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Dissertations / Theses on the topic 'Late Proterozoic'

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Published: 10 December 2022
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1

Phillips, Johnnie O. "Petrology of the Late Proterozoic(?) - Early Cambrian Arumbera Sandstone and the Late Proterozoic Quandong Conglomerate, East-central Amadeus Basin, Central Australia." DigitalCommons@USU, 1986. https://digitalcommons.usu.edu/etd/6684.

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Throughout the James Ranges and Gardiner Range the Arumbera Sandstone forms prominent strike ridges with distinctive dark reddish slopes and pale red to orange-white cliffs. Because of their lithologic and stratigraphic similarities, the names Eninta and ''Quandong" for these units should be suppressed in favor of the name of Arumbera Sandstone, which has precedence. The stratigraphic and lithologic differences observed between the Quandong Conglomerate in the type locality and the Arumbera Sandstone in the study area suggest that these units are not equivalent. Similarites with the Areyonga Formation suggest the Quandong Conglomerate could be part of the Areyonga Formation. Lithofacies la, ld, and 2b, and Unit 3 of the Arumbera and its equivalents are typically recessive arkoses, subarkose, and mudrocks. They are interpreted as nearshore-marine to coastal deltaic deposits which include intertonguing tidal-flat, tidal-channel, and beach sediments. Lithofacies 1b and 2a consist of cliff-forming arkoses, subarkoses, and lithic arkoses. Lithofacies 2c is also resistant, and consists of orthoconglomerates and conglomeratic sandstones. Lithofacies 1e is moderately resistant, and consists of paraconglomerates, conglomeratic sandstones, and mudrocks. It and lithofacies 2c contain pebbles and small cobbles of chert, quartzite, vein quartz, silicified ooids, and limestone, dolostone, shale, and sandstone. These four lithofacies are interpreted as braidplain and fluvial sheet sands. In the east-central part of the Amadeus Basin the Arumbera Sandstone probably was deposited in a coastal environment as a sequence of deltaic sediments that was dominated by fluvial processes. The Arumbera Sandstone appears to be the molasse derived from the Late Proterozoic and Early Cambrian Petermann Ranges orogeny. Source rocks include sedimentary, low- to middle-rank metamorphic, and plutonic granites. Grain mineralogy and weathering characteristics suggest a hot, semiarid climate during deposition of the Arumbera. The Arumbera Sandstone and Quandong Conglomerate contain fair to good porosity and permeability, and petrographic evidence shows mesogenetic generation of secondary porosity. Previous and present burial depths are adequate for the generation of petroleum. The presence of suitable underlying .source rocks, overlying salt of the Chandler for a seal, and stratigraphic and structural traps suggest a good potential for petroleum. Production of dry gas from the lower part of the Arumbera at Dingo field, north of Deep Well Homestead, confirms the petroleum potential of this formation.
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2

Teitz, Martin W. "Late proterozoic Yellowhead and Astoria Carbonate Platforms, southwest of Jasper, Alberta." Thesis, McGill University, 1985. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=63371.

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3

Haines, Peter W. "Carbonate shelf and basin sedimentation, late Proterozoic Wonoka Formation, South Australia /." Title page, contents and summary only, 1987. http://web4.library.adelaide.edu.au/theses/09PH/09phh152.pdf.

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4

Smith, Peter B. "The alteration history of late Proterozoic Wooltana volcanics, Mount Painter Province, S.A. /." Adelaide, 1992. http://web4.library.adelaide.edu.au/theses/09SB/09sbs656.pdf.

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Thesis (B. Sc.(Hons.))--University of Adelaide, Dept. of Geology, 1992.
National grid reference SH54 - 6737-2. One coloured folded map in pocket inside back pocket. Includes bibliographical references.
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5

Kasolo, Pius Chilufya-Bwalya. "Fluid-channelling and gold mineralization within the Late Proterozoic Mwembeshi Shear Zone,Zambia." Thesis, University of Southampton, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.315515.

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6

Poole, S. "The Late Proterozoic orogenic igneous activity of the Kadaweb area, Red Sea Hills, Sudan." Thesis, University of Portsmouth, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.370180.

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7

Hapugoda, Hapugoda Udage Sarath. "Late Archaean and Early Proterozoic crustal evolution of the Georgetown Block, Northeast Queensland, Australia /." St. Lucia, Qld, 2002. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe16503.pdf.

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8

Andreasen, Kyle C. "Does the Southern Farmington Canyon Complex Record a late Archean/Early Proterozoic Accretionary Complex?" DigitalCommons@USU, 2007. https://digitalcommons.usu.edu/etd/6753.

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The Farmington Canyon Complex, situated along the Wasatch front in northern Utah, has been the target for many studies. The FCC has been interpreted to be a passive margin sedimentary wedge. Previous studies have yielded isotopic ages that broadly support an Archean age of formation, and a prominent mid-proterozoic amphibolite grade metamorphic event. Based on this study, a new interpretation for the FCC is presented. Field relations and whole-rock geochemistry as well as recent advances in understanding Archean crustal processes have resulted in the FCC to be considered as an accretionary complex that formed along the SW margin of the Wyoming province in the early Archean. Rock assemblages such as mafic and ultramafic metavolcanics have chemistries that resemble oceanic crust and arc related volcanics. The extensive quartzo-felspathic gneiss and schist units have compositions that reflect greywacke, and are presented here as a melange matrix. The quartzites have chemistries, which may represent cherts or silicified microbial mats. The field relations and timing of these rocks indicate that the FCC may represent a continental arc synchronous with the closing of an ocean basin, forming an accretionary wedge. This culminated with the mid-proterozoic metamorphic event as this continental arc collided with the Santaquin arc, as well as the SW margin of Laurentia. This amphibolite grade metamorphic event has subsequently reset or overprinted isotopic evidence and obscured any textures that may have existed. Although much has yet to be learned about Archean processes, comparison to other recognized Archean accretionary complexes has yielded striking similarities, and it is presented here that the FCC represents an active margin, and is likely an accretionary melange.
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9

Valentino, David W. "Tectonics of the lower Susquehhanna River region, southeastern Pennsylvania and northern Maryland: late proterozoic rifting to late paleozoic dextral transpression." Diss., Virginia Tech, 1993. http://hdl.handle.net/10919/30108.

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10

Pimentel, Marcio Martins. "Late Proterozoic crustal evolution of the Tocantins Province in central Brazil : an isotopic and geochemical study." Thesis, University of Oxford, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.280038.

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11

Thomas, Katherine S. S. M. Massachusetts Institute of Technology. "Stable isotope and organic biomarker analysis of the late Proterozoic Coppercap formation in the MacKenzie Mountains." Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/114138.

