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Report of the Committee on Sedimentation 1939-1940 Presented at the Annual Meeting of the Division of Geology and Geography (1940)
National Research Council (NRC)

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102
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-- 102 - _ Exhibit 11dE I~POR14~CE OF ~V1Z SPINAL ANALYSIS OR :~EGfONAL STORY PhlBOI`aCY D. J. ~eglas Lab. N.~. Bat. Petr. ~ij Amsterdam' Netherlands Introduction During the last five years nearing all reapers dealing with heavy mineral studies have contained reads about the accuracy of the laboratory methods necessary to obtain comparable results. Any investigators propose improvements of the methods and some of these have-already been Widely applied, e.~., the examination of a limited grade, and court 300 or more grains per slide. this refinement of the method of excitation may be useful for sedimentary A. studies, ice., an accurate descry ?- Clan of the ~r.ine=~ content, structure and texture of the sediments. The sedimentary petrologist, however, is not so much interested in the exact mineral composition of sediments. He wonts to determine the source, ~;eo ~ra~hical and strati~ra~hical distribution of sedimentary grouts and therefore only needs those characteristics of a sediment which are related to these features. Ends doszg;ned for sedimentary Metrological ~nvesti cations may therefore be less exact, as long as the error of the results remains m thin the limits of the probable variations ,~ a homogenoous sed^- meD~tary group. qh`3 method used by the B. P. M. for heavy mineral studies was designed by Sideman in 1928 and is more or less similar to that des- cribed by other investigators, e.~;., Pettliohn (17~. So far tens of thousands of samples Tom many strat~graphic sections have been ex~ined and we have been able to determine the origin of ~ groups and _ _ , , . _ . ., - , ,. _ their geograph~ca1 and stratigraphical distribution in various Tertiary sedimentary basins in different parts of the world. :Edelma:~ axed his fol lowers t1, Z. 3, 4, ~Z-15J used the same titled for :~are sci enti~c problems related to recent Continental and marine sediments. In neither case Alas the necessity ever been Belt of refini~ the method. -- ~- _ __ rig AS co nr~ clenc e in t be methods to be used is a prime requirement if satisfactory results are to be obtained and as eve have band that lack of confidence, stil ~ common among sedimentary petrologists, is ant a consequence of ~mpertect~or~ of the laboratory method, but of the manner upon Rich the in~resti&~tion has been planned, Liz., on a local or on a regional scale, we hope that publication of the results of one of our examinations and of scne particulars of the method used will stimulate the development of sedimentary petrology. , ... . , ~ , Published with the permission of the Bataatsche Petroleum ~astschappij, The Hague, Netherlands.

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Exhibi t G . . _ __ 105 _- In1;o~retation of Bea~ tori floral Data . , ~ , ~ Tho main object a sedimentary petrologist must have in anew when he starts to e:~:amine sedim - ~s is to find those characteristics which will serve hum as clues to their source and geograph~ca:t ~d stratigraphic~ distribution. Other particulars in which a petrologist may be interested, viz. ~ cures in the mineralogical composition due to ph,,~rsic~ and ck-=i Cal coalitions during transport, deposition and after deposition, can only be determined ~f ~t ~s knossn: that the sediments in question nave been derived from the same s~ce or sources. Consequently, the first characteristics we have to deter~ni;ae are those related to the origin of the sewing. We know, however, that the mineral composition of ~ sediment Amy bo altered by various physical iOtiU=GBS. The marination of one sample of ~ sodimmiary coral Ox may thus show a somewhat alte:~d picture ~f the che~actoristics of its source. During deposition of a sedimentary layer physical conditions gr,enera~ly vary considerably Within a relatively short Apace of limes It we take many satins from d~ifferent parts of this lay=, Ace shall be able to determine the i:~luence of these cha=es on the mino3~0gical composition of the s eat~ts . It must be boxne in mind, however, that even if samples are taken close together' they may be derived froTa diet souroes. This feature has been o~roriookeS by may investigators, generally owing to the fact . that they did not examine Cede on a r~ioml scum. This loaf to the assumption that changes in ~neralogica1 cocnposi~on were generally Mused by differences ~n grain size and by shortcc~mi$~gs of the laboratory methods used. =ter the e~:amination of hundreds of samples derived trom one source, however, we have found mat deviations in the mineralogical colon - sition due to di~e:re:~ces in g;rax~ s~ze and laboratory netbods Jie within narrow baits. Be have called these charms ~n Me m'~eralogical. . . . . composition "cMuce Creations", as they have no relation to the origin of the ma$e:~al. All other chafes in the ~ ~ are due to ~ , _ ~ chelates ~n the origin of the material. Both kinds of changes can easily ~ ~ . .. be detent if many samples are examined a~ the investigation is made on a large scale with respect to the geog;ra~?~c~ aM strat~graph~c~ di$- tribution of the petrologica~ units. It we know the mineralogical c~pos'1ion of the detritus ~ river is transporting to the sea, it Will not be difficult to find the geography-L distribution of tale material (sedimentary petrologica;1 province) on the sea bottom. Nor the mouth of the river the composition of the sediments of the sea bottle will be si~ilar-to that of the river. -Further cat to sea. however. the com~osit'~n may be changed, owing to

