Oct., 1914
T H E J O U R N A L O F I N D C ' S T R I A L A N D ENGILVEERING C H E M I S T R Y
8.3 7
eastern p a r t of Pennsylvania a n d is included between t h e parallels of 40' 30' a n d 40' 45' a n d t h e meridians 7 5 ' I j' a n d 7 5 ' 30' west, covering a n area of a b o u t 2 2 6 s q u a r e miles. I t lies in Lehigh a n d N o r t h a m p t o n counties with its southeastern corner in Bucks county. Most of t h e rocks in this section are more or less crystalline, being either sediments which have changed t o slates, quartzites, schists a n d gneisses b y varying degrees of metamorphism, or igneous rocks, such as granite a n d diabase which have solidified from a molten magma. T h e basal complex1 of t h e region consists chiefly of gneisses a n d schists. Following t h e formation of these deep-seated rocks occurred a long period of erosion, after which a portion of t h e land was submerged beneath t h e sea, a n d s a n d , gravel, mud a n d TABLEVI so11 Time Cc. Ba(0H)z G. Parts per Pounds per calcareous ooze were laid down in t h e form of marine 14-4-16 Minutes. used bv soil CaO million acre foot sediments. I n these deposits, now hardened t o sand1,946 5,838 20 24.32 0.04864 25 g. 1,063 3,189 0.02658 13.29 and stone, conglomerate, shale a n d limestone, are t o be 590 1,770 7.38 0.01476 50 cc. 318 954 3.97 0.00794 seen fragments of waste from t h e igneous a n d metaBa(OHh J 63 189 0.00158 0.79 90 morphic rocks of t h e adjacent land. Those s t r a t a are 20 2,870 8,610 0.07172 35.86 40 1,705 5,115 0,04262 21.31 not continuous sheets, for portions of t h e sea b o t t o m 1,060 3,180 60 0,02648 13.24 75 6.99 560 1,680 0.01398 were, a t times, uplifted into land a n d t h e sediments 3.12 250 750 0,00624 90 14-1-109 0.10833 4,333 12,999 t h a t h a d been deposited were subjected t o erosion, 39.90 2,639 7,919 0.06597 25 g. soil 24.30 while other portions were still submerged. The sea and 0.037466 1,499 4,497 13.80 1 8 7.41 50 cc. 805 2,415 0.02012 in which these sediments were laid down was a body 503 1,509 4.63 0.01257 Ba(OH)z 20 0,092005 3,680 11,040 33.89 of water occupying t h e interior of t h e American con0.04447 1,779 5,337 35 16.38 7.46 tinent a n d its eastern shore oscillated back a n d forth 810 2,430 50 0.020254 0.42 0.001140 46 138 65 across what is known as t h e Appalachian province. in 29 87 0.27 80 0.000733 t h e eastern part of which the Allentown Quadrangle is T h e figures shown are for t h e t o t a l t i m e given. As more a m m o n i a was freed t h e barium hydroxide held situated. Submergence began a t least as early as t h e b y t h e soil was decreased until a t t h e e n d of 80 or 90 Cambrian, probably as early as t h e Algonkian, a n d minutes i t h a d been decreased t o a n insignificant continued t o t h e close of Carboniferous Time. Several great cycles of sedimentation are recorded a m o u n t which in t h e acid soil might have been reduced t o nothing if a blank h a d been r u n on this soil. T h e in t h e rocks of this region. T h e first sedimentary t o t a l volume of distillate was a b o u t 450 cc. a n d was r o cks-c on gl o mer a t e s , sa n ds t o ne s an d sh a1e s- we re distributed among t h e aliquots a b o u t in proportion laid down early in Cambrian time along the eastern border of t h e interior sea as it encroached on t h e sinking t o t h e time of each separate collection. A brief survey of t h e d a t a presented seems t o es- land. As the land was worn down a n d erosion became tablish t h e fact t h a t t h e lime requirement found b y t h e less active, t h e sediments became finer until in late m e t h o d of Bizzell a n d Lyon is proportionate t o t h e Cambrian time very little mechanical detritus reached b a r i u m hydroxide used a n d not t o t h e acidity of t h e t h e sea a n d t h e deposits were mainly carbonates of soil. T h e lime requirement is considerably lower t h a n lime a n d magnesia. This condition continued into when t h e Veitch m e t h o d is used. T h e lime require- Ordovician time with no marked break in sedimenm e n t varies with t h e length of time of t h e distillation tation. During Silurian time, however, great beds a n d volume of distillate until a zero lime requirement of quartz s a n d a n d pebbles were laid down over t h e limestones of t h e preceding age. T h e Carboniferous is obtained. No consideration of t h e speed of a method is worth began with t h e formation of marine deposits, in large while when i t s performance is such as is indicated b y p a r t limestone, which, in t h e southern p a r t of t h e this s t u d y . However, t h e experience in this laboratory province, are of great thickness. T h e sedimentary rocks of t h e Quadrangle are those shows t h a t a t least as much attention on t h e p a r t of laid down in pre-Cambrian, Cambrian a n d Ordovician