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Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2010.
Cataloged from PDF version of thesis.
Includes bibliographical references (unnumbered pages 56-59).
Sulfur and carbon stable isotope ratios and organic biomarker abundance were performed on drill core samples from the Coppercap Formation of the Coates Lake Group in the Windermere Supergroup of the MacKenzie Mountains to reconstruct an environmental condition proceeding the first Neoproterozoic Snowball Earth event. The Coppercap Formation directly underlies the Rapitan Group, Sturtian glacigenic deposits, and represents a depositional environment existing directly before the Cryogenian glacial episodes. Based on aryl isoprenoids, n-propyl cholestane, isopropyl cholestane, total organic carbon, carbonate mineral analysis, [delta]34S from pyrite, [delta]13Corganic and [delta]13Ccarbonate values, environmental conditions of the Coppercap Formation were reconstructed. The Coppercap Formation was found to be a shallow euxinic marine basin with purple and green sulfur bacteria microbial mats. This suggest persistent hydrogen sulfide rich waters in the shallow photic zone persisted until the Sturtian.
by Katherine S. Thomas.
S.B.
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12

Jacob, Jana. "Late Proterozoic bedrock geology and its influence on neogene littoral marine diamondiferous trapsites, MA1-Sperrgebiet, Namibia." Master's thesis, University of Cape Town, 2001. http://hdl.handle.net/11427/8742.

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Bibliography: leaves 117-128.
Namibia's south western coast, the Sperrgebiet, hosts one of the world's largest diamond placer deposits. Diamond distribution in this placer deposit is directly related to the presence of a diamond-carrying gravel, the degree of reworking of the gravel and the quantity and quality of the diamond trapsites. The diamond-carrying gravel is present in the form of palaeo-beaches. Six Plio-Pleistocene beaches have been identified lying onshore between the Orange River mouth and Chameis Bay. The Plio-Pleistocene beaches are underlain by Late Proterozoic footwall. The Late-Proterozoic footwall has undergone extensive marine erosion and development of marine platforms during different sea-level stillstands. Diamond trapsites in the form of potholes and gullies are incised into palaeo platforms formed during the sea-level stillstands. The marine erosion palaeo-platforms have been cut into the predominantly siliciclastic rocks of the Gariep Belt. The Late Proterozoic Gariep Belt is divided into an eastern para- aulochthonous passive continental margin zone, the Port Nolloth Zone, and a western allochthonous Marmora Terrane. Previous work suggested that the Marmora Terrane had been thrust on top of the Port Nolloth Zone in a south-easterly direction and that the Marmora Terrane could be subdivided into three tectonostratigraphic units: the Schakalsberge Complex, the Oranjemund Complex and the Chameis Complex. In addition, previous work indicated that the Oranjemund Complex had been stacked tectonically between the Chameis Complex in the northwest and the Schakalsberge Complex in the southeast. However, this study questions the subdivision of the Marmora Terrane into three separate tectonic complexes. The rocks in the study area forms part of the newly defined Oranjemund Group, Oranjemund Sub-terrane.
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13

Leaver, Julie. "The petrological and geochemical evolution of the Late Proterozoic Lithospheric mantle below Seiland Province northern Norway." Thesis, University of Bristol, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.296735.

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14

Roots, Charles F. (Charles Frederick) Carleton University Dissertation Geology. "Regional tectonic setting and evolution of the late proterozoic Mount Harper volcanic complex, Ogilvie Mountains, Yukon." Ottawa, 1987.

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15

Cooper, Andrew McGregor. "Late Proterozoic hydrocarbon potential and its association with diapirism in Blinman #2, Central Flinders Ranges, South Australia /." Title page, abstract and contents only, 1991. http://web4.library.adelaide.edu.au/theses/09SB/09sbc776.pdf.

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Thesis (B. Sc.(Hons))--National Centre for Petroleum Geology and Geophysics, University of Adelaide, 1991.
"National grid reference 1:250 000 - Parachilna SH54-13." Includes bibliographical references (leaves 45-47).
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16

Starling, Antony. "Tectonic and chemical evolution of a late Proterozoic gold deposit, Gebeit Mine, Northern Red Sea Hills, Sudan." Thesis, University of Southampton, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.358662.

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17

Chandonais, Daniel. "Deformation and Fluid History of Late Proterozoic and Early Cambrian Rocks of the Central Appalachian Blue Ridge." Bowling Green State University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1343055132.

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18

Pearce, Andrew M. "Carbon and oxygen isotopic compositions of some late Proterozoic and early Cambrian carbonates in the southern Adelaide geosyncline /." Title page, contents and abstract only, 1992. http://web4.library.adelaide.edu.au/theses/09S.B/09s.bp359.pdf.

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Thesis (B. Sc.(Hons.))--University of Adelaide, Dept. of Geology and Geophysics, 1993.
"National grid reference: Noarlunga SI (54-4) 6627 IV Cassini SI (53-16) 6326 I Stokes Bay SI (53-16) 6326 IV." Includes bibliographical references.
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19

Simpson, Edward L. "Sedimentology and tectonic implications of the Late Proterozoic to Early Cambrian Chilhowee Group in southern and central Virginia." Diss., Virginia Polytechnic Institute and State University, 1987. http://hdl.handle.net/10919/53660.

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Few detailed facies analyses of rift to passive-margin transitions have been undertaken in exhumed orogenic belts. In the central Appalachians, the Chilhowee Group records such an evolution. The Unicoi and basal Hampton Formations record the transition from rifting to opening of the Iapetus Ocean. The majority of the Hampton Formation and the overlying Erwin Formation represent an overall regressive sequence punctuated by five progradational packages that accumulated along a passive margin. The rift to passive·margin phases of sedimentation in the central Appalachians reflect a continuum from fault·influenced to thermotectonic subsidence. Alluvial sediments and intercalated basalts of the lower Unicoi Formation developed in a rift setting. Paleontological data indicate that rifting continued into lower Cambrian time. The upper Unicoi Formation represents the incipient phase of passive-margin sedimentation related to a first-order, sea level rise. Differences in degree of crustal attenuation controlled the distribution of sedimentary environments during transgression. On the most attenuated crust to the east, initial transgressive facies consist of tidal sandwave and sandridge deposits intercalated with proximal and medial braid-pIain deposits. As transgression progressed cratonwards onto less attenuated crust, tidal sedimentation was supplanted by tide- and wave-influenced sedimentation characterized by sandwave complexes, tidal inlets and longshore bedforms. Drowning at the top of the Unicoi Formation is indicated by outer-shelf black mudstones. Deepening may have been enhanced by continued movement along listric faults throughout the incipient phase of passive-margin development. Examination of outcrops of the Hampton and Erwin Formations on different thrust sheets has permitted an across-strike reconstruction of the Early Cambrian Chilhowee shelf in space and time. Progradational packages developed under storm- and fair·weather wave conditions. Coarsening· and thickening-upward sequences on westerly thrust sheets were generated during progradation of shoreface, inner-shelf and outer-shelf environments. Outer-shelf facies predominate on easterly thrust sheets. Intertidal-flat deposits on the most westerly thrust sheet erosively overlie progradational shoreface sediments and developed during transgression in an embayment in which the tidal wave was amplified. More distal transgressive deposits consist of fining- and thinning·upward sequences with glauconitic horizons, and condensed sections in mudstones.
Ph. D.
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20

Hamp, Lonn P. "Petrology of the Late Proterozoic(?)-Early Cambrian Arumbera Sandstone, Western MacDonnell Ranges, North-Central Amadeus Basin, Central Australia." DigitalCommons@USU, 1985. https://digitalcommons.usu.edu/etd/6679.