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-- 10dL ~hibi ~ G _ _ : . . . . . . . . the sortie action of currents and waves or to a&iz:ture of material from other rivers. The latter feature, Iris., mixing of mineral matter derived from different sources, has Floured to be leery come-on In marine and conti- nental sed~rner~ts' erg., I~urri (7), 3iXlelman (13-153, Back (2). and ~118r (18), . . . In order to distinguish these "mixed"' sediments, the situation of this slipup of sediments with respect to -their sources and the:mine:ralogical composition of the eolJ.rce materials must be known. This is especially important if heavy minerals are to bee used for correlation of st~ti- graphic zones and we wish to know whether the mineralogical composition of mineral zones =11 remain constant in a certain area or not. Thence fore it must be known wI:other the $edunents present in such a zone have been derived frcm one source (original sediments),. ox from dil'£erent; sources (mixed sediments). In the latter case the Dipteral composition will change ~n tm or more directions, ~r~.,~ ire the direction of each.source separately. In the former case their composition will nof alter towards the ~:'urce a~ in i;he.opposite direction it only =11 change it foreign Interim has been admixed. Operas zones containing; sediments Groin one source are there:f ore ch more reliable for ~orre3.ation af stratigraphim1 units than fllose containing "r=; OCR for page 105
Alibi t G , , . . _ -- 105 _~ However, before we pass on to the dete~.i~tion of the original mineral associations sullied to a basin by me&es of' the changes in mineral composition occurring 'n one stratigraphical section, the meaning of these changes roust be well understood and will be discussed first. In studying the distribution of the mineral zones present in the younger Tertiary of last Java all changes In heavy mineral composition whi ch may occur In a sedimentary- basi$~,^11 be found. :Rig. 1 glYes a cross section through four petrographicaI sections in this basin which are more or less situated on a line riming north-south (right to left). The distance between section ~ Ad II is 13 miles, between II and ITI eight miles and between ITI and IV fat rifles. The fo1lowi~ mineral zones can be distinguished in ascending stratigraphical order: Tn sectzorr I: TO-DO Stauro~ite-zircon zone containing about 10% of staumlite and further Fir eon, twine, rutile am titanite. DO -Ed Zircon-ri ch zone, only containing zircon ~ 70%), tourmaline , ru tile and titanite. E LULL A2Ldalusite-zircon zone with 15% of andalusite in addition to zircon, twine, rutile and titanite. oveG ~Eo~cnblende~ zone-with 100% hornblende and augite. In section lI: A-D D-E Staurolite-opidote zone cants about 8% of staurolite and va~yi~ percentages of ep~dote (O-60q) ,- further zircon, taumnaline, :cutile and titanite. p~dote-x, roon cope, practically without staurolite. The Dote percentage varies from 0-60%. The remained heavy minerals are zircon, tou:}:maline, r'}tiIe and titrate. ~dote-andalusite zone with about 55% epidote and 10% a~alusite; further again zircon, tou~mal~ne, refile and titanite. Above G Ep~dote-anda~usite-hornblende zone. Near H a hornblende-~ch layer occurs .

