Calcareous Deposits of Southwestern British Columbia
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BRITISHCOLUMBIA DEPARTMENT OF MINES HON. W.K. KIERNAN,Minisfer JOHN F. WALKER, Depltfy Minisfer BULLETIN No. ~40 Calcareous Deposits of Southwestern British Columbia by W. H. MATHEWS and I. W. McCAMMON VICTORIA, B.C. Printed by DONMCDURMID, Prinfcr 10 the Queen’s Most B~cellentMajesty 1957 PAW 34 35 37 38 38 40 40 41 42 43 44 44 45 46 47 47 47 47 47 49 51 51 51 52 52 55 55 56 56 58 58 58 60 66 61 71 72 74 11 78 79 19 80 DRAWINGS I'IOURB PAOS 1. Limekiln Bay quarry ........................................................................................... 12 2 . Distribution of magnesia in strata, Limekiln Bay quarry..................................... 29 3 . Geology andcalcareous deposits of southwestern British Columbia pocket 4 . Anderson Bay area,Texada Islan-" .................................... .................. 48 5. Home Lake area, Vancouver Island&................................................................. 50 6 . Geological map of northern Texada Island.................................................. In pocket 7 . Geological map of Blubber Bay area, Texada island^." in pocket 8 . Dykes in No . 3 quarry, Gypsum Lime and Alabastine property ........................ 57 9. Gypsum Lime and Alabastine abandoned quarries .............................................. 61 '10 . Cross-section of Gypsum Lime and Alabastine quarries~".................................. 62 '1 1. Gypsum Lime and Aiabastine No . 4 quarry ......................................................... 64 '12 . British Columbia Cement quarry, Grilse Point .................................................... 70 .13 . BealeQuarries, Vananda................................................... ........-.......................... 75 '14 . Davie Bay area^ .................................................................................................... 81 15 . Open Bay area, Quadra ~sland............................................................................. 83 16. Blind Bay area, Nelson island^"^-" ....................................................................... 96 6 Calcareous Deposits of Southwestern British Columbia INTRODUCTION This bulletin includes reports of surveys of most of the known commercial or poten- tially commercial, readily accessible calcareous deposits of southwestern British Colum- bia. It is essentially a revision of Bulletin No. 23, Calcareous Deposits of the Georgia Strait Area, by W. H. Mathews, that was published by the British Columbia Department of Mines in1947. The reports cover the same area asBulletin No. 23 except that material dealingwith the State of Washington has been omitted. There has been no change in organization of material, and the four introductory chapters of Bulletin No. 23 have been retained withlittle alteration. Manyof the reports on individual deposits have been used,with only minor changes made in the original text as writtenby Mathews. Some reports have required extensive revision to bring them up to date and descriptions of a few new deposits have been added-these are all marked by asterisks. Fieldwork upon which the revisionis based was carried out in the 1956 field season by J. W. McCammon. During the course of the work all of the large deposits and most of the small ones wereexamined. The writer gratefullyacknowledges the assistance given him by the operators of the various deposits and by R. H. Farquhar, who served as student assistant. DEFINITIONS, CHEMICALSYMBOLS AND ABBREVIATIONS The classification of limestoneused in thisbulletin follows closely that used by Goudge (1944), and differs from Goudge principally in using " High-calciumLime- stone " as a separate class rather than part of the " Calcium Limestone " class. Limestone denotes a rock of sedimentary origin consisting mainly of calcium car- bonate (calcite) or the double carbonate of calcium and magnesium (dolomite). A rock containing less than 50 per cent* combined calcite and dolomite is, therefore, not con- sidered to be a limestone. Limestone may be subdivided on the basis of chemicalcomposition into four classes:- (1) High-calciumLimestone.-Denoting a limestone containing at least 95 per cent* calcium carbonate (CaC03) and not more than 2 per cent magnesium carbonate (MgCO,); these are equivalent to 53.3 per cent lime (CaO) and 0.96 per cent magnesia (MgO). (2) Calcium Limestone.-Denoting a limestone whose calcium content greatly predominates, but which cannot be classed as high-calciumlimestone. Calcium limestone may contain up to 4.79 per cent magnesia, equivalent to 10 per cent magnesium carbonate. (3) Magnesium Limestone-Denoting a limestone containing more than 4.79 per cent and less than 19.15 per cent magnesia. (4) Dolomitic Limestone.