Today it is clear that "changing climates" are the
result of changing conditions at the polar caps. Long term variations of
climate are slow, but predictable. Short term variations are sudden
and unpredictable and in turn have catastrophic effects. In particular the heat absorbing
capacity of the ice caps [Albedo] when the ice becomes slightly colored can have a
relatively sudden erratic
influence upon the immediate world climate and on sea levels.
The eustatic changes of the ocean
pre-historic and historic times are recognized as erratic and steep. A hypothesis is
proposed to explain these erratic changes with albedo and the reflectivity
of the whiteness changes at the polar ice caps,
were caused in turn by erratic volcanic and terrestrial dust and ash fall-out. Ash layers in Antarctic
ice cores are connected and correlated with historic dislocations of salt
production on sea coasts
and of maritime civilizations.
Albedo changes through the dusting of the ice caps
are proposed to be the cause for the decline glaciation periods generally. Such albedo
changes are connected with volcanic activity on the one hand, and loess formation on the
other, caused in turn by the growth of the ice caps.
Posted: 18 March 2002
Updated: 21 March 2002 14:40 MST
, Palaeoclimatology, Palaeoecology, 1965 127-142-Elsevier Publishing Company,
Amsterdam-Printed in The Netherlands
FOR THE CHANGE OF OCEAN LEVELS DEPENDING ON THE ALBEDO OF THE POLAR ICE CAPS-
M.R. BLOCH (Received October 6, 1964)(Resubmitted January 1965)
HISTORICAL DATA USED AS
AN INDICATION OF OCEAN LEVELS
Excluding hypothetical tectonic changes as an explanation, particularly
where no indication of tilting can be found, the following is an attempt to survey
indications of coastal movements consistent with known data since 6000 B.P. For this, the
rebound of the Scandinavian landmass after the last glaciation, is taken as real and
worldwide eustatic changes of the ocean level are traced.
The present level of the sea designated as O. (Ordnance Data), N.N.
(Normal Niveau), N.P. (Normal Pegel) is a normalized height on the surface of the
earth, generally the mean height of the sea between high and low water. For surveyors’
purposes, the sea level is defined and marked according to a set of actual measurements.
During the last 100 years the sea level rose by some 15 cm; this fact was especially well
established from Dutch pegels.
As we are not in a position to estimate the sea level at any time
before 1850 exactly, a difference of 30 cm cannot be considered as significant. The more
general term “present sea level” will therefore be used here; to this we will relate
all indications of “sea level changes” compiled from data relating to historic or
pre-historic timesThe “present sea level” seems to have been reached in the 16th
century; since that date there have been no indications of any permanent change of an
order greater than 30 cm. However, there are definite signs that between 700 A.D. and 1600
A.D. one or more distinct sea level minima occurred (Fig. 4B).
During the 15th and 16th century A.D. (Fig.4A) a
general rise in the price of salt all over Europe was the reason for serious political and
social unrest (K(LNER, 1920). This links up with the fact that the salt producing broads,
meres, clair’s and kogs (KOSTER, 1960), in East Anglia, (CLARKE, 1960, pp. 22,24;
KESTNER, 1962, p.469) in Holland, France and Friesland (BANTELMANN, 1960, p.52; BUSCH,
1960, p.128) respectively, were flooded, and peat salt production had to cease.
In Holland , this producti was prohibited by law , because of weakening
of the sea defences (DENDERMONDE and DIBBITS, 1956, p.48). Prussia and Livonia became
susceptible to salt famine in the late 14th century (TANNER, 1932).
The peat broads and meres are still flooded today, and the extent of
these areas indicates that millions of tons of peat were produced when the sea level was
at a low. Also the Chersonesus settlements seemed to decay at this time (MONGAIT, 1961,
p.189), probably due to the same cause.
Between 700 a 800 A.D. (Fig. 4B) people had moved
to the Broadlands area in East Anglia (CLARKE, 1960, p.147) and peat cutting and salt
The Domesday Book records at least 1,200 salt making area (Salinae)
(BRIDBURY, 1955, p.19); another indication that the level of the sea must have been lower
than today (Fig. 4B).
In the 11th century (Fig. 4B), the isla of
Walcheren (BRONSTED, 1960, p.37) boasted a flourishing community; the fact that it was
unprotected by dykes during this period (BRIDBURY, 1955, p.4) is indicative that the sea
was considerably lower than the present level, even when we take in account that it was
probably somewhat protected by natural sandbars.
The area of Haithabu (near Schleswig) flourished during the period of
900 A.D. (Fig. 4B); as the land was 1 m higher above the level of the sea than today, it
follows that the sea must have been at a low (K(STER, 1960). Until the 13th century
Yarmouth was at least 10 ft. higher above the sea than now (CLARKE, 1960, p.22).
IVES (1803) says that about the time Edward the Confessor
(1042-1066) (Fig. 4B) the sea “retreated from the sand of the
estuary on which Great Yarmouth now stands. A similar pattern of emergence at that time
occurred in L(beck (K(STER, 1960).