t h e operator is needed for t h e m e t h o d of Bizzell a n d Lyon as for t h e Yeitch method. T h e time consumed time. T h e pre-Cambrian formations of t h e Quadrangle are in evaporating, a n d so forth, does not enter i n t o conknown as t h e Shimer graphite schist a n d t h e Franklin sideration when a chemist has other work in progress. limestone a n d are of no importance in this investigation. DEPARTMENT O F AGRICULTURAL CHEMISTRY T h e Cambrian formations are known as t h e H a r d y UNIVERSITY OF MISSOL-RI, COLUHBIA -ston quartzite, t h e Leithsville limestone a n d t h e BllenA STUDY OF THE DOLOMITIC LIMESTONES OF THE t o w n limestone. ALLENTOWN QUADRANGLE Of t h e Ordovician formations, t h e only one of imBy SAMUEL H SALISBURY, J R , AND GEORGEC. BECK portance t o us is t h e Coplay limestone. was such a s t o raise t h e question whether t h e lime requirement could not be varied b y t h e length of distillation of t h e ammonia. Some of t h e samples a t t h e e n d of 2 0 minutes h a d used up all t h e hydrochloric acid in t h e receiving flask, showing a n alkaline reaction. Five cc. more of acid were a d d e d a n d again t h e solution in t h e flask t u r n e d alkaline a t t h e e n d of 2 5 minutes, necessitating a second addition of acid which was largely used up. To f u r t h e r test this continued freeing of a m m o n i a , some determinations were made a n d t h e distillate was caught in different receiving flasks b y means of a n a d a p t e r having a two-way stopcock between condenser a n d receiving flask. About 450 cc. of water were used a n d a n 800 cc. Kjeldahl. T a b l e V I gives results on b o t h t h e acid a n d alkaline soil.
1 ;!
Received June 16, 1914
T h e Allentown Quadrangle is located in t h e extreme
1 G. W. Stose, ~ ~ e r c e r s b u r g - C h a m b e r s b u rFolio, g Geofogiral Allac of the United Stales, No 170.
838
T H E J O U R N A L O F I N D C S T R I ‘ 4 L i l i I T D E,VGINEERING C H E M I S T R Y
T‘ol. 6 , S O .I O
a n d resting unconformably upon the pre-Cambrian gneiss which forms t h e basal complex of this whole Conformably overlying t h e Hardyston quartzite there is a layer of limestone some two thousand feet region. These beds of sediment consist of successive thick, known as t h e Leithsville formation. There is layers of Hardyston quartzite, Leithsville limestone, abundant evidence t h a t this limestone was laid down Allentown limestone a n d Coplay limestone, all conin shallow water; t h e finding of ripple marks a n d sun formable with each other. Across the quadrangle, cracks in ‘shaly layers, t h e occurrence of shaly layers separating t h e Allentown limestone from t h e Coplay having a wavy structure which probably indicates t h e limestone, there exists a local fault line which probably surface of beds eroded b y wave action a n d the presence originated when the gneiss, which forms t h e Camel’s of sandy layers interbedded with t h e limestone. all H u m p , was thrust through t h e sediments. The oldest rocks in t h e area are t h e pre-Cambrian lead t o t h e presumption t h a t t h e water could not have gneisses forming t h e ridge known as South Mountain h a d a n y great depth.. Fossils seem t o have been entirely absent from this formation a n d rather suggest a n d presumably underlying t h e whole area. These rocks were probably formed by a sediment which grew t o a chemical origin for t h e limestones. a thickness undetermined and in a period not definitely A L L E N T O W N LIMESTONE1-The upper half of t h e known. The beds were subsequently uplifted a n d then Cambrian limestone is more dolomitic t h a n t h e Leithsdepressed, t h e depression became filled with water and ville formation a n d consists of a dense bluish rock, during t h e long period following, t h e sedimentary which is very .hard a n d brittle and does not effervesce rocks-the Hardyston quartzite, Leithsville limestone, with cold, dilute hydrochloric acid, b u t usually gives Allentown limestone a n d Coplay limestone-were laid a strong kaolin odor when breathed kpon. The only down. During this period of lime deposition t h e fossil t h u s far recognized in this formation is C r y p t erosion of t h e surrounding land was probably very small, ozootz Prolijerum, which occurs in rounded heads varyor a t least little land derived material was transported ing in diameter from I inch t o 1.j feet. One of t h e t o this region, and, since wave marks and various other principal characteristics of t h e Allentown is t h e layers indications of shallow water occur in t h e area, t h e sea of oolite which are commonly found in this formation which existed here could not have been of any great closely associated with t h e fossils. As in the case of t h e depth. However, t h e occurrence of thin shaly s t r a t a Leithsville, i t is