xt7z348gft8z https://exploreuk.uky.edu/dips/xt7z348gft8z/data/mets.xml Shaler, Nathaniel Southgate, 1841-1906. 1877  books b96-12-34887969 English Stereotyped for the Survey by Major, Johnston & Barrett, Yeoman Press, : [Frankfort, Ky. : Contact the Special Collections Research Center for information regarding rights and use of this collection. Lead Kentucky. On the origin of the galena deposits of the Upper Cambrian rocks of Kentucky  / by N.S. Shaler. text On the origin of the galena deposits of the Upper Cambrian rocks of Kentucky  / by N.S. Shaler. 1877 2002 true xt7z348gft8z section xt7z348gft8z 


         ON THE ORIGIN



               oF nR


        BY N. S. SHALER.


                            277 & 278

 This page in the original text is blank.



The deposits of galena in the Cambrian district of the
State differ in some important regards from those which have
been observed in the sub-carboniferous limestone, although
there is in both cases a general agreement in the circumstances
of occurrence. In both cases these deposits are limited to true
fissure veins of a peculiar type. In both regions they occur in
limestones only, and are not observed in the overlying sili-
cious and argillaceous rocks. The associated minerals in both
cases are substantially the same, though differing in their pro-
portions and general appearance. We are driven by the facts
to the conclusion that all these veins have been formed by
infiltration of water charged with the substances that form
the vein matter, the cavity of the vein having been first devel-
oped by a movement of the rcsks in which it is found. There
are, however, differences of character between the galena
veins of the Livingston district and those of Central Ken-
tucky that compel us to make a strong line between them.
As is shown by the report of Mr. Norwood (see reports Ken-
tucky Geological Survey, first volume, new series), the veins
in the Livingston district very often give indications of abrupt
faulting, and, in some cases at least, of several successive ver-
tical disturbances acting in the same spot. There seems to
have been a good deal of irregularly acting dislocating force
in this region, which did not result in the formation of distinct
mountain curves, but expended itself in the numerous sharp
breaks that have disturbed all this district.
  I am inclined to attribute many of these veins of the Liv-
ingston district to this faulting action, combined with the



shrinking of the whole rock system from the loss of heat
and other changes. The result was the formation of fissures
of possibly great depth, the walls of which gaped apart, re-
maining perhaps closed near the surface, where there was
perhaps only a small contraction, or, possibly, none at all.
The next stage of the process seems to have been the in-
filtration of waters charged with carbonate of lead in solution,
and its deposit by crystallizing action within these cavities.
Subsequent changes brought about still further movements
of the same character as those that formed the cavity at
first, and through them the original deposits were often curi-
ously broke up and mingled with other materials.
   In the Cambrian district, particularly in Henry county, the
tendency to faulting seems to have been much less than in
the western field. All the crevices I have seen do not show
any distinct vertical movement of the wall rocks, but seem to
have been formed by lateral dislocation alone. It is not easy
to determine the causes of this shrinkage in the mass of rock
throughout this region, but the evidence of its occurrence is
tolerably clear at all points. It is manifested in every line of
the section by the breakage of the mass of rock into vertical
crevices, which have become to a greater or less extent filled
with clay and other substances. At some points these crevices
indicate a reduction of at least one fifteenth of the horizontal
dimensions of the rock mass. Generally these shrinkage

  I am inclined to think that the general absence of mineral deposits in all the well-defined
faults which I have seen in Kentucky is strong presumption against the occurrence of exten-
sive mineral deposits in such breaks within this Commonwealth. The Pine Mountain fault,
one of the most extensive and readily observable in the whole Appalachian district, has not
yet given a trace of metallic deposits. The same is the case with the Kentucky River faults.
In the case of the lode near Smithland, Livingston county, that on which the Royall mines are
situated, there seems good evidence of a fault. With this evidence from other fissures I should
feel it necessary to examine with care for evidence as to the time of formation of the fault itself
as distinguished from the vein stuff. These deep-reaching contraction fissures naturally form
lines of weakness, along which faults would propagate themselves in case the rocks were
submitted to a breaking strain tending to form such disruptions In the case of the Royal1
mines and other openings on the fissure just referred to, this question would have little practi-
cal value, inasmuch as the vein stone at that point may be reasonably expected to extend quits
through the Waverly rock, as well as the sub-carboniferous limestone, on account of the cal-
careous character of the former rock in its western extension.
Without taking up the history of these dislocations of Kentucky in detail-a matter which
will be reserved for use of the special memoirs on the geology of the State-it may be worth
while to say that all the facts as yet collected point to the conclusion that al the faults, in
Eastern Kentucky at least, are of a comparative recent origin, probably dating from a time
long after the action of the forces concerned in making the deposits in the galena veins.