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The Arumbera Sandstone consists of mappable informal units which are repeated in a vertical, cyclic succession. Sandstones of fluvial origin form resistant strike ridges separated by strike valleys, which consist of recessive sandstones and mudrocks of marine origin. Lithofacies 1a, 2b, and 3a are probably of marine origin in intertidal environments. Trace fossil assemblages in lithofacies 3a suggest Skolithos and Cruziana inchnofacies were present. Lithofacies 1e, 2a, 2c, 3b, and 4a are probably of fluvial origin, as the result of coalescing braided stream deposits. The Arumbera Sandstone probably was deposited in a deltaic environment characterized by low wave energy, a micro tidal range, and high input of sand-sized sediment br braided streams. In the western MacDonnell Ranges, the Arumbera overlies the Julie or Pertatataka formations along a sharp but conformable contact. The present upper contact is a low-angle regional unconformity which contains paleotopographic elements that resemble pediments, stripped structural plains, and steep erosional scarps. These paleotopographic surfaces are overlain from east to west by the Chandler, hugh River, and Cleland formations in an onlap relationship. The Arumbera Sandstone is considered part of a molasse sequence associated with the Late Proterozoic and Early Cambrian Petermann Ranges orogeny, which occurred along the present southern and southwestern margin of the Amadeus Basin. The uplifted Petermann Ranges shed detritus from metamorphic, sedimentary, and minor amounts of plutonic rocks. Paleocurrents suggest most terrigenous material was derived from the southwestern margin of the basin. The composition of detrital grains and lack of weathering features in labile detrital grains suggest a hot, semiarid to arid climate in the source area and in the basin of deposition. Sandstone samples examined petrographically primarily are subphyllarenites, subarkoses, arkoses, feldspathic litharenites, and lithic arkoses. The inferred paragenetic sequence is: Eogenetic: (1) mechanical compaction, (2) "dust rims" of hematite, illite, and chlorite, and (3) hematite cement; Mesogenetic: (4) syntaxial feldspar overgrowths, (5) syntaxial quartz overgrowths, (6) hematite cement, (7) carbonate cement, (8) kaolinite replacement, (9) formation of secondary porosity; Telogenetic: (10) chert cement and (11) gibbsite or hematite cement.
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21

Von, Veh Mark Wolter. "The stratigraphy and structural evolution of the late Proterozoic Gariep belt in the Sendelingsdrif-Annisfontein area, northwestern Cape Province." Doctoral thesis, University of Cape Town, 1988. http://hdl.handle.net/11427/17695.

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Bibliography: pages 128-143.
A geological investigation of the Port Nolloth metasediments in the central external parts of the Gariep Beit has led to a re-interpretation of tbeir lithostratigraphy and Pan-African geotectonic evolution. During the rifting stage of passive continental margin evolution, the basal elastic Stinkfontein Sequence was deposited in an alluvial fan environment. Fluviatile conglomerates and quartz arenites (Lekkersing Formation) interfinger with feldspathic arenites and minor volcanics (Vredefontein Formation), and prograde into marginal marine elastics and carbonates (Gumchavib Formation). Rift faulting produced local grabens into which massflow sediments (Kaigas Formation) and volcaniclastics (Rosh Pinah Formation) were shed. During the sea-floor spreading stage, a shallow-water carbonateclastic unit, the Hilda Sequence, was deposited. Conglomerates, quartzites, and schists with resedimented gravity-flow characteristics (Wallekraal Formation) are sandwiched between lower and upper platform carbonates (Pickelhaube and Dabie River Formations). The Hilda is unconformably overlain by the Numees Sequence, consisting of a widespread glaciogenic diamictite (Sendelingsdrif Formation) and a near-basal banded iron formation (Jakkalsberg Formation). A deep-water elastic unit, the Holgat Sequence, was laid down during the early stage of the lower Nama transgression.
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22

Kathol, Benno. "Evolution of the rifted and subducted Late Proterozoic to Early Paleozoic Baltoscandian margin in the Torneträsk section, northern Swedish Caledonides." Doctoral thesis, Stockholms universitet, Institutionen för geologiska vetenskaper, 1989. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-81676.

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23

Briner, Andreas. "The anatomy of a late proterozoic continental margin at mid-crustal level: the crystalline basement of Salalah, Dhofar region, Sultanate of Oman /." [S.l.] : [s.n.], 1997. http://www.ub.unibe.ch/content/bibliotheken_sammlungen/sondersammlungen/dissen_bestellformular/index_ger.html.

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24

Jansyn, Joanne. "Strato-tectonic evolution of a large subsidence structure associated with the late Proterozoic Wonoka Formation at Wilpena Pound, central Flinders Ranges, South Australia /." Title page, table of contents and abstract only, 1990. http://web4.library.adelaide.edu.au/theses/09SB/09sbj35.pdf.

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Thesis (B. Sc. (Hons))--University of Adelaide, Dept. of Geology and Geophysics, 1991.
One col. map + one col. chart in pocket. National grid reference : Parachilna sheet H54-13 (1:250 000). Includes bibliographical references.
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25

Koeksoy, Elif [Verfasser], and Andreas [Akademischer Betreuer] Kappler. "Biogeochemical Fe-S-cycling in a late Archean and Proterozoic ocean model habitat - the high alpine Arvadi Spring / Elif Koeksoy ; Betreuer: Andreas Kappler." Tübingen : Universitätsbibliothek Tübingen, 2018. http://d-nb.info/1198973374/34.

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26

Temperley, Stephen. "The late Proterozoic to early Palaeozoic geological development of the Glen Banchor area in the Monadhliath Mountains of Scotland : with particular reference to deformation in late-Precambrian shear zones and in the Central Highland steep belt." Thesis, University of Hull, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.293171.

