<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html>
<head>
<title>UTas ePrints - Characteristics and origin of peperite involving coarse-grained host sediment</title>
<script type="text/javascript" src="http://eprints.utas.edu.au/javascript/auto.js"><!-- padder --></script>
<style type="text/css" media="screen">@import url(http://eprints.utas.edu.au/style/auto.css);</style>
<style type="text/css" media="print">@import url(http://eprints.utas.edu.au/style/print.css);</style>
<link rel="icon" href="/images/eprints/favicon.ico" type="image/x-icon" />
<link rel="shortcut icon" href="/images/eprints/favicon.ico" type="image/x-icon" />
<link rel="Top" href="http://eprints.utas.edu.au/" />
<link rel="Search" href="http://eprints.utas.edu.au/cgi/search" />
<meta content="Squire, R.J." name="eprints.creators_name" />
<meta content="McPhie, J." name="eprints.creators_name" />
<meta name="eprints.creators_id" />
<meta content="J.McPhie@utas.edu.au" name="eprints.creators_id" />
<meta content="article" name="eprints.type" />
<meta content="2007-09-04" name="eprints.datestamp" />
<meta content="2008-01-30T04:17:41Z" name="eprints.lastmod" />
<meta content="show" name="eprints.metadata_visibility" />
<meta content="Characteristics and origin of peperite involving coarse-grained host sediment" name="eprints.title" />
<meta content="pub" name="eprints.ispublished" />
<meta content="260100" name="eprints.subjects" />
<meta content="restricted" name="eprints.full_text_status" />
<meta content="basalt-gravel peperite; basaltic sill; polymictic volcanic conglomerate; submarine volcanic succession; Fiji; Pliocene" name="eprints.keywords" />
<meta content="The definitive version is available online at http://www.sciencedirect.com/" name="eprints.note" />
<meta content="Peperite involving basalt and polymictic volcanic conglomerate occurs in the Pliocene Ba Volcanic Group at
Yaqara in northern Viti Levu, Fiji. Because the host sediment is coarse-grained and dominated by basalt clasts, the peperite could be easily overlooked and mistaken for another coarse volcaniclastic facies. However, the presence of groups of basalt clasts that show jigsaw-fit texture, fluidally shaped basalt clasts with complete glassy margins,
gradational contacts with adjacent sedimentary facies and the absence of stratification indicate that molten basalt
mingled with unconsolidated gravel. Using these criteria, we show that other superficially similar, coarse, polymictic
facies with fluidal basalt clasts are not peperite. Both blocky and fluidal basalt clasts occur together in the peperite.
The amoeboid basalt clasts in the fluidal peperite result from dismembering of ductile, low-viscosity, relatively hot
magma. At this stage, propagating magma lobes were probably insulated from direct contact with the wet sediment by
a vapour film. The angular, polyhedral basalt clasts in the blocky peperite indicate brittle disintegration of somewhat
cooler, higher-viscosity magma. The presence of jigsaw-fit texture and polyhedral clasts with glassy margins suggest
that quench fragmentation of the basalt was important in the formation of the blocky peperite. Although there is no
positive evidence for steam explosivity, the presence of steam could be recorded by small quartz-filled cavities that
occur within the host sediment. The co-existence of fluidal and blocky basalt clasts is interpreted to reflect successive ductile then brittle fragmentation of intruding magma. The change from fluidal to blocky peperite might have resulted from progressive cooling of the magma during intrusion, and also from the breakdown of fluidisation when the limited supply of fine sediment in the host gravel was exhausted." name="eprints.abstract" />
<meta content="2002-05" name="eprints.date" />
<meta content="published" name="eprints.date_type" />
<meta content="Journal of Volcanology and Geothermal Research" name="eprints.publication" />
<meta content="114" name="eprints.volume" />
<meta content="1-2" name="eprints.number" />
<meta content="45-61" name="eprints.pagerange" />
<meta content="10.1016/S0377-0273(01)00289-X" name="eprints.id_number" />
<meta content="UNSPECIFIED" name="eprints.thesis_type" />
<meta content="TRUE" name="eprints.refereed" />
<meta content="0377-0273" name="eprints.issn" />
<meta content="http://dx.doi.org/10.1016/S0377-0273(01)00289-X" name="eprints.official_url" />
<meta content="Boulter, C.A., 1993. High-level peperitic sills at Rio Tinto, Spain: implications for stratigraphy and mineralisation. Trans. Inst. Min. Metall. (Sect. B: Appl. Earth Sci.) 102, B30-B38.