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- 106 ~- In ibit ~ ~. - _ In sect~ an IIl: . . - . . :: AS D2.. D2-~2 - Stauro~it;e-epidote-~ndalusite zone containing 35~0 epidote' . 20%.anda1us~e,: 8% staurolite and further zircons. tourmaline ad rift 1~. .i . ;. . , ~ Zi ~con-epi dot e zone Hi th 60% ep i dot e and further zi rcon, : tome am :cuti:le* leaky sales of Chin zane^¢ontaix~ traces . ~ < -~%) of andalus' to.. ~ . :E:2-Gz . . I;pidote-andalusite zone with 15-60/0 epidote, 0-15% andalus~te and further zircon, Coaling and rattles . Above G :Ep~dote-andalusite-hor~blende zone Pith 35,a7o epidote, 15% 2 andaltu~-te, 5-85% hornblexrd~e and ~-rt;her z:LrcorL, Routine and Futile. Near H2 & ho:~blen~de-r~ch zone has been found. . . . ... . . . . . . ; . ... In section IV: . .. . . · . . . . . . Only a s~11 part of this :sectiQ~; is give:: in order to show that andalusite-rich sands ( 60% of a=ial7~s~te) occur in ~ the northern part of Cast Java. ~ lines which Protect the Points marked with the Sam letters, e.g., -;;4 and ~ or Dl, ~ arid D straw top and botton.of. the -~x~inera]: zoners These: zones are parallel to stratigraphical zoned leased oral. other correla- tion methods, so that there is nc, doubt that the sediments occurring between suc.cess~ve lines, em;. j D .-E1 in section ~ and. D-E in section I3:, w.~e deposited in the Cue ~ g;eological time. If we -compare the m~neralog i c al coat or`t of the spaces store heavy. nuneral zones in the four sections the mineralogical composition of th~ . original materials and the places where they.entered the East Java basin can easily be found: ·, ; . 1. Zircon-ri¢~ ass;oci;at~ontcont~ni~ 70% of zircon and further tou:m~aline, Futile arLd-~*tan~te. This associLatic~Q is free of iep~dote, s'taurolite acid andalusite and orally occurs in section I from ~ and in ~ few thin layers in~ section I-I, erg., near Cc As it is not present in sections in the : western, noxth;~m and eastern parts of the basing it must have been derived: :trctn tlie SO~the * · . : ~ , .; ., . . ~ . . . ? Staurol~te-zircon association with about 15io staurolite and further zircon, tou~al~ne, Futile and t~tanite. antidote and a0da~te are absent. Ill only access ire section I be- *ween - -pi and in th;in lays section IT between ~ and D. ... ... ;

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Exhibit ~ _ ~ _ . , _. -- 107 -- 4. Me source of this association must tore Mar occurred south or southeast of section 1. ndalusite-rich associations containing 60% of andalusite and without apidote only occur in section IV. It moist therefore originate from the north. Ep~dote-rich association. Lois es sociat~on containing 70% ep~dote Is free of staurolite and andalusite In sections to the rest of the cross section given In fig. 1. As it is not present irk sediments in the eastern and southern part'; of the basin, the origin most be in the western part of the basin. . Hornblende-r~ch associations With lOOfo hornblende and White occur in the ok layers in section I above GO . In the other sections only thin layers have been found. A volcanic area occurring south of section ~ must be the source of the associatiaDrt. After the origin of the original mineral associations has been found, their geographical distribution throughout the basin can be deterr~in- ed ~ Tf, for instance, we take the time ~ntervaI between A and D it is known that staurolite-z' rcon associations were supplied from the South, epidote~riah from the West and andalusite-=ch associations from the North. Zone A-D in secti on II, howovor ~ contains ep~dote-staurol~te associations. The percentage of erudite in succeeding samples varies considerably. As the original opidote association is tree of staurolite, the epidote-staurolito association roust be a mixture of the staurolite- zircon and the ep~dote association. ~ these refixtures may contain varying; proportions of both components Ire different layers, the percentages of epidote, staurolite am Or con will also crazy. At two points in zone AD (section II) pure staurol~te-z~:rcon associations were found, viz.,. near C. These thin pure staurol~te layers represent wedges of the Staurol~te zone of section ~ (:L-D1) which dies out towards the North and Vest. In the St~roli~ zone of section T (4-D1) a few thin layers containing opidote were found. These are wedges of the antidote zone of the western area. The Staurolite and Apt dote zones ix~terfinger in th each other in the area of section II. . . .. In the overI=ng zone D-:S zircox~-rich associations severe supplied from the South arid ep~dote-rich associations were deposited in section III , . .

