scholarly journals Geochemical comparison of mafic, felsic, and ultramafic rocks in the Hurricane Mountain mélange to the Boil Mountain ophiolite complex, west-central Maine

10.4138/1969 ◽  
2001 ◽  
Vol 37 (1) ◽  
Author(s):  
Harriet E. Van Vleck ◽  
Rachel J. Beane
Keyword(s):  
Ultramafic Rocks ◽  
Ophiolite Complex ◽  
West Central

Microearthquake surveys in the Central and Northern Philippines

1979 ◽  
Vol 69 (6) ◽  
pp. 1889-1902
Author(s):  
H. K. Acharya ◽  
J. F. Ferguson ◽  
V. Isaac
Keyword(s):  
Short Duration ◽  
Ultramafic Rocks ◽  
Tectonic Feature ◽  
North Central ◽  
Manila Trench ◽  
Highly Active ◽  
West Central ◽  
Manila Bay ◽  
Large Earthquakes

abstract Microearthquake surveys were carried out in three sections of Central and Northern Philippines during 1975-1976 for a period of 5 months. A 4-month survey of Bataan Peninsula identified a major tectonic feature near Manila Bay which could not have been postulated from examination of seismicity maps. This feature appears to be situated near the southern end of ultramafic rocks of West Central Luzon and West Luzon Trough and trends W-SW from east of Corregidor Island toward Manila Trench for a distance of about 100 km. This survey also showed no microearthquake activity beneath two presently inactive volcanoes on Bataan Peninsula. The rate of activity in Bataan Peninsula region was found to be very low (8.4 events/1000 km2/yr). A short-duration survey (16 days) of the Philippine Fault in North Central Luzon revealed no microearthquake activity on the fault. During a third short-duration survey (16 days), the Verde Island Passage area between Luzon and Mindoro was found to be as highly active at the microearthquake level as it is for large earthquakes.

Leka Ophiolite Complex as analogy to the serpentinization-carbonation system on Mars.

2021 ◽  
Author(s):  
benjamin bultel ◽  
Agata M. Krzesinska ◽  
Damien Loizeau ◽  
François Poulet ◽  
Håkon O. Astrheim ◽  
...  
Keyword(s):  
Near Infrared ◽  
Nir Spectroscopy ◽  
Ground Truth ◽  
Ultramafic Rocks ◽  
Ophiolite Complex ◽  
Spectral Parameters ◽  
Thin Sections ◽  
Accessory Minerals ◽  
Mineral Assemblages ◽  
Alteration Minerals

