal processes and environmental impact. tification of the dense rock equivalent (DRE) We demonstrate a robust approach to recognize them at one of the best-preserved intraplate volume of the erupted deposit (Pyle, 2000). large igneous provinces, leading to the discovery of two new super-eruptions. Each generated However, several similar deposits may coexist huge and unusually hot pyroclastic density currents that sterilized extensive tracts of Idaho in a succession, presenting a challenge to dis- and Nevada in the United States. The ca. 8.99 Ma McMullen Creek eruption was magnitude tinguish and correlate individual deposits. Suc- 8.6, larger than the last two major eruptions at Yellowstone (Wyoming).
    [Show full text]
  • Geoscenario Introduction: Yellowstone Hotspot Yellowstone Is One of America’S Most Beloved National Parks
    Geoscenario Introduction: Yellowstone Hotspot Yellowstone is one of America’s most beloved national parks. Did you know that its unique scenery is the result of the area’s geology? Yellowstone National Park lies in a volcanic Hydrothermal Features caldera, an area that collapsed after an Hot springs are naturally warm bodies of eruption. Below the caldera is a hotspot. water. Hot magma heats water underground There, huge amounts of magma sit just below to near boiling. Some organisms still manage Earth’s surface. In this geoscenario, you’ll to live in these springs. learn some of the geologic secrets that make Yellowstone such a special place. Its vivid colors and huge size make Grand Prismatic www.fossweb.com Spring the most photographed feature at Yellowstone. Extremely hot water rises 37 m from a crack in Earth’s crust to form this hot spring. permission. further Berkeley without use California of classroom University than the of other use or Regents The redistribution, Copyright resale, for Investigation 8: Geoscenarios 109 2018-2019 Not © 1558514_MSNG_Earth History_Text.indd 109 11/29/18 3:15 PM The water in mud pots tends to be acidic. Hotspot Theory It dissolves the surrounding rock. Hot water Most earthquakes and volcanic eruptions mixes with the dissolved rock to create occur near plate boundaries, but there are bubbly pots. some exceptions. In 1963, John Tuzo Wilson Other hydrothermal features include (1908–1993) came up with a theory for these fumaroles and geysers. Fumaroles exceptions. He described stationary magma are cracks that allow steam to escape chambers beneath the crust.
    [Show full text]
  • Pleistocene Volcanism in the Anahim Volcanic Belt, West-Central British Columbia
    University of Calgary PRISM: University of Calgary's Digital Repository Graduate Studies The Vault: Electronic Theses and Dissertations 2014-10-24 A Second North American Hot-spot: Pleistocene Volcanism in the Anahim Volcanic Belt, west-central British Columbia Kuehn, Christian Kuehn, C. (2014). A Second North American Hot-spot: Pleistocene Volcanism in the Anahim Volcanic Belt, west-central British Columbia (Unpublished doctoral thesis). University of Calgary, Calgary, AB. doi:10.11575/PRISM/25002 http://hdl.handle.net/11023/1936 doctoral thesis University of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission. Downloaded from PRISM: https://prism.ucalgary.ca UNIVERSITY OF CALGARY A Second North American Hot-spot: Pleistocene Volcanism in the Anahim Volcanic Belt, west-central British Columbia by Christian Kuehn A THESIS SUBMITTED TO THE FACULTY OF GRADUATE STUDIES IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY GRADUATE PROGRAM IN GEOLOGY AND GEOPHYSICS CALGARY, ALBERTA OCTOBER, 2014 © Christian Kuehn 2014 Abstract Alkaline and peralkaline magmatism occurred along the Anahim Volcanic Belt (AVB), a 330 km long linear feature in west-central British Columbia. The belt includes three felsic shield volcanoes, the Rainbow, Ilgachuz and Itcha ranges as its most notable features, as well as regionally extensive cone fields, lava flows, dyke swarms and a pluton. Volcanic activity took place periodically from the Late Miocene to the Holocene.
