DOCSLIB.ORG

Talc-Bearing Serpentinite and the Creeping Section of the San Andreas Fault

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Talc-Bearing Serpentinite and the Creeping Section of the San Andreas Fault Vol 448 | 16 August 2007 | doi:10.1038/nature06064 LETTERS Talc-bearing serpentinite and the creeping section of the San Andreas fault Diane E. Moore1 & Michael J. Rymer1 The section of the San Andreas fault located between Cholame Andreas fault (SAF). In 2005, drilling successfully crossed the active Valley and San Juan Bautista in central California creeps at a rate trace of the SAF at ,3 km vertical depth12, where the measured as high as 28 mm yr21 (ref. 1), and it is also the segment that yields temperature is ,112 uC (ref. 13). The drillhole terminated in sedi- the best evidence for being a weak fault embedded in a strong mentary rocks of the Great Valley Sequence (K. McDougall, personal crust2–5. Serpentinized ultramafic rocks have been associated with communication) east of the fault. Since then, a portion of the well creeping faults in central and northern California6–8, and serpen- casing has been actively deforming in response to creep on a fault tinite is commonly invoked as the cause of the creep and the low strand12. Serpentine was identified in X-ray diffraction patterns of strength of this section of the San Andreas fault. However, the cuttings14 collected at the eastern margin of the zone of active frictional strengths of serpentine minerals are too high to satisfy deformation (Supplementary Fig. 1). Aeromagnetic surveys15 indi- the limitations on fault strength, and these minerals also have the cate the presence of a flat-lying slab of serpentinite at .3 km depth on potential for unstable slip under some conditions9,10. Here we the northeast side of the fault (Fig. 1). This body may be $2 km thick, report the discovery of talc in cuttings of serpentinite collected and it abuts the fault for 50–60 km (ref. 15). The serpentinite slab is from the probable active trace of the San Andreas fault that was probably part of the Coast Range ophiolite, the oceanic basement on intersected during drilling of the San Andreas Fault Observatory which the sediments of the Great Valley Sequence were deposited. at Depth (SAFOD) main hole in 2005. We infer that the talc is Serpentinized ultramafic rock has a relatively low density compared forming as a result of the reaction of serpentine minerals with to the overlying rock column, and a fault intersecting such a rock unit silica-saturated hydrothermal fluids that migrate up the fault provides the pathway for the migration of serpentinite to shallower zone, and the talc commonly occurs in sheared serpentinite. This depths16. The Table Mountain serpentinite17 east of Parkfield (Fig. 1) discovery is significant, as the frictional strength of talc at elevated is an extrusive body that formed as a result of the diapiric rise of temperatures is sufficiently low to meet the constraints on the shear low-density serpentinite from the deeply buried slab along faults that strength of the fault, and its inherently stable sliding behaviour is served as ‘fissure feeders’17. The serpentinite associated with the consistent with fault creep11. Talc may therefore provide the con- active trace in the SAFOD drillhole14 and outcrops of serpentinite18,19 nection between serpentinite and creep in the San Andreas fault, if fault gouge (Fig. 1) suggest that the same process is occurring along shear at depth can become localized along a talc-rich principal-slip the SAF. surface within serpentinite entrained in the fault zone. Serpentinite has been suggested as a possible cause of creep, The SAFOD drillsite is located 14 km northwest of Parkfield in because of its close association with creeping faults in central and central California (Fig. 1), along the creeping section of the San northern California6–8. The SAF creeping section coincides with the a Figure 1 | Distribution of serpentinite along the SAF CALIFORNIA creeping section. a, The creeping section lies between areas