<p>Serpentinization and carbonation have affected ultramafic rocks on Noachian Mars in several places called here serpentinization-carbonation systems (SCS). Among the most prominent SCS revealing mineral assemblages characteristic of serpentinization/carbonation is the Nili Fossae region [1]. Jezero crater – the target of the Mars 2020 rover –hosted a paleolake which constitutes a sink for sediments from Nili Fossae [1]. Thanks to the near infrared spectrometer onboard Mars2020 [2], the mission has the potential to offer ground truth measurement for other putative serpentinization/carbonation system documented on Mars. Several important aspects that may be addressed are: Do carbonates result from primary alteration of olivine-rich lithologies or are they derived by reprocessing of previous alteration minerals [3]? What is the composition? and nature of the protolith, which appear to be constituted of considerable amounts of olivine [4]? To reveal critical information regarding the conditions of serpentinization/carbonation, accessory minerals need detailed studies [1; 5]. In case of Jezero Crater, and serpentinization on Mars in general, the main alteration minerals are identified, but little is known about the accessory minerals.</p> <p>The Nili Fossae-Jezero system has potential analogues in terrestrial serpentinized and carbonated rocks, such as the Leka Ophiolite Complex, Norway (PTAL collection, https://www.ptal.eu). Here, distinct mineral assemblages record different stages of hydration and carbonation of ultramafic rocks [6].</p> <p>We perform petrological and mineralogical analyses on thin sections to characterize the major and trace minerals and combine with Near Infrared (NIR) spectroscopy measurements. A set of spectral parameters are defined and compare to spectral parameters previously used on CRISM and OMEGA data [1, 4, 7, 8]. We study the significance of the mineralogical assemblages including nature of accessory minerals. Effect of the presence of accessory minerals on the NIR signal is investigated and their potential incidence on the amount of H<sub>2</sub>/CH<sub>4</sub> production in mafic or ultramafic system is discussed [5].</p> <p>We started to apply the newly defined spectral parameters on several SCS on Mars. Results confirm local carbonation of earlier serpentinized rocks and suggest that different protoliths could have led to diversity of mineralogical associations in SCS on Mars. Multiple detection of brucite are also suggested for the first time on Mars. Altogether our results help to better describe key geochemical conditions of the SCS on Mars for habitability potential of the martian crust and Mars’s evolution.</p> <p><strong> </strong></p> <p>References:</p> <ul> <li>Brown, A. J., et al. <em>EPSL</em>1-2 (2010): 174-182.</li> <li>Wiens, R.C., et al.  <em>Space Sci Rev</em><strong>217, </strong>4 (2021).</li> <li>Horgan, B., et al. <em>Second International Mars Sample Return</em>. Vol. 2071. 2018.</li> <li>Ody, A., et al. <em>JGR: Planets</em>2 (2013): 234-262.</li> <li>Klein, F., et al. <em>Lithos</em>178 (2013): 55-69.</li> <li>Bjerga, A., et al. <em>Lithos</em>227 (2015): 21-36.</li> <li>Viviano-Beck et al, <em>JGR: Planets 11</em>8.9 (2013)</li> <li>Viviano-Beck et al, <em>JGR: Planets 119.6</em> (2014)</li> </ul>

Talc–carbonate alteration of ultramafic rocks within the Leka Ophiolite Complex, Central Norway

Lithos ◽  
2015 ◽  
Vol 227 ◽  
pp. 21-36 ◽  
Author(s):  
A. Bjerga ◽  
J. Konopásek ◽  
R.B. Pedersen
Keyword(s):  
Ultramafic Rocks ◽  
Ophiolite Complex

scholarly journals ON THE METAMORPHIC MODIFICATION OF CR-SPINEL COMPOSITIONS FROM THE ULTRABASIC ROCKS OF THE PINDOS OPHIOLITE COMPLEX (NW GREECE)

2007 ◽  
Vol 40 (2) ◽  
pp. 781 ◽  
Author(s):  
A. Kapsiotis ◽  
B. Tsikouras ◽  
T. Grammatikopoulos ◽  
S. Karipi ◽  
H. Hatzipanagiotou
Keyword(s):  
Ultramafic Rocks ◽  
Cation Diffusion ◽  
Ophiolite Complex ◽  
Ferrian Chromite ◽  
The Common ◽  
Northwestern Greece ◽  
Common Association

Serpentinites and serpentinised ultramafic rocks from the Pindos ophiolite complex, northwestern Greece, contain Cr-spinel grains that are usually altered. The extent of alteration differs among Cr-spinels and two alteration trends can be distinguished. The most dominant is characterised by Cr-spinel overgrown by Cr-magnetite, while the second shows gradual replacement of Cr-spinel by ferrian chromite locally combined with Cr-magnetite development. Compared to cores, the altered rims are enriched in Fe and show elevated Cr# in both types of alteration, while they are impoverished in Mg and Al only at the second one. The common association of Crmagnetite with serpentine and ferrian chromite with chlorite provides insights to the metamorphic context of their formation through processes that include metasomatism by cation diffusion exchange

Leka Ophiolite Complex as analogy to the serpentinization-carbonation system on Mars.

