Brill, KG (Jnr.)

University of Tasmania Open Access Repository

PAPERS AND PROCEEDINGS OF THE ROYAL SOCIETY OF TASMANIA, VOLUME 90 CYCLIC SEDIMENTATION IN THE PERMIAN SYSTEM OF TASMANIA By KENNETH G. BRILL, JNR. St. Louis University, St. Louis, Missouri Formerly Visiting Professor of Geology, University of Tasmania (WITH Two TEXT FIGURES) Communicated by P1'ofessor S. Warren Carey ABSTRACT Detailed stratigraphic sections 'of the Berriedale Limestone were measured in five quarries in the Derwent Valley. In these are thin beds of volcanic ash which is now altered to montmorillonite clay. These clay beds provide a means of precise correlation within the Berriedale. A study of the insoluble residues of the limestone beds indicates rhythmic and cyclic deposition and suggests deposition in relatively deep water. Glacial erratics seem to be concentrated in or near the clastic layers. The Berriedale cycles are probably Leonard in age. Cyclic sedimentation of another type occurs in the lower Woodbridge Formation near Clifton Beach. INTRODUCTION During the winter of 1953 the writer measured in detail a number of stratigraphic sections of Permian strata. Five of these sections are of the Berriedale Limestone which is well exposed in quarries in the Derwent Valley north-west of Hobart. One is a section of the basal Woodbridge formation north of Clifton Beach. These exceptional expos-ures provide detailed information that can be obtained at few localities in the State. This paper is an interpretation of the sedimentary cycles that occur in these strata. The writer wishes to thank the staff of the Geology Department of the University of Tasmania for the many courtesies shown to him during his stay. Special thanks are due to Mr. M. R. Banks of the Geology Department and to Mr. G. E. Hale of the Tasmanian Museum who shared freely their knowledge of the Permian and who guided the writer in the field on many occasions. Some of the insoluble residue studies were made at the Museum under the direction of Mr. Hale. The writer wishes to thank Dr. Harold Wanless and Mr. F. W. Booker, who were kind enough to read the manuscript. 131 132 CYCLIC SEDIMENTATION IN THE PERMIAN SYSTEM OF TASMANIA BERRIEDALE LIMESTONE Cyclic sediments: The Berriedale Limestone which was named for exposures near the village of Berriedale (Lewis, 1946), is widespread in eastern Tasmania (Banks in Hill, 1955). Typically it consists of beds of marine limestone interbedded with mudstone. Glacial erratics are scattered through the formation. It becomes less limy toward the south and south-east, where it interfingers with the Grange mudstone (Banks in Hill, 1955). This paper deals primarily with the exposures in quarries in the Derwent Valley; however, excellent exposures occur on Maria Island and in the vicinity of St. Marys. At these two localities the lithology of the Berriedale is much like that in the Derwent Valley, but the writer was unable to make a bed for bed correlation. No detailed section of the type Berriedale Limestone has been published; therefore a section is appended to this paper. This section was measured by the writer in Weily Quarry near Glenorchy. Although this is not the type locality of the Berriedale, it is only about three miles from the type and is a longer and better exposure. Columnar sections of the Berriedale Limestone shown in Fig. 1 do not represent the total thickness of the formation, but illustrate only those portions well enough exposed to allow a detailed study to be made. Sections were measured in the following quarry faces: 1. Weily Quarry, at reservoir, about 2 miles south west of Glenorchy. 2. Abandoned quarry on Old Collinsvale Road, about 3 miles west of Berriedale. 3. Abandoned quarry about 1'5 miles airline west of Granton. 4. Rathbones Quarry about 3 miles west of Granton. 