of the fault that ruptured during great Serpentinite body Table Mountain at >3 km depth serpentinite earthquakes in 1857 and 1906. N on east face Serpentinite occurs in rare surface Calaveras fau exposures of the fault18,19 and in the lt Hollister Paicines fault probable active trace of the fault 1857 surface encountered at ,3 km vertical ace 1906 surf Parkfield break depth in the SAFOD drillhole12,14. break San Juan San Andreas fault SAFOD Cholame The extrusive serpentinite at Table Bautista Serpentinite Mountain17 is derived from the outcrops same serpentinite body that abuts b the fault on the northeast side at ) .3 km depth15. b, Recently updated –1 30 creep rates measured at distances of NW SE 10 m to 1 km from the fault1. Total 20 offset rates along the San Andreas 10 Intermediate system in the creeping section are scale (±1 km) considered to be between 28 and 0 34 mm yr21 (ref. 1). Creep rate (mm yr Creep 0 50 100 150 Distance along the SAF from San Juan Bautista (km) 1US Geological Survey, 345 Middlefield Road, Mail Stop 977, Menlo Park, California 94025, USA. 795 © 2007 Nature Publishing Group LETTERS NATURE | Vol 448 | 16 August 2007 mapped extent of Coast Range ophiolite and overlying Great Valley decreases with increasing velocity) and velocity-strengthening Sequence rocks on the northeast side of the fault7,8,20. Ultramafic (strength increases with increasing velocity) behaviour9,10 at different rocks of the Coast Range ophiolite are variably serpentinized. The temperature–pressure–velocity conditions; as a result, they can slip most extensive serpentinite body along this section is the one east of either unstably or stably, respectively, depending on the depth and SAFOD15 that is associated with the highest creep rate (Fig. 1). On the slip rate. basis of aeromagnetic and gravity surveys, a slab of serpentinite 1–1.5 We examined serpentinite grains from the washed SAFOD cut- km thick at $3 km depth extends northeastwards from the SAF a few tings that were collected at ,3 m intervals during drilling. Polished kilometres southeast of San Juan Bautista to the Calaveras fault grain mounts were prepared from cuttings samples for analysis with around Hollister20. Serpentinite continues at somewhat greater an optical microscope, scanning electron microscope (SEM) and depth20 east of the Calaveras fault in that area. Other, smaller masses electron microprobe. The serpentinite contents of the bulk cuttings, of serpentinite are present at $2.4 km depth between the San estimated from point counts of thin sections, exceeds 2% by volume Andreas and Paicines faults7. The Calaveras–Paicines faults creep at in the interval 3,319–3,350 m measured depth (MD), with a spike of rates of 6–10 mm yr21 south of Hollister21. ,8% in the 3,325 m MD sample (Supplementary Fig. 1). A powder The creeping section provides the best evidence for a weak SAF2–5. X-ray diffraction pattern of a separate of serpentinite grains shows Because the creeping section is characterized by aseismic slip and prominent peaks consistent with lizardite and chrysotile, the two microearthquakes, the apparent weakness of this segment cannot low-temperature serpentine minerals. No relict olivine or pyroxene be explained through some dynamic weakening process accompany- has been found. On the basis of the common occurrence of both ing a major earthquake, as it can for the locked sections. The restric- mesh texture after olivine and bastite texture after pyroxene, the tions on shear strength in the creeping SAF imposed by heat-flow22,23 original ultramafic rock was probably a harzburgite16, similar to and stress-orientation24,25 data are delimited in Fig. 2; also included the Table Mountain serpentinite17. The pseudomorphic mesh and are the frictional strengths of synthetic fault-gouge materials9–11,26 bastite textures have been extensively modified by recrystallization, prepared by grinding and sieving rock or mineral separates. The brecciation and shearing. strength experiments were conducted in a triaxial machine fitted with The serpentinite contains