known, by the conglomeratic basal (see samples 7 a n d 1 2 , Quarry “ E ” ) , a n d scattered s t r a t a a n d other evidences. t h a t this limestone was laid seams of sandstone interbedded with t h e limestone down in rather shallow water. hfr. G. I$’, Stose2 shows a n influx of land sediments a t recurrent intervals, suggests t h a t these formations were deposited in interrupting t h e formation of t h e limestone. water so shallow t h a t t h e waves oscillated t h e growing During t h e limestone-forming periods, instead of particles on t h e sea bottom and so produced t h e contransporting mechanical detritus, t h e streams carried c r e t i o n ~ . ~However, t h e Leithsville formation, which calcium and magnesium a n d other soluble salts disshows ample evidence of having been deposited in solved from t h e decomposing rocks by t h e combined shallow water, differing only from t h a t in which t h e action of rain water and carbon dioxide. Some of t h e Allentown was deposited by being more muddy, is calcareous material was, no doubt, secreted from t h e entirely lacking in oolites. sea water by molluscs, corals a n d other types of marine organisms. I n t h e larger part of the deposits, however, 0RD 0V I C I A N F 0R N AT10S T H E C O P L A Y LIJIESToxE-This formation, having a few or no fossils can be found, due probably t o t h e fact t h a t conditions were not favorable t o life in t h e limethickness of 2 0 0 0 f t . , is t h e lowest of t h e Ordovician depositing sea, so there is ground for t h e belief t h a t formations found in t h e Allentown Quadrangle. I t most of t h e limy sediment was a result of direct preconsists of dark blue dolomitic limestone which, i n . cipitation from water a n d was not produced by secret h e hand specimens, closely resembles t h e Allentown tion of organisms. This almost complete absence of limestone. I n t h e field i t is distinguished by t h e abfossils seems t o have been apparently due t o t h e large sence of Cryptozooit Prolijeruw a n d by a laminated amount of magnesium salts present in the water, alappearance on t h e weathered surface of many of t h e though dolomitic rocks found in other parts of t h e beds, due t o their impurities. Fossil remains of cephregion covered by the Paleozoic sea contain large numalopods a n d gastropods are of somewhat common bers of fossils.’ occurrence, but are not very well p r e s e r ~ e d . ~Layers The deposition of rock ended near t h e close of t h e high in lime content sometimes show crystal faces of * Carboniferous period, t h e interior of t h e great sea was calcite scattered through t h e ground mass a n d will effervesce with cold, dilute acid. Near t h e base of raised into land, t h e muds a n d sands were compacted t h e formation are sometimes found silicious, banded a n d t o a large extent hardened by their own weight, b u t t h e compression a n d folding consolidated them beds. into firm rocks and materially altered their constitution S T R U C T U R E S I N THE Q U A D R A N G L E a n d texture. Since t h a t time t h e Allentown QuadT h e greater part of t h e quadrangle is covered b y rangle, with t h e exception of t h e southeast corner. has thick beds of sediments conformable with each other not been below t h e sea and t h e rocks have been sub1 B . L. Miller, R e p o r t N o . 4, Topographic and Geologic Survey of Pa, jected t o erosion during t h e long lapse of time since Mercersburg-Chambersburg Folio, Geol. Allas of the U . S. then. CAMBRIAN FORMATIONS
3
M o n . U . S. Geol. Surv. Vol. 11, 6 1 (1885). 189.
’ B. L. Miller, R e p l . No. 4, Topographic a n d Geologic Survey of
Pa.
1
G. W.Stose, C . S. Geological Ailas, No. 170.
Oct., 1914
D E LVGIAVE E RI S G C H E M I S T R Y T H E J O C R S d L O F I S D C S T R I . I L d *Ir ESP E RI 11E S TA L P A. R T
T h e chemical work in connection with this investigation consists of t h e analyses of some one hundred samples of magnesian limestones t a k e n from quarries so located t h a t t h e whole area is well represented. 8 1 1 t h e samples were analyzed for magnesium oxide from which the equivalent magnesium carbonate was calculated, while a few samples were analyzed for silica, iron a n d alumina a n d lime. From a consideration of the results of these analyses and from deductions drawn from observations in t h e field we beliei-e t h a t the Allentown a n d Coplay limestones of this region viere laid down as chemical precipitates and were not formed b y the alteration of calcium carbonate, although we concede t h a t probably the high percentages of magnesia were caused in part b y t h e leaching a w a y of calcium carbonate. We shall also a t t e m p t t o explain t h e presence of silica in these formations a n d also the occurrence of quartz crystals a t points where no extensive metamorphosis has taken place.'