5. Abandoned quarry on east flank of Mt. Dromedary near station of Bundella. In each columnar section it may be seen that (a) beds of impure limestone alternate with calcareous mudstone, (b) beds of limestone tend to be thicker than beds of mudstone, (c) limestone is more resistant to weathering. The repetition of such bedding indicates cyclic sedimenta-tion. In all sections the writer found thin beds of devitrified volcanic ash which has been altered to montmorillonite. These beds are associated with the mudstone layers. At least 13 beds of altered ash have been found in the Glenorchy section. Some of them can be traced through several sections. The most persistent bed is about an inch thick and is here referred to as the Lower Marker bed. Some 15 feet above this is another persistent layer called the Upper Marker bed. By means of these two markers, bed for bed correlation between sections is possible (Fig. 1). Although some beds of volcanic ash may be present in the Berriedale Limestone on Maria Island, it is not possible at the present time to correlate them with any of the beds in the Derwent Valley. No evidence of ash beds was found in the detailed section near St. Marys. FIG. 1,-""Coilmmar sedions of Permian strata. Sections 1-5, parts of the Berriedale Limestone. Woodbridgrc Formation. The percentage of solubles shown in the graph at the rigbt of ?; PO.l Z " ~ "'1 :J; f' I;d 2 i~-I <., 7; p ,"" Co'; of tlw lo"wer ').0' 134 CYCLIC SEDllVIENTATJON IN THE P-ERMIAN l]1}' fASI\;lANIA Pebbles and boulders of rocks are :sea tiered a bouldermol'e a foot in diameter in thp quarry west Berriedale. 1 shows that the tend to be more nur.nerous in or ncar the mudstone Coneentratlons of erratics oceur in several below the Lower Marker the of the top 5, the of 6 and the of 6. is «G,O>UJ,HCC that these that have rafted to their present position out of several hundred examined of of several data for taken at about In of the these 4-inch about 20 grams face. Each digested in acid, and the soluble matter thus obtained for residue each sample is dry, The per cent plotted on the right side r } I --I ~ ~-%SOL. ------------FIG. 2.-----I"our types of solubility curves in limestone hl-Jds. A. Gradational contacts with bed" above and below, typical of Berriedale Limestone, suggesting: relatively water below wave base, uniform cyeJk level 01' supply of sediment. B. contacts with beds of formation (Lower County, Missouri, . : ('ontrol by vertical fluctuations -wave base, cycles c. Gradational contact below, non-gradational thetica! case : a decrease tion lim.estone due to bacterial shale (Shroek, 1$)48, p, 31). 1), Gradational contact above, thetical ease increase in supply a of of the columnar of each each section a:nd the to another. The followed limestone in mudstone of the most KENNETH Gc BRILL, JNR. <,,1.: .10,] were not taken from all sho\vs a. features or it can be traced one sedion showf'. a maximum of mudstone in clastic material until 11 maxim urn of This is followed to the of the beds occurs at or indieate Four types of curves that are for a limestone bed are shown in curve a set of conditions under which the was deposited. The solubility curve that is characteristic of the Berriedale Limestone shows a gradual increase in insolubles at the top and bottom of the bed (Fig. 2A). This condition indicates continuous deposition with variation in the volume of clastic sediment. The lack of rapid changes in lithology between beds suggests deposition in relatively deep water unaffected by violent wave action. Angularity and freshness of mineral grains in the Permian was inter-preted by Banks (1952, p. 72) as evidence or quiet water deposition. The presence of large numbers of productid brachiopods, pectenoid pele-cypods and bryozoa in the Berriedale does 110t militate against the theory of moderately deep water. Barrell (1916, p. 803) states that marine mudstone seems to give the most favourable conditions for eontinuous record, and is wen adapted espeeially where alternating with lime or silt beds to give a basis for the analysis of rhythms. In this respect the Berriedale Limestone Reems to be an ideal formation for studying rhythms; however, the problem is complicated by three different types of