The Viking occupied the low lying island on Noirmoutier, on the
Atlantic coast of France, an area where at that time the salt pans of Bourgneuf developed
(AGATE, 1904, p.5) . At about the same period (860 A.D. Fig.4B) they
occupied a similar low island on the mouth of the Rh(ne “Camargue” , an area of salt-
making until today. Simultaneously the salterns of the Crimea in the Black Sea were
emerging and were likewise occupied by a Viking taskforce, taking the landway (BRONSTED,
Ravenna, like Aquileia, became land-locked then (Fig.4B) due to the
receding sea, and consequently lost all her salt, fish-salting industries, trade and power
to the lower lying Venice. “Fishing and the refining of sea salt were at first the
principal resources of the inhabitants of Venice” (PIRENNE, 1958, p. 185).
The salt makers in Friesla began to work in the emerging peat area of
the Wadden (tidal flats) and traded intensively with all of northern Europe (Fig.4B) (PIRENNE, 1957, pp. 236-239; HALLAM, 1959-1960; NENQUIN, 1961,
The salterns of the Pyrenean coast are mentioned in 929 and 978 A.D.
under the name of Lima, do Cavado, do Ave, do Rio Leca, do Douro, do Vouga, do Mondego
(ELLIS, 1955, p.36) and it is probable that they were flooded for several hundred years
before this period (Fig.4B).
The Popes had solar salt pans in the Ostia salt flats, where such
activity had ceased after Trajan because of flooding (FEA, 1831).
The fortunes of the salt makers suffered disastrously from the effect
of floods which occurred in 1362, A.D. and 1634 A.D. in all Lowlands (BANTELMANN, 1960,
p.52). The destructive power of these floods, which invaded the coasts of Europe, seems to
have been enhanced by a general rise in the sea level again; this rise can be deduced from
the dyke-building activity designed to counteract it in the last 600 years all along the
threatened coasts of northern Europe (Fig.4A) (DENDERMONDE and DIBBITS, 1956, p.47;
CLARKE, 1960, p.22; KESTNER, 1962, p. 469). The minimum of the sea level of the 11th
century (Fig.4B) was preceded by a maximum in the first millennium A.D. (Fig.4C).
It is known that on the East Anglian coa (NENQUIN, 1961, p.136),
practically no salt was produced after 425 A.D. (Fig.4C). and hardly any was consumed. The
area was almost uninhabited until ca. 700 A.D. (Fig.4B) (CLARKE, 1960, p. 147). Duurstede
in Holland had a small population, which lived basically from the fishing and saltfish
trade. Only the upper peat bogs in Ireland, the salty sands of the Isle of Man and the oil
shales in Dorset made a comparatively high standard of civilization possible.
However, the sea must have already been high at about 100 A.D.
(Fig.4D) because of the evidence that in the first half of the 2nd century A.D. (Fig.4C) a
port was utilized by Roman merchants in the vicinity of the Norfolk broads now inland
(CLARKE, 1960, p. 119). The port of Classis near Ravenna was capable of harbouring 100
ships during the period of the Roman Emperors (Fig.4C), starting shortly after the time of
Augustus and it was still busy during the reign of the Gothic kings (GOETZ, 1913, pp.13,
136). BURY (1958, pp.161, 213) quotes in his History of the later Roman Empire that during
that period a visitor from Gaul described the Ravenna- Classis area as if it were Venice
itself, with its lagoons and canals; in 800 A.D. (Fig.4B) it must have
been already several kilometres inland, because the island of Venice was now inhabited
(Saint Mark’s relics transferred to the town in 826 A.D.). The port at the mouth of the
Tiber were built on progressively higher ground by Claudius and Trajan (Fig.4C).
The Augustan Port near Ostia suffered the loss of 200 ships when Rome
was flooded in 62 A.D. (TACITUS, 1829); a catastrophe which led to the construction of
Trajan’s port (Fig.4D).
In his article “Observations on the Temple of Serapis Pozzuoli in
Naples” BABBAGE (1847) writes of the discovery in the year 1749 of three marble columns,
which formed part of a large temple supposedly dedicated to the God Serapis (before 100
B.C.). According to his description these columns were still in an upright position, and
throughout part of their height, were perforated in all directions by a species of boring
marine animal, Lithophaga (YONGE, 1963). Today the highest of these perforations are 1.80
m above the present sea level. If these columns have really remained vertical all this
time, then it is proof that they are “non-tilting”; consequently local earthquakes are
not sufficient reason to explain the up and down movements of several metres amplitude.
In the ancient port Caesarea, south of Haifa, stands a wall which must
have been built between the time of Herod and the 2nd century. (A. Negev , personal
communication , 1962). The tope of this wall, now 1.50 m above the present sea level, is
perforated with the typical holes made by the Lithophaga. The wall stands vertical and
shows no sign of tilting. Near this wall are the remains of two aqueducts which once
supplied Caesarea with water. Of the two, the older one was built near the present shore
line; the parallel and newer aquaduct, situated further inland, must have been constructed
when the sea was threatening and ultimately destroying the first one (REIFENBERG, 1951,
pp. 27-28). It is most probable that the original aqueduct was constructed during
Herod’s reign or shortly after, and that it was situated at that time quite far inland.
It is estimated that it was destroyed towards the middle of the first millennium A.D. and
the sea, therefore, must have been temporarily 1-2 m higher than it is now ((Fig.4C).