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27

Urlwin, Ben. "Carbon isotope stratigraphy of the late Proterozoic Wonoka formation of the Adelaide fold belt : diagenetic assessment and interpretation of isotopic signature and correlations with previously measured isotopic curves /." Title page, abstract and contents only, 1992. http://web4.library.adelaide.edu.au/theses/09SB/09sbu77.pdf.

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Thesis (B. Sc.(Hons.))--University of Adelaide, Dept. of Geology and Geophysics, 1993.
On title page : "National Grid reference : Copley 1:250,000 SH54-9 6636." Folded map in back cover pocket. Includes bibliographical references (leaves [50-65]).
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28

Ayliffe, Damien. "Geological setting of the late Proterozoic Wonoka Formation carbonate ramp and canyon sequence at Pichi Ric hi Pass Southern Flinders Ranges, South Australia : geoch emical, stable isotope, and diagenetic analysis /." Title page, contents and abstract only, 1992. http://web4.library.adelaide.edu.au/theses/09S.B/09s.ba978.pdf.

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Thesis (B. Sc.(Hons.))--University of Adelaide, Dept. of Geology and Geophysics, 1992?
On title page: "National Grid reference: Port Augusta sheet SI 53-4 (1:250000) Onnoroo sheet SI 54-1 (1:250 00 0)." One map in pocket inside back cover. Includes bibliographical references (leaves 52-60).
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29

Piercey, Patricia. "PROTEROZOIC METAMORPHIC GEOCHRONOLOGY OF THE DEFORMED SOUTHERN PROVINCE, NORTHERN LAKE HURON REGION, CANADA." Ohio University / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1149204676.

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30

Delpomdor, Franck. "Sedimentology, geochemistry and depositional environments of the 1175-570 Ma carbonate series, Sankuru-Mbuji-Mayi-Lomami-Lovoy and Bas-Congo basins, Democratic Republic of Congo: new insights into late Mesoproterozoic and Neoproterozoic glacially- and/or tectonically-influenced sedimentary systems in equatorial Africa." Doctoral thesis, Universite Libre de Bruxelles, 2013. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209486.

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The one of the most important Eras of the Earth history, i.e. Neoproterozoic (1000-542 Ma),

was an enigmatic period characterized by the development of the first stable long-lived ~1.1-

0.9 Ga Rodinia and 550-500 Ma Gondwana supercontinents, global-scale orogenic belts,

extreme climatic changes (cf. Snowball Earth Hypothesis), the development of microbial

organisms facilitating the oxidizing atmosphere and explosion of eukaryotic forms toward the

first animals in the terminal Proterozoic. This thesis presents a multidisciplinary study of two

Neoproterozoic basins, i.e. Bas-Congo and Sankuru-Mbuji-Mayi-Lomami-Lovoy, in and around the Congo Craton including sedimentology, geochemistry, diagenesis, chemostratigraphy and radiometric dating of carbonate deposits themselves.

The Mbuji-Mayi Supergroup sequence deposited in a SE-NW trending 1500 m-thick siliciclastic-carbonate intracratonic failed-rift basin, extends from the northern Katanga Province towards the centre of the Congo River Basin. The 1000 m-thick carbonate succession is related to the evolution of a marine ramp submitted to evaporation, with ‘deep’ shaly basinal and low-energy carbonate outer-ramp environments, marine biohermal midramp (MF6) and ‘very shallow’ restricted tide-dominated lagoonal inner-ramp (MF7-MF9) settings overlain by lacustrine (MF10) and sabkha (MF11) environments, periodically

submitted to a river water source with a possible freshwater-influence. The sequence stratigraphy shows that the sedimentation is cyclic in the inner ramp with plurimetric ‘thin’ peritidal cycles (± 4 m on average) recording a relative sea level of a maximum of 4 m, with fluctuations in the range of 1-4 m. The outer/mid ramp subtidal facies are also cyclic with ‘thick’ subtidal cycles characterized by an average thickness of ± 17 m, with a probable sealevel

fluctuations around 10 to 20 m. The geochemistry approach, including isotopic and major/trace and REE+Y data, allows to infer the nature of the dolomitization processes operating in each carbonate subgroup, i.e dolomitization may be attributed to evaporative reflux of groundwater or to mixing zones of freshwater lenses. The latest alteration processes occured during the uplift of the SMLL Basin. New ages, including LA-ICP-MS U-Pb laser ablation data on detrital zircon grains retrieved in the lower arenaceous-pelitic sequence (BI group), combined with carbon and strontium isotopic analyses, yielded a new depositional time frame of the Mbuji-Mayi Supergroup between 1176 and 800 Ma reinforcing the formerly suggested correlation with the Roan Group in the Katanga Province.

In the Democratic Republic of Congo, the Sturtian-Marinoan interglacial period was previously related to pre-glacial carbonate-dominated shallow marine sedimentation of the Haut-Shiloango Subgroup with stromatolitic reefs at the transition between greenhouse (warm) and icehouse (cold) climate periods, commonly marked by worldwide glacigenic diamictites and cap carbonates. This thesis highlights that these deposists record as a deepening-upward evolution from storm-influenced facies in mid- and outer-ramps to deepwater environments, with emplacement of mass flow deposits in toe-of-slope settings controlled by synsedimentary faults. In absence of diagnostic glacial features, the marinoan Upper Diamictite Formation is interpreted as a continuous sediment gravity flow deposition along carbonate platform-margin slopes, which occurred along tectonically active continental margins locally influenced by altitude glaciers, developed after a rift–drift transition. The maximum depth of the deepening-upward facies is observed in the C2a member. The

shallowing-upward facies exibit a return of distally calcareous tempestites and semi-restricted to restricted peritidal carbonates associated with shallow lagoonal subtidal and intertidal zones submitted to detrital fluxes in the upper C2b to C3b members.

The geochemistry highlights (i) the existence of a δ13C-depth gradient of shallow-water and deep-water carbonates; (ii) the carbonate systems were deposited in oxic to suboxic conditions; and (iii) all samples have uniform flat non-marine shale-normalized REE+Y distributions reflecting

continental detrital inputs in nearshore environments, or that the nearshore sediments were

reworked from ’shallow’ inner to mid-ramp settings in deep-water slope and outer-ramp

environments, during the rift-drift transition in the basin. The pre-, syn- and post-glacial

carbonate systems could record a distally short-lived regional synrift freshwater-influenced

submarine fan derived from nearshore sediments, including gravity flow structures, which are

attributed to regional tectonic processes due to a sudden deepening of the basin caused by

differential tilting and uplifting of blocks, related to the 750-670 Ma oceanic spreading of the

central-southern Macaúbas Basin.