cracks extend only through a fbot or two of the beds in a
continuous way, the different beds yielding at different points,
so that nothing like a continuous crevice is found. On the
other hand, from point to point, we have these continuous
deep-reaching fractures with separation of the walls, which
to my mind are certain indications of a contraction that has
extended through a great thickness of beds, and differs only
in the magnitude of its action from the small crevices so
abundantly found throughout the rocks.
  The deep-reaching crevices of considerable width seem most
abundant where the small open joints are rare. In Campbell
and the adjoining counties, where the limestone abounds in
these open joints, I have never found an ore-bearing crevice;
while in the counties within the Cambrian district, along the
Kentucky river, where the rock is peculiarly free from small
joints, these wide ore-bearing fissures are frequently found.
We may, therefore, reasonably conclude that both these forms
of fissuring are due to the same contraction of mass, and that
some local conditions, possibly the difference in the massive-
ness of the beds, determine which shall be the type formed in
any particular region.
  The cleanness of these fractures, and the absence of all
evidence of violence, is to my mind sufficient evidence that
these fractures have not been attended by any wide-reaching
movements. The fossil shells on the rock are often cut in
two with perfect neatness, their broken edges being not in
the least shattered or rubbed as they would have been had
there been any such collision of the sides as is sure to occur
where there has been true faulting. This is not the place for
an exhaustive inquiry into the nature of the forces that have
brought about this change in mass; but some idea of the
nature of the forces involved is necessary to the compre-
hension of the condition under which the vein-stones that
fill them have been formed.
  There can be no doubt that this region was once buriedt
under several thousand feet of strata, which have been worn
away during the time since the emergence of the region from




the sea. During the time these beds lay deep buried there
was an accession of heat which may well have amounted to
several hundred degrees of Farenheit. This expansion must
have done much to pack the rocks together, and to bring
about chemical changes attended by a loss of volume. When,
therefore, the continued loss of heat, caused by the wearing
away of the old rock covering, had greatly lowered the tem-
perature, the tendency of the rock to contraction would be con-
siderable. As against pressure rocks are tolerably elastic, but
to tension they are much less so, and rend apart easily under
its action; so that any considerable loss of heat would not
be required in order to account for these deep-reaching rifts.
A change of not over one hundred degrees Farenheit would
be sufficient to cause the formation of a considerable number
of rifts, probably as many as occur in this region.
  The possibilities are that these rifts began to form with the
first considerable decrease of temperature, and increased in
width as time went on and cooling advanced. As will be seen
from the figures in Mr. Norwood's report, there is a very gen-
eral tendency of these veins to be grouped in the shape of
two or three gashes placed near to each other. The immedi-
ate partitions are often thin walls, yet undisturbed by any
violent movements. This affords another evidence of the
tranquil nature of the movements involved in their production.
It will also be seen that there is no evidence whatever of a
vertical movement of the rocks on either side of the fissure.
The beds lie at equal heights in both walls, and every feature
of fault veins is quite wanting. We are therefore compelled
to hold to the opinion that these veins are the product of
shrinkage of the rocks.
  Having now briefly discussed the formation of the fissures
in which these deposits occur, it remains for us to examine the
methods of accumulation of the deposits contained within
them. This inquiry, though touching on the domain of ab-
stract theory concerning the genesis of such veins, is neces-
sary to any proper understanding of their character, and of
the prospects of their downward extension.