Brooks, E.R., 1995. Paleozoic Fluidization, folding, and peperite formation, northern Sierra Nevada, California. Can.
J. Earth Sci. 32, 314-324.
Brooks, E.R., Wood, M.W., Garbutt, P.L., 1982. Origin and
metamorphism of peperite and associated rocks in the Devonian Elwell Formation, northern Sierra Nevada, California. Geol. Soc. Am. Bull. 93, 1208-1231.
Busby-Spera, C.J., White, J.D.L., 1987. Variation in peperite textures associated with differing host-sediment properties. Bull. Volcanol. 49, 765-775.
Colley, H., Flint, D.J., 1995. Metallic mineral deposits of Fiji. Mem. 4, Miner. Resour. Dept. Fiji.
Colley, H., Greenbaum, D., 1980. The mineral deposits and
metallogenesis of the Fiji Platform. Econ. Geol. 75, 807-829.
Colley, H., Hindle, W.H. (Eds.), 1984. Volcano-tectonic evolution of Fiji and adjoining marginal basins. Marginal basin geology; volcanic and associated sedimentary and tectonic processes in modern and ancient marginal basins Geol. Soc. London, Spec. Publ. 16, 151-162.
Dickinson, W.R., 1968. Sedimentation of volcaniclastic strata of the Pliocene Koroimavua Group in northwest Viti Levu, Fiji. Am. J. Sci. 266, 440-453.
Gill, J.B., 1987. Geodynamic and geochemical evolution of the Fiji region. Proc. Pacific Rim Congr. Aust. Inst. Min. Metall., pp. 125-128.
Goto, Y., McPhie, J., 1996. A Miocene basanite peperitic dyke at Stanley, northwestern Tasmania, Australia. J. Volcanol. Geotherm. Res. 74, 11-120.
Hanson, R.E., 1991. Quenching and hydroclastic disruption of
andesitic to rhyolitic intrusions in a submarine island-arc
sequence, northern Sierra Nevada, California. Geol. Soc.
Am. Bull. 103, 804-816.
Hanson, R.E., Hargrove, U.S., 1999. Processes of magma/wet
sediment interaction in a large-scale Jurassic andesitic peperite complex, northern Sierra Nevada, California. Bull. Volcanol. 60, 610-626.
Hanson, R.E., Wilson, T.J., 1991. Submarine rhyolitic volcanism in a Jurassic proto-marginal basin; Southern Andes, Chile and Argentina. In: Harmon, R.S., Rapela, C.W.
(Eds.), Andean Magmatism and its Tectonic Setting. Geological Society of America, Boulder, CO, pp. 13-27.
Hanson, R.E., Wilson, T.J., 1993. Large-scale rhyolite peperites (Jurassic, Southern Chile). J. Volcanol. Geotherm. Res. 54, 247-264.
Kokelaar, B.P., 1982. Fluidization of wet sediments during the emplacement and cooling of various igneous bodies. J. Geol. Soc. London 139, 21-33.
Kokelaar, B.P., 1986. Magma-water interactions in subaqueous
and emergent basaltic volcanism. Bull. Volcanol. 48, 275-289.
Le Maitre, R.W., Bateman, P., Dudek, A., Keller, J., Lameyre
Le Bas, M.J., Sabine, P.A., Schmid, R., Sorensen, H.,Streckeisen, A., Woolley, A.R., Zanettin, B., 1989. A Classification of Igneous Rocks and Glossary of Terms. Blackwell, Oxford.
McPhie, J., 1995. A Pliocene shoaling basaltic seamount: Ba
Volcanic Group at Rakiraki, Fiji. J. Volcanol. Geotherm.
Res. 64, 193-210.
Mills, A.A., 1984. Pillow lavas and the Leidenfrost effect.
J. Geol. Soc. London 141, 183-186.
Mueller, W., Chown, E.H., Potvin, R., 1994. Substorm wave
base felsic hydroclastic deposits in the Archean Lac des
Vents volcanic complex, Abitibi Belt, Canada. J. Volcanol.
Geotherm. Res. 60, 273-300.
Rawlings, D.J., 1993. Mafic peperite from the Gold Creek
Volcanics in the Middle Proterozoic Mc Arthur Basin,
Northern Territory. Aust. J. Earth Sci. 40, 109-113.