83 9
cent. Sample -1-4shows a very large increase in CaO with a drop of 0.8 per cent MgO from the average of t h e quarry. This large increase of CaO in Sample L l - 4 over the beds A-I-b a n d A-9 o n both sides of it is significant and will be noted later. Q U A R R Y '(B"
Quarry "B" is located in Northampton county, ' ' ' 2 mile north of Broadheads on the Nazareth turnpike, 4" miles from t h e northern boundary and 1'/?miles from t h e eastern boundary of t h e Quadrangle. This quarry faces t h e west, is j o o feet long and about 3 0 feet high, with bedding and cleavage planes nearly I
Q r A R R Y "A"
Quarry "A" is situated in Northampton c o u n t y , of a mile west of Georgetown Four Corners on t h e Centreville road and is miles from t h e northern boundary of the Quadrangle. As can be seen from Plate I , t h e s t r a t a here are nearly vertical and vary 8
"B"
PLATE 1 1 - Q V 4 R R Y
indistinguishable. as may be seen in Plate 11. Samples were taken every 3 j feet a t various heights from t h e base.
PLATE I-QVARRY "A"
in thickness from 2 t o 8 ft. Near the center some folding and faulting occur so t h a t i t is difficult t o follon- t h e s t r a t a t o t h e t o p of t h e quarry. Sample
A-I-b A-I-c .4 -2 A-3
.i-4 .I-5 .4-6
hlgO 15 . 4 1 1; 14 16 81 18.95 I; 09
16.78 I R no 18.45 18 48 1; 32 17.56 I i i2
AlgCCh
SiOz
32.20 3.5.84 .35.12 39.60 35.72 35.05
. . .
3 ; 64 ,38.54
5.82
R201
CaO
. .
. . . .
1.13
28 19
. . . . . . . . . . . . .
Thickness of bed South face Southface South face
. . . .
10.35
~ : 2 j
. . . . . . . . . . . . . . . . . . . . . . . . . , , . .
A-7 38.74 .A-8 1.5.20 A-9 36 6 5 7.35 3 85 u--10 .3;.04 . . . . . . . A-I 1 18.33 38.34 . . . . . . 2-12 1 7 . 12 35.80 . . . . . . . . . . . . .I-I ,3 18.68 ,?9 00 . . . . . . . . . . . .-\-I4 I 7 59 36.67 . . . . . . . . . A - 15 15.29 31.93 .,.,, , , . , , .%- 16 18.40 38.47 8.92 2'90 27.48 Highest is 11-13-18 6Sc; Greatest difference .3.,39vc Lowest is A- 15-15.29:: .4verage l i . 5 1 c ;
2 ft. 8' 'If t . 2' i it. I ' bit. S o r t h race
These results show quite small variation. considering the number of s t r a t a . t h e greatest difference being 3.39 per c e n t ; yet the difference is large enough in our opinion t o preclude t h e idea of replacement. The average of the CaO seems t o be about 28.41 per
Sample B- 1 B- 2 B- 3 B- 4 B- 5 B- 6 B- 7 B- 8 B- 9 B-10 13-1 I B-12 B-13 B-14 0-15 B-16 B-I7 R- 18 B-19
MgO
19.13 20.49 18 68 19.94 20. I6 19.43 19.98 20.25 2Y.35 2 0 . ~54 20.47 19.75 19.88 19.29 70.37 20 34 19 85 18.79 20 16 R-20 19.00 -~ Highest B-10-20
hIgCOs 39,98 42.83 39.04 41 68 42.14 40.61 41.76 42.32 42 5 3 42.93 42.i8 41.28 41,55
40.32 42.57 42.51 41.49 39.27 42.14
39,il 54%
Height irom base 2.36 3 it. . . . . . . . . . . . . . 10 f t . . . . . . . . . . 20 f t . $176 3.85 28.29 15ft. . . . . . . . . . . 13 it. . . . . . . . . . . . . 3 it. . . . . . . .,. . 25 i t . ... . . . 5 ft. . . . . . . . . . . . . . loft. 8 it. i.ii 1 : i i %1:43 15ft.
SiOa
R203 1.97
CaO 28.89
.... .. . . . . . . . . . . . . ., .
2.45
6193
. . . . . . .
29.50
. . . . .... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..
.
10 it.
25 It. 7 ft. 7 it. ift. 7 ft. i ft. i It.
7 It.
Lowest B-3--18.68CG
T h e greatest difference is 1.86 per cent I l g O and the average is 19.84 per cent N g O . The results here, as might be expected from t h e structure. show less variation t h a n in Quarry "X," while t h e average is 2 . 3 per cent higher. The greatest difference is only 1.86 per cent N g O . this quarry being the most regular in t h e distribution of the magnesia of a n y t h a t we have analyzed. T h e lime content is also quite regular, t h e greatest \-ariation of Zny of t h e constituents being in the percentages of silica. Q G A R R Y "C"
Quarry "C" is located in Lehigh County. nbout one hundred yards north of t h e Coplay station of t h e Lehigh Valley railroad: 3' miles from t h e western boundary of t h e Quadrangle a n d 6 l 1 miles from t h e northern boundary. As can be seen from Plate 111. the beds here are of varying thickness. are vertical, or nearly s o , and some of t h e m are intricately folded.