Not only are the aquaducts of Caesaria (REIFENBERG, 1951) and the
columns at Puteoli still in the original positions of construction (two things which would
be almost impossible if there had been a tectonic movements of 3 m vertical amplitude
since their erection) but many other old buildings in the reputedly unstable Mediterranean
area are still vertical, a sign that the instability in many places was not great enough
to cause a tilt. At the old shore the Etang of Vendres, near the mouth of the Aude, are
the ruins of a Roman Therme of the 1st or 2nd century A.D. (locally called the temple of
Venus). There the walls have been washed out by waves so that they now have a deep double
notch about 1.80 m above present sea level (Fig. 4C). The remaining walls of the
“temple” are not tilted at all.
Salamis on Cyprus was flooded in 345 A.D. (NEWMAN, 1953, p.65) Tyre was
separated from the mainland 380 A.D. (ST. JEROME, 1933). The population of maritime Greece
had dwindled in the 2nd century A.D.; trade by-passed it (NILSSON, 1962) (Fig. 4C).
Radiocarbon and pollen analys data have been used for studying sea
level changes after the last glaciation, and extensively compared by JELGERSMA (1961).
Unfortunately these methods can only give estimates of within time
intervals of several hundred years and differences of heights of half metres at best.
Still, it is clear that the sea level at the Frisian coast according to 14C peat
determination was higher ((Fig. 4C) in the middle of the first millennium A.D. than it is
today and much higher than it was in the first millennium B.C. (Fig. 4F). The maximum in
the middle of the first millennium A.D. is also supported by 14C data in the stable Recife
area of Brazil (VAN ANDEL and LABOREL, 1964) (Fig. 4D).
Similarly the studies of GODWIN (1943), (archaeological , palynological
and ecological) show for the middle of the first millennium A.D. (Fig. 4C) a definite rise
of 1 m in the Fenlands of East Anglia over the present day sea level there, and a
subsequent fall of several metres below today’s level in the 11th century A.D. (Fig.
Trajan succeeded in renewing a “Suez Canal” built originally by
Ramses II (1230 B.C.) (MUIR, 1924) (Fig. 4D).
In the first half the first millennium A.D. all the areas which were
connected with salt trade from inland sources had a peak in their development: the Judean
hill towns, Tripolitania (GOODCHILD, 1950) and Asia Minor (NICEPHOR, 1562) (Fig. 4C) a
strong indication that the salt pans at the ocean coasts were flooded and unseless-so that
the inland salt sources had to be used in spite of more expensive and difficult over land
If one accepts a connection between the melting of the Antarctic ice
cap and the small eustatic oscillations of the oceans during the Holocene, then the ice
core of “Little America” (Ross ice shelf) deep sounding is significant (BLOCH and
HESTER, 1962). It shows an ash layer circa 100 A.D. (Fig. 4D) which indicates a
considerable volcanic outbreak at that time (CRARY et al., 1962, p.2806) and a strong
albedo change over a wide area of the Antarctic ice mass with consequent increased
absorption of solar radiation. This outbreak must have been especially albedo changing ,
as the methods used up to now for the detection of solids in the ice core have not shown
any subsequent ash falls (although it is, e.g., known that the Krakatoa outbreak which
occurred in 1883 must have distributed world wide albedo changing ash).
The ocean was several metres below present day level during most of the
first millennium B.C. (Fig. 4F). This is indicated by the local results of GODWIN (1943)
in the Fenlands of East Anglia as well as by 14C data relating to the Dutch coast where no
warping is supposed to have taken place (JELGERSMA, 1961). It would seem that all Greek
and Phoenician ports between 700 B.C. and 50 A.D. (Fig. 4F) were built
in the sea, or more probably, at a sea level several metres below the present. However,
this has to be verified, because no erratic changes of sea level at such ports have ever
been taken into consideration, even as a remote possibility (LEHMANN-HARTLEBEN, 1923).
The fact that several fastening devices for ships found in ports of the
1st millennium B.C. (Fig. 4F) were metres below present sea level, has been explained as a
tectonic emergence; this applies to those in Petuoli, the Adriatic coast near Triese,
Sicily and in Asia Minor. The same explanation is given for the Roman salt pans which were
found 3 m below present sea level (Fig. 4F) in excavation at Venice (DE BIZZARO, 1901).
All facts are better explained with eustatic sea level oscillations.
About the middle of the first century B.C. (Fig. 4F)
the island of Iktin (which was the chief source of supply of tin from the British island
to the East) was described by Diodorus Siculus as an island connected by ridge with the
mainland, passable at low tide. If DE BEER’S (1960, pp. 161-162) identification of this
island is correct, then it follows that the sea was somewhat lower in Diodorus’ time
In the Crimean area, ports and towns which were founded and inhabited
from about 500 B.C. to 300 B.C. are now partly under water (Fig. 4F) , and even their
defensive walls are inundated (MONGAIT, 1961, p. 199). Thus the Black Sea- like the North
Sea, the Atlantic and the Mediterranean- was considerably lower in the middle of the first millennium B.C. (Fig. 4F) than at present.
A short rise of the ocean levels might be indicated for about 400 B.C.
(THUKYDIDES) by high salt prices reported for Athens (EHRENBERG, 1951, p. 223), and by the
fact that at about that time new positions were selected for salt pans in the Ostia area
(MEIGGS, 1960, p. 269).
During 600 B.C. (Fi 4E), however , there is
evidence that the Mediterranean in Marseilles was almost at the same level as it is now
(DIOL(, 1954, p. 285). At this time intensive colonization of the Mediterranean coasts by
maritime people (Phoenicians, Helenes, Etruscans) started. The Judean hill towns, on the
other hand, underwent and extremely difficult period.