Rickwood, P.C., 1989. Boundary lines within petrologic diagrams which use oxides of major and minor elements. Lithos 22, 247-263.
Rodda, P., 1967. Outline of the geology of Viti Levu. N.Z.
J. Geol. Geophys. 10, 1260-1273.
Rodda, P., 1976. Geology of northern and central Viti Levu.
Bull. 3, Miner. Resour. Div. Fiji.
Rodda, P., Kroenke, L.W., 1984. Fiji : a fragmented arc. In:
Kroenke, L.W. (Ed.), Cenozoic Tectonic Development of
the Southwest Pacific. CCOP/SOPAC Tech. Bull, pp. 87-
109.
Seeley, J.B., Searle, E.J., 1970. Geology of the Rakiraki district, Viti Levu, Fiji. N.Z. J. Geol. Geophys. 13, 52-71.
Shaw, H.R., 1969. Rheology of basalt in the melting range.
J. Petrol. 10, 510-535.
Whelan, P.M., Gill, J.B., Kollman, E., Duncan, R.A., Drake,
R.E., 1985. Radiometric dating of magmatic stages in Fiji.
In: Scholl, D.W., Vallier, T.L. (Eds.), Geology and Offshore
Resources of Pacific Island Arcs-Tonga Region. Circum-pacific Counc. Energ. Miner. Resour., Earth Sci. Ser., pp. 415-440.
White, J.D.L., Busby-Spera, C.J., 1987. Deep marine arc
apron deposits and syndepositional magmatism in the Alisitos
Group at Punta Cono, Baja California, Mexico. Sedimentology
34, 911-927.
Yamagishi, H., 1991. Morphological and sedimentological
characteristics of the Neogene submarine coherent lavas
and hyaloclastites in southwest Hokkaido, Japan. Sediment.
Geol. 74, 5-23." name="eprints.referencetext" />
<meta content="Squire, R.J. and McPhie, J. (2002) Characteristics and origin of peperite involving coarse-grained host sediment. Journal of Volcanology and Geothermal Research, 114 (1-2). pp. 45-61. ISSN 0377-0273" name="eprints.citation" />
<meta content="http://eprints.utas.edu.au/1868/1/Squire%2C_McPhie_JVGR_2002.pdf" name="eprints.document_url" />
<link rel="schema.DC" href="http://purl.org/DC/elements/1.0/" />
<meta content="Characteristics and origin of peperite involving coarse-grained host sediment" name="DC.title" />
<meta content="Squire, R.J." name="DC.creator" />
<meta content="McPhie, J." name="DC.creator" />
<meta content="260100 Geology" name="DC.subject" />
<meta content="Peperite involving basalt and polymictic volcanic conglomerate occurs in the Pliocene Ba Volcanic Group at
Yaqara in northern Viti Levu, Fiji. Because the host sediment is coarse-grained and dominated by basalt clasts, the peperite could be easily overlooked and mistaken for another coarse volcaniclastic facies. However, the presence of groups of basalt clasts that show jigsaw-fit texture, fluidally shaped basalt clasts with complete glassy margins,
gradational contacts with adjacent sedimentary facies and the absence of stratification indicate that molten basalt
mingled with unconsolidated gravel. Using these criteria, we show that other superficially similar, coarse, polymictic
facies with fluidal basalt clasts are not peperite. Both blocky and fluidal basalt clasts occur together in the peperite.