    [Show full text]
  • Protocols for Geologic Hazards Response by the Yellowstone Volcano Observatory
    Prepared in cooperation with Yellowstone National Park, the University of Utah, the University of Wyoming, the Idaho Geological Survey, the Montana Bureau of Mines and Geology, the Wyoming State Geological Survey, and UNAVCO Protocols for Geologic Hazards Response by the Yellowstone Volcano Observatory Circular 1351 Version 2.0, November 2014 U.S. Department of the Interior U.S. Geological Survey Cover: Images clockwise from upper left: Schematic organization of an Incident Command incorporating Yellowstone Volcano Observatory. University of Utah and Yellowstone National Park staff during wintertime equipment deployment. Example of data routing for monitoring data from Yellowstone Seismic Network. Logo of Yellowstone Volcano Observatory. Protocols for Geologic Hazards Response by the Yellowstone Volcano Observatory By the Yellowstone Volcano Observatory Circular 1351 Version 2.0, November 2014 U.S. Department of the Interior U.S. Geological Survey U.S. Department of the Interior SALLY JEWELL, Secretary U.S. Geological Survey Suzette M. Kimball, Acting Director U.S. Geological Survey, Reston, Virginia First release: 2010 Revised and reprinted: November 2014 (ver. 2.0) For more information on the USGS—the Federal source for science about the Earth, its natural and living resources, natural hazards, and the environment—visit http://www.usgs.gov or call 1–888–ASK–USGS For an overview of USGS information products, including maps, imagery, and publications, visit http://www.usgs.gov/pubprod To order this and other USGS information products, visit http://store.usgs.gov Suggested citation: Yellowstone Volcano Observatory, 2014, Protocols for geologic hazards response by the Yellowstone Volcano Observatory (ver. 2.0, November 2014): U.S.
    [Show full text]
  • Young Tracks of Hotspots and Current Plate Velocities
    Geophys. J. Int. (2002) 150, 321–361 Young tracks of hotspots and current plate velocities Alice E. Gripp1,∗ and Richard G. Gordon2 1Department of Geological Sciences, University of Oregon, Eugene, OR 97401, USA 2Department of Earth Science MS-126, Rice University, Houston, TX 77005, USA. E-mail: [email protected] Accepted 2001 October 5. Received 2001 October 5; in original form 2000 December 20 SUMMARY Plate motions relative to the hotspots over the past 4 to 7 Myr are investigated with a goal of determining the shortest time interval over which reliable volcanic propagation rates and segment trends can be estimated. The rate and trend uncertainties are objectively determined from the dispersion of volcano age and of volcano location and are used to test the mutual consistency of the trends and rates. Ten hotspot data sets are constructed from overlapping time intervals with various durations and starting times. Our preferred hotspot data set, HS3, consists of two volcanic propagation rates and eleven segment trends from four plates. It averages plate motion over the past ≈5.8 Myr, which is almost twice the length of time (3.2 Myr) over which the NUVEL-1A global set of relative plate angular velocities is estimated. HS3-NUVEL1A, our preferred set of angular velocities of 15 plates relative to the hotspots, was constructed from the HS3 data set while constraining the relative plate angular velocities to consistency with NUVEL-1A. No hotspots are in significant relative motion, but the 95 per cent confidence limit on motion is typically ±20 to ±40 km Myr−1 and ranges up to ±145 km Myr−1.
    [Show full text]
  • Geoscenario Resources—Yellowstone Hotspot
    Geoscenario Resources—Yellowstone Hotspot: Geologist Task Now that you have explored as a team, the general story of the Yellowstone Hotspot, it is time for each of you to dive into more specialized information. The geologist focuses on the historic path of the Yellowstone Hotspot and how the major geothermal features work. Add helpful details to your notes for Geoscenario Team Questions. Then work together and combine all the information to successfully present your story of the Yellowstone Hotspot. Questions for the Geologist to Consider • How do the major geothermal features in Yellowstone work? • What is the historic path of the Yellowstone Hotspot? Information Water cools near the vent’s surface. Yellowstone National Park is known for its This cooler water “caps” the hotter diverse hydrothermal features. How do they water below. Eventually, superheated work? These diagrams explain how geysers build Side channels can often release pressure water flashes to steam, expanding and within thermal systems. Side channels lifting the water above the vent in an pressure to erupt and why hot springs are so blue. can act as indicators of when primary- eruption. The brilliant colors in hot springs come from feature eruptions may occur. archaebacteria. Aptly called extremophiles for Silica is dissolved from rhyolite (the their ability to survive in extreme environments, Side Channel volcanic rock) and precipitates as these colorful organisms can live in extremely sinter, which forms the geyser cone. high temperatures. Scientists study these bacteria Sinter Sinter to understand how their cells and proteins can Sinter is deposited on the walls and acts High-pressure area caused by survive and function in environmental conditions like a throttle in the vent by constricting expanding water and steam.