Between 1200 and 7 B.C. (Fig. 4C) we have evidence of an high sea
level: Ramses II succeeded in connecting the Niles to the Red Sea by a canal (1200 B.C.)
(Fig. 4G) (MUIR, 1924) which re-used later by Trajan and still later by the Arabs, as
mentioned before (650 A.D.) (Fig. 4C).
In Schleswig (Haitabu area) a cutba river is indicative of a sudden
rise of the sea level (1000 B.C.) (Fig. 4G) (K(STER, 1960).
At the Brazilian coast, a maximum was found for 900 B.C. 14C dating
(Fig. 4G) (VAN ANDEL, 1964).
Two ash layers, corresponding to period between 1700 and 600 B.C. (Fig.
4G) were found in the “Little America” core (CRARY et al., 1962, p. 2806). They should
have caused a considerable rise of the ocean level.
That the sea level was high in 1200-700 B.C. (Fig. 4G) can be deduced
from the sudden decline of the Mycenaean civilization, the emergence of the sea-faring
people in the Syrian and Egyptian areas, and the growing importance of the towns of the
Judean hills, especially those on the watershed between the Dead Sea and the
Mediterranean, as they were the main centres for feeding , sheltering, taxing and probably
controlling the salt caravans. These salt caravans had a growing importance when less and
less salt could be obtained from the flooded ocean coast salterns.
An error of ca. 250 years is to be reckoned wi concerning the two ash
layers in the Antarctic ice core of these times (Fig. 4G) , as an
exact dating of their occurrence is impossible at present. Historical data, therefore ,
might legitimately be preferred for the estimation of sea levels.
The maritime Mycenaean civilization flourished between 1400 and 1200
B.C. This would correspond to a lower sea level (Fig. 4H) than the present one. At the
same time the civilization in Jericho declined to an extreme low in 1300 B.C. (ALBRIGHT,
1960, p.99). Salt-making between 1400 and 1200 B.C. was easily possible along the
Mediterranean coast if the ocean was low at that time; consequently the salt sources of
Jericho were unimportant and neglected then and its civilization declined.
During 170 1550 B.C. (Fig. 4I) the Jordan valley civilization
flourished (ALBRIGHT, 1960, p.86-87) whereas the Agean Minoan culture was low; at that
time salt had to be brought from Jericho (Dead Sea area) to the coastal plains.
In England the submergence of the 14C dated forest connected with the
tin island Iktin (Fig. 4I), indicated a sudden rise of sea level for 1700 B.C. In Brazil
(VAN ANDEL, 1964) a maximum is indicated by 14C dating (1700 B.C.) (Fig. 4I) (DE BEER,
1960, pp. 163-164). Before 1700 B.C. (Fig. 4I) the sea, at this same spot, was clearly
below present level. In accordance with this, a period of desolation in the Jordan valley
ended about this time; this state of affairs had lasted from 2200 to 1800 B.C. Vice versa,
the Agean-Minoan coast prospered during this period (Fig. 4K.).
Previous to this, dating becomes even more difficult. We can only guess
that early Bronze and Chalcolithic culture oscillated between the sea coast and the desert
salt lakes according to the changed of the sea level. However, it is clear that the steep
post-glacial overall rise of the ocean (from 30 m below present sea level), which ended
about 5000 B.C., must have had a profound influence on the location of emerging
SEE THE ICE MELT DAILY
The Cryosphere at a glance
(image updated daily)
ARCTIC AND ANTARCTIC ICE MASSES GOVERNING THE OCEAN LEVELS
THE ALBEDO ARCTIC AND ANTARCTIC ICE MASSES GOVERNING THE OCEAN LEVELS
According to GODWIN (1943),
SHEPARD and SUESS (1956), JELGERSMA and PANNEKOEK (1960) and CURRAY (1961), the level on
the oceans rose by 40 m or more at the end of the last glacial period. This rise slowed
down about 7000 B.P. so much that since then the level of the oceans has not changed more
than ca. 2 or 3 m. The general character of this so-called eustatic rise is depicted by curve 1 in Fig. 1
Fig.1 General character of ocean level oscillations
after 15000 Curves from 15000 to 7000 B.P. largely governed by ice conditions over the
northern hemisphere, after 7000 B.P. by ice conditions in the Antarctic
DUBOIS (1924), GODWIN (1943 FAIRBRIDGE (1958), CURRAY
(1961), all had to interpret their measuring results so that the rise was not smooth, but
interrupted by several regressions; also, after 5000 B.P. it seems that the level of the
seas has been changing in oscillations of ca 2 m. Curve 2 in Fig.1 represents these
oscillations which do not all have the same degree of probability. The changes of the sea
level have reached several centimetres per year at times.
Since the theory of DALY (1920), the rise of the
oceans at the end of the last glaciation has been explained by the volume of the water
derived form melting ice of the retreating glaciers near the poles. The ice crust of the
northern hemisphere covered some 40 million km2. A 50 m rise of the world oceans level
indicated that an ice layer of more than ½ km average thickness had to be melted on that
area, depending on the precise estimation of the porosity of ice. About 6000 B.P. most of
the ice masses on land, except Greenland glaciers, had vanished, and further changes in
the mass of ice then floating on the polar sea, could not have had any appreciable
influence on the level of the world oceans.