numerous calcite- and some quartz- an internal furnace, at various combinations of temperature, confin- filled veins, possibly resulting from focused fluid flow within the fault ing and fluid pressure, and sliding velocity. For a given mineral to zone. Talc replaces serpentine minerals along the vein walls (Fig. 3a, control the behaviour of the creeping section, it must be very weak as b), and it fills narrow cracks that extend into the serpentinite from the well as characterized by stable shear. The frictional properties of the wider veins. Talc also forms along the foliation in sheared serpenti- serpentine minerals do not satisfy the weakness criterion and under nite grains (Fig. 3c, d). The talc-forming reaction is: certain conditions do not satisfy the stability criterion. The serpent- 9 ine minerals lizardite and antigorite are not substantially weaker Mg3Si2O5(OH)4 1 2SiO2 5 Mg3Si4O10(OH)2 1 H2O than granite26 under hydrothermal conditions (Fig. 2). Chrysotile serpentine talc satisfies the heat-flow constraint to depths of ,3 km, but its strength 9,10 increases substantially at greater depths . Furthermore, all three The SiO2 comes from the dissolved silica content of heated ground serpentine minerals show both velocity-weakening (strength water (Fig. 3a, c, d) and from quartz deposited metastably in veins (Fig. 3b). Talc is stable relative to the assemblage quartz 1 serpentine 27 0 throughout the stability range of serpentine . The veins and shears with which talc is associated overprint all other textural features in Frictional strengths the serpentinite grains, suggesting that the talc is of recent origin. Talc extrapolated to SAF 2 + a b Tc Tc Pores 4 Tc Tc Sp Antigorite Granite Cc Q Tc Sp 6 + Sp Sp Sp Lizardite Tc Chrysotile Tc Depth (km) Cc Q 8 Cc Tc Pores + c d Sp 10 365 mm Tc TAL Sp C Tc Sp yr Tc 12 - 1 Tc Stress- Heat-flow orientation Tc constraint Tc constraint Cc Sp 14 Sp 0 20 40 60 80 100 Cc Shear strength (MPa) Tc Figure 2 | Shear strength versus fault depth.
Load more

Recommended publications
  • Facts About Serpentine Rock and Soil Containing Asbestos in California
    University of California Division of Agriculture and Natural Resources http://anrcatalog.ucdavis.edu Publication 8399 / August 2009 Facts about Serpentine Rock and Soil Containing Asbestos in California JULIE FRAZELL, Program Representative, and RACHEL ELKINS, Pomology Farm Advisor, University of California Cooperative Extension, Lake County; ANTHONY TOBY O’GEEN, Associate Soil Resources Specialist in Cooperative Extension, Department of Land, Air and Water Resources, University of California, Davis; ROBERT REYNOLDS, Director Emeritus, Lake County Air Quality Management District; JAMES MEYERS, Occupational and Environmental Health Specialist Emeritus, Department of Biological and Agricultural Engineering, University of California, Davis What is Serpentine? The term “serpentine” refers to a group of minerals that make up serpentinite rock. “Serpentine” and “serpentinite,” however, are often used interchangeably. Serpentinite is a metamorphic rock formed when water and rock are exposed to low temperatures (about 400 to 600 ºC) and metamorphic processes (high pressures) within the earth’s crust. Serpentinite is a type of ultramafic rock, consisting predominantly of magnesium silicate and iron oxide minerals. Most ultramafic rocks, including serpentinite, contain naturally occurring asbestos (NOA) particles (fig. 1), microscopic needlelike particles of asbestos or asbestos-like fibers. The term “NOA” also refers to a group of relatively common fibrous minerals in rock (U.S. Geological Survey 2007). NOA minerals include chrysotile and fibrous forms of five amphiboles. These forms include a complex group of widely distributed magnesium-iron silicates (rock-forming minerals), crocidolite, amosite, anthophyllite, actinolite, and tremolite. The most common NOA particle in ultramafic rocks is chrysotile. NOA particles are a known human health risk. Asbestos has been classified as a carcinogen by state, federal, and international agencies.