    [Show full text]
  • Yellowstone Plume Head: Postulated Tectonic Relations to the Vancouver Slab, Continental Boundaries, and Climate
    Pierce and others—Yellowstone Plume Head: Postulated Tectonic Relations 5 Yellowstone Plume Head: Postulated Tectonic Relations to the Vancouver Slab, Continental Boundaries, and Climate Kenneth L. Pierce,1 Lisa A. Morgan,2 and Richard W. Saltus2 ABSTRACT and 0.706 line in intermediate crust, and the area of cen- tral and southern Nevada east of the 0.706 line in Pre- We trace the Yellowstone hotspot track back to an cambrian continental crust. Geophysical modeling is con- apparent inception centered near the Oregon-Nevada sistent with a dense crust north of the Nevada-Oregon border. We and others have concluded this is the locus of border and an asthenospheric low-density body that ex- a starting plume or plume head. Consideration of this tends several hundred kilometers south and north of the plume-head model leads us to discuss the following three Nevada-Oregon boundary. A reconstruction of the initial implications. contact of the plume head with the lithosphere suggests (1) The apparent center of the relic plume head is about relatively thin lithosphere at 17 Ma beneath Oregon and 250 km west of the location where both the trends of the Washington, which would favor the spreading of the younger hotspot track and the inferred plate motions plume northward in this direction, more decompression would place the hotspot at 16 Ma. A possible explanation melting in this “thinspot” area, and the eruption of basalt for this discrepancy is the westward deflection of the through dense, oceanic lithosphere. Thus, preferential plume up the bottom of the inclined Vancouver slab. Plate extrusion of flood basalts north of the plume center may tectonic reconstructions and an intermediate dip for the be the result of differences in the pre-plume lithosphere, Vancouver slab indicate a plume head would have inter- and not the location of the center of the plume head.
    [Show full text]
  • 7.09 Hot Spots and Melting Anomalies G
    7.09 Hot Spots and Melting Anomalies G. Ito, University of Hawaii, Honolulu, HI, USA P. E. van Keken, University of Michigan, Ann Arbor, MI, USA ª 2007 Elsevier B.V. All rights reserved. 7.09.1 Introduction 372 7.09.2 Characteristics 373 7.09.2.1 Volcano Chains and Age Progression 373 7.09.2.1.1 Long-lived age-progressive volcanism 373 7.09.2.1.2 Short-lived age-progressive volcanism 381 7.09.2.1.3 No age-progressive volcanism 382 7.09.2.1.4 Continental hot spots 383 7.09.2.1.5 The hot-spot reference frame 386 7.09.2.2 Topographic Swells 387 7.09.2.3 Flood Basalt Volcanism 388 7.09.2.3.1 Continental LIPs 388 7.09.2.3.2 LIPs near or on continental margins 389 7.09.2.3.3 Oceanic LIPs 391 7.09.2.3.4 Connections to hot spots 392 7.09.2.4 Geochemical Heterogeneity and Distinctions from MORB 393 7.09.2.5 Mantle Seismic Anomalies 393 7.09.2.5.1 Global seismic studies 393 7.09.2.5.2 Local seismic studies of major hot spots 395 7.09.2.6 Summary of Observations 399 7.09.3 Dynamical Mechanisms 400 7.09.3.1 Methods 400 7.09.3.2 Generating the Melt 401 7.09.3.2.1 Temperature 402 7.09.3.2.2 Composition 402 7.09.3.2.3 Mantle flow 404 7.09.3.3 Swells 405 7.09.3.3.1 Generating swells: Lubrication theory 405 7.09.3.3.2 Generating swells: Thermal upwellings and intraplate hot spots 407 7.09.3.3.3 Generating swells: Thermal upwellings and hot-spot–ridge interaction 408 7.09.3.4 Dynamics of Buoyant Upwellings 410 7.09.3.4.1 TBL instabilities 410 7.09.3.4.2 Thermochemical instabilities 411 7.09.3.4.3 Effects of variable mantle properties 412 7.09.3.4.4 Plume
    [Show full text]
  • Yellowstone Science a Quarterly Publication Devoted to the Natural and Cultural Resources
    Yellowstone Science A quarterly publication devoted to the natural and cultural resources A Chat with a Geophysicist Yellowstone’s Architecture Windows into the Earth Reviewed A Tribute to Aubrey Haines Volume 8 Number 4 NPS photo Through a Glass, Darkly? On the surface of the wild “Wonder- that reflect a motley collection of styles Haines passed from his earthly life, caus- land” that is today called Yellowstone, and eras. ing mourning among many Yellowstone modern Americans have noticeably left Underneath the park teem the unseen, fans. In his NPS career and afterward, their mark, in the buildings they have uncontrollable forces of the earth’s geol- Aubrey pursued the facts behind count- constructed over the last century or more. ogy, only hinted at by the surface mani- less tales and traditions of park history. A historic structure can be especially val- festations of geothermal energy. Many Looking through the windows Aubrey ued—or censured—based on how it re- scientists and visitors long to see and opened onto Yellowstone Park’s “cre- lates to the surrounding human-built and understand what lies beneath Yellow- ation,” some viewers saw light and others natural landscape. Nowadays whenever a stone. Robert B. Smith has worked to saw shadows cast upon a sacred story; new building is proposed in the park, open such a window for the better part of they even tried to close the window. I was extensive discussion precedes (and con- four decades and, in this issue, shares honored to know him, briefly, and hope siderable criticism follows) the chosen some of his journeys of geologic discov- that park managers and others will al- architectural design.
    [Show full text]