T H E J O U R N A L OF I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y
840
This latter is quite characteristic of t h e Coplay limestone. Sample c- 0 c- I c- 2 c- 3 c- 4 c- 5 C- 6 c- 7 C- 8 c- 9
c-IO
c-11 c-12 C-13 C-14 c-15 C-16 c-17 C-18 C-19 c-20 c-2 1 c-22 C-23
MgO MgCOa 13.29 27.72 17.54 36.66 15.10 31.56 00.97 2.03 00.76 1.40 16 72 34.95 8.46 17.68 15.57 32.54 15.46 32.31 00.87 1.82 13.76 28.76 No sample 16.98 35.49 16.47 34.42 No sample 15.66 32.73 17.33 36.22 16.19 33.84 14.41 30.12 1.52 3.18 12.58 26.29 16.77 35.05 14.29 29.87 16.64 34.78
Si02
RrOz
CaO
..... .....
.....
.....
15.57
.....
.....
.....
....
42.64 54.58
5.36
32.77
....
....
.... ....
.....
.....
.....
12.38
6.30
53.47 32.34
..... .....
....
.....
.....
.... .... 3.96 ....
..... 6.44 .....
.... 4.60 ....
..... 6.22
..... ..... 6.01
.... ....
5.13
Thickness of beds
......
4‘/3 f t . 2l/3 f t . 8 ft. 15 f t . 21/6 f t . 11/12 f t . 1I/? It. 2 ft. 81/3 f t . 32/3 f t .
ft.
.....
Z1/3
.....
13/r f t . 21/12 f t . 1‘/4 f t . 2 ft. 4 ft. 41/3 f t . 12/3 f t . 1?/3 f t . 11/? f t .
29.22
..... .....
52.48
.....
28.64
.....
29.73
17/11 f t .
Vol. 6 , NO. I O
mine a n d in Plate 1%’it can be seen t h a t t h e beds are nearly vertical while t h e h a n d specimens show considerable weathering. This quarry shows t h e greatest difference in magnesia of a n y of t h e quarries, yet t h e average is within about 0.3 per cent of t h a t of Quarry “A,” located near t h e northern boundary of t h e Quadrangle. These beds are characterized b y rather low lime content a n d high silica. I n particular, Samples I I a n d I 2 show, for reduced magnesia, a n increase in silica rather t h a n in lime, as might be expected. QUARRY “E”
Quarry “E”is located in Northampton County,
T h e highest is C-1-17. j 4 per cent MgO a n d t h e lowest is C - 2 0 - 1 2 . j 8 per cent MgO. This is with samples 3 , 4, 6 , 9 , a n d 19 excluded. T h e average is about 15.58 per cent of MgO. T h e very low per cent of MgO in Samples 3, 4, 6 , 9 a n d 19 can be accounted for b y a n inspection of t h e
PLATE111-QUARRY “ C ”
h a n d samples, each of which shows crystals of calcite scattered throughout t h e ground mass. All these samples effervesce greatly with cold dilute hydrochloric acid a n d the analysis shows t h e m t o be nearly pure limestone. I n connection with t h e high lime, t h e high silica a n d low magnesia in Samples 6 a n d IO are t o be noted. QUARRY “D”
Quarry “ D ” is located i n Lehigh County about l/z mile north of Friedensville, 43/r miles from t h e southern Thickness Sample MgO MgC03 Si02 Rr03 CaO of beds D- I 18.11 37.88 ..... .... ..... 45/6 f t . D- 2 19.60 40.98 ..... .... ..... 6?/3 f t . D- 3 40.15 19.20 6.40 1.39 18.23 5113 f t . D- 4 41.38 1.40 19.79 3.89 28.33 2=/3 f t . D- 5 18.33 38.34 2.31 27.44 8.91 4616 f t . D19.56 40.90 6.75 2.75 28.10 1 ft. D- i 19.00 ..... .... ..... 39.73 3l/6 f t . D- 8 16.80 35.13 .............. 41/3ft. D- 9 16.62 34.75 . . . . . . . . . . . . . . 3112 f t . D-10 16.54 34.59 ..... . . . . . . . . . 6ft. D-I1 12.95 27.08 13.60 3.31 22.75 3ft. D-12 15.59 32.60 13.61 3.48 24.33 211%f t . D-13 17.97 37.58 ......... 4I/z f t . D-14 17.69 36.90 ..... ......... 32/3 f t . D-15 18.62 38.93 ..... ......... 71/3 f t . D-16 16.39 34.27 ..... . . . . . . . . . 111/12 f t . D-17 19.09 39.92 ..... 4 ft. Highest: D - P l 9 . 7 9 % M g O Greaies’t diff&ehce 6 . 8 4 7 , MgO Lowest D-11-12.5570 MgO Average l7.87Y0 MgO