    [Show full text]
  • Sulfide Mineralization in an Ultramafic-Rock Hosted Seafloor
    Marine Geology 245 (2007) 20–39 www.elsevier.com/locate/margeo Sulfide mineralization in an ultramafic-rock hosted seafloor hydrothermal system: From serpentinization to the formation of Cu–Zn–(Co)-rich massive sulfides ⁎ Ana Filipa A. Marques a,b, , Fernando J.A.S. Barriga a, Steven D. Scott b a CREMINER (LA/ISR), Universidade de Lisboa, Faculdade de Ciências, Departamento de Geologia, Edif. C6 Piso 4. 1749-016 Campo Grande, Lisboa, Portugal b Scotiabank Marine Geology Research Laboratory, Department of Geology, University of Toronto, 22 Russell St., Toronto, Canada M5S 3B1 Received 12 December 2006; received in revised form 2 May 2007; accepted 12 May 2007 Abstract The Rainbow vent field is an ultramafic rock-hosted seafloor hydrothermal system located on the Mid-Atlantic ridge issuing high temperature, acidic, metal-rich fluids. Hydrothermal products include Cu–Zn–(Co)-rich massive sulfides with characteristics comparable to those found in mafic volcanic-hosted massive sulfide deposits. Petrography, mineralogy and geochemistry of nonmineralized and mineralized rocks sampled in the Rainbow vent field indicate that serpentinized peridotites host the hydrothermal vent system but serpentinization reactions occurred prior to and independently of the sulfide mineralization event. The onset of sulfide mineralization is reflected by extensive textural and chemical transformations in the serpentine-group minerals that show clear signs of hydrothermal corrosion. Element remobilization is a recurrent process in the Rainbow vent field rocks and, during simple peridotite serpentinization, Ni and Cr present in olivine and pyroxene are incorporated in the pseudomorphic serpentine mesh and bastite, respectively. Ni is later remobilized from pseudomorphic serpentine into the newly formed sulfides as a result of extensive hydrothermal alteration.
    [Show full text]
  • Analysis of Iron-Containing Weathering Products in Serpentine Soils and Their Implications for Mars T
    49th Lunar and Planetary Science Conference 2018 (LPI Contrib. No. 2083) 2904.pdf ANALYSIS OF IRON-CONTAINING WEATHERING PRODUCTS IN SERPENTINE SOILS AND THEIR IMPLICATIONS FOR MARS T. A. Bamisile1, E. M. Hausrath1, O. D. Tschauner1, Z. R. Harrold1, C. Adcock1, C. M. Phillips-Lander1, S. Gainey1 and R. Gabriel1. 1 Department of Geoscience, University of Nevada, Las Vegas. Nevada, 89154 [email protected] Introduction: Abundant X-ray amorphous materi- refusal [12], and samples were collected from each soil al has been detected at Gale Crater by X-ray diffraction horizon using a spatula that had been previously (XRD) using CheMin. Approximately 27% - 40% X- cleaned with 70% ethanol. Samples were placed in ray amorphous material [1,2] has been found inter- sterile Whirlpak® bags and stored in a cooler until mixed with primary basaltic minerals at the Rocknest returned to the laboratory. Samples were stored at 4°C aeolian bedform. In XRD patterns, it was best fit by in the laboratory before analysis. either basaltic glass or allophane (a hydrous alumino- Isolation of clay-sized materials: The clay sized- silicate with a molar Si: Al ratio of typically 1:2 or fraction was isolated from the soils via flocculation and 1:1), although it is believed based on chemical data to centrifugation following methods modified from Iyoda contain Fe [1,3]. The X-ray amorphous material is also et al. [13]. Briefly, 10 g of soil was weighed into a volatile-rich based on Sample Analysis at Mars (SAM), 250mL LDPE bottle, and 25 – 50 mL of 18.2 MΩ de- which suggests that the amorphous material may con- ionized water was added to each sample.