The amoeboid basalt clasts in the fluidal peperite result from dismembering of ductile, low-viscosity, relatively hot
magma. At this stage, propagating magma lobes were probably insulated from direct contact with the wet sediment by
a vapour film. The angular, polyhedral basalt clasts in the blocky peperite indicate brittle disintegration of somewhat
cooler, higher-viscosity magma. The presence of jigsaw-fit texture and polyhedral clasts with glassy margins suggest
that quench fragmentation of the basalt was important in the formation of the blocky peperite. Although there is no
positive evidence for steam explosivity, the presence of steam could be recorded by small quartz-filled cavities that
occur within the host sediment. The co-existence of fluidal and blocky basalt clasts is interpreted to reflect successive ductile then brittle fragmentation of intruding magma. The change from fluidal to blocky peperite might have resulted from progressive cooling of the magma during intrusion, and also from the breakdown of fluidisation when the limited supply of fine sediment in the host gravel was exhausted." name="DC.description" />
<meta content="2002-05" name="DC.date" />
<meta content="Article" name="DC.type" />
<meta content="PeerReviewed" name="DC.type" />
<meta content="application/pdf" name="DC.format" />
<meta content="http://eprints.utas.edu.au/1868/1/Squire%2C_McPhie_JVGR_2002.pdf" name="DC.identifier" />
<meta content="http://dx.doi.org/10.1016/S0377-0273(01)00289-X" name="DC.relation" />
<meta content="Squire, R.J. and McPhie, J. (2002) Characteristics and origin of peperite involving coarse-grained host sediment. Journal of Volcanology and Geothermal Research, 114 (1-2). pp. 45-61. ISSN 0377-0273" name="DC.identifier" />
<meta content="http://eprints.utas.edu.au/1868/" name="DC.relation" />
<link rel="alternate" href="http://eprints.utas.edu.au/cgi/export/1868/BibTeX/epprod-eprint-1868.bib" title="BibTeX" type="text/plain" />
<link rel="alternate" href="http://eprints.utas.edu.au/cgi/export/1868/ContextObject/epprod-eprint-1868.xml" title="OpenURL ContextObject" type="text/xml" />
<link rel="alternate" href="http://eprints.utas.edu.au/cgi/export/1868/ContextObject::Dissertation/epprod-eprint-1868.xml" title="OpenURL Dissertation" type="text/xml" />
<link rel="alternate" href="http://eprints.utas.edu.au/cgi/export/1868/ContextObject::Journal/epprod-eprint-1868.xml" title="OpenURL Journal" type="text/xml" />
<link rel="alternate" href="http://eprints.utas.edu.au/cgi/export/1868/DC/epprod-eprint-1868.txt" title="Dublin Core" type="text/plain" />
<link rel="alternate" href="http://eprints.utas.edu.au/cgi/export/1868/DIDL/epprod-eprint-1868.xml" title="DIDL" type="text/xml" />
<link rel="alternate" href="http://eprints.utas.edu.au/cgi/export/1868/EndNote/epprod-eprint-1868.enw" title="EndNote" type="text/plain" />
<link rel="alternate" href="http://eprints.utas.edu.au/cgi/export/1868/HTML/epprod-eprint-1868.html" title="HTML Citation" type="text/html; charset=utf-8" />
<link rel="alternate" href="http://eprints.utas.edu.au/cgi/export/1868/METS/epprod-eprint-1868.xml" title="METS" type="text/xml" />
<link rel="alternate" href="http://eprints.utas.edu.au/cgi/export/1868/MODS/epprod-eprint-1868.xml" title="MODS" type="text/xml" />
<link rel="alternate" href="http://eprints.utas.edu.au/cgi/export/1868/RIS/epprod-eprint-1868.ris" title="Reference Manager" type="text/plain" />
<link rel="alternate" href="http://eprints.utas.edu.au/cgi/export/1868/Refer/epprod-eprint-1868.refer" title="Refer" type="text/plain" />
<link rel="alternate" href="http://eprints.utas.edu.au/cgi/export/1868/Simple/epprod-eprint-1868text" title="Simple Metadata" type="text/plain" />