Combining sedimentology, isotopes and trace elemental geochemistry, the thesis highlights

that the δ13C variations in the Neoproterozoic carbonates are complex to interpret, and can be

related to: (i) the existence of a δ13C-depth gradient; (ii) the exchange between isotopically

light carbon in meteoric waters and carbonate during lithification and early diagenesis; and

(iii) isotopic perturbations due to regional metamorphism. Considering the possible englaciation of the Earth (Snowball Earth hypothesis), the Mbuji-Mayi Supergroup and West

Congolian Group seem reflected the intimate relationship between glaciations and tectonic

activity during the break-up of the Rodinia supercontinent, followed by the rift–drift

transition, and finally the pre-orogenic period on the passive continental margin.
Doctorat en Sciences
info:eu-repo/semantics/nonPublished

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Chubb, Peter T. A. "Petrogenesis of the Eastern portion of the Early Proterozoic East Bull Lake gabbro-anorthosite intrusion, district of Sudbury/Algoma, Ontario." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1994. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/MQ46471.pdf.

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32

Habib, Shanif Sadrydin. "The petrology and geochemistry of Proterozoic ultrapotassic, diamond-bearing lamprophyre dikes of the Gibson-MacQuoid Lake Belt, District of Keewatin, Northwest Territories." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0030/MQ30724.pdf.

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33

Riegler, Thomas. "Système d'altération et minéralisation en uranium le long du faisceau structural Kiggavik-Andrew Lake (Nunavut, Canada) : modèle génétique et guides d'exploration." Thesis, Poitiers, 2013. http://www.theses.fr/2013POIT2313/document.

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Ce travail présente une étude multi-échelle des relations entre altération et minéralisation en uranium le long de la bordure Sud Est du bassin Méso-Protérozoïque du Thelon, au Nunavut, Canada. Les altérations associées aux minéralisations sont développées dans une série volcano-sédimentaire Archéenne appartenant à la ceinture de roche verte du Woodburn Lake Group (WLG). Elles s'expriment majoritairement par un assemblage à illite (polytypes 1Mcis & 1Mtrans) ± sudoite ± hématite et phosphates sulfates d'aluminium hydratés (APS). De plus des composés carbonés, cogénétiques des minéralisations, ont été identifiés comme des produits des réactions hydrothermales. La signature de l'altération, fortement guidées par les structures Est-Ouest du corridor de Kiggavik-Andrew Lake, apparaît alors très similaire à celle rencontrée dans les roches de socles des parties profondes des autres gisements d'uranium de type discordance du bassin d'Athabasca (Canada) ou de la Kombolgie (Australie). L'étude des marqueurs minéralogiques tels que les APS ont permis de mettre en évidence les transferts élémentaires au cours des processus métallogéniques et de distinguer les caractéristiques pétrographique et chimiques des processus diagénétiques et hydrothermaux. Enfin la compréhension fine de l'expression de marqueurs cristallographiques issus de l'irradiation naturelle des minéraux argileux donne de nouvelles pistes pour le traçage et la compréhension des circulations des radios-éléments à l'échelle géologique
This work presents a multi-scale study of the relationships between alteration and uranium mineralization along the South Eastern margin of the Meso-Proterozoic Thelon Basin, Nunavut, Canada. The ore associated alterations are hosted in an Archean volcano-sedimentary sequence belonging to the Woodburn Lake Group (WLG). Their main expression is a mineral assemblage composed of dominant illite (1Mcis & 1Mtrans polytypes) together with sudoite ± hematite and aluminum phosphate sulfate minerals. Moreover carbonaceous materials cogenetic with the uranium mineralization have been identified as potential indicators of the hydrothermal conditions. At a regional scale, alteration is strongly controlled via East-West faults forming the main frame of the Kiggavik-Andrew Lake structural trend. Then from the regional to the mineral scale, alterations signatures at Kiggavik are similar to the ones described in deep basement rocks of unconformity type uranium deposits in both Athabasca (Canada) and Kombolgie (Australia) Paleoproterozoic basins. In addition mineralogical markers studies (APS minerals) lead to the distinction between hydrothermal and diagenetic processes as well as elemental transfers during fluid rock interaction. Finally, detailed studies on radiation induced defects on illite revealed new ways to tracing and better understanding the radio elements mobility in such deep seated natural systems
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Haines, Peter W. "Carbonate shelf and basin sedimentation, late Proterozoic Wonoka Formation, South Australia." Thesis, 1987. http://hdl.handle.net/2440/21574.

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Five folded ill. in pocket; Bibliography: leaves 141-152; ix, 152, 12 leaves, [17] leaves of plates : ill. (some col.) ; 31 cm.
Thesis (Ph.D.) -- University of Adelaide, Dept. of Geology and Geophysics, 1987
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Smith, P. B. "The alteration history of Late Proterozoic Wooltana Volcanics, Mount Painter Province, S.A." Thesis, 1992. http://hdl.handle.net/2440/131151.

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The Wooltana Volcanics experienced a pervasive low grade hydrothermal alteration prior to the Delamerian. The timing of this event is poorly constrained. However the available evidence is consistent with the metasomatism occurring during the active stretching thought to have caused the uplift related refrigeration responsible for the formation of the Merinjina Tillite. This study confirms the proposals of previous workers that the Wooltana Volcanics, Beda Volcanics and Gairdner Dyke Swarm are temporal equivalents, although this study has shown the Gairdner Dyke Swann to be a systematically fractionated end member. The Wooltana Volcanics are very like the Parana low-Ti CFB of Brazil and also the dolerites from the Atlas Mountains of Morocco. Both are associated with magmatic events immediately preceding the first openings of the Atlantic Ocean. The occurrence of the Port Pirie Volcanics within Burra Group sediments suggests a reoccurrence of mantle decompression due to lithospheric stretching further to the south.
Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Physical Sciences, 1992
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36

Gueneli, Nur. "Late Mesoproterozoic Microbial Communities." Phd thesis, 2016. http://hdl.handle.net/1885/109340.