    [Show full text]
  • Petrology on Mars†K
    American Mineralogist, Volume 100, pages 2380–2395, 2015 INVITED CENTENNIAL ARTICLE REVIEW Petrology on Mars†k HARRY Y. MCSWEEN JR.1,* 1Department of Earth and Planetary Sciences and Planetary Geoscience Institute, University of Tennessee, Knoxville, Tennessee 37996-1410, U.S.A. ABSTRACT Petrologic investigations of martian rocks have been accomplished by mineralogical, geochemical, and textural analyses from Mars rov- ers (with geologic context provided by orbiters), and by laboratory analyses of martian meteorites. Igneous rocks are primarily lavas and volcaniclastic rocks of basaltic composition, and ultramafic cumulates; alkaline rocks are common in ancient terranes and tholeiitic rocks occur in younger terranes, suggesting global magmatic evolution. Relatively uncommon feldspathic rocks represent the ultimate fractionation prod- ucts, and granitic rocks are unknown. Sedimentary rocks are of both clastic (mudstone, sandstone, conglomerate, all containing significant igneous detritus) and chemical (evaporitic sulfate and less common carbonate) origin. High-silica sediments formed by hydrothermal activity. Sediments on Mars formed from different protoliths and were weathered under different environmental conditions from terrestrial sediments. Metamorphic rocks have only been inferred from orbital remote-sensing measurements. Metabasalt and serpentinite have mineral assemblages consistent with those predicted from low-pressure phase equilibria and likely formed in geothermal systems. Shock effects are com- mon in martian meteorites, and impact breccias are probably widespread in the planet’s crustal rocks. The martian rock cycle during early periods was similar in many respects to that of Earth. However, without plate tectonics Mars did not experience the thermal metamorphism and flux melting associated with subduction, nor deposition in subsided basins and rapid erosion resulting from tectonic uplift.
    [Show full text]
  • AREAS MORE LIKELY to CONTAIN NATURALLY OCCURRING ASBESTOS August, 2000
    OPEN-FILE REPORT 2000-19 A GENERAL LOCATION GUIDE FOR ULTRAMAFIC ROCKS IN CALIFORNIA - AREAS MORE LIKELY TO CONTAIN NATURALLY OCCURRING ASBESTOS August, 2000 DEPARTMENT OF CONSERVATION Division of Mines and Geology (:Jl ll lltCRt•Jlll CON'.!!"1\/'AnoN, STATE OF CALIFORNIA GRAY DAVIS GOVERNOR THE RESOURCES AGENCY DEPARTMENT OF CONSERVATION MARY D. NICHOLS DARRYL YOUNG SECRETARY FOR RESOURCES DIRECTOR STATE OF CALIFORNIA - GRAY DAVIS, GOVERNOR OPEN-FILE REPORT 2000-19 DIVISION OF MINES AND GEOLOGY THE RESOURCES AGENCY - MARY NICHOLS, SECRETARY FOR RESOURCES A GENERAL LOCATION GUIDE FOR ULTRAMAFIC ROCKS IN CALIFORNIA - JAMES F. DAVIS, STATE GEOLOGIST DEPARTMENT OF CONSERVATION - DARRYL YOUNG, DIRECTOR AREAS MORE LIKELY TO CONTAIN NATURALLY OCCURRING ASBESTOS 124° 42° B 120° B B 42° A General Location Guide for Ultramafic Rocks 97 DelDel NorteNorte in California - Areas More Likely to Contain ModocModoc 5 SiskiyouSiskiyou Naturally Occurring Asbestos 101 395 Compiled By Ronald K. Churchill and Robert L. Hill August 2000 c·~-.✓- MAP PURPOSE MAP USAGE AND LIMITATIONS ··, ,. _ ~ This map shows the areas more likely to contain natural occurrences of asbestos The small scale of this map (1:1,000,000) precludes showing detailed boundaries ~-r in California. Its purpose is to inform government agencies, private industry and of ultramafic rock units and small occurrences of ultramafic rocks. It should be used HumboldtHumboldt I LassenLassen the public of the areas in the State where natural occurrences of asbestos may only as a general guide to the presence of ultramafic rocks that may contain asbestos. be an issue. In these areas, consideration of the implications of the presence or This map is derived from the Geologic Map of California (1:750,000 scale - one inch TrinityTrinity ShastaShasta absence of asbestos through examination of more detailed maps and site-specific equals about 12 miles), Jennings (1977).