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-- 108 - ~ D~ ) and . i n ~ octi ons . further West ~ ~hibi ~ ,g'! ___ _,, . .. ,. _ . . .. . . ~ i;. . In Section IT considerable change in the mineral composition was also found. Tile ep~dot¢ percentage Between :D and E varies from 0-60%, which -at be the remit of the refixing of zircon-rich and epidote-~,ch associations in ditterent proportions. Thin layers free of epidote are present and repres~e~t wedges of the zircons rich zone of section T. This again points to an: inte.rti~gerir~ of two mineral zones, this time the Zirco~-.rich and the Antidote zones. . Other "mixed"' sediments occurring in the sections IT And IRIS e.g., in the :E;pidote-andalusite-hor~ler~de zone (above G am Go. respectively) can be e2~\ai~ed in a similar way. This proves the assumption:made above, viz., that near the source pure mineral association (derived from this sa.urce) occur and that fu~- ther inside the basin "mi~:ed" associations consisting of mated don different Sources are present. :F¢rthe~ore, it has beers found float mind zones intert~nger WIth1 each other. . . ~ i, The vertical and horizontal distribution of heavy mineral associa- tions in the :East Java Tertiary is .~i~.t.an ;e;i~:ceptional case.; The same [eaters have been found in every area so far steadied for the heaver Minerals and they are of major importance for the interpretation of heavy mineral data. The conceptions found above are the tollowi~: : · · . . . · · - .. .. . . . . .. . . . . . . . . . 1. A sedi;~ent~$ defined as an "'Association of detrital minerals". Thins &~ition Isis consciously made ignoring; the consists of organic origin, much is the palaeo:ntologistts sphere, and those o* comical origin. For sedimentary petrological: investigations the following thus of mineral associations should be dist~gu~ed: A: Original or pie m3he~1 associations. . B: ~ }~:~ed ~era] associate cons. .,, ~ , · . . . . . . . This distinction is rather arbitrary, as i t depends on the problem in hum. If marine deposits are examined regionally, "original" .sed~mentary mate: id the detritus supplied: to the sea by each river and "mixed" mat~i~:.~t which has :~een forded in the sea by the maxim; of two or more of the pure associat~o~is supplied by the rivers. It, however, we are concerned with; the - study of the bott~ samples of a l~:ege river, Allen the material transported in its tributaries is the original and the Thermal in the ~in; river is called £; 2. ~ comple:~ of sediments which by their geographical distribution, age and origin to~s ~ natural unit is called a "Sedimentar.y-petrolo~ic~ pi tBa~rin' 1931 5) .

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Prohibit- G -- 109 -- 3. In a strat~graphical or `3eographica1 sequence of sediments the following changes in the mineral Composition can be distinguish~L: `) Chance Vari ations ~ ~ _.__ Owen to physical and chemical conditions during transportation and deposition, no sediment cantultil the ideal of beers entirelyhomo~ geneous and deviations front the average composition will Ways be found. The larger such deviations are, the less frequently they are encountered. The observations made, therefore, approximate to the average. The more sables are coned Britain a certain area or stratigraphic~ section, the better the cause of such deviations con be judged. These variations anal those due to the counting method have . . . been called "Chance Variations". These changes of the percentages lie within narrow limits, as can easily be seen from fig. 1, egg., SOCtiQl1 I, G~-~, section lI, BEG and above H. and section III, D2-~2. B) Pro~ncia:L Alterations latest changes in mineral content are preserve in areas which are situated at the [border of two or more sedimentary Metrological provi:n¢es. During the deposition the area in mention fell repeatedly within the spheres of intlum¢e of two or more supplies of ~neralog' ca;Lly different material, wretch resulted in an intert~ngering of the heavy :mane~als from the two zones. The changes in the minemlogica~ c=~posi- tion (provir~cial alternations) of this type are ~llustrat;ed in Fig. 1, e.~., in section II between ~ and :E. ~ These ~ in mineral content co~ohly coincide with c:ha:ng;es in grain so. This is reader underst~dable~ as :the sedimentary ~ ~ v ~ ~ ~ ~ matinal of the alternating layers ~ s of different origin. Many investigators consider these Aviations In mineral compo- sition as a result of.grain size differences eyed ~ the sorting effect of current am wave action. We latter variations, however, Ball under Chance variations", as they remain Ashen narrow fits. Here it must be mentioned that mechanical analysis without preceding mineral examination of the sediments cannot have much value for comparative sedimentary studies. First the mineralogical: examination must decide whether the source of the sediments is the same or not and whether the sediments represent original or mixed material, before charges in grain size regencies can be understood. C) Provincial Accession. Within a sedimentary Metrological province only chance var~a