It is our working hypothesis that after 6000 B.P.
oscillations of the level of the world oceans must have been caused mainly by changes of
the ice mass resting on the Antarctic continent. Such oscillations, which were taking
place in pre-historic and historic times, must have had a definite influence on the
development of humanity; the vital salt industry, especially, was sensitive to these
changes since both peat salt and solar salt are produced only on low lying and flat ocean
coasts (BLOCH, 1963).
Local ocean level changes in both pre-historic and
historic times have been attributed to local vertical movements of the shores, or to local
changes of impediments in the flowing of the tides. Only world wide synchronized changes
of the ocean level are thought to be caused by the melting or freezing of the ice shields
on the poles. In general, tectonic movements were thought to be slow and of the order of
millimetres per year particularly if there was no proof of visible faulting. The same
order of magnitude was expected for the velocity of eustatic level changes of the oceans.
As long as the possibility of short, eustatic
oscillations was not considered, all signs found on the coast of relatively sudden sea
level changes were taken as an indication of tectonic movements.
In order to give consistent explanation for all local
indications of past sea levels, the occurrence of vertical oscillations of the geological
strata had to be hypothetically accepted; these oscillations would have to be accepted as
real, and sometimes in opposite directions very near to each other in place and time.
Characteristic of this is what JARVIS (1936, pp.9,10)
says of the conditions on the old salt port of Mariut in Egypt: “I do not know if Mariut
is considered to have sunk in level or risen, -to the ordinary uninstructed mind it would
appear to have done both”.
It would seem then, that by tacitly excluding the
possibility of sudden eustatic sea level changes, comparatively rare and often hypothetic
tectonic changes would have caused the submergence, and almost contemporary emergence of
important coastal features like ports.
Our hypothesis makes it possible to explain these
sudden changes of shore lines by sudden eustatic changes of ocean level (BLOCH and HESTER,
1962) . The Antarctic ice has, under present conditions, an albedo of over 90%. This means
that of the solar energy which is incident there (almost 95 kg/cal./cm2/year) about 80-85
kg/cal./cm2 are reflected. Even if we assume that great areas of ice recrystallize and
absorb long wave light in consequence, then there are still some 35 kg/cal./cm2 in the
form of visible short wave light which is reflected also when the surface is melting.
There are several practical sets experience with the
radiation conditions of white surfaces where very small quantities of colouring substances
have changed the albedo considerably (BLOCH and MARTIN, 1935; BLOCH et al. 1951). In the
solar pond area of the large potash and salt factories like the one at the Dead Sea, 3
p.p.m. of naphthol green are sufficient to colour the brines in such a way that the albedo
of the white salt floor of those ½ m deep pans is reduced form 50 to 5% ; the originally
white surfaces appear dark after colouring and evaporation rises by some 20%. In a similar
way, it was possible to double the output of a hydro-electric power station in the Andes
by colouring the glacier with coal dust distributed by a helicopter (W.B. Hester, personal
communication , 1962).
Such an albedo change can be considered as possible
for the ice surfaces of the poles, (1) through terrestrial volcanic dust, by volcanic
outbreaks like the Krakatoa or Craterlake; (2) through terrestrial surface dust as we know
it in arid areas in the form of loess; (3) through cosmic dust; (4) through biological
material; and (5) through artificial colouring.
In this connection, only the dust of volcanoes and the
dust from loess seem to be great importance up to now. The effect which can be created by
such dust is an additional absorption of 35 kg/cal./cm2/year in the form of visible light.
This again is equal to a heating and melting of a water column (originally- 28( C) of
about 3 m height.
If such a melting process occurs on the Antarctic
continent, the level of the world oceans would rise by 12 cm. In this calculation no
change of albedo in the long wave range of light is taken into account since these changes
might possibly be compensated by better emission.The discoloration of ice fields might
have very different effects if the intensity of discoloration is different. A weak
reduction of albedo would simply increase the temperature of the polar ice with little
effect on the melting of the ice; but this temperature increase of the poles would
diminish the difference of temperatures between pole ad equator, and consequently the
intensity of the atmospheric circulations that are caused by these temperature
differences. If there is a comparatively weak outbreak (as for instance that of the
Krakatoa in 1883 of 14 km3 of dust), then only a weak change of albedos in the Antarctic
area would be caused. A slight increase of temperature on the south pole would then
diminish the temperature difference between pole and equator; consequently the southern circulation
would weaken and a shift in the climatic conditions of the border area of this circulation
It might not be accidental that lakes like the Great
Salt Lake, Utah, or the Dead Sea, which
have the character of rain gauges, show the beginning of an extraordinary level rise in
the winter season 1883- 1884 (Fig. 2A, B) (HARDING, 1935; KLEIN, 1961). In the spring of
1883, the famous outbreak of the Krakatoa began, which culminated in August. Our working
hypothesis postulates that a change of albedo can only have its effect at the beginning
and during the Antarctic summer; although the change of albedo on the south pole might
have been in April, the northern hemisphere could only have the consequences in the
following winter season; actually the first definite observation after the Krakatoa
eruption of a higher Dead Sea level, dates from 1885 (KLEIN, 1961). In accordance with the
fact that the dust of the Krakatoa remained in the air for several years, a Dead Sea level
rise was observed during the same time. Whether the molten layer found by Gow (1963) in
his ice core for 1883 was really caused by dust induced albedo change will only be
determined by his analytical results.