sedimentation-glacial and sedimentary cycles and volcanic ash deposits. The cause of rhythmic and cyclic sedimentation in the Berriedale is obscure. If it is due to eustatic changes in sea level, the problem is not unlike that of cyclothems in many parts of the world. The fact that thin beds of volcanic ash are associated with the mudstone beds and that commonly glacial erratics occur in or close to the mudstone beds suggests that all three may be related genetically. Several hypotheses suggest themselveR: (a) Volcanic outbursts in areas of glaciation may have increased glacial melting and thereby increased clastic deposition. (b) Volcanism may have increased precipitation on land and thereby increased discharge of streams and glacial flow. (c) The vertical movements of the sea floor may have resulted from earth move-ments associated with volcanism, in which case the presence of glacial deposits may have been fortuitous. Changes in the ratf; of sedimentation may reflect of glaciers, in which case the presence of volcanic been fortuitous. map (Inset, Fig. 1) that the toward the north-east. Southward and south-eastward it with mudstone. thickness of limestone seems to be in the No.4 Bore at ""'"71'1,''' 13(; CYCL1C SFDII\:[ENTA .. TION lN THE: Some of the information on this map are borne out -Berriedale in the I)er'Vvent lTI'Ore Detailed data are available for of the Berriedale at all tlve localities. Table 1 shov'.'s the total of each of rock in each section for the 8 below the Lower Marker TABU;; 1 Section ;:~>;.nd8t01H Sjit;.;tone r~AlJ.nRtO:ne Shak~ Lim·est.one Glenol'chy I' ~)n 8" 17' f''' J Berriedale If 4~" 17' ;4 ft Granton ,,' 4" I' 3'f l' S" 17' 1" Rathbone ;~" e: n 3' ]4' 10" " u Dromedary ()ff 4' J Iff 1" 14' These thicknesses indicate that the amount of clastic material toward the west. A greater number of beds bearing glacial erratics occur in the Dromedary and Granton sections, suggesting that the source of pebbles may have been to the west or north-west. More beds of volcanic ash occur in the Glenorchy section which may be significant as to source direction, or may indicate only deeper water. In the Glenorchy, Granton and Rathbone columnar sections lithologic data are available for the strata between the Lower Marker and Upper Marker beds. These also indicate that the amount of clastic sediment increases toward the west. Although comparative figures on lithofacies are available for only it portion of the Berriedale Limestone, they appear to be significant and consistent for this geographical area. Age: The waxing and waning of ice sheets in the Southern Hemis-phere has been suggested by Wanless and Shepard (1936, p. IH)3) as a possible cause of cyclothems in Upper Carboniferous and Lower Permian strata in the United States. Moon:, (1950, p. 16), on the other hand, cites evidence to the contrary. Although the Berriedale cycles may be related to fiuetuations of gladers, it is doubtful that they can be correlated with any known sedi· mentary cyeles in the United States. Faunal studies of the Berriedale by Banks (1955) indicate that it contains L!rropoTl311a.. StrelilotrypCL and Fenestella which are also found in the Callytharra Limestone of the Carnarvon Basin in Western Australia. The Berriedale also con-tains Taeniothacr-a8 81[IJquadrcLtIL8 and N e08pirifer Cf.nI008akhailensis which occur in theWandagee Formation of the same area in Western Australia. According to Teichert ( p, 36) the Callytharra Limestone is very early Artinskian in ag'e, Teichert (1942, 222 states that the ¥landagee, although stratigraphically higher than is also A rtinskian. If these correlations are correct the I;imestone is approximately Leonard in than any of the well-known coal WOODBRIDGE FOlnVIATION 'I'he Glacial Fon-nation the Berriedale Limestone. mudstone and sandstone about 200 feet thick in the Derwent about thick on Freycinet about 25 feE't thick in the I'Io. /j (Voisey, 19i38), and 3 feet thick at St. In the three localities last mentionecl it is .At least SIX sedimentary occur in