    [Show full text]
  • Diamond Forms During Low Pressure Serpentinisation of Oceanic Lithosphere
    ©2020TheAuthors Published by the European Association of Geochemistry ▪ Diamond forms during low pressure serpentinisation of oceanic lithosphere N. Pujol-Solà1*, A. Garcia-Casco2,3, J.A. Proenza1,4, J.M. González-Jiménez2, A. del Campo5, V. Colás6, À. Canals1, A. Sánchez-Navas2, J. Roqué-Rosell1,4 Abstract doi: 10.7185/geochemlet.2029 Diamond is commonly regarded as an indicator of ultra-high pressure conditions in Earth System Science. This canonical view is challenged by recent data and interpre- tations that suggest metastable growth of diamond in low pressure environments. One such environment is serpentinisation of oceanic lithosphere, which produces highly reduced CH4-bearing fluids after olivine alteration by reaction with infiltrating fluids. Here we report the first ever observed in situ diamond within olivine-hosted, CH4-rich fluid inclusions from low pressure oceanic gabbro and chromitite samples from the Moa-Baracoa ophiolitic massif, eastern Cuba. Diamond is encapsulated in voids below the polished mineral surface forming a typical serpentinisation array, with methane, serpentine and magnetite, providing definitive evidence for its meta- stable growth upon low temperature and low pressure alteration of oceanic litho- sphere and super-reduction of infiltrated fluids. Thermodynamic modelling of the observed solid and fluid assemblage at a reference P-T point appropriate for serpentinisation (350 °C and 100 MPa) is consistent with extreme reduction of the fluid = − Δ = − to logfO2 (MPa) 45.3 ( logfO2[Iron-Magnetite] 6.5). These findings imply that the formation of metastable diamond at low pressure in serpentinised olivine is a widespread process in modern and ancient oceanic lithosphere, questioning a generalised ultra-high pressure origin for ophiolitic diamond.
    [Show full text]
  • 4. Geochemistry of Serpentinite Muds and Metamorphic Rocks from the Mariana Forearc, Odp Sites 1200 and 778–779, South Chamorro and Conical Seamounts1
    Shinohara, M., Salisbury, M.H., and Richter, C. (Eds.) Proceedings of the Ocean Drilling Program, Scientific Results Volume 195 4. GEOCHEMISTRY OF SERPENTINITE MUDS AND METAMORPHIC ROCKS FROM THE MARIANA FOREARC, ODP SITES 1200 AND 778–779, SOUTH CHAMORRO AND CONICAL SEAMOUNTS1 Ivan P. Savov,2 Steve Guggino,2 Jeffrey G. Ryan,2 Patricia Fryer,3 and Michael J. Mottl4 1Savov, I.P., Guggino, S., Ryan, J.G., Fryer, P., and Mottl, M.J., 2005. Geochemistry of serpentinite muds and metamorphic rocks from the Mariana forearc, ODP Sites 1200 and 778–779, South Chamorro and Conical Seamounts. In Shinohara, M., Salisbury, M.H., and Richter, C. (Eds.), Proc. ODP, Sci. Results, 195, 1–49 ABSTRACT [Online]. Available from World Wide Web: <http://www-odp.tamu.edu/ New geochemical data on serpentinite muds and metamorphic clasts publications/195_SR/VOLUME/ recovered during Ocean Drilling Program Legs 195 (Holes 1200A– CHAPTERS/103.PDF>. [Cited YYYY- MM-DD] 1200E) and 125 (Holes 778A and 779A) provide insights into the pro- 2Department of Geology, University of portions of rock types of various sources that compose the serpentinite South Florida—Tampa, 4202 East mudflows and the fluid-rock interactions that predominate in these Fowler Avenue, SCA 528, Tampa FL muds. We interpret the metamorphic rock fragments as derivatives of 33620-5201, USA. Correspondence mostly metamorphosed mafic rocks from the descending Pacific oce- author: [email protected] 3Hawaii Institute of Geophysics and anic crust. Based on their mid-ocean-ridge basalt (MORB)-like Al2O3, Planetology, School of Ocean and TiO2, CaO, Si/Mg, and rare earth element (REE) systematics, these meta- Earth Science and Technology, morphic rocks are classified as metabasalts/metagabbros and, therefore, University of Hawaii at Manoa, 1680 ~30-km depths represent an active subduction zone setting.