<link rel="alternate" href="http://eprints.utas.edu.au/cgi/export/1868/Text/epprod-eprint-1868.txt" title="ASCII Citation" type="text/plain; charset=utf-8" />
<link rel="alternate" href="http://eprints.utas.edu.au/cgi/export/1868/XML/epprod-eprint-1868.xml" title="EP3 XML" type="text/xml" />
</head>
<body bgcolor="#ffffff" text="#000000" onLoad="loadRoutine(); MM_preloadImages('images/eprints/ePrints_banner_r5_c5_f2.gif','images/eprints/ePrints_banner_r5_c7_f2.gif','images/eprints/ePrints_banner_r5_c8_f2.gif','images/eprints/ePrints_banner_r5_c9_f2.gif','images/eprints/ePrints_banner_r5_c10_f2.gif','images/eprints/ePrints_banner_r5_c11_f2.gif','images/eprints/ePrints_banner_r6_c4_f2.gif')">
<div class="ep_noprint"><noscript><style type="text/css">@import url(http://eprints.utas.edu.au/style/nojs.css);</style></noscript></div>
<table width="795" border="0" cellspacing="0" cellpadding="0">
<tr>
<td><script language="JavaScript1.2">mmLoadMenus();</script>
<table border="0" cellpadding="0" cellspacing="0" width="795">
<!-- fwtable fwsrc="eprints_banner_final2.png" fwbase="ePrints_banner.gif" fwstyle="Dreamweaver" fwdocid = "1249563342" fwnested="0" -->
<tr>
<td><img src="/images/eprints/spacer.gif" width="32" height="1" border="0" alt="" /></td>
<td><img src="/images/eprints/spacer.gif" width="104" height="1" border="0" alt="" /></td>
<td><img src="/images/eprints/spacer.gif" width="44" height="1" border="0" alt="" /></td>
<td><img src="/images/eprints/spacer.gif" width="105" height="1" border="0" alt="" /></td>
<td><img src="/images/eprints/spacer.gif" width="41" height="1" border="0" alt="" /></td>
<td><img src="/images/eprints/spacer.gif" width="16" height="1" border="0" alt="" /></td>
<td><img src="/images/eprints/spacer.gif" width="68" height="1" border="0" alt="" /></td>
<td><img src="/images/eprints/spacer.gif" width="68" height="1" border="0" alt="" /></td>
<td><img src="/images/eprints/spacer.gif" width="68" height="1" border="0" alt="" /></td>
<td><img src="/images/eprints/spacer.gif" width="82" height="1" border="0" alt="" /></td>
<td><img src="/images/eprints/spacer.gif" width="69" height="1" border="0" alt="" /></td>
<td><img src="/images/eprints/spacer.gif" width="98" height="1" border="0" alt="" /></td>
<td><img src="/images/eprints/spacer.gif" width="1" height="1" border="0" alt="" /></td>
</tr>
<tr>
<td colspan="12"><img name="ePrints_banner_r1_c1" src="/images/eprints/ePrints_banner_r1_c1.gif" width="795" height="10" border="0" alt="" /></td>
<td><img src="/images/eprints/spacer.gif" width="1" height="10" border="0" alt="" /></td>
</tr>
<tr>
<td rowspan="6"><img name="ePrints_banner_r2_c1" src="/images/eprints/ePrints_banner_r2_c1.gif" width="32" height="118" border="0" alt="" /></td>
<td rowspan="5"><a href="http://www.utas.edu.au/"><img name="ePrints_banner_r2_c2" src="/images/eprints/ePrints_banner_r2_c2.gif" width="104" height="103" border="0" alt="" /></a></td>
<td colspan="10"><img name="ePrints_banner_r2_c3" src="/images/eprints/ePrints_banner_r2_c3.gif" width="659" height="41" border="0" alt="" /></td>
<td><img src="/images/eprints/spacer.gif" width="1" height="41" border="0" alt="" /></td>
</tr>
<tr>
<td colspan="3"><a href="http://eprints.utas.edu.au/"><img name="ePrints_banner_r3_c3" src="/images/eprints/ePrints_banner_r3_c3.gif" width="190" height="31" border="0" alt="" /></a></td>
<td rowspan="2" colspan="7"><img name="ePrints_banner_r3_c6" src="/images/eprints/ePrints_banner_r3_c6.gif" width="469" height="37" border="0" alt="" /></td>
<td><img src="/images/eprints/spacer.gif" width="1" height="31" border="0" alt="" /></td>
</tr>
<tr>