-Denoting a limestone containing more than 19.15 per cent and less than 21.86 per cent magnesia, the theoretical magnesia content of the mineral dolomite. The term " dolomite " is restricted to the pure mineral (CaMg (C03)*). The term " marble " is used in this report in its geological sense as crystalline limestone, not in the popular sense as an ornamental limestone. All percentages are by weisht. 7 3 In the chemical analyses quoted in this bulletin the components of limestone are given in terms of oxides and " ignition loss," the latter consists chiefly of carbon dioxide (COO,). The essentialoxides in limestone,lime (CaO), and magnesia (MgO)are reported in some publications as calcium carbonate (CaCO,) and magnesium carbonate ("CO,). These oxides may be recalculated as the carbonates or vice versa using the following data:- 1 per cent CaO is equivalent to 1.78 per cent CaCOR. 1 per cent MgO is equivalent to 2.09 per cent MgCO,. 1 per cent CaCO, is equivalent to 0.560 per cent CaO. 1 per cent MgC03 is equivalent to 0.478 per cent MgO. In order to save space, chemical formulz and other abbreviations have been used in the tables of chemical analyses throughout this bulletin. The abbreviations used are explained below:- Symbolic Formula Full Chemical Name FezO3............. Iron oxide; contains 69.94 per cent iron byweight. MnO............... Manganese oxide; contains 77.44 per cent manganese by weight. P,O, ...............Phospharus pentoxide; contains 43.65 per cent phosphorus by weight. Ti0 ............. ..Titaniumdioxide; contains 59.95 per cent titaniumbyweight. Al,0 ........... ..Aluminium oxide (alumina); contains 52.91 per cent alu- minium by weight. CaO calcium oxide (lime); contains 71.47 per cent calcium by weight. MgO ...............Magnesium oxide (magnesia); contains 60.32 per cent magne- sium by weight. S...................... Sulphur. Insol ............... i acid insoluble matter; contains those minerals, chiefly silicates, which do not dissolve when heated with hydrochloric acid as described on page 30. R203........... --.Aluminiumoxide, with those oxides of titanium,zirconium, beryllium, chromium, quinquavalent phosphorus, quinqua- valent arsenic, and quinquavalent vanadium present in the limestone.Usually for limestones RzOa is essentially aluminiumoxide, the remaining substances listedbeing present in very low percentages if at all. Ig. Loss ...........The percentage loss in weight when the limestone is ignited in a furnace. Such ignition decomposes the carbonates of cal- cium and magnesium, forming calcium and magnesium oxides and gaseous carbon dioxide. This carbon dioxide escapes and, together with the minor amounts of water and organic matter present, accounts for practically all the loss in weight on ignition. H20105" ...... Water whichis released from the sample when it is heated at 105" C. 8 CHAPTER 1.-GEOLOGY ORIGIN OF CALCAREOUS DEPOSITS Carbonates of calcium and magnesium may be precipitated from aqueous SOhtiOnS, usuallysea-water, by several different agencies. The calcareousdeposits thus formed may be subdivided into several mbre or less independent types based on their modes of origin:- (1) Those consisting of the accumulated shells, or fragments of shells, pre- cipitated by the larger organisms. (2) Those precipitated by micro-organisms in which shells or shell fragments are not evident, at least to the unaided eye. (3) Those precipitated by chemical means, such as a change in the tempera- ture or in the COa content of the solution. (4) Those composed of any two or all of the above agencies. Except where limestones have been extensively recrystallized, those formed by the accumulation of largershells and shell fragments are easilyrecognizable. Where the limestone is fine-grained and devoid of visible shells or shell fragments, however, the origin may be doubtful. Sucha limestone may have been precipitated originally as a fine-grained ooze, either by micro-organisms or by chemical action, or by a combina- tion of the two. Where shells and shell fragments are found in a matrix of fine-grained limestone, larger organisms and also micro-organisms or chemical action, or both, were responsible for the originaldeposition. Such a case is found at one horizonin the limestone of Texada Island where, however, shell fragments are exceeding widely scat- tered. It is clear that this horizon and the adjacent unfossiliferous limestone originated almost entirely through microbiological or chemical action. The scarcity of shells in most of the limestone deposits, except in some of the Palzozoic crinoidal limestones of the area, suggests that larger organisms played but a minor part in the precipitation of the original material, but in several deposits the recrystallization of limestone has been sufficient to obliterate fossil remains and their origin must remain