  The old view that attributed the formation of mineral veins
to the ejection from a reservoir of molten matter of mineral
substances, which penetrated along the passages leading to-
wards the surface, has been quite abandoned as a usual ex-
planation to be assigned to such phenomena. In its place
has grown up the conviction that most veins are formed in
essentially the same fashion as is the stalactitic material that
accumulates in caverns, viz: by the deposition of matter dis-
solved by water in one part of its course through the crust
of the earth and laid down at another.
  The belief of metallurgists and others who have most
studied the history of metals is, that the original condition of
those substances was that of extensive dissemination, and
that this local accumulation has been the result of actions
that have come about in the changes of temperature, &c.,
taking place since the deposition of the beds containing the
  Until within a few years this opinion, very general in its
outlines, has been the accepted view as to the origin of me-
tallic deposits. It will be seen that it is imperfect, in that it
does not sufficiently explain the curious limitation of certain
species of metals to certain geological formations.
  In i862 a decided advance towards a clearer theory was
made in the report of J. D. Whitney oil the lead district of
Wisconsin, in which the ground was distinctly taken that the
process of formation of mineral veins went oni in something
like the following manner, viz: First, the dissolving out from
the rocks of the earth of the mineral substances which were
originally widely distributed therein, and their transportation
to the waters of the sea. Second, the precipitation of these
materials by the action of the decaying organic life on the sea
floor, which, as we know, is capable of effecting such work.
Third, the concentration of these materials through the action
of the various processes that build up the veins. The follow-
ing extract from the work of Prof. Whitney will serve to show
the fashion in which this was suggested by him. On account
of the close general resemblance of the geological condition




of the upper Mississippi lead region to the Kentucky lead
district, I have, by permission of the author, made extensive
extracts from his report.
  These important suggestions remained practically unconsid-
ered and without addition until many years after their publica-
tion. In a course of unpublished lectures given by Professor
Raphael Pumpelly at Harvard University in I869-'70, the
idea of the cooperation of the secretive power of organic life
in the series of actions leading to the formation of mineral
veins was suggested and extensively discussed, though from a
somewhat different point of view.  For the first time the
capacity of organic species to separate metals from the sea
water and build them into their structure was publicly sug-
gested as a means whereby the fixing of metals in strata
could be brought about. In this process of concentration
Professor Pumpelly gave great weight to the action of marine
currents in accumulating masses of sea weeds and other
organic substances on particular parts of the sea floor, and so
leading to deposits in great part made up of the remains of
animals which might contain some one metal in considerable
quantities. By permission of Professor Pumpelly this lecture
is published in the second appendix to this report.
  In i870 Dr. T. Sterry Hunt brought the matter to the
notice of geologists in an extended discussion of the action
of organic life in the localization of mineral substances. We
seem to have here, as in many other cases in the process of
scientific progress, the coincident and independent discovery
of a series of facts by two observers, each working in ignorance
of the other's researches. The first public announcement of
this discovery was made by Professor Pumpelly; but priority,
as determined by actual publication, is clearly to be awarded
to Dr. Hunt.
  The researches that have been made into the composition
of sea water and of sea weeds has gone far to support this
hypothesis as to the function of marine organic life in the

See Appendix No. I, taken from a "Report of a Geological Survey of the Upper Missis-
sippi Lead Region, by J. D. Whitney, Albany, N. Y., 1862."



making of mineral deposits. There can be no reasonable
doubt that all the substances which have been detected by
chemists have their place in the universal solution of the sea.
The presence of silver, gold, copper, and other metals in the
sea water is evident on a concentration of its contents. Some
of these substances exist in considerable quantities.  The
assertion even been made that the silver of the sea will amal-
gamate with the copper employed in sheathing ships, so that
old copper long exposed to the moving sea may be worked for
its silver won from the water. The idea prevails that this sep-
aration of silver by the copper takes place more rapidly on
the west shore of South America than in any other region.
The researches of Forchhamer and others on the composition
of marine invertebrate animals and plants long ago showed
that there is a considerable amount of metallic substances laid
up in the structure of marine forms, which, on their death and
decay, would be laid down with the accumulating sediments
of the sea floor. It is my impression, as above remarked,
that this important function of organic life in the production
of mineral deposits was first suggested by Professor Pumpelly
in his lectures above referred to, of which no printed report
was ever made. It is important to notice, however, that, as
long ago as 1858, Dr. T. Sterry Hunt began a series of inves-
tigations as to the action of organic life in the deposition of
various substances, such as carbonate and phosphate of lime,
&c., which had been built into their structures, that led natu-
rally to the inquiry into the important action of marine life in
the deposition of metallic substances. A discussion of this
important hypothesis will be found in the assembled papers
of Dr. Hunt.
  It does not come within the province of this report to at-
tempt an exhaustive inquiry into this question of the origin
of these lead deposits of the upper Cambrian. From the sug-
gestions already given, it will be seen that this balance of
opinion among the best informed chemists and metallurgists
inclines to the conclusion that organic life is closely concerned
'See Appendix No. III at the end of this report.