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The first eukaryotes are found in the geological record at ~1.6 Ga, a further 800 million years later they became more abundant and diverse, and only during the Ediacaran did they start shaping ecosystems. This work studies a marine and a lacustrine aquatic ecosystem at the edge of the Mesoproterozoic (~1.1 Ga) to gauge the role of eukaryotes and to investigate the environmental conditions that may have prohibited their proliferation. The evolutionary state of the earliest eukaryotic fossils remains unresolved. The first unambiguous stem group eukaryote appears at 1.2 Ga, but modern ferns occur around 0.8 Ga. Extreme bias on fossil preservation prevents estimation on how ecologically abundant early eukaryotes were. Here we use biomarkers to close this gap. They have low taxonomic resolution but afford a quantitative view of relative organism abundances. We combine biomarkers with inorganic, isotope geochemical and microscope analysis to investigate successions of the marine Taoudeni Basin and lacustrine Nonesuch Formation. Further, we include an analysis of the Cretaceous Maracaibo Basin to obtain a clear point of contrast from a period of time where redox environments were similar but eukaryotes were abundant. The extraordinary black shales of the Taoudeni Basin have high TOC (< 31 %), lack eukaryotic steranes despite present eukaryotic microfossils, contain aromatic steroids, and are mostly deposited under ferruginous and euxinic conditions. This implies at first sight a stagnant deep water environment. Yet, clear crinkly mats are preserved, invoking a non-uniformitarian ecosystem. Low atmospheric oxygen levels facilitate to explain clear, anoxic, shallow (<20 m) waters above phototrophic microbial mats. Biomarker data imply that the microbial community was composed of cyanobacteria, anoxygenic purple and green sulfur bacteria, and microaerophilic methanotrophs. It is likely that cyanobacteria switched between oxic and anoxic photosynthesis and dominated the photosynthetic community. The latter is supported by nitrogen isotopic composition of individual porphyrins, which range between 5.6 and 10.2 per mil and yield epsilon-porphyrin values of 0.5 to - 5.1 per mil. This study is the first unambiguous report of Mesoproterozoic geoporphyrins. The dominant species contain Ni and their structures relate to chl a, chl b/chl c3 and a chl c-like molecule. The biomarker and iron speciation results of Nonesuch shales qualitatively resemble the ones of the marine Taoudeni Basin including a mainly ferruginous depositional setting, absence of diagnostic eukaryotic biomarkers despite eukaryotic microfossils and biomarkers specific for cyanobacteria, anoxygenic purple and green sulfur bacteria, and microaerophilic methanotrophs. The bitumens of the Phanerozoic Maracaibo Basin were composed of degradation products of marine algae, green sulfur bacteria and archaea as well as terrestrial higher plants and lacustrine algae. The mixing of two components, marine and terrestrial organic matter, can explain the distribution of biomarkers. The data describe the restricted Maracaibo Basin as a stable, stratified sea influenced by upwelling waters near a shallow shelf. The results exemplify that biomarkers of primary producers such as algae are in fact preserved in similar environments as in the Mesoproterozoic and that the absence in ~1 Ga samples is not a preservation artefact.
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Hoffe, Brian H. "Deep seismic evidence of late middle Proterozoic rifting beneath the Kalahari, Western Botswana /." 1996. http://collections.mun.ca/u?/theses,35598.

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Zang, Wenlong. "An analysis of late Proterozoic - early Cambrian microfossils and biostratigraphy in China and Australia." Phd thesis, 1988. http://hdl.handle.net/1885/140928.

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39

Brem, Arjan Gerben. "The Late Proterozoic to Palaeozoic Tectonic Evolution of the Long Range Mountains in Southwestern Newfoundland." Thesis, 2007. http://hdl.handle.net/10012/2748.

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Ever since the first plate-tectonic model for the Appalachians was proposed, the Laurentian margin has been interpreted as having experienced a collision-related dynamo-thermal event during the Middle Ordovician Taconic orogeny. In the western Newfoundland Appalachians, evidence for this collision is well-preserved in the Dashwoods subzone. Nevertheless, rocks of the neighbouring Corner Brook Lake block (CBLB), which is located in the heart of the Laurentian realm, did not show evidence for such an event. Instead, it was affected by Early Silurian Salinic deformation and associated peak metamorphism. Even though this difference in Early Palaeozoic tectonic history between the Dashwoods and the CBLB is widely known, it has not been satisfactorily explained. To better understand the Early Palaeozoic history of the region, in particular to test and better explain the lack of a Taconic dynamo-thermal event in the CBLB, field mapping, microscopic work, and U-Pb and 40Ar/39Ar geochronological studies were undertaken in the western and northern part of the Dashwoods subzone, and in the southern part of the CBLB. In addition, the kinematic history of the Baie Verte-Brompton Line - Cabot Fault Zone (BCZ), the tectonic zone that separates the two unique tectonic fragments, was studied. The western and northern parts of the Dashwoods subzone contain variably foliated igneous units of Middle Ordovician age (ca. 460 Ma) that are associated with the regionally voluminous Notre Dame continental arc. A ca. 455 Ma conjugate set of late syn-tectonic pegmatite dykes in the BCZ demonstrates a dextral sense of shear along the BCZ (DBCZ-1) during the Late Ordovician to earliest Silurian, and constrains the minimum age of the main phase of ductile deformation in the Dashwoods subzone. The fault-bounded CBLB has been affected by a single west-vergent deformational event, constrained between ca. 434 and ca. 427 Ma. More importantly, no evidence – neither petrographic nor geochronological – is present that would indicate that the CBLB was affected by a significant Taconic dynamo-thermal event. Hence, the CBLB and Dashwoods could not have been juxtaposed until after the late Early Silurian. Furthermore, the basement to the CBLB is devoid of any Grenville (sensu lato; ca. 1.0-1.3 Ga) U-Pb ages, which is in sharp contrast with crystalline basement elsewhere in the region, such as the Long Range Inlier. Therefore, it is highly unlikely that the CBLB represents the para-autochthonous leading edge of the Laurentian craton in the Newfoundland Appalachians, as commonly accepted. The CBLB is interpreted as a suspect terrane that has moved over 500 km parallel to the strike of the orogen. Docking to the external Humber Zone is likely to have occurred during the Early Silurian. Final juxtaposition with the Dashwoods took place after the late Early Silurian (post-Salinic) as a result of protracted dextral movement along the BCZ (DBCZ-2 and DBCZ-5). Current tectonic models for the Newfoundland Appalachians mainly focus on well-documented Early Palaeozoic orthogonal convergence of various terranes with the Laurentian margin, but large-scale orogen-parallel movements have rarely been considered. The possibility of large-scale strike-slip tectonics documented here, in addition to the convergent motions, may have significant implications for the tectonic interpretation of the Early Palaeozoic evolution of the Newfoundland Appalachians.
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Kukla, Peter Alfred. "Tectonics and sedimentation of a late proterozoic Damaran convergent continental margin, Khomas Hochland, central Namibia." Thesis, 1990. https://hdl.handle.net/10539/26381.

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A Dissertation submitted to the Faculty of science, University of the Witwatersrand, Johannesburg, for the Degree of Doctor of Philosophy
The Late Proterozoic Damara Oroqen (750-450 Ma} in Namibia forms part of the Pan-African mobile belt system which dissects southern Africa. The Khomas Trough in the inland branch of the orogen comprises thick multiply deformed metagraywackes and pelites of the Kuisab Formation. (Abbreviation abstract).
Andrew Chakane 2019
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41

Wang, Shih-chung, and 王世忠. "The geological significance and Ar datings of the late Proterozoic - early Paleozoic metamorphic rocks in Fujian area." Thesis, 1998. http://ndltd.ncl.edu.tw/handle/99615616988385222967.

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42

Lemon, Nicholas M. "Diapir recognition and modelling with examples from the late proterozoic Adelaide Geosyncline, Central Flinders Ranges, South Australia." Thesis, 1988. http://hdl.handle.net/2440/18825.

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Lemon, Nicholas M. "Diapir recognition and modelling with examples from the late proterozoic Adelaide Geosyncline, Central Flinders Ranges, South Australia / Nicholas M. Lemon." 1988. http://hdl.handle.net/2440/18825.

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1v. / 2 maps
Title page, contents and abstract only. The complete thesis in print form is available from the University Library.
Thesis (Ph.D.)--University of Adelaide, Dept. of Geology and Geophysics, 1988
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Meredith, K. "Geological history of the Waukarie Creek canyon complex, southern Flinders Ranges, South Australia." Thesis, 1997. http://hdl.handle.net/2440/131148.

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Many regional disconformities or 'sequence boundaries' have now been identified throughout the late Proterozoic Wilpena sediments of the Adelaide Geosyncline, South Australia. The most prominent of these appears near the base of the Wonoka Formation and has been related to the formation of incised valleys or 'canyons'. Early interpretations of these canyons suggested they were of submarine origin, cut and filled in a deepwater environment. However, more recent work has focused on a subaerial model whereby the incisions were cut fluvially. Work was carried out on the Waukarie Creek Canyon Complex in the Southern Flinders Ranges. Observations gained from field mapping tend to favour a subaerial origin for canyon development. Some localities were found that provide evidence that there was some tectonic activity, expressed by deformation of sediments, prior to the formation of the Wonoka canyons. Palaeocurrents from flute casts and current ripples show that numerous reversals were found throughout the canyon, substantiating a tectonic influence on the formation of the canyons. This activity may be approximately coeval with the Beardmore Orogeny of Antarctica. The compressional Cambro-Ordovician Delamerian Orogeny subsequently deformed the sedimentary prism in a complex array of north-south trending tight folds and reverse faults.
Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Physical Sciences, 1997
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45

Jansyn, J. "Strato-tectonic evolution of a large subsidence structure associated with the late Proterozoic Wonoka Formation at Wilpena Pound, central Flinders Ranges, South Australia." Thesis, 1990. http://hdl.handle.net/2440/86719.

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The coincidence between the timing of the subsidence of a trough-like structure adjacent to Wilpena Pound and the initiation of canyons associated with the late Proterozoic Wonoka Formation in other parts of the Flinders Ranges provides circumstantial but not necessarily compelling evidence for a tectonic control being involved with the formation of the canyons. The trough, here termed The Wilpena Trough, is characterised by the presence of a deep central sag and shoulder sags bounded by steep north-easterly trending faults. Other canyons may have marginal faults; and the numerous reversals of current indicators within them, rather than simple unidirectional current trends as expected with turbidite erosion, substantiate a tectonic influence in their generation. Small scale faulting in the Wearing Dolomite Member of the Wonoka Formation reflects the dominantly extensional regime in which the Wilpena Trough was formed. A phase of warping prior to deposition of the Wonoka Formation may have provided the necessary trigger to produce stress zones in strata, where growth faults controlling the sedimentation in the Wilpena Trough were initiated. After deposition of the Wearing Dolomite Member in a shallow water palaeoenvironment, Units 2 and 3 of the Wonoka Formation were deposited in deeper water settings on a shelfal slope. This idea supports a submarine environment prior to subsidence of the Trough. Measured stratigraphic thickness changes give a precise timing for the initiation of fault movement that caused thickened packages of sediments. Major fault movement and corresponding sediment subsidence became active near the Unit 2/Unit 3 transition and dominated the deposition of Unit 3 through to Unit 7. Units 4 to 9 represent a wedge of prograding shelf sediments. Unit 10 is a shallow transgressional sequence and a sequence boundary has been proposed of the base of this unit, due to the marked change in sedimentary style. Stable carbon and oxygen isotope data from the sediments of the Wonoka Formation in the central Flinders Ranges shows an initial low negative plot which is succeeded by an interval showing a strong negative excursion which then makes a shift back to low negative values. A possible correlation between the late Proterozoic units in the Adelaide Fold Belt and the eastern Officer Basin enables the data from the Wonoka Formation to be added to information which Pell (1989) obtained from the Rodda Beds to show a continuous trend from the negative excursion to a broad positive one. Comparison with the corresponding overseas data provides a potential tool for late Proterozoic inter-regional basin correlation.
Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Earth and Environmental Sciences, 1990
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46

Ayliffe, D. "Geological setting of the Late Proterozoic Wonoka Formation at Pichi Richi Pass, southern Flinders Ranges, South Australia: geochemical, stable isotope and diagenetic analysis." Thesis, 1992. http://hdl.handle.net/2440/131142.

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Carbon, oxygen and strontium isotope stratigraphy has increased the resolution of Proterozoic stratigraphic correlation. Isotopic analysis was performed on the late Proterozoic Wonoka Formation canyon and carbonate platform sequences. Highly depleted and homogenised carbon and oxygen isotopes characterise the canyon fill (13C = -8 to -7%o, (18O = - 17 to -15%o PDB ) whilst a major positive excursion was observed in the Wonoka Formation carbonate platform sequence ((13C = -8 to -0.5%o, (18O = -15.0 to -7.0%o PDB). These values correlate closely with other established isotopic trends throughout the Adelaide Geosyncline. However, similar aged late Vendian strata throughout the world show low positive values. Strontium isotopic analysis revealed relatively 87Sr enrichment in the carbonate platform deposits compared to the canyon sequence. This was attributed to the input of 87Sr enriched terrestrially derived strontium. The 87Sr/86Sr ratio of the Wonoka Formation correlates closely with established late Proterozoic seawater trends. Therefore, a primary strontium isotopic composition is implied for the Wonoka Formation. Major and trace element geochemical analysis (Ca, Mg, Sr, Fe, Mn, and Rb) was performed to assess the diagenetic alteration of the late Proterozoic strata. Samples with low Mn/Sr, high Ca/Sr, high strontium, and low rubidium have the highest probability of preserving a primary geochemical signal. Most samples from the Pichi Richi region analysed plotted under the altered Mn/Sr (<2) and Ca/Sr (<2000) values. The high remnant strontium-concentrations of the Wonoka Formation suggest neomorphism from an aragonitic precursor. Micritic carbonate of the Wonoka Formation was probably a primary marine precipitate of aragonite derived from late Proterozoic supersaturated seas. Therefore, the majority of sediment diagenesis probably occurred in the marine phreatic zone, resulting in the observed primary isotopic composition.
Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Physical Sciences, 1992
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Urlwin, B. "Carbon isotope stratigraphy of the Late Proterozoic Wonoka Formation of the Adelaide Fold Belt: diagenetic assessment and interpretation of isotopic signature and correlations with previously measured isotopic curves." Thesis, 1992. http://hdl.handle.net/2440/105305.

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The Wonoka Formation of the Adelaide Fold Belt represents the only well­ described example of a late Proterozoic storm dominated carbonate shelf sequence with the considerable thickness and lateral extent of the formation making it an excellent opportunity for applying the principles of isotope stratigraphy. Sequences exposed at Warraweena, which lies on the boundary between the Central and Northern Flinders Zones, were analysed for stable isotope ratios of carbon and oxygen. Geochemical, petrographic and cathodoluminescent analysis of individual samples was used to identify those carbonates which have experienced significant diagenetic alteration. These values were not included in the interpretation of the formation's isotopic signal. Plotting of the least altered values against stratigraphic height revealed a consistent carbon isotopic trend. This trend was divided into two sections, termed the Lower Wonoka Signal and the Upper Wonoka Signal. The Lower Wonoka Signal is defined by the extremely consistent negative signal (delta13c = -8 to -7o/oo) characteristic of the lower- to mid-Wonoka Formation. This signal is interpreted to be a product of deposition and lithification in basinal waters that contain anomalously light dissolved carbonate. The Upper Wonoka Signal comprises a shift to more positive values (a13c = -5 to +6 o/oo) and is interpreted to be a reflection of carbonate deposition in shallow surface waters, possibly in association with the formation of a partially restricted lagoon. Strontium isotopic analysis reveals 87Sr/86Sr values that are interpreted to be of primary origin. These values, when compared to data obtained by previous authors for the equivalent time period, give an estimated age of 560-590 Ma for the Wonoka Formation.
Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Physical Sciences, 1992
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48

Dolozi, Michael B. "Physical volcanology of the Early Proterozoic Bear Lake mafic metavolcanic succession, Flin Flon, Manitoba." 1988. http://hdl.handle.net/1993/6875.

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The 3.3-km thick, Early Proterozoic, Bear Lake mafic metavolcanic succession near Flin Flon, Manitoba, is a vertically dipping homoclinal sequence within a fault block. The base of the mafic succession is a fault, and the mafic units are overlain by 1.8 km of felsic to intermediate metavolcanic rocks. Six formations have been defined within the mafic sequence: formation 1, 3 and 5 are dominantly pillowed flows, formation 2 comprise equal abundances of pillowed and massive flows, and formations 4 and 6 are dominantly bedded breccias and tuff-breccias with intercalated pillowed flows. These formations show an increase in amygdule abundances with stratigraphic height; amygdule abundance increases from 0 to 25% in the lower part to 10 to 75% in the upper part, the formations thus record the evolution of an upward shoaling, flank section through a mafic sheild volcano. High amygdule abundances and the possible presence of a flow-foot breccias in formation 5 indicate that the volcano may have become locally emergent. The main focus of this study was the bedded fragmental units of formation 4. This 416-m thick formation is lens-shaped, and has been traced laterally for 11.2 km. The dominant lithology is breccias and tuff-breccias that are commonly matrix-supported but are occasionally clast-suported. Bed thicknesses are 0.5 to 15 m, and beds are upgraded, normally graded or reversely graded with non-erosive bed contacts. Fragments are commonly amygdaloidal (range 5-55%; mean 31%), angular to subangular, and 0.5 to 100 cm in size with partial or complete chilled rims; the matrix is microlitic and weakly microlitic, blocky, vesicular and non-vesicular lapilli and ash. A few tuff-breccia beds contain irregular, plastically deformed particles and an unusually high proportion of vesicular matrix particles. Medium- to thinly-bedded lapilli-tuffs and tuffs that are dominantly normally graded with sharp bed contacts and occasional scour-and-fill and flame structures form a small proportion of the formation. The enclosing and intercalated pillowed flows have a lower amygdule content (range 5 to 35%, mean 21%) with amygdules concentrated near pillow margins. Breccias and tuff-breccias were apparently deposited by a series of debris flows generated by slumping of preexisting fragmental material that was explosively erupted in shallow water by a combination of magmatic and contact steam explosions. During the eruptions, the fragmental material was periodically transported to deeper water depositional environments and locally incorporated some fragments derived from pillowed flows. Tuff-breccias with plastically deformed particles and more vesicular matrix probably indicate hot emplacement, possibly by block-and-ash flows. These hot units are stratigraphically restricted and thus indicate temporal variations in the types of explosive activity. The medium- to thinly-bedded tuffs at the top of the formation were probably deposited by turbidity currents during the wanig stages of explosive activity.
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49

Wadien, Rita. "Mineralogical and chemical characteristics of hydrothermal alteration associated with the Proterozoic Vamp Lake Cu-Zn sulfide deposit, Flin Flon area." 1993. http://hdl.handle.net/1993/7347.

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The Vamp Lake deposit is a stratiform, metamorphosed Cu-Zn massive sulfide deposit in the Proterozoic Flin Flon-Snow Lake greenstone belt of northern Manitoba. The deposit occurs at the contact between underlying mafic flows and overlying intermediate to felsic volcaniclastic rocks and flows in a 500 m thick and overturned supracrustal sequence. The host rocks and the deposit have been metamorphosed to middle amphibolite grade... The deposit, consists of two separate ore zones that occur at the same stratigraphic level but are about 400 m apart and in different fault blocks. The sulfide assemblages in each zone are mineralogically simple, consisting of pyrite, pYrrhotite, sphalerite and chalcopyrite... Each ore zone is associated with alteration that is both in direct contact with the mineralization (proximal), and underlies, but is separated from, the ore by relatively unaltered rocks (distal). Proximal alteration is well developed in a thin zone below one ore zone, and poorly developed above it; the other zone has a well developed proximal alteration envelope... Chemical changes associated with the development of both distal and proximal alteration zones are gains in K, and for those assemblages where trace element data are available, Ni, Cr, Ba and Au. Athough somewhat variable in behavior, Rb, Mg, Mu, P, Fe, and Si are gained in most assemblages. Ca is consistently depleted in the distal alteration zones, but is gained in the tremolitic proximal alteration assemblage which is characterized by anomalously high Mg, Cr, and Ni relative to all other rocks in the Vamp Lake area. Na, Sr, and Nb are depleted in most assemblages.
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