This dust of Krakatoa has not yet been identified as
such in Antarctic ice cores, but melting of the ice is identifiable with the Krakatoa and
other out- breaks in form of ice lenses in the core layers corresponding with the years of
such outbreaks. Previously , much bigger volcanic catastrophes have left their traces much
more clearly. CRARY, et al. (1962, p. 2806) have identified three ash layers in the
Antarctic ice cores of Gow and cooperators, and coordinated them to the years 100 A.D.,
1250 B.C. and 1350 B.C. According to Crary’s theory, the ice cores have been reduced in
thickness by a factor of 3 on their way from Byrd Station to Little America, so that the
ash layers identified must have been of a considerable thickness. It is likely that the
ashes came from far away, because Gow recognizes them as being of andesitic character and
not as the ashes from the nearer Mount Erebus; so it is very probable that these dust
layers covered substantial part of the Antarctic surface.
The question of how fast a coloring dust layer can be
made ineffective by snowfall and wind-drift can be answered from Fig. 3. There, it is
shown that the reflectivity of new snow can be strongly reduced even if a dark dust layer
is buried by it to a depth of 5 cm (GIDDINGS and LACHAPELLE, 1961). It also seems most
probable that ash outbreaks last for considerable periods, as we could see in Costa Rica
in 1964, and also that fine ash remains in the atmosphere for a long time so that falling
snow can use it as a nucleus for snow formation which then accumulates constantly in new
layer. The working hypothesis that volcanic ash or loess can help to melt polar ice masses
by the albedo change might be applicable to the explanation of ice ages and their nature
as such; if such an hypothesis was right then it should be really true that, as the
calculations of BROOKS (1949) and the measurements of LISTER (1959) suggest , the white
continental ice cover of the Antarctic is in itself constantly growing.
According to this working hypothesis, this growth is
only accidentally interrupted when discoloration of dust surface caused by volcanic
outbreaks takes place. It might be that these outbreaks are not entirely accidental, but
connected with tectonic disturbances caused by the growing weight of the ice on the
The Arctic ice masses growing on the continent would
also, according to our hypothesis, grow in virtue of their deficit of radiation as long as
they are white. When the surrounding continents are sufficiently arid, however, formation
of loess takes place, and then this loess, disturbed by storms and carried into the air,
would finally settle on to the progressive ice masses,
cause discoloration, reverse the balance of radiation, and push back the limits of the
glaciers of the north polar sea. Volcanism might also have played its part in the north as
proposed for the Antarctic.
Our working hypothesis would lead to the following:
a] - Glaciation periods on the north and
south pole might coincide only accidentally.
b] - levels of the oceans are under the
influence of changed in the Arctic when the ice masses have started to cover the American
, European and Asian continents. Changes in the Antarctic can only be eustatically
effective when they have reached the Antarctic continent. The surface of the continents,
which can have an effective role to play by glaciation, have an approximate ratio of
15:50; 15,000 km2 for the south pole to 50,000 km2 for the north pole. The variations on
the poles can compensate or amplify each other.
c] - temperature changes, in connection with the
glaciation periods, lag behind the glaciation changes, the melting and freezing of the ice
masses. The changes of climate are the consequence of the changing radiation balance of
the ice masses and not the cause of melting and freezing.
d] - Albedo changes of a weak nature change the
temperature of the very cold. Antarctic ice masses long before substantial melting can
take place; since the Arctic ice masses are floating on the Arctic ocean and are nearer to
the melting temperature, the albedo effect is buffered there now.
e] - Antarctic albedo conditions and temperature
effects, as for instance the change of atmospheric circulation, can only become apparent
during Antarctic summers.
Thus albedo changes on the Antarctic can be expected
to have an effect on the climate of the northern atmosphere only during the northern
winter, this, except in so far as events in the atmospheric and ocean circulation during
the winter season, may themselves have some influence upon the following summer.
2. Fluctuations of the level of:
A. Great Salt Lake, Utah. B. The Dead Sea
3. Variation of albedo with snow thickness
In Fig. 1 , where curve 2 represents the changing sea level since 5000 B.C.
(as it can be constructed according to the foregoing collection of data), each maximum and
minimum is marked with a letter corresponding to an equally marked paragraph in the text,
demonstrating our hypothesis.
The most certain
maximum in this eustatic curve seems to be transgression of the first half of the first
millennium A.D. Then follows the minimum in the middle of the first millennium B.C. We
consider that the other features are real but might have a fine structure. As a hypothesis
the foregoing has many point which require further experimental investigation, both by
archaeological and geological research, so that they can be refuted, varied or proved.
concerning the hydrology of glaciers should be made, especially to clear up how
ablative-melt water behaves on porous, very cold ice (-300C) (FUCHS, 1960) and to
establish whether impermeable layers are formed and where, how deeply the water refreezes
periodically at night and how ash and dust particles are carried away, classified and
redeposited. The transport of energy through melt water should be investigated. Erosion
canyons at the periphery of the ice shield should be explored.