in the localization of the metallic deposits, at least in the little
changed rocks, such as compose all our Kentucky formations,
and that in this work the action takes place in two ways:
Firstly, by the taking into the organic structure of the metal-
lic substances which pass into the sea bottom on its decay.
Secondly, by the effect of the gases, particularly the sulphur-
etted hydrogen, released by decay, in precipitating the me-
tallic substances dissolved in the sea. The practical opera-
tion of these processes is somewhat as follows: The fixed,
and to a certain extent the swimming, animals of the sea,
taking this or that substance in their growth, deliver it up at
their death to certain tracts of the ocean bottom, and in their
decay take continually more of these substances into imprison-
ment in the accumulating sediment.
  As this power of separating metallic substances varies in
different species, it therefore differs in different sections of the
ocean floor and in different periods in the earth's history. If
this theory be true, then, other things being equal, we should
expect to find that those formations which indicate the ex-
istence of abundant organic life on the sea floor where they
are being deposited would be the most likely to furnish con-
siderable quantities of metals. Such, in fact, we find to be
the case wherever these deposits have been worked under
similar conditions to those existing in the region we are now
considering. The evidence cannot be safely regarded as
affording a basis for definite and final assertion; but there can
be no reasonable doubt that, in going downwards into rocks
containing little evidence of organic life, we have reason to
fear that we shall pass out of the richest part of a galena vein
and into leaner territory. Some of the metal derived from
the rock where it was deposited will, doubtless, often work
downwards into the fissure when it runs in sandstones or
other rocks where life has never been abundant. But this
must be, in a good degree, accidental, as the deposit gener-
ally takes place at the point where the metal-charged waters
oozed through the walls of the fissure. There is little reason
to suppose that there could be more of the metallic substance



in the sandstone or shale beds than in the limestone beds.
Another reason to fear the unprofitable nature of galena
veins in sandstone beds would be from the contraction of the
fissure, owing to the change of rock. We have seen that the
most of the veins found in Kentucky are the product of con-
traction or shrinkage taking place in the stratified rocks.
This form of vein is always characterized by very variable
width, and is likely to widen in the limestones and to contract
in sandstones and shales.
The general character of the deposits of ore in the mineral
veins of Kentucky may be the better understood when we
consider some of the facts of distribution of these veins. The
blue or Cambrian limestone abounds in these veins, especially
in its upper part, where the organic life has left abundant fos-
sil record of its existence. The equivalents of the Niagara
series, rather carboniferous, have little trace of lead. The
black or Ohio shale is almost without mineral beds of any
importance; the. same may be said of the Waverly series in
Eastern Kentucky, where we find sandstones and argillaceous
limestones rarely penetrated with lead-bearing rocks. When,
however, we come up to the sub-carboniferous limestone, then,
again, we find the lead-bearing veins in great abundance.
Now when, as in Central Kentucky, we follow the line over
which the carboniferous limestone has retreated, we are struck
with the fact that, where it has been worn away from the lower
lying beds, the Waverly and black or Ohio shale, these beds
from which the carboniferous limestone has been stripped
away, are characterized by the want of mineral veins, as above
set forth. We have no reason to doubt that the limestone
that once overlaid these beds was as well marked by its
mineral veins as are the areas which still exist. We are,
therefore, led to believe that these veins we find in the sub-
carboniferous limestone do not extend into the subjacent sand-
stones and shales. It should, however, be distinctly noticed
that this difference depends not upon the geological position
of the rock, but on its mineralogical character; and that
where, as in Western Kentucky, the Waverly series takes on