<td colspan="3"><img name="ePrints_banner_r4_c3" src="/images/eprints/ePrints_banner_r4_c3.gif" width="190" height="6" border="0" alt="" /></td>
<td><img src="/images/eprints/spacer.gif" width="1" height="6" border="0" alt="" /></td>
</tr>
<tr>
<td colspan="2"><img name="ePrints_banner_r5_c3" src="/images/eprints/ePrints_banner_r5_c3.gif" width="149" height="1" border="0" alt="" /></td>
<td rowspan="2" colspan="2"><a href="/information.html" onMouseOut="MM_swapImgRestore();MM_startTimeout()" onMouseOver="MM_showMenu(window.mm_menu_0821132634_0,0,25,null,'ePrints_banner_r5_c5');MM_swapImage('ePrints_banner_r5_c5','','/images/eprints/ePrints_banner_r5_c5_f2.gif',1);"><img name="ePrints_banner_r5_c5" src="/images/eprints/ePrints_banner_r5_c5.gif" width="57" height="25" border="0" alt="About" /></a></td>
<td rowspan="2"><a href="/view/" onMouseOut="MM_swapImgRestore();MM_startTimeout()" onMouseOver="MM_showMenu(window.mm_menu_0821133021_1,0,25,null,'ePrints_banner_r5_c7');MM_swapImage('ePrints_banner_r5_c7','','/images/eprints/ePrints_banner_r5_c7_f2.gif',1);"><img name="ePrints_banner_r5_c7" src="/images/eprints/ePrints_banner_r5_c7.gif" width="68" height="25" border="0" alt="Browse" /></a></td>
<td rowspan="2"><a href="/perl/search/simple" onMouseOut="MM_swapImgRestore();MM_startTimeout()" onMouseOver="MM_showMenu(window.mm_menu_0821133201_2,0,25,null,'ePrints_banner_r5_c8');MM_swapImage('ePrints_banner_r5_c8','','/images/eprints/ePrints_banner_r5_c8_f2.gif',1);"><img name="ePrints_banner_r5_c8" src="/images/eprints/ePrints_banner_r5_c8.gif" width="68" height="25" border="0" alt="Search" /></a></td>
<td rowspan="2"><a href="/perl/register" onMouseOut="MM_swapImgRestore();MM_startTimeout();" onMouseOver="MM_showMenu(window.mm_menu_1018171924_3,0,25,null,'ePrints_banner_r5_c9');MM_swapImage('ePrints_banner_r5_c9','','/images/eprints/ePrints_banner_r5_c9_f2.gif',1);"><img name="ePrints_banner_r5_c9" src="/images/eprints/ePrints_banner_r5_c9.gif" width="68" height="25" border="0" alt="register" /></a></td>
<td rowspan="2"><a href="/perl/users/home" onMouseOut="MM_swapImgRestore();MM_startTimeout()" onMouseOver="MM_showMenu(window.mm_menu_0821133422_4,0,25,null,'ePrints_banner_r5_c10');MM_swapImage('ePrints_banner_r5_c10','','/images/eprints/ePrints_banner_r5_c10_f2.gif',1);"><img name="ePrints_banner_r5_c10" src="/images/eprints/ePrints_banner_r5_c10.gif" width="82" height="25" border="0" alt="user area" /></a></td>
<td rowspan="2"><a href="/help/" onMouseOut="MM_swapImgRestore();MM_startTimeout()" onMouseOver="MM_showMenu(window.mm_menu_0821133514_5,0,25,null,'ePrints_banner_r5_c11');MM_swapImage('ePrints_banner_r5_c11','','/images/eprints/ePrints_banner_r5_c11_f2.gif',1);"><img name="ePrints_banner_r5_c11" src="/images/eprints/ePrints_banner_r5_c11.gif" width="69" height="25" border="0" alt="Help" /></a></td>
<td rowspan="3" colspan="4"><img name="ePrints_banner_r5_c12" src="/images/eprints/ePrints_banner_r5_c12.gif" width="98" height="40" border="0" alt="" /></td>
<td><img src="/images/eprints/spacer.gif" width="1" height="1" border="0" alt="" /></td>
</tr>
<tr>
<td rowspan="2"><img name="ePrints_banner_r6_c3" src="/images/eprints/ePrints_banner_r6_c3.gif" width="44" height="39" border="0" alt="ePrints home" /></td>
<td><a href="/" onMouseOut="MM_swapImgRestore()" onMouseOver="MM_swapImage('ePrints_banner_r6_c4','','/images/eprints/ePrints_banner_r6_c4_f2.gif',1);"><img name="ePrints_banner_r6_c4" src="/images/eprints/ePrints_banner_r6_c4.gif" width="105" height="24" border="0" alt="ePrints home" /></a></td>
<td><img src="/images/eprints/spacer.gif" width="1" height="24" border="0" alt="" /></td>
</tr>
<tr>
<td><img name="ePrints_banner_r7_c2" src="/images/eprints/ePrints_banner_r7_c2.gif" width="104" height="15" border="0" alt="" /></td>