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~ - ~ - - Rio - ~. r Inhibit -G ~a _ toxoids occur. In Te:~ti~xy strat~;~aphiml sections, however, a certain evolution of th;e mineral composition has been found, resulting sometimes in a succession of :;enerall~r tick mineral cores, e.g. ~ in Alp. I, Secti.cn I, DlEl, I:lG1 aced G1\ ~ :3etween the succeeding mineral Z0~8S transit~on~i layers are present. During the time in which a transition zone was formed the old -simply of, for induce, epidote-rich material ended ~d a Phi supply of, ~say, andalusite-epidot~ material bras distributed through the basin, or the old supply continued to exist hut a new supply of abdalusite-bearing . . .. . - ;=ter~dI was added and mixed with the old material. The resulting mixture built up an ~idote-arldalusite zone, erg,, Fig. ]:, Section lIl, D2li: Ed 2 ~ cot . ,, . . . Th:e conceptions '"Provincial alternations'' and~rovincial succession" have the same minim as nAbno,~al and; I~oa:,nal variations" respectively, which have been used in earlier papers (13-16~. The latter sesames have been dir;carded, as they were misunderstood. . . . . . . .. . . , Only it we understand the above principles shall we be able to separate the or~gi:nal mineral associations present: ~n ~ basin; from the mi red as so ci ati ons . . ,. ; Now assuming that we have only examined section II of the East Java basin (rig. I) for heavy minerals, we so try to find tile minemlogi Cal composition of the materials originally supplied to tibias basin. . . . .. . . Studding petrographic Section i] (~g, i) in Arcadia strati- graphical order, the following data can be found: . ~ . . . . . . · . . 1 . Between ~ and D alterriating opt dote~staurolite ~ near B ~ Ed st~rol~te-z~rcon layers (near C) able present. This points to Provincial alternations" between op~dote-rich and stauroli:te~zircon material. The changes in the ratio epidote-staurolite, Liz., near A, B. C and D, suggest ~:~:ing of epidote-rich and staurol'%e-zircon material in diverge proportions. The concI.usion i'$: Section II is situated at the borders of the :E~idote- a~ Staurolite-z~n provinces. ~ At least . . . . two original: mineral associations haYe beer; supplied to this basin, viz., an ep~ote-rich association with at least 60% epidote Ad a staurolite- zircon association with at least log staurolite. . . . . . . . . · . . . ... . · · . . 2. Between I) and :E alternating epidote-rich Ed zircon-rich layers Occur. Staurol~te, which is present ire practicaIly =11 sediments below D, ~s absent between D and I:. Provincial alternations are ~present. Conclusion. - The section imst be located on: the border of the bp~dote Sand Zircon-rich provinces. ~ third original mineral association can be distinguished, which has been called zircon-rich association.

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Exhibit ~ a_ an= _ -- 111 -- lye Staurol~te-zircon association found between A and D is probably a mixed association (st~ro1ite association arid zircon associa- tion) . 3. Between ~ and G epidote-andalusite associations are present. The percentages of epidote and andalusite vary independently, e.g., near the opi dot o-andalus~te ratio is lo, at G and above E it is ~ and 3 respoctivoly. This mews that epidote =d a~dalusito-boari~ curatorial have been me ed in Margin proportions. Conclusion: It is probable that Origim1 andalusite associations with at least 155 andalusite will be found anywhere in the basin In tolerations of the same age as those between E and ~ In S<3cti on II . 4. Just below X a ho~blende-augite layer occurs. This is no doubt an original association. fixture of this association to ep~dote- ~dalusite-bearing material ~ s found between ~ am :3:. From one stratigraphica1 section In this basin it has been possible to find at least five original mineral supplies: ~ (l) Zirco~i-r~ch association with lOO5o zircon, tou~line, Futile arid titivate. (2) Staurolite-zircon association with about 105 staurolite; further zircon, tour~.~aline, Futile and titanite. Andalusite association, containing probably rare than loo andalusite and flirt her zircon' tore, Futile and perhaps mall percentages of staurolite am epidote. (4) :$pidote association w'th more there 60% of epidote, further zircon, tou:~=alir~e and rattle. . Hornblende or hornblende-augite association with 100% hornblende Bald augite. When we compare this list of associations with that of the asso- c~atio~ actually present In the Tertiary of East Java (pp. 106~-107) only the composition of the original andalusite association is much different. It we had shamed the sections ~ or III in the same manner the sane original mineral associations would have been found. rioting the nag mineral associations present ir! ~ sedimentary basin, we ~st fry to locate the places where these associations entered the basin. This car. be done by 3;nvesti.~ti~g more stratigraphical section along the border of the basin, or the origin may be deduced from 'geological data ad reedy available. For 13a st Java, for example, the source of the andalusite association s'nculd be sought in the andalusite

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-- 112 Exhibit G _ _ beatnik schists of the Sch~;aner Gebsr~te (central Borneo) and the volcanic area to the south of the basin Imps ~ be the origin of the hornblende-augite associations. The definitions given abme are also applicable to sedimentary Metrological investigations of recant continental and marine sediments ana have Ready been used by Ede~rmn and Bask (11~5 Ed 2~. In these investigations we always Bind the sedimentary petrological provinces side by sidle. Lowing from the investigations of st:~graphic~ sections that in the area bordering the provinces ~?ro~incial alternations' - or, in other words, overlaps or interfingeri:~ - of both mineral groups occur, it wil' be clear that on the recent sea floor the mineral provinces also overlap each other. Methods i_ The method designed b.,r :l~de1~= in 1928 and used in the B.P.~. Idea 1~7ineral Laboratories for economic, and ~,~,r ~d(3ImaD and his students [or scientific problems follies the following rec~uireme:~ts: The method must be uniform arid applicable to the ex.~i~a- tion of End, sandstone, clay, linestone, dolomite and other rocks. 2. The results obtained lty different investigators rat be comparable. The meted trust not be tedious, as many samples List be examined, in coder to understand the variations present. lhe main outline of the treatment of the scruples used bar the B.P*~. is as follows: 1. Card-indexing. 2. to croscopi c des cri ption. 3. Bifocal of contaminations present at the surface of the samples ~ dri ~ ling mild ~ . 4. Estimation of size ct sample nocessar:- in order to obtain a suitable heavy fract~cn. 5. Crushing of hard rocks Stones Ed marls only to 1,/~t' pieces). 6. Solution of li':~estonos and marls with cold I~C1 (25~)e