the nature of a limestone, it may happen that it will protract
the lead-yielding fissures downward to great depths. I am
inclined to believe that the lead-yielding veins in that district
may in some cases be followed about a thousand feet down
before they pass into rock of a sandy constitution.
  The question will, perhaps, be asked why, inasmuch as we
find some of the ancient rocks, as gneiss, mica schist, and
other similar materials, containing lead veins, there should be
a basis for the idea that organic life is necessary for the con-
centration of such metals. This question opens one of the
broad fields of geology, and it cannot be discussed in detail
in this report. The answer can, however, be indicated in a
general way. It is now the belief of most geologists that all
the rocks now visible on the surface of the earth have been
laid down on the sea floors by the action of water; that they
were once limestones, sandstones, and shales, essentially like
our familiar rocks, that still carry in their fossils and their
structure most evident marks of their origin. These rocks,
having been deep buried beneath subsequent accumulations
of like materials, subjected to great and long continued pres-
sure heat, and the manifold changes that go in their train,
have gradually had their particles so re-arranged that their
original character is often quite lost or only traceable by slen-
der threads of evidence. In the vast periods of time, and amid
the ever changing circumstances of these metamorphic rocks,
the metals may have been carried from point to point, and
from level to level, in the series of rocks, being again and
again dissolved by heated and gas-containing waters, which
took them up at one place to lay them down at another. The
veins in the highly altered rocks, the mica schists, for instance,
may have been originally laid down in some much higher
rocks of another character, and only brought to their present
level by the long-continued circulation of heated waters, be-
ing, perhaps, several times deposited and redissolved in the
course of their downward journey. In our Kentucky rocks.
however, we get but the first stage only of this migration of
the particles of metal after their deposition in the organic



remains. The metals have been concentrated into fissures
in the immediate neighborhood of their deposition, but have
been subjected to no further change.
  The following figure will show, in a diagrammatic way, the
apparent condition of the Kentucky series of rocks. It should
be understood that this figure is intended as an illustration
of an opinion rather than as a graphic representation of the

     I 10

   .-S, t;


VoL l.-K9




  It will be noticed that this diagram indicates generally ver-
tical fissures with tolerably regular walls, all clearly the work
of a contraction of the mass. On examining Professor Whit-
ney's work, "1 The Lead Region of the Upper Missouri," it will
be seen that there have been extensive deposits of the lead
and associated substances in ordinary caverns in that region-
a large part of the workable deposits coming from beds that
have been formed in caverns rather than as fissures. Possibly
some of the lead deposits of Western Kentucky, occurring in
the carboniferous limestones, may also be regarded as occupy-
ing caverns rather than fissures; but at this time I am quite
convinced that the evidence is rather against this view and
in favor of the theory that this class of deposits has never,
in this region, been found in caverns excavated by water. I
have carefully observed many such underground channels,
both in the Cambrian and Sub-carboniferous limestones, with
a view to ascertaining whether any such deposit is now going
on, with the definite result that not a trace of such action is
observable at the present time. I am satisfied that the upper-
most caves .in Kentucky date back at least a million of years,
and that they were probably in existence during the middle
Tertiary period; yet in none of them is there the least trace
of the deposition of lead. It seems to me that this fact clearly
proves that the formation of these veins is most explicable by
the supposition that they were segregated while the rocks
were subjected to conditions of heat that do not now exist in
them. At the same time it must be said that their mechanical
condition forbids the supposition that they have ever been
subjected to any very high temperature.
  To sum up in brief the general condition of our Kentucky
vein metals, we may make the following propositions, viz:
  ist. That the fissures or veins in which they occur have
generally been formed by the shrinkage of the rocks in which
they are found, and not by the deeper-seated causes which
form fault veins.
See Antiquity of the Caverns and Cavern Life of the Ohio Valley, Memoirs KentuCkY
Geological Survey, volume I, part I, 1876.