    [Show full text]
  • Serpentinization, Carbon, and Deep Life Matthew O
    Reviews in Mineralogy & Geochemistry Vol. 75 pp. 575-606, 2013 18 Copyright © Mineralogical Society of America Serpentinization, Carbon, and Deep Life Matthew O. Schrenk, William J. Brazelton Department of Biology East Carolina University Greenville, North Carolina 27858-2502, U.S.A. [email protected] [email protected] Susan Q. Lang Department of Earth Sciences ETH Zürich 8092 Zürich, Switzerland [email protected] INTRODUCTION The aqueous alteration of ultramafic rocks through serpentinization liberates mantle carbon and reducing power. Serpentinization occurs in numerous settings on present day Earth, including subduction zones, mid-ocean ridges, and ophiolites and has extended far into Earth’s history, potentially contributing to the origins and early evolution of life. Serpentinization can provide the energy and raw materials to support chemosynthetic microbial communities that may penetrate deep into Earth’s subsurface. Microorganisms may also influence the composition and quantity of carbon-bearing compounds in the deep subsurface. However, conditions created by serpentinization challenge the known limits of microbial physiology in terms of extreme pH, access to electron acceptors, and availability of nutrients. Furthermore, the downward transport of surface carbon and subsequent mixing with calcium-rich fluids at high pH contributes to the precipitation and immobilization of carbonate minerals. The following chapter will explore the physiological challenges presented by the serpentinite environment, data from studies of serpentinite-hosted microbial ecosystems, and areas in need of further investigation. THE PROCESS OF SERPENTINIZATION Physical and chemical consequences of serpentinization Serpentinization is an alteration process of low-silica ultramafic rocks, characteristic of the lower oceanic crust and upper mantle. These rocks are rich in the minerals olivine and pyroxene.
    [Show full text]
  • Detection of Carbonates in Martian Weathering Profiles Benjamin Bultel, Jean-Christophe Viennet, François Poulet, John Carter, Stephanie Werner
    Detection of Carbonates in Martian Weathering Profiles Benjamin Bultel, Jean-christophe Viennet, François Poulet, John Carter, Stephanie Werner To cite this version: Benjamin Bultel, Jean-christophe Viennet, François Poulet, John Carter, Stephanie Werner. Detection of Carbonates in Martian Weathering Profiles. Journal of Geophysical Research. Planets, Wiley- Blackwell, 2019, 124 (4), pp.989-1007. 10.1029/2018JE005845. hal-03127708 HAL Id: hal-03127708 https://hal.archives-ouvertes.fr/hal-03127708 Submitted on 1 Feb 2021 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. RESEARCH ARTICLE Detection of Carbonates in Martian Weathering Profiles 10.1029/2018JE005845 Benjamin Bultel1 , Jean‐Christophe Viennet1,2,3,4 , François Poulet5 , John Carter5 , 1 Key Points: and Stephanie C. Werner • Carbonates mixed with clay 1 2 minerals can be detected with the Centre for Earth Evolution and Dynamics, Department for Geosciences, University of Oslo, Oslo, Norway, Now at use of a unique spectral feature in Laboratoire d'Archéologie Moléculaire et Structurale, CNRS
    [Show full text]
  • THEORIES for the ORIGIN of OIL by Mike Westlund A. Biological
    THEORIES FOR THE ORIGIN OF OIL By Mike Westlund A. Biological Method--Plant and Animal Sources Almost all geologists today believe that oil (petroleum) was made biologically, that is from plant and animal fossils. Hence, the name fossil fuels was coined. Large mats of floating vegetation, swamps, and shallow seas were covered with sediments. Over millions of years the accumulating sediments of sand, silt, clay, shells, and gravel were changed to sedimentary rock. The dead vegetation and animals, which was preserved by the lack of oxygen, was slowly changed to oil shale by bacteria and the weight of the sediments. Then over millions of years, the increasing heat and pressure from the accumulating sediments changed the oil shale into petroleum. Plants have never been turned into oil in the laboratory because the geologists say the process takes millions of years. http://en.wikipedia.org/wiki/abiogenic_petroleum_origin_ Everything not documented in this article comes from the above website. http://whyfiles.org/100oil/2.html (Picture of oil pool under sedimentary rock) http://www.leeric.lsu.edu/bgbb/3/origin.html (Diagrams of biotic origin) B. Abiotic Method-- Bacterial Action on Non-biotic Sources Deep in the crust or in the mantel of the earth, bacteria may make oil abiotically, that is from sources that were never alive. One suspect is archaea, a microorganism in a different kingdom than bacteria. Archaea are found growing in Yellowstone National Park hot springs at 100oC or at boiling. For food, Archaea use hydrogen that has been leached by water out of igneous rocks such as basalt.