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Inhibit ~ _ Re _. -- 117 - and named accordi~lyc Some heaps alto coin pieces of rocks. These too are useful for correlation. Ihe finer light fraction met equal ~ ~ O.25 mm) mined by means of a petrographical microscope. cante deter The ~s tinction between quartz and unt~ir~ned [eldspar can be :~add accurately but the universal stage method (Douglas, 8) Heavy =~=al Tables and Graphs. The results of the counts arc given in tablos. Tho most convenient way to compare sodimer~ts ~s based on vari ations of the percontagos of those non-opaque minerals who ch ago not soluble in warm HOl and H~Q, so that every type of sediment can be compared. The3perc~tage of this group of minerals shout d therefore always be given in reports on hover mineral studies. In scme samples other heavy ~ne~l$ may be important, A.;., opaque minerals, biotito ma apatite. ~ The percentages of these minerals with respect to the town number of groins present in the loran' mineral slide Would be given In addi tion to the percentage of the mn-soluble transparent grains mentioned above. It necessary, the percentage of these minerals with respect to the soluble grains can be calculated. ~ _ If the percentages of the light fraction have been dete~in- ed2 these can be given as an addition in the same manner. The percentage of the :heavy fraction with respect to the entire sand fraction can be added as a percentage by weight, or the determination of the light fraction minerals -can be based on the material not separated in bromoform, the heavy mineral percentage being determined by counting. The latter method Is better. After the variations of the mineral percentages in a section or series have been studied =~ the mineral tables, it is nearly always found that certain mineral species are present ~n all Bangles, e.g., zircon, tou~aline, rude. These are called non-diagnostic minerals. The percentages of the other mineral Species (diagnostic minerals) are plotted graphically in ~ petrographical section. After many experiments the type giver in :Fig. 1 has teem selected, as this method can be used for cross sections aid for repre- sentation of mineral ~da" on maps. ..

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- - - 118 -- Exhibit ~ ~_ Definite colors or hr~tch,~;s are need for garnet, epidote, staurolito and hornblende, as these m~norals are important for correlation Purposes In many areas. The colors and hatchers for other minerals may be changed, as it is important to use distinctive colors or Matchings Ma graphs and in every area other mineral species are important for compel son of s edimentary groups . Percentages below Rio are nof; plotted in the graphs as they are not use ~n ~ preliminary stage of investigation. There- fore tables with mineral percentages should always be inch deaf in reports or papers. It it is found afterwards tat ~ manor constituent ray give additional Notion, the slides are studied again and the presence or absence of this mineral is rioted in the tables and shown by a colored line on the right side of the graphic section . So tar, however, we have met only a few samples in Nigh any definite help was obtained from these minor constituents. Such samples represent problems in areas that have been worked out in detail, where we knots the source end the horizontal a?rx3 vertica:L distribution of nearly each ~nine:=l. Conclusion . . The aim of this paper is to show that the doubt still exist- ing in the minds of may sedimentary petrologists concerning laboratory method and interpretation of heavy mineral work is not justified. The examples given in this paper have been selected from many others all givi:E~g similar results. From the examination of 60,000 sales of many stratigraphical sections in d~feren-t parts of the world it may be concluded that: l. Percentages of minerals determined by the line counting method are more in accordance with percentages by volume or weight and less sub ject to the human element then those obtained by counting minerals prese::~t in fields. Furt~e~ore, each grain to be determined occurs in the center of the find, width ~ s very conv~imt. 2. Ire non-opaque minerals, which are not soluble in wann TICK (25%) and IN (50570), are most suitable for the distir~tion of sedimentary groups, as they can be separated from eY<3ry type of sedi- ment. The values for this Group is ~2~es of the _on~ague a~ ~ . . ~ ~ minerals) therefore should always be included in reports and papers. ., - ~... . . ~