2021 ◽  
Author(s):  
Benjamin Bultel ◽  
Agata Krzesinska ◽  
Damien Loizeau ◽  
François Poulet ◽  
Håkon O. Astrheim ◽  
...  
Keyword(s):  
Near Infrared ◽  
Nir Spectroscopy ◽  
Remote Sensing Data ◽  
Ground Truth ◽  
Ultramafic Rocks ◽  
Ophiolite Complex ◽  
Thin Sections ◽  
Accessory Minerals ◽  
Mineral Assemblages ◽  
Alteration Minerals

<p>Serpentinization and carbonation have affected ultramafic rocks on Noachian Mars in several places. Among the most prominent systems revealing mineral assemblages characteristic of serpentinization/carbonation is the Nili Fossae region [1]. Jezero crater – the target of the Mars 2020 rover –hosted a paleolake which constitutes a sink for sediments from Nili Fossae [1]. Thanks to the near infrared spectrometer onboard Mars2020 [2], the mission has the potential to offer ground truth measurement for other putative serpentinization/carbonation system documented on Mars. Several important aspects that may be addressed are: Do carbonates result from primary alteration of olivine-rich lithologies or are they derived by reprocessing of previous alteration minerals [3]? What is the composition? and nature of the protolith, which appear to be constituted of considerable amounts of olivine [4]? To reveal critical information regarding the conditions of serpentinization/carbonation, accessory minerals need detailed studies [1; 5]. In case of Jezero Crater, and serpentinization on Mars in general, the main alteration minerals are identified, but little is known about the accessory minerals.</p><p>The Nili Fossae-Jezero system has potential analogues in terrestrial serpentinized and carbonated rocks, such as the Leka Ophiolite Complex, Norway (PTAL collection, https://www.ptal.eu). Here, distinct mineral assemblages record different stages of hydration and carbonation of ultramafic rocks [6].</p><p>We perform petrological and mineralogical analyses on thin sections to characterize the major and trace minerals and combine with Near Infrared (NIR) spectroscopy measurements. We study the significance of the mineralogical assemblages including solid solution composition and nature of accessory minerals. Effect of the presence of accessory minerals on the NIR signal is investigated and their potential incidence on the amount of H<sub>2</sub>/CH<sub>4</sub> production in mafic or ultramafic system is discussed [5; 8]. This could improve our understanding of serpentinization and carbonation processes on Mars, which can guide future in-situ operations and also help for a better interpretation of the remote sensing data acquired on other possible serpentinization/carbonation systems.</p><p><strong> </strong>References:</p><p>1. Brown, A. J., et al. EPSL297.1-2 (2010): 174-182.</p><p><span>2. Wiens, R.C., et al.  Space Sci Rev217</span><strong>, </strong><span>4 (2021).</span></p><p>3. Horgan, B., et al. Second International Mars Sample Return. Vol. 2071. 2018.</p><p>4. Ody, A., et al. JGR: Planets118.2 (2013): 234-262.</p><p>5. Klein, F., et al. Lithos178 (2013): 55-69.</p><p>6. Bjerga, A., et al. Lithos227 (2015): 21-36.</p><p>7. Bultel, B. (Doctoral dissertation, Lyon). (2016).</p>

Olivine fabrics in the Bay of Islands Ophiolite: implications for oceanic mantle structure and anisotropy

1985 ◽  
Vol 22 (12) ◽  
pp. 1757-1766 ◽  
Author(s):  
Matthew H. Salisbury ◽  
Nikolas I. Christensen
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Plastic Flow ◽  
Upper Mantle ◽  
Mafic Rock ◽  
Ultramafic Rocks ◽  
Slip Systems ◽  
Mantle Structure ◽  
Ophiolite Complex ◽  
Crust And Upper Mantle

Petrofabric analysis of oriented ultramafic and mafic rock samples from six traverses representing all four massifs of the Bay of Islands ophiolite complex, Newfoundland, indicate that the ultramafic rocks are tectonites displaying fabrics consistent with high-temperature plastic flow on the olivine (010) [100] and (0kl) [100] slip systems. The fabric orientation is uniform in three of the four massifs but varies between massifs, suggesting differential rotation before or during emplacement. Within North Arm Mountain, the olivine a axes are aligned approximately perpendicular to the sheeted dikes in both the ultramafic tectonites and the overlying gabbroic tectonites. In Blow Me Down Mountain, the olivine a axes in the gabbros are perpendicular to the dikes, but they are parallel to them in the ultramafic rocks. It is concluded that the ultramafic rocks on Blow Me Down Mountain were rotated 90° during emplacement or that local decoupling and rotation occurred between the crust and upper mantle prior to emplacement. Within the Lewis Hills, the olivine fabrics rotate and weaken near the shear zone in the center of the massif. A second deformation, perhaps associated with low-temperature plastic flow, appears to have obliterated the fabric patterns still observed in the ultramafic rocks to the east.