  2d. That these fissures, dependent for their origin on the
peculiarities of constitution of particular beds, cannot safely
be expected to continue indefinitely downwards below the
level of the beds in which they are seen.
  3d. That the absence of metallic veins in the sandstones
that were originally overlaid by limestones, which limestones
are vein-bearing, is a corroboration of the view that these
veins are limited to the limestone rocks.
  4th. That the general presence of metalliferous veins in
the limestones of the State, and their general if not universal
absence in the sandstones, is a strong proof of the truth of
the theory that assigns to organic life the function of separat-
ing these metals from the sea and laying them down in the
stratified rocks.
  5th. That the cycle of change of metals, as, indeed, of all
substances, is as follows: Dissolved from the earth by the
water, which is aided in its work by its contained gases and
heat, they find their way to the sea; then the organisms living
in the waters or on the bottom, select the substances accord-
ing to their peculiar organic laws; built into the growing
deposits of the sea bottom, they become part of the earth's
crust, and come again within the action of those forces that
work them into their concentrated state, or, mayhap, wash
them again into the sea, and so repeat the eternal circle.
  In the appendix to this report I have, by permission of the
authors, reprinted extracts from the writings of Professors J.
1). Whitney and Raphael Pumpelly and Dr. T. Sterry Hunt,
thus bringing together all the important contributions known
to me that bear on this question.
  The reader is requested to bear in mind that the views
above suggested, though they seem to satisfy the facts better
than is usually the case in geological theories, must not be
taken as matters of final demonstration. There can be no
d(oubt that the balance of probabilities is greatly in their favor,
and that they may fairly be made the basis of a judgment by
those who seek even the least light where else would be only



  With reference to the economic bearing of these conclu-
sions above set forth, little needs be said. The economic side
of the problem is not greatly affected thereby, save in the
conclusion that few of our lead deposits, if any, may reason-
ably be expected to be continuous to great depths or to im-
prove in descending. The reports of Dr. Peter make it plain
that all our lead ores are singularly poor in silver; in no case
has enough been found to warrant extraction. With careful
mining some of the lodes will possibly pay for working; but
there can be no doubt that at least half a dozen other sources
of mineral wealth within the State promise a better return
for capital and enterprise. Already there has been a large
amount of money expended in the opening of lead ores in
the State; probably not less than half a million dollars has
bee" spent in such workings. Very little lead has been mar-
keted. I doubt whether four hundred tons have ever been
obtained from all the workings put together, and but two or
three openings can now be said to be promising in their ap-
pearance. I feel, therefore, compelled to say, that however
single ventures may turn out, the prospect of the industry to
the Commonwealth is by no means good.



                      APPENDIX 1.

oItem a Raptm -th  Uppe  Wiiippi LEd Reo  by Proem  J. D. Whitinm, eapelned bY P-1-h
                          of the Author.]
  "In view of all these facts, we consider it as a matter settled
beyond all possibility of doubt, that the lead deposits of the
Northwest must have been introduced into the fissures from
above, and by precipitation from a solution. In reference to
this last clause, we have not thought it necessary to adduce
any evidence to disprove the theory of the igneous origin
of the ore, or of its having been brought up from below,
either by sublimation, or by actual injection. Since, how-
ever, both of these ideas have been maintained by different
persons writing on the region, although every fact seems to
be entirely opposed to any hypothesis of igneous action, it
may be proper to sum up as concisely as possible the evidence
in favor of aqueous deposition.
  '1ist. The generally recognized aqueous origin of the sul-
phurets: deposits of sulphurets of iron and other metals are
frequently produced accidentally or intentionally in the chem-
ist's laboratory, by the decomposition of solutions containing
the metals by sulphuretted hydrogen.
  H 2d. The occurrence of the sulphurets of lead and iron in
the lead region, in forms which they could not have assumed,
except as deposited from a solution-as in the form of casts
of fossils, and in connection with stalactites and stalagmitic
masses of calcite. An instance of this kind is to be seen
in the Wheatley collection at Union College, and is shown
in the annexed wood-cut, which represents a large stalag-
               m     ,,  mite, with a small mass of galena on the
                        end of it, in a position which it would be
                        difficult to imagine it to have reached,
                        except in solution, dropping from above,
eStalagmie    Gk,  exactly as the rest of the stalagmite was
                        formed. Instances have been mentioned