<td colspan="8"><img name="ePrints_banner_r7_c4" src="/images/eprints/ePrints_banner_r7_c4.gif" width="517" height="15" border="0" alt="" /></td>
<td><img src="/images/eprints/spacer.gif" width="1" height="15" border="0" alt="" /></td>
</tr>
</table></td>
</tr>
<tr><td><table width="100%" style="font-size: 90%; border: solid 1px #ccc; padding: 3px"><tr>
<td align="left"><a href="http://eprints.utas.edu.au/cgi/users/home">Login</a> | <a href="http://eprints.utas.edu.au/cgi/register">Create Account</a></td>
<td align="right" style="white-space: nowrap">
<form method="get" accept-charset="utf-8" action="http://eprints.utas.edu.au/cgi/search" style="display:inline">
<input class="ep_tm_searchbarbox" size="20" type="text" name="q" />
<input class="ep_tm_searchbarbutton" value="Search" type="submit" name="_action_search" />
<input type="hidden" name="_order" value="bytitle" />
<input type="hidden" name="basic_srchtype" value="ALL" />
<input type="hidden" name="_satisfyall" value="ALL" />
</form>
</td>
</tr></table></td></tr>
<tr>
<td class="toplinks"><!-- InstanceBeginEditable name="content" -->
<div align="center">
<table width="720" class="ep_tm_main"><tr><td align="left">
<h1 class="ep_tm_pagetitle">Characteristics and origin of peperite involving coarse-grained host sediment</h1>
<p style="margin-bottom: 1em" class="not_ep_block"><span class="person_name">Squire, R.J.</span> and <span class="person_name">McPhie, J.</span> (2002) <xhtml:em>Characteristics and origin of peperite involving coarse-grained host sediment.</xhtml:em> Journal of Volcanology and Geothermal Research, 114 (1-2). pp. 45-61. ISSN 0377-0273</p><p style="margin-bottom: 1em" class="not_ep_block"></p><table style="margin-bottom: 1em" class="not_ep_block"><tr><td valign="top" style="text-align:center"><a href="http://eprints.utas.edu.au/1868/1/Squire%2C_McPhie_JVGR_2002.pdf"><img alt="[img]" src="http://eprints.utas.edu.au/style/images/fileicons/application_pdf.png" border="0" class="ep_doc_icon" /></a></td><td valign="top"><a href="http://eprints.utas.edu.au/1868/1/Squire%2C_McPhie_JVGR_2002.pdf"><span class="ep_document_citation">PDF</span></a> - Full text restricted - Requires a PDF viewer<br />1523Kb</td><td><form method="get" accept-charset="utf-8" action="http://eprints.utas.edu.au/cgi/request_doc"><input value="2353" name="docid" accept-charset="utf-8" type="hidden" /><div class=""><input value="Request a copy" name="_action_null" class="ep_form_action_button" onclick="return EPJS_button_pushed( '_action_null' )" type="submit" /> </div></form></td></tr></table><p style="margin-bottom: 1em" class="not_ep_block">Official URL: <a href="http://dx.doi.org/10.1016/S0377-0273(01)00289-X">http://dx.doi.org/10.1016/S0377-0273(01)00289-X</a></p><div class="not_ep_block"><h2>Abstract</h2><p style="padding-bottom: 16px; text-align: left; margin: 1em auto 0em auto">Peperite involving basalt and polymictic volcanic conglomerate occurs in the Pliocene Ba Volcanic Group at
Yaqara in northern Viti Levu, Fiji. Because the host sediment is coarse-grained and dominated by basalt clasts, the peperite could be easily overlooked and mistaken for another coarse volcaniclastic facies. However, the presence of groups of basalt clasts that show jigsaw-fit texture, fluidally shaped basalt clasts with complete glassy margins,
gradational contacts with adjacent sedimentary facies and the absence of stratification indicate that molten basalt
mingled with unconsolidated gravel. Using these criteria, we show that other superficially similar, coarse, polymictic
facies with fluidal basalt clasts are not peperite. Both blocky and fluidal basalt clasts occur together in the peperite.