6
boundary a n d jl/?miles from t h e western boundary of t h e Quadrangle. This location is a n abandoned zinc
PLATEIV-QUARRY “ D ”
mile west of Quarry “B,” being a cut of t h e Lehigh a n d New England railroad. As may be seen in Plate V, the b e d s a r e sharply inclined t o t h e north. Thickness Samole Me0 Mac03 Si02 Rz03 CaO o f beds ...... 4.06 29.03 3f.47 E- 1 16.97 12.03 9/3 ft. 4 . 5 3 28.26 8 . 7 1 E- 2 15.00 31.35 25ia f t . 16.62 1.30 12.25 23.93 E- 3 11.45 1’/* f t . ..... .... 30.49 E- 4 14.59 1Z/a f t . ..... .... E- 5 13.60 ..... 28.42 4‘/8 f t . 24.54 8.08 5.39 28.99 E- 6 13.87 l’/n f t . .... ..... ..... 15.85 E- 7 7.58 4’/3 f t . .... E- 8 12.65 26.44 11/2 f t . ..... 32.96 E- 9 15.77 =/3 f t . ..... .... 30.74 E-10 14.71 6 1 / ~f t . .... ..... ..... 34.23 E-11-a 16.38 61/e f t . 8.10 18.08 21.52 27.55 E-11-b 13.18 1 ft. ..... .... 14.00 E-I2 6.70 151, f t . .... ..... 30.60 E-I3 14.64 I/, f t . . . . . . . . . . 30.33 ..... E-I4 14.51 ...... 31.42 3.08 5.20 38.37 E-15 18.36 25lS ft. 33.63 3 . 7 6 2.55 33.45 E-16 16.01 21/6 f t . 20.38 E-I7 9.75 691s f t . .... 35.24 E-18 t16.86 9 ft. .... 31.02 E-I9 14.84 E-20 14.76 ..... .... 30.85 _ Highest E-15-18 36% MgO Lowest E-8-12.65% MgO, excluding Samples 3, 7, 12, 13 Greatest difference 5 , 7 1 70MgO Average 15 1Oyo M g O
.....
.....
. I . .
Samples 3, 7, 1 2 a n d 13 are excessively low in magnesia. Inspection of t h e h a n d specimens shows t h a t
Oct., 1914
T H E J O U R N A L O F I N D U S T R I A L -4 N D E N G I N E E R I N G C H E M I S T R Y
3 a n d 17 contain crystals of calcite throughout t h e ground mass, while 7 a n d 1 2 are clay shales a n d give off a n earthy odor when breathed upon. The difference in content of lime is also t o be noted, ranging from 16.62 per cent in E-3 t o 33.63 per cent in E-16, a difference of 1 7 per cent. There is also considerable variation in t h e silica. CONSIDEI$ATION O F RESULTS
The comparatively small variation in the averages of t h e contents of magnesia in these several quarries, located so close together a n d t h e sharp differences in t h e amounts of magnesia a n d lime occurring in t h e various s t r a t a in t h e same quarry, lead us t o t h e belief t h a t t h e rocks of this section were laid down b y chemical precipitation rather t h a n b y alteration of t h e limestone; a fact which tends t o support this theory is t h e thinness of t h e s t r a t a in t h e various quarries. This, together with the occurrence of clayey layers as in “Quarry E” a n d t h e fact t h a t we f n d ripple marks a n d other evidences of shallow water commonly occurring in this formation shows t h a t t h e Paleozoic sea was very shallow a n d probably receded frequently.