the basal W Forma-tion :at the north end of Clifton Beach near Deslac 1) . The in the cliff 104 feet above The s€ction above not exposed. Each cycle cOIlsists of two members. In the lower member is a and sub· of mudstone, to 8 inche;;; The lower members of eoarsc-sandstone. The members of all are fmer·· sandstone. In four of the the upper member is thinner the lower. The lower member one eycle contains a few fossils indieating that these Aediments are marine. rrhese cvcles mav be a modification of the deltaic cvclothems of Wanless and 'Shepard (1936), and may have developed on a mildly unstable shelf near a source of glaeial outwash. The members of the Woodbridge cycles are much thinner than any 'Of those illustrated by Wanless and Shep.ard . . Good exposures of this particular part of the Woodbridge were not seen elsewhere in this area, therefore the areal extent of these eycIothems is not known. They do not seem to be in the seetion along the New Norfolk road west of Rathbone quarry. Sedimentary cycles have been reeognized in the Tomago CoallVIeasul'es in New South Wales (Booker, et aI, 1954, p. 147). It is doubtful that the Woodbridge cycles are related in age to those of the Tomago; they may be n:lated genetieally. REFERENCES BANKS. M. E., 1952.-Permian, Triassie, and Jurassi.e Rodes in Tasmania. on the Gondwarll1a series, l.Gth Internal:. Geot. Conp. ---~-~~------, UJ55.-The Permian System in Tasmania. Geol. Soc. pp. 83-107. In review by D. Hill. BARRELL, .T., HIHL-Rhythms and Measurement of Geologie Time. fico!. SOl;. Am. Bull. VoL 28, pp, 745-904. BOOKER, F. W.; BURSILL, C. AND JVICELlWY, C. Coal Measures in the I1nd 1'roc. N,S.W L;~WIS, i\, N., liJ4G.---Geo!ogy '::\-iOORE, I{ .. C'j lB50.---Late Paleozoic. 18th fnternat. R. It., 1948,---Seqnenee in Layered T~'ICHK!(T, Coo 1942,-Permian Ammonoids from . Vol, 16, 221-232. 1954.---Sedimentation of the Tomago Coalfield. Jour. "-.-.----~~~.-'~----. 1949.-,,- Crinoid Ca1coJ.ispo-n{tia. GCDl. Soc< VorSEv, A. H:, 1938,--The Paleozoie Rocks of Tasmania, 1'1'0(:, Linn. Soc. N.S. W., ilO!)-338. \\TANLKSS, II. R, AND Level and Chn1atic Chang(;s Related fico!. HuH Vol, 47, Elp. 1177-1206, CYCLIC SEDI1'vl1-'0NTATI0-N rrHE PERl\:fIAK SYSTErvl OF ApPENDIX Detailed section of a part of the Berriedale Limestone ill IN eily's Quan'y about 3 miles south of Glenol'chy. Top of sedion: Grange Mudstone-65. Mudstone weathers exposed in top Berriedale LimestoYlu-,-beds one foot to 18 inehps thick, 64. Shale dusky yellow, metabentonitp 63. Mudstone weathprs shalp band in middle of intprval, a inches ahove cusp; pectpns, fenestellids 62. Shale dusky yellow, laminated, metabentonite 61. Mudstone gray, pPl'haps slightly about 1 foot thiek, prominent bedding plane 1 foot below top 60. Limestone medium dark gray, massive, rounded fragment of schist 8 inches diameter near base, 8trophalosia 5n. Mudstone olive gray, masRive, numerous fenestellids give impres-sion of laminae 58. Shale dusky yellow, silty, perhaps metabentonite ... 57. Limestone medium dark gray, muddy streaks, broken into thirds by two bedding planes; globular Strophalosia or Tnen'iotha.erus in middle of interval 56. Shale dusky yellow, silty, perhaps metabentonite .... .... . ....... 55. Mudstone olive gray, slightly calcareous 54. Shale dusky yellow, waxy feel, metabentonite 53. Mudstone olive gray, slightly calcareous, one bed, laminae due to fenestellids 52. Shale dusky yellow, soft 51. Limestone medium dark gray, slightly muddy streaks, discontinnous shale (metabentonite?) 4 inches above base; StTophalosia, large S/:enopora ...... . .. 50. Shale dusky yellow, thin-bedded, soft, probably metabentonite 49. Mudstone olive gray, ealcal'eous streaks dne to many fenestellids, silty, poorly bedded, bedding planes at 12, 23, 44, 513 inches above ~~ ... 48. Limestone medium dark gray, many muddy streaks and lenses, laminations due to fenestellids 47. Mudstone olive gray, calcareous streaks, laminations due to fenes-tellids ... OVerlying layers generally muddier than those below. 