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Exhibit G _ -- 119 -- 3. The perce:lt~s of the other heavy minerals, edged opaque, biot~te, apatite, etc., when determined, should be g;ive:n In addition as percentages of the entire heavy fraction. . . 4. The examination of more samples within a; certain area or stratigraphical interval gives a greater improvement in final results than counting more than 100 non-op~que grains per slide. 5. Variations in heavy mineral percentages due to the influence . . , of grain size and to cc~unti~ only a small number of grains kc within narrow limits. 6. Variations in the p~c~e3 of mineral Species present in different sed~mer~ts within a certain area or ~i~hi=1 section are ~_ . . generally due to the presence or Axing of detritus of ditterent ~ , _ _ . 7. The distinction between t'orig~al" (pure) and ~m~xedt' mineral Lesson ations ( sediments) is of primary importmce for the interpretation of the mineral results. This distinct' on can easily- be made when the sedimentary-petrological investigation is made on a removal scale. 8, The distinction of "original" and 'nixed' mineral associa- tions present in ~ certain area and the acknowledge of the proportion of the originalmineral associations present in the "mixed" associations in different pits of the area (variations in the percentages of the minerals) leads to the final conclusion, wall ch comprises: the localities of the sources of the "orig~r~al" mineral assoc~aticns, the geographical and stratigraphical distribution of each association and of their mixtures and of the relation lbetv~een the different mineral provinces. 9. The heavy mineral fraction of only one grade is investigated in order to avoi d variations in the mineral percentages. As these variations are very important for the ~nterpretat~n of the results, this manner of investigation is not justified. The mineral ~nvestiga- t~on of different grades of one sediment complicates the interpretation considerably. . . . . . 10. Heavy mineral studies should always be made first on a regional scale. The examination of fear Apples over a large area or . . . . . . . strat~graph~1 period discloses the presence of different sedimentary metrological pro~nces~ax~d zones. More detailed work done afterwards . . . . gives the exact bo~nd~ies between these p=wnces and zones. 11. Comparison of the results of mechanical analysis of sediments should always be preceded by ~ mineral examination, as chances in the grain size frequencies, due to different origin or to mixing of met eria1 from different sources in various proportions, Carl at present only be found by mineral examination. The Hague, Area (3 ~ 1940.

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-- 120 -- References ' .~dree, E. 2. Baak, ~ . A. 3. Baren ~ F. A. van 5. Barren, V. P. 6. Bo~ell, P. 0, E. ?. Barrio O. 8. Dooglas, D. J. 9 . Dryd~, A. L. 10. 11. Eden man, C ~ H. 12. loci bi t G - Di ~ Schwe=~neralien der ~lt eren oberbayri s- chen t~lasse, N.;fb.~n., Beil. Bd 71, lbt. A, pi . 59-120, 1936. Regions petrology of the Southern North Sea, Wagon, Nether ends, 1936 ~ Thesis ~ ~ Bet voorkomerr en de beteekenis van kalihou- dende mi-neralen in Ned erlandsche gronden, Wagen~ngen, Netherlands, 1934. (stasis). Sedimentary petrology of the Somda Sea, Netherlands mast Indies. twill be published in due course). Petrography of the sods and sandstones of the productive series, Transact. A~erbaidjan Petr. Inst., Pap. of general and practical geol., B~11. 1, pp. 1-9S, ~ 931~ :nera:Logy of Sedimentary Rocks, 1933. sedilaBxitpetrographi s che Untersuch~ngen an alpinerL Plussanden; I, Die Sande des Tessin, Schweiz, Bin. Petr. bitt., IX, pp. 235-40, 1929. A reliable and rapid method for d~sti'~ishing Quartz from u:atw~nned fed dear by ~ he u~versa;L stage, Amer, ~in. (in print). Accuracy in percentage represen~on of heavy mineral frequencies, Proc. Nat. Acad. SCi ., CYST, pp . 233-408, i935. ~ statistical meted for the comparison of h - cry mineral suites, An. J. Sci*, Vol. XUX, Up ~ 393-408, 1935. The occurrence of ~.~ss~its ~ S' ~ i con Carbide) in sediments, T. Sed. Petr., Ad, p. a=8, ~931. Pet:co:Log~sche provincies in ket Neder~andsche Ewartair, Amsterdam, 1933.