PLATEV-QUARRY “E”
Hence this area could not have been far removed from land, from whence i t would receive, b y drainage, waters containing not only carbonate of lime in solution, b u t also carbonate of magnesia. Provided t h e two carbonates were in solution at t h e same time, the shallowness of t h e sea would facilitate their precipitation because t h e evaporation taking place a t t h e surface would throw t h e salts out of solution while at t h e same t i m e this same shallowness would prevent t h e m from going back into solution as they settled t o t h e bottom. The theory t h a t t h e rocks in this section were originally of marine origin, t h a t is, t h a t t h e y were more or less pure calcium carbonate, which was afterward removed from solution a n d was replaced by carbonate of magnesia, would, in the first place, presuppose a sea of enormous extent a n d great d e p t h : a sea large enough in extent so t h a t t h e waters flowing from t h e surrounding igneous rocks could not carry a n y appreciable amount of magnesia t o this area. During this time, then, limestone would be deposited, not in t h i n s t r a t a , b u t in thick ones, which, as can be seen from a n inspection of the region, d o not occur,
841
I n order t o replace t h e carbonate of lime with carbonate of magnesia, there would be requiied a body of water containing a comparatively large content of soluble magnesium salts. I n consideration of t h e f a c t t h a t in water free from carbonic acid, magnesium carbonate is about sixty times as soluble as calcium carbonate a n d t h a t in water saturated with carbon dioxide t h e magnesium salt is about twenty-seven times as soluble as t h e corresponding calcium salt, we can not comprehend how percolating waters, or t h e lower layers of sea water, can enrich t h e rock with magnesia b y extracting t h e lime. And even if this were possible, due t o some selective action of t h e solution which in t u r n might depend upon its content of other soluble salts, we do not believe t h a t a compact rock would result. This conclusion has also been reached by E. Blackwelder. I n case such replacement could take place i t is reasonable t o assume t h a t such replacement would be quite uniform within narrow limits; b u t in our investigation we find just t h e opposite t h e case. For instance, in Quarry “C,” Sample 2 carries I j . 1 0 per cent; Sample 3 ! 00.98 per cent; Sample 4,00.67 per cent; and Sample 5, 16.72 per cent of magnesia. I n each of these cases t h e content of calcium carbonate fluctuates accordingly, being very high where t h e magnesia is low. Other instances can be seen in Quarries “ A “ a n d “E.” From such evidence we do not believe t h a t t h e high magnesia is a result of secondary action b u t t h a t i t was originally laid down in this condition. I t m a y be a n d probably is t r u e t h a t some of t h e limestone in this region has been enriched in magnesia b y .the solution of portions of t h e lime by percolating waters saturated with carbon dioxide; still why these waters should shun t h e s t r a t a represented b y Samples E-3 and E-4, leaving a high content of magnesia, we can not understand, when t h e s t r a t a on both sides are lower in calcium carbonate and higher in magnesium carbonate. If a n y enrichment has taken place, i t must have been locally a n d did not affect t h e region as a whole. The scarcity of fossils in these rocks is also significant. Both t h e Allentown a n d t h e Coplay limestones are rather deficient in organic forms of life a n d those t h a t are found are not very well preserved. I n a way this proves our contention t h a t t h e rocks are chemical precipitates, for i t shows t h a t t h e original material of t h e rocks has not been withdrawn from t h e sea water b y organic forms of life. While it may be possible t h a t t h e life which existed has been obliterated, yet i t is a well known fact t o biologists t h a t increasing percentages of magnesium salts cause stupefaction of such organic forms as sea anemones a n d t h e like a n d i t m a y well be t h a t waters of high magnesia content are not conducive t o t h e growth of lime-secreting forms of life.2 Another evidence of chemical precipitation is t h e 1 “Origin of the Big Horn Dolomite of Wyoming,” Bull. Geol. S O C . Of Am., Dec., 1913. 2 Tullberg, Arch. Zoolog. E x p e r . et Gen., 10 (1892). 11; Redenhaugh, Amer. Naturalist, 89 (1895), 399; Journ. Royal Micro. SOC.,1896, p. 385; Gerould. Bull. Mus. Comp. Zoology, Harvard, 29 (18961, 123.
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occurrence of oolitic layers interbedded with t h e Allentown limestone and closely associated with t h e only fossil recognized in this formation, namely t h e C ~ y p t ozoon Proliferum. It is conceded by various authorities t h a t these formations are caused b y chemical precipitation' and in addition they are evidences of the shallowness of t h e sea during their formation. A shallow sea seems t o be necessary t o t h e formation of limestone, for t h e ocean depths are covered with red clay. Lastly, even a t t h e present time we have waters which contain comparatively large quantities of magnesia as compared with the lime. For instance, Thresh2 gives analyses of waters which are derived f r o m argillaceous beds of t h e early Eocene period a n d which underlie clays in which t h e content of carbonate of lime ranges from 1.75 t o 3 9 . 0 0 parts per I O O , O O O , while t h e magnesium carbonate ranges from 0 . 3 j t o 1 1 . 7 j parts per IOO,OOO. These figures are in ratios which compare favorably with t h e ratios found in t h e rocks under investigation. I n concluding, then, t h a t these formations were caused by t h e precipitation of carbonates of magnesia and lime at t h e same time, we must consider t h e presence of t h e silica. If our hypothesis is correct t h a t no replacement of calcium carbonate b y magnesium carbonate subsequent t o formation has taken place; also t h a t no enrichment of t h e magnesia b y t h e leaching away of t h e lime has taken place-at least t o no appreciable extent a n d only locally-it must be t h a t t h e silica content of t h e rock was deposited a t t h e same time as t h e other constituents. From t h e analyses i t will be seen t h a t t h e silica cont e n t varies with the amounts of magnesia and lime present. I n most cases we find t h a t low percentages of magnesia are accompanied by higher percentages of silica a n d these are increased! in some cases, by t h e low content of lime as in Sample E-11-b, where t h e magnesia is lower t h a n t h e average, t h e silica is very high a n d t h e lime is much lower t h a n t h e average of t h e lime. If these substances were in solution originally, some such ratios might readily be expected from t h e differences in their solubilities. A n inspection of t h e hand specimens shows t h a t no silica can be detected a n d i t is probable t h a t t h e silica is distributed quite evenly through t h e rock. This, together with t h e variation, tends t o support t h e theory of precipitation. T h a t silica has, in t h e past, been carried in the waters of this region is evidenced by t h e finding of quartz crystals north of Camel's H u m p or about in the center of t h e Quadrangle. The formation of quartz crystals from solution has been noted in many cases.3 Silica is more or less soluble in water.4 the amorphous forms more readily t h a n t h e crystallized forms, and t h e solubility is appreciably increased by t h e presence in t h e water of dissolved carbon dioxide and particularly by t h e presence of dissolved carbonates of t h e alkali 1