46. Limestone medium dark gray, slightly muddy, massive 45. Mudstone olive gray, Don-calcareous, laminations due to fenestellids 44. Shale dusky yellow, waxy feel, thinly laminated, metabentonite. Upper marker bed 43, Limestone medinI'll gray, slightly muddy, upper 6 inches muddier, massive, prominent bedding plane 19 inches above base. Floor of upper bench 42. Shall' dusky yellow and dark greenish-gray, fceL metabentonite tJ1. Lirnestone medium dark gray, muddy near inassive, small enerusting bryozoa 40. Dolomite medium dark laminae due to fenestellid~ 38. Limestone medium and sandy streaks, scattered smati small muddy nodules, eontaining bryozoa; rnany fenestE~nids, few spiriferids 38. rv[udstone diseontinuo1..ls bed 87. Lirnestontl fetid odoy, hut thin brpaks 33 inches above ; fenestellids, Ft. II" 15 0 0 (d .. ' '1 0 10 0 '1 4 6 :l 1 0 8 0 Go!; 2 6 0 0 0 1 2 8 0 0:1: 1 8 0 ot 5 " , 2 0 0 10 1 8 0 4 0 4-2 ] 0 1 1 5 0 5 2 1 I' ,j 1 4 a 35. Lin1f~Btone Jnedill1TI daTk rounded pebbles up Shale and n11ld"tone interbedded: nletabeuionite; lTIudstone Limestone medium dark 111ud.dy, :fetid odor, . Y.n.an'-/ Srenopofn shale d{lSky yellow, perhapB 83. 3ilt.y~ hase without 82. Stropho·-'upper 2 :JL Limestone dark mudstone Trigo'no-tretn, 30. Limestone dark a coquina at top of small Strophalosia and other fragrnents 29. Limestone medium dark gray, many thin muddy breaks; about one-third calcareous mudstone on fresh surface 28. Limestone medium dark gray, muddy, one bed 27. Limestone similar to Int. 25; thin muddy breaks in upper 3 inches 26. Mudstone dark gray, thin-bedded, calcareous 25. Limestone medium dark gray, slightly muddy, muddy breaks 3, 5 inches above base; numerous brachiopods 24. Limestone medium dark gray, slightly muddy, massive; a I-inch soft muddy streak 7 inches above base; coarse angular quartz and I'ork ; subangular fragments of quartzite 5 inches diameter top. Seems to he a thin metabentonite here Shale waxy feel, thin-,bedded, mixed with limestone, 22, Limestone medium dark finely crystalline, 2-inch shaley at base 21 inches above; Ewrudewrna, composed of white 21. Limestone medium gray, fetid odor, 2-inch muddier band 5 inches above base; many Forms floor of 3rd bench in quaI'I'Y, Cross small fault 20. Mudstone dark gray, very limy, weathers brown at top; many Strophalosin 19, Limestone dark grey, massive, fossiliferous beds with thin shale breaks at 21, 29, 36, 40, 43, inches above base. Large Stenopora, but spiriferids, smaller than farther north 18. Mudstone dark gray, thin calcareous streaks; fene~-tellids, SI;ruphalosia Limestone dark gray, rounded pebbles of up to 4 inches 16. Limestone dm'k gray, Strophalosia; Hi. medium dark , scattered 14. Limestone medium lenses of dark carbonaceous shale: £)0 inches above tluse ' of white calcite, of 2nd beueh 111 beds at 18H Ft. In. 0 1 !) 0 5 2 D 0 4 2 0 2 5 1 11 1 7 0 3 1 9 ;3 0 0 3 n , 0 0 5 7 ,1 0 4 2 }) 0 6 1 8 o 110 11. 10. D. CYCLIC SEDI~lgNTATION L"\ THE VSTC\1V\I\ SYSTEl\l OF TAS~L\.KfA n1as~ive, irregular sandstone, 5n indles above argiLiite up to ',vhit{~ prane:,;; at subangular pebbles of in diarnetcl' <f:~speciaHy R. interhedded; mnd~t()ne olive calcareous. many fenestellids. Basal 1 inch contains of meta-Ton of bed is three feet below access road i. Mudstone olive gr'ay, spiriferids and fenesteHids Mudstone olive angular fragrnents, small clarns and 5. .1VIudstone olive gray, silty, many fenestellids 4. Shale dusky yellow, hard, silty 8. Limestone olive gray, muddy, seattered sand grains, and lumps of gray mudstone . 2. Nfudstone dark gray, weathers slightiy calcareous, numerous grains and pockets of quart7. ; pectens, spiriferids, small bryozoa, Diclasm.a, 1. Sand8tone medium gray, muddy with limy spots, subangular pebbles up to 2 inches diameter; basal 1 foot partly covered Covered by dump. 

Cyclic sedimentation in the Permian system

of Tasmania

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Cyclic sedimentation in the Permian system of Tasmania

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