Core drillings in
the ice shields should establish periods of melting in the past more precisely. Physical
appearance and solid content in the cores should be determined and more precisely the
chemical and physical quality of the solids, their colour and settling characteristics
of dust in the atmosphere, after volcanic outbreak should be systematically recorded and
summer ablation systematically observed, measuring albedo , radiation , heat and mass
transfer. Observations should be made to determine the mechanism by which the colour
effect is again diminished and obliterated.
surveys of ancient ports should be made for dating inundations and emergence of buildings.
The stability of investigated areas should be tested by measuring and dating tilts on
buildings, on stalagmites and stalactites in caves, and on natural and artificial basins
with horizontal stratification like salt pans.
Shifts in salt technology
and salt trade should be treated as a main part of an historical study intended for
tracing sea level and climatic changes.
Fig. 4. Estimated ocean level changes in
pre-historic and historic time.
Bibliography for Sealevel
changes- e-mail David Bloch
Agate, A., 1940. Der Hansische
Baienhandel. Winter’s Universitatsbuchhandlung, Heidelberg, 120 pp.
Albright, W.P., 1960. Th Archaeology of
Palestine. Penguin Books, Harmondsworth, Middlesex, 271 pp.
Babbage, Ch., 1847. 0bservations on the
Temple of Serapis at Pozzuoli near Naples. Private Publication.
Bantelmann, A., 1960 Forschungsergebnisse
der Marschenarchaologie zur Frage der Niveauveranderung an der Schleswig-holsteinischen
Westkuste. Kuste, 8:45- 65.
M.R., 1963. The social influence of salt. Sci. Am., 209 (1):88 98.
M.R. and Hester, W.B., 1962. Climate and volcanic outbreaks. Bull.Res.Council Israel,
Sect. G. 11(4): 173-174.
M.R., and Martin, H. 1935. Verfahren zur Gewinnunge von Salzen aus Salzhaltigen laugen
durch Verdampfen mittels Sonnenergie. Deutsche Reichspatent 660490.
M.R. Farkas, L. and Spiegler, K.S., 1951. Solar evaporation of salt brine. Ind. Eng.
Chem., 43: 1544-1553.
Bridbury, A.R., 1955. England and the Salt
Trade in the Later Middle Ages. Clarendon Press, 0xford, 198 pp.
Bronsted J., 1960. The Vikings. Penguin
Books. Harmondsworth, Middlesex, 320 pp.
Brooks, C.E.P., 1949. Post-glacial climatic
changes in the light of recent glaciological research. Geograf. Ann., 31:21-24.
Bury, J.B., 1958. History o the Later Roman
Empire from the Death of Theodosius I to the Death of Justinian. 2. Dover Publications,
New York, N.Y., 494 pp.
Busch, A., 1960 Eine alte Landoberflasche
und Kulturpuren in Nordstrader Watt. Kuste 8:R., 1960. East Anglia. Thames and Hudson,
London 240 pp.
Crary, A.P., Robinson, E.S., Bennett, H.F.
and Boyd, W.W., 1962. Glaciological regime of the Ross ice shelf. J. Geophys. Res., 67(7):
Curray, J.R., 1961 Late Quaternary sea
level: a discussion. Bull.Geol. Soc. A., 72: 1701- 1712. Daly, R.A., 1920. A recent
world-wide sinking of the ocean level. Geol.Mag., 57: 246-261
De Beer, G., 1960. Iktin. Geograph. J., 126:
De Bizarro, P.C., 1901. Tipografia Seitz,
Gorizia, 23 pp. Dendermonde, M.an
Dibbits, H.A.M.C., 1956. The Dutch and their
Dikes. De Bezige Bij, Amsterdam, 173 pp.
Diole, Ph., 1954. 4000 Years under the Sea.
Sidwic an Jackson, London, 320 pp.
Dubois, G., 1924. Recherches sur les
terraines Quarternaires du nord de la France. Mem. Soc. Geol. Nord, 8(1).
Ehrenberg V., 1951. The People of
Aristophanes. Blackwell, 0xford, 417 pp.
Ellis, M. 1955. 0 monopolio do sal do Estado
do Brasil, 1631-1801. Historica da Civilizacao Brasileira, 14. Univ. Sao Paulo, Bol., 197:
Fairbridge R.W., 1958. Dating the latest
movements of the Quaternary sea level. Trans. N.Y. Acad. Sci., 20: 471-482.
Fea, D.C., 1831. Storia delle Saline
d’0stia Dissertazione storica, fisica, legale. Nella Stamperia della Rev. Camera
Apostolica, Rome 91 pp.
Fuchs, V. and Hillary, E., 1960. The
Crossing o Antarctica. Penguin Books, Harmondsworth, Middlesex, 320 pp.
Giddings J.C. and LaChapelle, E., 1961.
Diffusion theory applied to radiant energy distribution and albedo snow. J. Geophys. Res.,
Godwin, H. 1943. Coastal peat beds of the
British Isles and North Sea. J.Ecol., 31: 199- 247.
Goetz, W., 1913. Ravernna. Seemann, Leipzig,
Goodchild, R.G 1950. Roman Tripolitania.
Reconnaissance in the desert frontier zone. Geograph.J., 115 (4-6): 161-178.
Gow, A.J., 1963. The inner structure of th
Ross ice shelf at Little America V, Antarctica, as revealed by deep core drilling. Assoc.
Intern. Hydrol. Sci., Comm. Snow Ice, Publ., 61: 272- 284.