F. W. Clarke, " D a t a of Geochemistry," pp. 146, 5 2 5 .
"Examination of Water and Water Supplies." Spezia, G., Jouv. Chem. Soc., 76 (1899). Pt. 2, 300: Clarke, F. \V., "Data of Geochemistry," p. 344; Levallois, F., Ceramiyiie, 1 5 , . 335. 4 Rogers, W. B. and R. E., A m w J . S c i . , [ 2 ] 5, 1848: Headon, W. P., Ibid., [4] 16, 190.3; Hilgdrde, E. W , I b i d . , [ 4 ] 2, 1896; Comey, A . M., "Dictionary of Chemical Solubilities;" Clarke, F . W., " D a t a of Geochemistry," pp, 457-8. 2
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metals and those of the alkaline earths. Dienert' asserts t h a t there is a definite relationship between t h e alkalinity of water a n d t h e dissolved silica which can be expressed by t h e formula x - y = K y . The formation of quartz crystals from a water solution presupposes t h e united action of heat and pressure, both of which can be readily assumed t o have been present. The pressure was due t o the weight of the overlying material, of which it is safe t o say there has been removed by solution r j , o o o t o 20,000 ft. f r o m this region. The heat was due partially t o pressure, but more particularly, we believe. t o friction caused b y t h e upheaval and bending of t h e s t r a t a . I n several places, notably a t Coplay, this bending of t h e strata has been so great t h a t contractions of a s much as from j f t . t o I f t . have taken place. I n such cases enormous amounts of heat must have been generated, enough in several instances t o have caused t h e rock t o have become partially plastic, since in t h e folds a t Coplay no fissuring has taken place even in t h e case of s t r a t a , which have been almost bent back upon themselves. The heat which would cause t h e smooth bending of t h e rock would, in our opinion, be much more t h a n necessary t o produce quartz crystals 'from a water solution, since, according t o hlaschke,2 t h e amount of heat necessary is equivalent t o something over 180' C., and according t o K. Chrustschoff3 2 4 0 ' t o 300' C.. and according t o Ramsay a n d Hunter4 about 200' C. As a matter of interest we have calculated t h e amount of heat t h a t would be.generated by a column of magnesian limestone, 15,000 ft. in height a n d I sq. ft. in cross section, slipping a distance of one foot in a minute. We have taken t h e coefficient of friction t o be 0.6.j a n d t h e specific heat of magnesian limestone t o be 0.217. The amount of heat liberated, then, is enough t o raise t h e temperature of 2 1 7 pounds of rock I C., which, added t o the rise in temperature due t o pressure alone, mould give heat enough t o satisfy t h e requirements for crystallization. ,41so since the specific heat of limestone is high, it is safe t o assume t h a t most of t h e heat would be confined close t o t h e region a t t h e point of slippage. The limestone in t h e neighborhood of the Camel's H u m p and generally throughout t h e region shows more or less metamorphism b u t a t no point is this enough t o indicate the formation of quartz from a state of fusion. From t h e facts and assumption above outlined vie believe i t is safe t o conclude t h a t t h e silica found in t h e region was originally in a solution and was deposited when t h e other materials were laid down a n d was not deposited as a result of subsequent seepage of waters. I n conclusion, we believe t h a t the following facts support t h e theory of chemical precipitation : I-The magnesia content does not vary greatly over t h e region. 1
Compf. vend., 111, i9i.
2
Pogg. .Inn., 146, 549; 146, 90.
d
Amer. Chemist. 3 ( I 8 i 3 ) , 281: Compt. vend., 104 ( 1 8 8 i ) , 6 0 2 ; S e u e s
Jairrb., 1897. P t . I , 240. 4
R e p f . British Assoc. A h ' . S c i . , 1882, p. 239.
Oct.. i g , +
THE /Ol.K
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I I - ~ - T h e s t r a t a iii'c separated at scvcral points by beds of nearly pure limestone. III~--Ferr fossils arc found in the rocks of tile region. IV--The occiirrence o€ ooiitic iaycrs in t h e Allent o x n limestone. V-The silica seems t o havc been in solution and
I
was laiil down v h e n the rest of t h e constituents were precipitated. TI- rvc find bvaters containing carbonates of magnesia and liinc in about t h e samc proportion t h a t we find them i n t h e rocks of this region. La,* I(GT,,LE,