scholarly journals Geochemistry of Ophiolite Complex in North Konawe, Southeast Sulawesi

EKSPLORIUM ◽  
2016 ◽  
Vol 37 (2) ◽  
pp. 101 ◽  
Author(s):  
Ronaldo Irzon ◽  
Baharuddin Abdullah
Keyword(s):  
Mass Spectrometry ◽  
Inductively Coupled Plasma ◽  
High Field ◽  
Ultramafic Rocks ◽  
High Field Strength ◽  
Ophiolite Complex ◽  
X Ray ◽  
Inductively Coupled ◽  
Icp Ms ◽  
Plasma Mass Spectrometry

ABSTRACTSoutheast Sulawesi is crosscutted by Lasolo Fault into two geological provinces: Tinondo and Hialu. Tinondo Geological Province is occupied largely by Ophiolite Complex in the northern part of Southeast Arm of Sulawesi. No study was conducted in relation to the geochemistry composition of Ophiolite Complex in North Konawe Regency. The aim of this study is to describe the ultramafic rock of the Ophiolite Complex in North Konawe Regency using field, geochemical, and petrographical analysis. Megascopically, the selected nine samples are described as greyish to blackish and fine to medium grains ultramafic rocks, which consist of pyroxene and olivine. Microscope, X-Ray Fluorescence (XRF), and Inductively Coupled Plasma Mass Spectrometry (ICP-MS) devices were used to obtain both petrography and geochemistry data. Major oxides data confirm that the selected samples are classified into ultramafic rocks as SiO2, MgO, and Fe2O3T are the most abundant oxides. The studied samples presumably came from arc tholeiitic environment tectonic setting. Ultramafic rocks often contain promising economic metals whereas the average numbers of Ni, Mn, Cr, and Co of this study are 2,675; 1,074; 2,386; and 117 ppm respectively. The rocks are generally enriched in high field strength elements whilst rare earth elements value are low, ranging from 2.11 to 7.10 ppm. Microscopically, samples can be classified into three groups: olivine-hornblende pyroxenite, lherzolite, and olivine websterite. Geochemical data describes more about the discriminant analysis of the groups. ABSTRAKWilayah Sulawesi Tenggara dipotong oleh Sesar Lasolo yang membagi daerah ini menjadi dua lajur: Tinondo dan Hialu. Lajur Tinondo diisi sebagian besar oleh Komplek Ophiolit, yang berada di bagian utara dari Lengan Tenggara Sulawesi. Belum ada studi yang terfokus kepada kandungan geokimia Komplek Ophiolit tersebut di wilayah Kabupaten Konawe Utara.Studi ini bertujuan untuk mempelajari karakter batuan ultramafik dari Komplek Ophiolit di Kabupaten Konawe Utara melalui kegiatan lapangan, analisis geokimia, dan analisis petrografi. Secara megaskopis, sembilan contoh batuan terpilih teridentifikasi sebagai batuan ultramafik berwarna kelabu hingga hitam, berukuran butir sedang hingga halus, dan mengandung piroksen maupun olivine. Perangkat mikroskop, X-Ray Fluorescence (XRF), dan Inductively Coupled Plasma Mass Spectrometry (ICP-MS) dimanfaatkan untuk memperoleh data geokimia maupun mikroskopis. Data oksida utama mengklasifikasikan contoh terpilih ke dalam batuan utramafik dengan SiO2, MgO, dan Fe2O3T sebagai oksida dengan kelimpahan tertinggi. Contoh terpilih mungkin terbentuk pada lingkungan busur tektonik tholeitik. Batuan ultramafik sering mengandung logam ekonomis dengan kadar rata-rata Ni, Mn, Cr, dan Co pada studi ini adalah: 2.675, 1.074, 2.386, dan 117 ppm secara berurutan. Batuan telah mengalami pengayaan unsur high field strength elements meskipun dengan kadar unsur tanah jarang yang rendah, berkisar dari 2,11 hingga 7,10 ppm. Secara petrografi, batuan terpilih dapat dibagi menjadi tiga kelompok: olivine-hornblende pyroxenite, lherzolite, and olivine websterite. Data geokimia menjelaskan lebih lanjut mengenai perbedaan dari kelompok-kelompok tersebut.