    [Show full text]
  • On the Origins of Deep Hydrocarbons Mark A
    Reviews in Mineralogy & Geochemistry Vol. 75 pp. 449-465, 2013 14 Copyright © Mineralogical Society of America On the Origins of Deep Hydrocarbons Mark A. Sephton Earth Science & Engineering Imperial College London, South Kensington Campus London SW7 2AZ, United Kingdom [email protected] Robert M. Hazen Geophysical Laboratory, Carnegie Institution of Washington 5251 Broad Branch Road NW Washington, DC 20015, U.S.A. [email protected] INTRODUCTION Deep deposits of hydrocarbons, including varied reservoirs of petroleum and natural gas, represent the most economically important component of the deep carbon cycle. Yet despite their intensive study and exploitation for more than a century, details of the origins of some deep hydrocarbons remain a matter of vocal debate in some scientific circles. This long and continuing history of controversy may surprise some readers, for the biogenic origins of “fossil fuels”—a principle buttressed by a vast primary scientific literature and established as textbook orthodoxy in North America and many other parts of the world—might appear to be settled fact. Nevertheless, conventional wisdom continues to be challenged by some scientists. The principal objectives of this chapter are: (1) to review the overwhelming evidence for the biogenic origins of most known deep hydrocarbon reservoirs; (2) to present equally persuasive experimental, theoretical, and field evidence, which indicates that components of some deep hydrocarbon deposits appear to have an abiotic origin; and (3) to suggest future studies that might help to achieve a more nuanced resolution of this sometimes polarized topic. BIOGENIC ORIGINS OF DEEP HYDROCARBONS Types of hydrocarbons Deep hydrocarbons include a rich diversity of organic chemical compounds in the form of petroleum deposits, including oil and gas in various reservoirs, bitumen in oil sands, coal and clathrate hydrates.
    [Show full text]
  • Serpentine and Serpentinization: a Link Between Planet Formation and Life
    Serpentine and serpentinization: A link between planet formation and life Othmar Müntener Institute of Mineralogy and Geochemistry University of Lausanne, CH-1015 Lausanne, Switzerland Ultramafi c rocks, composed mainly of olivine and pyroxenes, are a system on the Atlantis Massif at 30°N, ~15 km west of the Mid-Atlantic major component in the lithosphere of early terrestrial planets, where they Ridge, which is associated with serpentinization (Kelley et al., 2001). formed by direct crystallization of mantle-derived magmas on the planet’s Coupled with the knowledge that the undifferentiated crust of terrestrial surface or by partial crystallization as cumulates from a magma ocean. planets such as Mars and the early Earth is largely composed of mafi c and On modern Earth, ultramafi c rocks are commonly exposed near and ultramafi c rocks (Longhi et al., 1992), these observations have led to an along slow- and ultraslow-spreading ridges (e.g., Dick et al., 2003), along increased interest in the origin of life, both terrestrial and extra terrestrial, magma-poor passive margins (e.g., Boillot et al., 1980) and in tectonically especially since the discovery of exoplanets (Mayor and Queloz, 1995). active zones in mountain belts. The way that ultramafi c rocks alter into This has fueled a new interdisciplinary research direction called astrobiol- serpentine is central to a variety of processes at the interface between the ogy, and recent efforts on Mars pointed out the importance of serpentiniza- solid earth, the hydrosphere, the atmosphere, and the biosphere. tion on Mars in the formation of molecular hydrogen and methane (Oze There are three main serpentine polymorphs—chrysotile, lizardite, and Sharma, 2005; Schulte et al., 2006).
    [Show full text]