The amoeboid basalt clasts in the fluidal peperite result from dismembering of ductile, low-viscosity, relatively hot
magma. At this stage, propagating magma lobes were probably insulated from direct contact with the wet sediment by
a vapour film. The angular, polyhedral basalt clasts in the blocky peperite indicate brittle disintegration of somewhat
cooler, higher-viscosity magma. The presence of jigsaw-fit texture and polyhedral clasts with glassy margins suggest
that quench fragmentation of the basalt was important in the formation of the blocky peperite. Although there is no
positive evidence for steam explosivity, the presence of steam could be recorded by small quartz-filled cavities that
occur within the host sediment. The co-existence of fluidal and blocky basalt clasts is interpreted to reflect successive ductile then brittle fragmentation of intruding magma. The change from fluidal to blocky peperite might have resulted from progressive cooling of the magma during intrusion, and also from the breakdown of fluidisation when the limited supply of fine sediment in the host gravel was exhausted.</p></div><table style="margin-bottom: 1em" border="0" cellpadding="3" class="not_ep_block"><tr><th valign="top" class="ep_row">Item Type:</th><td valign="top" class="ep_row">Article</td></tr><tr><th valign="top" class="ep_row">Additional Information:</th><td valign="top" class="ep_row">The definitive version is available online at http://www.sciencedirect.com/</td></tr><tr><th valign="top" class="ep_row">Keywords:</th><td valign="top" class="ep_row">basalt-gravel peperite; basaltic sill; polymictic volcanic conglomerate; submarine volcanic succession; Fiji; Pliocene</td></tr><tr><th valign="top" class="ep_row">Subjects:</th><td valign="top" class="ep_row"><a href="http://eprints.utas.edu.au/view/subjects/260100.html">260000 Earth Sciences > 260100 Geology</a></td></tr><tr><th valign="top" class="ep_row">Collections:</th><td valign="top" class="ep_row">UNSPECIFIED</td></tr><tr><th valign="top" class="ep_row">ID Code:</th><td valign="top" class="ep_row">1868</td></tr><tr><th valign="top" class="ep_row">Deposited By:</th><td valign="top" class="ep_row"><span class="ep_name_citation"><span class="person_name">Mrs Katrina Keep</span></span></td></tr><tr><th valign="top" class="ep_row">Deposited On:</th><td valign="top" class="ep_row">04 Sep 2007</td></tr><tr><th valign="top" class="ep_row">Last Modified:</th><td valign="top" class="ep_row">30 Jan 2008 15:17</td></tr><tr><th valign="top" class="ep_row">ePrint Statistics:</th><td valign="top" class="ep_row"><a target="ePrintStats" href="/es/index.php?action=show_detail_eprint;id=1868;">View statistics for this ePrint</a></td></tr></table><p align="right">Repository Staff Only: <a href="http://eprints.utas.edu.au/cgi/users/home?screen=EPrint::View&eprintid=1868">item control page</a></p>
</td></tr></table>
</div>
<!-- InstanceEndEditable --></td>
</tr>
<tr>
<td><!-- #BeginLibraryItem "/Library/footer_eprints.lbi" -->
<table width="795" border="0" align="left" cellpadding="0" class="footer">
<tr valign="top">
<td colspan="2"><div align="center"><a href="http://www.utas.edu.au">UTAS home</a> | <a href="http://www.utas.edu.au/library/">Library home</a> | <a href="/">ePrints home</a> | <a href="/contact.html">contact</a> | <a href="/information.html">about</a> | <a href="/view/">browse</a> | <a href="/perl/search/simple">search</a> | <a href="/perl/register">register</a> | <a href="/perl/users/home">user area</a> | <a href="/help/">help</a></div><br /></td>
</tr>
<tr><td colspan="2"><p><img src="/images/eprints/footerline.gif" width="100%" height="4" /></p></td></tr>
<tr valign="top">
<td width="68%" class="footer">Authorised by the University Librarian<br />
© University of Tasmania ABN 30 764 374 782<br />
<a href="http://www.utas.edu.au/cricos/">CRICOS Provider Code 00586B</a> | <a href="http://www.utas.edu.au/copyright/copyright_disclaimers.html">Copyright & Disclaimers</a> | <a href="http://www.utas.edu.au/accessibility/index.html">Accessibility</a> | <a href="http://eprints.utas.edu.au/feedback/">Site Feedback</a> </td>
<td width="32%"><div align="right">
<p align="right" class="NoPrint"><a href="http://www.utas.edu.au/"><img src="http://www.utas.edu.au/shared/logos/unioftasstrip.gif" alt="University of Tasmania Home Page" width="260" height="16" border="0" align="right" /></a></p>
<p align="right" class="NoPrint"><a href="http://www.utas.edu.au/"><br />
</a></p>
</div></td>
</tr>
<tr valign="top">
<td><p> </p></td>
<td><div align="right"><span class="NoPrint"><a href="http://www.eprints.org/software/"><img src="/images/eprintslogo.gif" alt="ePrints logo" width="77" height="29" border="0" align="bottom" /></a></span></div></td>
</tr>
</table>
<!-- #EndLibraryItem -->
<div align="center"></div></td>
</tr>
</table>
</body>
</html>