Podiform and stratiform chromitite with PGE in Paleoproterozoic (2.1 Ga) Pados-Tundra ultramafic (ophiolite) complex (N-E part of the Fennoscandian Shield, Arctic region)

2020 ◽  
Author(s):  
Tamara Bayanova ◽  
Serov Pavel ◽  
Kunakkuzin Evgeniy ◽  
Steshenko Ekaterina ◽  
Borisenko Elena
Keyword(s):  
Arctic Region ◽  
Fennoscandian Shield ◽  
Ultramafic Rocks ◽  
Chromian Spinel ◽  
Ophiolite Complex ◽  
Enriched Mantle ◽  
Ultramafic Complex ◽  
Magma Sources ◽  
Podiform Chromitites ◽  
Research Contract

<p>Pados-Tundra ultramafic complex belong to Serpentinite belt in the northern Fennoscandian Shield and composed of dunite-harzburgite-orthopyroxenite with 7 rhythms and 4 Cr layers. The associated massif named as Malyi Pados are considered as a satellite intrusion (Mamontov, Dokuchaeva, 2005) or dislocated block detached according by (Barkov et al., 2016). Nevertheless the complex includes of Dunite Zone with podiform and stratiform chromitite with Ir subgroup PGE (Ru, Os, Ir – IPGE) and associated with chromian spinel in ophiolite (Joban, 2006). Fiestly unusual microtextures and mineralogical features with clinochlore, laurite and native Ru was found (Barkov et al., 2017).</p><p>Isotope U-Pb data on baddeleyite in core of zircon from mafic gabbronorite rocks of the Malyi Pados gave 2083±7 Ma and are coeval to ages of Cu-Ni Pechenga (1980 Ma) and PGE Bushveld deposits. Notably are measured new U-Pb ages with 2087±3 Ma for baddeleyite and metamorphic rutile with 1804±10 Ma from hornblendite dyke which are cutted ultramafic rocks of the Pados-Tundra complex.</p><p>New Sm-Nd mapping data for the main rocks of the complex are reflected model T<sub>DM</sub> ages of primary protolith from 2.78 Ga to 2.36 Ga and 3.13 Ga for host rock with positive εNd values from +2.7 to +2.1. New Sm-Nd investigations to podiform chromitites of the Pados-Tundra complex are similar to Sopcheozerskoe Cr-deposit (Dunite Block) of the Monchegorsk ore region with positive εNd and young protolith ages about 2.7 Ga for primary magma sources instead of Paleoproterozoic Co-Cu-Ni and PGE layered intrusions of the Fennoscandian Shield with 2.4 Ga to 2.5 Ga for origin and 3.2 - 3.5 Ga of the protolith EM-1 enriched mantle plume reservoir (Bayanova et al., 2009, 2014, 2018). All new U-Pb on baddeleyite and Sm-Nd studies to whole rocks of the Pados-Tundra complex infer about ophiolite (spreading or oceanization of the crust) and presence diamond in podiform chromitites according to new highlights of (Ballhause et al., 2017).</p><p>All investigations are supported by RFBR 18-05-70082 (Arctic resources), 18-35-00152, 18-35-00246, Scientific Research Contract N0.0226-2019-0053 and Program of Presidium RAS 8.48.</p>

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