Hallam, H.E., 1959-1960. Salt making in the
Lincolnshire Fenland durin the Middle Ages. Lincolnshire Architectural Archaeol. Soc.
Rept. Papers, New Ser. 8:85-112.
Harding , S.T., 1935. Changes in lake levels
in grea Basin Area. Civil Eng. (N.Y.), 5(2): 78-90.
Ives, J., 1803, Garianonum of th Romans.
Downes, Yarmouth, 54 pp.
Jarvis, C.S., 1936. Three Deserts Murray
London 290 pp.
Jelgersma, S., 1961. Holocene Sea Level
changes i the Netherlands. Van Aelst, Maastricht, 101 pp.
Jelgersma, S. and Pannekoek, A.J., 1960.
Post-glacial rise of sea level in The Netherlands. Geol. Mijnbouw, 39: 201-207.
Kestner, F.J. 1962. The old coastline of the
Wash. Geograph, J., 128 (4):455-478.
Klein, C., 1961. 0n the fluctuations o the
level of the Dead Sea since the beginning of the 19th century. State israel, Min. Agr.,
Water Comm., Hydrol. Serv., papers, 7:83 pp.
Klein, Cippora Fluctuations of the level of
the Dead Sea
Hebrew Universtity 1986
Kolner, P. 1920. Das Basler Salzwesen, seit
dem 13. Jahrhundert bis zur Neuzeit. Frobenius A.G. Basel, 127 pp.
Koster, R. 1960. Zur Frage der gegenwartigen
Senkung der schleswig-holsteinischen 0stkuste. Kuste, 8:139-159.
Lehmann Hartleben, K., 1923. Die Antiken
Hafenanlagen im 0stlichen Mittelmeer. Dietrich, Leipzig, 304 pp.
Lister , H ., 1959. The characteristics of
th Antarctic ice sheet. Geophys. J., 2(2): 164-168.
Meiggs, R., 1960. Roma 0stia. Clarendon
Press, 0xford, 598 pp.
Mongait, A.L., 1961. Archaeology i the
U.S.S.R. Penguin Books, Harmondswotch, Middlesex, 320 pp.
Muir, W. 1924. The Caliphate, its rise,
decline and fall. Grant Edinburgh, 633.
Nenquin J., 1961. Salt - A Study in Economic
Prehistory. Disseertationes Archaeologicae Gandenses, VI. De Tempel, Brugge, 162 pp.
Newman, Ph. 1953. A Short Story of Cyprus.
Longmans and Green, London 235 pp.
Nicephor, G., 1562. Byzant. Hist. Basileae,
per Ionnem 0porium, 271 pp.
Nilsson, M. 1962. Imperial Rom . Schocken
Books, Bell and Sons London, 312 pp.
Pirenne, H., 1957. Mohammed and Charlemagne.
Meridian Books, Norton, New York, N.Y., 293 pp.
Pirenne, H., 1958. A History o Europe. I.
Anchor Books, Doubleday, New York, N.Y. 282 pp.
Reifenberg, A. 1951. Caesarea, a study in
the decline of a town. Israel Exploration J., 1(1): 20-32.
Samuel, A.M., 1918. The Herring. Murray,
London, 199 pp.
Shepar F.P. and Suess, H.I., 1956. Rate of
post-glacial rise of sea level. Science, 123: 1082-108 3.
St. Jerome. In: Selected letters of St.
Jerome . With Englis transl. by F.A. Wright Heinemann, London, 510 pp.
Tacitus, P.C. 1829. An XV. 18.3 Jones,
London, 709 pp. Tanner, J.R., 1932. Cambridge Mediaeval History. 7. Cambridge Univ.
Press London, 230 pp.
Thukydides, 1850 History. 3. Parker, 0xford,
Van Andel, T.H. and Laborel, J., 1964.
Recent high relative sea level stand near Recife, Brazil. Science, 145:580- 581.
Yonge, C.M., 1963. Animals that bore through
rock. New Scientist, 328: 468-471.
Related Links | Activities | Email List |
PHYSIOLOGY | GEOLOGY | ARCHAEOLOGY | PALAEOCLIMATOLOGY | EUSTATIC SEALEVELS | DEAD SEA LEVELS | PALAEOGEOGRAPHY | PRODUCTION SALTPETER | RELIGION | ECONOMICS | INDIA Monopolies | CHINA Monopolies | FRANCE the Gabelle | THE MANY USES of Salt | ETYMOLOGY | MONOMANIA
|COPYRIGHT NOTICE AND DISCLAIMER © Copyright David Bloch, 1996. All rights reserved.
Copying of this document in any material form is prohibited other than as necessary for
the purpose of viewing on this Web site. The contents of this document is for general
information only. Nothing in this document constitutes legal advice.
||This web page and those derived from this page,
gives collected information derived from other sources believed to be accurate at the time
of storage on available Internet disk space.. These web pages are non commercial, and
academic in purpose, and are stored as personnel information for the page owner's own use.
No warranty of accuracy, reliability or completeness is given and (except in so far as
liability under any statute can be excluded) no responsibility arising in any other way
for errors and omissions or in negligence is accepted by the author and page owner, David
Bloch MRBLOCH SALT ARCHIVE, in the event that others access these pages
MRBLOCH SALT ARCHIVE,
is researching the significance, of SALT [NaCl] through the period 1000 BC . up to the
detailed references of statements made here, or Bibliography- Please mail: