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—92 8 — APPROXIMATE LiMIT OF PYROXENE —HORNFELS ISOGRAD Pig. Z Contacts between dountry rock', gabbros and laurvikites.
—93— (3) 'flow—layering' exhi)bited by anatexite are parallel to the contact and contact irregularities. C) presence of areas of breccia development. These field relations, schematically illustrated in Fig. 3, can best be explained by assuming the peripheral development of migma ,in the country rocks surrounding the cupola of gabbro. Breccia development appears to be, in part, the product of an irregular cooling history involving magma pulsatidn followed by fissuring and intrusion of more— peripheral areas. Note the abundant xenoliths in the gabbro (apparently reflecting the 'high' level of cupola exposure); the rheomorphic dikes of granophyre with tourmaline±prehnite in the anatexites; and dikes of laurvikite in the gabbros. The laurvikite dikes commonly show; (1) angular inclusions of gabbro, obviously locally derived; (2) contact relations indicative of emplacement during periods of extension; (3) composite appearance. Thin âections of the anatexites show porphyroblasts of •(in decreasing order of relative abundance); clinopyroxene, IC—spar, quartz, orthopyroxene (Fs 25—35), biotite, oxides, and sulfides. l4ineralogically the anatexites lie within the orthopyroxene clinopyroxene — plagioclase triangular field of an ACF plot for the pyroxene—honfels fades. Physical and/or optical alignment of some of the minerals especially plagioclase (An20 to An40), is not uncommon. The gabbros vary from fine to coarse grained but all varieties are essentially anhydrous two pyroxene gabbros with or without phenocrysts of plagioclase of (An65_70). The medium to coarse gabbros of 'Inner Border Zone A' show. anomalous amounts of quartz and K—spar, probably due to assimilation. OO Thin sections of the syenite dikes, generally composite, show perthites (generally extensively exsolved, patch perthite) with varying proportions of aegirine—augite, riebeckite, calcite, zircon, fluorite, quartz, and oxide (ilmenite ± magnetite). These dikes are considered to be apophyses from the main body of laurvikite. Turn round and proceed north towards Marathon.
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-ç — — I: .t. F Geology Superi
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TABLE OF CONTENTS INSTITUTE DIRECTO
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-2- "P R 0 G R A M" Tate day, Ma9 5
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-4- SESSTOM 2 1.00 Business Meeting
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-6- F'viday, May Slit, 1970 Page No
Page 11 and 12:
-8- SYNTHESIS OF EARLY PRECAMBRIAN
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-10- THE SOUTHERN ASSOCIATED PART O
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-12- THE STRUCTURE OF THE NORTHERN
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-14- MT. ST. JOSEPH - AN ARC}IAEAN
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-16- A MODEL FOR TECTONIC VARIATION
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-18- EARLY PRECAMBRIAN GEOLOGY OF T
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DEFORMATION OF THE SEINE CONGLOMERA
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-22- MINERAL POTENTIAL IN CREENSTON
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-25-- ROOT SEVERANCE AND TECTONIC T
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-27- STRUCTURE OF ThE DULUTH GABBRO
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-29- 1. Department of Geology and G
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-31-. KEWEENANWAN COPPER DEPOSITS I
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—33- The youngest rocks in the ar
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-35- STRUCTURAL AN!) METAMORPHIC HI
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-37.- ARCHAEAN VOLCANIC STRATIGRAPH
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______ __________ _____ IDEALIZED S
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—41- (3) The upper liimit of 30 p
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-43- Fjgire 2 The revised classific
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—45— EVIDENCE FOR A TROPICAL CL
Page 49 and 50: —47-- WIDESPREAD OCCURRENCE OF AL
Page 51 and 52: —49— PROTEROZOIC ROCKS IN THE T
Page 53 and 54: —51— Guide to the Proterozoic R
Page 55 and 56: WEST EAST f * . . .. . . S S S S 5S
Page 57 and 58: ________ — ;—=- — —-- —
Page 59 and 60: —53— The uppermost submember of
Page 61 and 62: —55— Morey notes that sediment
Page 63 and 64: —57— (c) layered mafic bodies,
Page 65 and 66: —59— DESCRIPTION OF STOPS Milea
Page 67 and 68: —6 P- Note downwarping of beds on
Page 69 and 70: —63— Note the lenticular chert
Page 71 and 72: —65— 0.0 From the intersection
Page 73 and 74: —67— STOP 16 In the roadcut to
Page 75 and 76: —69— ThE BEARDMORE-GERALDTON BE
Page 77 and 78: —72— the Quetico belt by Stockw
Page 79 and 80: —72 B— ABITIBI BELT —ø.jsour
Page 81 and 82: —74— Most of the metavolcanic
Page 83 and 84: —76— SELECTED REFERENCES Anonym
Page 85 and 86: —78— Stockwell, C. II., 1964; F
Page 87 and 88: —80— ae DESCRIPTION OF STOPS 0.
Page 89 and 90: —82— STOP 8 (Paint Lake Fault).
Page 91 and 92: -84— Outcrops near the road are o
Page 93 and 94: —87— Guide to the Port Coldwell
Page 95 and 96: AGE RELATIONSHIPS The volcanosedime
Page 97 and 98: .• ____________________ . — .._
Page 99: -I- + -4.- -I- - - - - — - 4- ; E
Page 103 and 104: GOSSAN ZONE IN SULPHIDE BEARING GAB
Page 105 and 106: —95— (3) feldspars variably fol
Page 107 and 108: —97— Fig. 6c Fig. 6b ;' TRAIL T
Page 109 and 110: Pig. 7 West contact of CROSS SECTIO
Page 111: PRINCE AR THUR HOTEL ® 0 ® SHOREL
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Program, Abstracts, and Guidebooks - University of Minnesota Duluth

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