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Exhibit G . _ 13. Yodels, O. E. 16. Edemas, C . H. & :Do~las, D. J. 17. E~umbein, W. C, & Petti John, F. J. 18. 19. Rub ey' W. M. 20 . Trask, P. D. -- 121 __ Petrology of recent sands of the Rhine and the Reuse in the Notherlands, Journ. Sed . Potr., Vol . 8 ~ No . 2, Up . 59-66, 1938 . . . . Petrologic relations of -the sediments of the Southern North Sea, Recent Brine Sed., pp. 543-47, 1939. :E:rgebui s se der s ed imexltp etro iogi s chen Forschung In den Niederlanden und den ar~grenzenden Gebieten, 1932-1937, Geol. ~lschau, Ed mix, 1938, pp. 223-266. Bi j drag e to t de p etro logi e van bet Neder- landsche Tertiair, Verb. Geol. Hi jnb. Genootschap ITS Ned. en Kol., Geol. Sects Dl ~ X, lste s tuk, pp. 1-38, 1932. Manual of Sedimentary Petrology, 1938. Die mech~n~sche und mineralogy sche Konsti tuition der Saanesande, Ber. Sch~yz, Nat. Forsch. Ges ., E.2, 1936-lg38. The size distribution of heavy minerals within a i~aterla~d sandstone, J. Sed. Petr., Vo.1. 3, pp. 3~29, 1953. Symposium on recent marine sediments, 1939. · ·. . .. . . . Note: Tn reproducing Figure 1, which.follows, it Was necessary to divide it into two parts due to the sr.:all scale of the original. P.I).T.

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YOUNGER TERTIARY, EAST JAVA N.E.I. \/E~TICAL SCALE 1 :1.000. SECTION I SECTION m 0 20 40 60 ~ t00% ~ , 1 , I . I , ~ · I ~H' 0 20 40 60 ~100 ~ SECTION 1T to ~5 or 2p ~G1 \ ~ \ 24 \ ~ . z7 \ OF \~ ~ 1 32 1 Z2 1 / 33 3¢ / /H ~ > I G - --F .,, , ~ TV -~2 G2 PALAEONTOLOGICAL ZONE 5 -- Upper half FIGURE I

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YOUNGER TERTIARY, EAST JAVA N.E.I. \/E~TICAL SCALE 1 :1.000. SECTION I SECTION m 0 20 40 60 ~ t00% ~ , 1 , I . I , ~ · I ~H' 0 20 40 60 ~100 ~ SECTION 1T to ~5 or 2p ~G1 \ ~ \ 24 \ ~ . z7 \ OF \~ ~ 1 32 1 Z2 1 / 33 3¢ / /H ~ > I G - --F .,, , ~ TV -~2 G2 PALAEONTOLOGICAL ZONE 5 -- Upper half FIGURE I

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YOUNGER TERTIARY, EAST JAVA N.E.I. \/E~TICAL SCALE 1 :1.000. SECTION I SECTION m 0 20 40 60 ~ t00% ~ , 1 , I . I , ~ · I ~H' 0 20 40 60 ~100 ~ SECTION 1T to ~5 or 2p ~G1 \ ~ \ 24 \ ~ . z7 \ OF \~ ~ 1 32 1 Z2 1 / 33 3¢ / /H ~ > I G - --F .,, , ~ TV -~2 G2 PALAEONTOLOGICAL ZONE 5 -- Upper half FIGURE I

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YOUNGER TERTIARY, EAST JAVA N.E.I. \/E~TICAL SCALE 1 :1.000. SECTION I SECTION m 0 20 40 60 ~ t00% ~ , 1 , I . I , ~ · I ~H' 0 20 40 60 ~100 ~ SECTION 1T to ~5 or 2p ~G1 \ ~ \ 24 \ ~ . z7 \ OF \~ ~ 1 32 1 Z2 1 / 33 3¢ / /H ~ > I G - --F .,, , ~ TV -~2 G2 PALAEONTOLOGICAL ZONE 5 -- Upper half FIGURE I

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YOUNGER TERTIARY, EAST JAVA N.E.I. \/E~TICAL SCALE 1 :1.000. SECTION I SECTION m 0 20 40 60 ~ t00% ~ , 1 , I . I , ~ · I ~H' 0 20 40 60 ~100 ~ SECTION 1T to ~5 or 2p ~G1 \ ~ \ 24 \ ~ . z7 \ OF \~ ~ 1 32 1 Z2 1 / 33 3¢ / /H ~ > I G - --F .,, , ~ TV -~2 G2 PALAEONTOLOGICAL ZONE 5 -- Upper half FIGURE I

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-Al -F -A ~ lc in -A JJ~ / /' I ~ ~ /'g I /// , ill / 1 ' I ' 1 ' I ' 1 ' I / 100 % so Go To 20 o -a -A LEG EN D E:3 fife ~ Ando/us/Xc ~ firm /ef? To r/~hf SIouro/'fc J /-Jom0 - e ~ J tar r/~hf To /oh ~ ~rr"/r/rg At~r~r~/s ~ S~m,o/~s /r~v~s/~9d>~ - D2 SECTION TV :: . l l Lower half FIGURE 1

Representative terms from entire chapter:

mineralogical composition