THE STRAIT OF GIBRALTAR

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          THE STRAIT OF GIBRALTAR - AKA THE PILLARS OF HERCULES




 
The Strait of Gibraltar in 3D   


 
This perspective view shows the Strait of Gibraltar, which is the entrance to the Mediterranean Sea from the Atlantic Ocean. Europe (Spain) is on the left. Africa (Morocco) is on the right. The Rock of Gibraltar, administered by Great Britain, is the peninsula in the back left.

The Strait of Gibraltar is the only natural gap in the topographic barriers that separate the Mediterranean Sea from the world’s oceans. The sea is about 3,700 kilometers (2,300 miles) long and covers about 2.5 million square kilometers (1 million square miles), while the Strait is only about 13 kilometers (8 miles) wide. Sediment samples from the bottom of the Mediterranean Sea that include evaporite minerals, soils, and fossil plants show that about 5 million years ago the strait was topographically blocked and the Sea had evaporated into a deep basin far lower in elevation than the oceans. Subsequent changes in the world’s hydrologic cycle, including effects upon ocean salinity, likely led to more ice formation in polar regions and more reflection of sunlight back to space, resulting in a cooler global climate at that time. Today, topography plays a key role in our regional climate patterns. But through the Earth’s history, topographic change, even perhaps over areas as small as 13 kilometers across, has also affected the global climate.

This image was generated from a Landsat satellite image draped over an elevation model produced by the Shuttle Radar Topography Mission (SRTM). The view looks eastward with a 3-times vertical exaggeration to enhance topographic expression. Natural colors of the scene (green vegetation, blue water, brown soil, white beaches) are enhanced by image processing. The scene includes some infrared reflectance (as green) to highlight the vegetation pattern as well as shading of the elevation model to further highlight the topographic features.

Landsat has been providing visible and infrared views of the Earth since 1972. SRTM elevation data matches the 30-meter (99-feet) resolution of most Landsat images and will substantially help in analyses of the large Landsat image archive.

Elevation data used in this image were acquired by the Shuttle Radar Topography Mission (SRTM) aboard the Space Shuttle Endeavour, launched on February 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. SRTM was designed to collect three-dimensional measurements of the Earth’s surface. To collect the 3-D data, engineers added a 60-meter-long (200-foot) mast, installed additional C-band and X-band antennas, and improved tracking and navigation devices. The mission is a cooperative project between the National Aeronautics and Space Administration (NASA), the National Imagery and Mapping Agency (NIMA) of the U.S. Department of Defense (DoD), and the German and Italian space agencies. It is managed by NASA’s Jet Propulsion Laboratory, Pasadena, CA, for NASA’s Earth Science Enterprise.


View Size: 46 kilometers (28 miles) wide, 106 kilometers (66 miles) distance
Location: 36 degrees North latitude, 5.5 degrees West longitude

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          THE AFRICAN (MOROCCO) SIDE OF THE STRAIT

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THE EUROPEAN SIDE - GIBRALTAR

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FROM:

THE SMITHSONIAN



The geology of the Strait of Gibraltar is important in interpreting the structural, stratigraphic, and

oceanographic history from the Miocene to the Recent of the Alboran Sea and the entire western

Mediterranean Sea, including the Alpine system. Despite this, almost no data were available on

submarine portions of the Strait. The data are presented on seismic profiles, bottom samples, detailed

bathymetry, and earthquake analysis. Detailed bathymetry and 3.5 - kHz seismic profiles show that the

geomorphology and the physiographic units differ largely from west to east of the Strait; smooth and

gentle shelves and slopes to the west, to rocky and steep shelves and slopes to the east; with a

hummocky and rough bottom floor dominated by two ridges and several closed basins. Geophysical

measurements indicate that most of the bedrocks or rock debris are standing at steep angles with dip

greater than 25 degree, and that the sea floor is generally blanketed by unconsolidated sediments,

mainly bioclastic gravel, and terrigenous sand. 

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FROM:   N A S A




Solitons, Strait of Gibraltar  Click here to view full image (306 kb) 


 
Surf’s up! This image is a mosaic of two photographs taken by astronauts aboard the International Space Station viewing large internal waves in the Strait of Gibraltar. These subsurface internal waves occur at depths of about 100 m, but appear in the sunglint as giant swells flowing eastward into the Mediterranean Sea.

The narrow Strait of Gibraltar is the gatekeeper for water exchange between the Atlantic Ocean and Mediterranean Sea. A top layer of warm, relatively fresh water from the Atlantic Ocean flows eastward into the Mediterranean Sea. In return, a lower, colder, saltier layer of water flows westward into the North Atlantic ocean. A density boundary separates the layers at about 100 m depth.

Like traffic merging on a highway, the water flow is constricted in both directions because it must pass over a shallow submarine barrier, the Camarinal Sill. When large tidal flows enter the Strait, internal waves (waves at the density boundary layer) are set off at the Camarinal Sill as the high tide relaxes. The waves—sometimes with heights up to 100 m — travel eastward. Even though the waves occur at great depth and the height of the waves at the surface is almost nothing, they can be traced in the sunglint because they concentrate the biological films on the water surface, creating slight differences in roughness.

In this image, the tidal bore creates internal waves (top arrow) that propagate eastward and expand outward into the Mediterranean in a big arc (near bottom). Other features can be traced in the sun’s reflections. Linear and V-shaped patterns (bottom arrow) are wakes of ships, providing evidence for the heavy ship traffic through the narrow waters between Spain and Morocco.

Water features in the sunglint pattern appear to the astronaut to be extremely transient, visible only briefly (a few seconds) as the spacecraft passes rapidly overhead. Photographs from space of the ocean sunglint pattern are a tool for studying physical oceanographic and atmospheric processes and other phenomena that affect surface roughness.



references:


Internal Waves, Strait of Gibraltar

Christopher O. Tiemann, Peter F. Worcester, Bruce D. Cornuelle, Effects of Internal Waves and Bores on Acoustic Transmissions in the Strait of Gibraltar, Conference Proceedings from Internal Solitary Wave Workshop, Victoria, B.C., Canada, October 1998. Woods Hole Oceanographic Institution Technical Report WHOI-99-07

Oceanography from the Space Shuttle, Solitons, Gibraltar




Astronaut photographs

Oceanography from the Space Shuttle, Solitons, Gibraltar

 
Astronaut photographs ISS009-E-9952 and ISS009-E-9954 were taken June 3, 2004 with a Kodak DCS760 digital camera equipped with a 180 mm lens, and are provided by the Earth Observations Laboratory, Johnson Space Center. The International Space Station Program supports the laboratory to help astronauts take pictures of Earth that will be of the greatest value to scientists and the public, and to make those images freely available on the Internet. Additional images taken by astronauts and cosmonauts can be viewed at the NASA/JSC Gateway to Astronaut Photography of Earth.
 


This page is a copy of the page as it originally appeared on the Earth Observatory Site.
If links are broken we recommend starting again from the Earth Observatory Homepage.   

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                                      M E S S I N I A N    S A L I N I T Y    C R I S I S




The Messinian Salinity Crisis, also referred to as the Messinian Event, is a period when the Mediterranean Sea evaporated partly or completely dry during the Messinian period of the Miocene epoch, approximately 6 million years ago.


Naming

The first observation of the result of the crisis may have been when the period's name was created. In the mid 1800s, Professor Mayer-Eymar of Zurich studied some fossils between gypsum layers and identified them as being just before the end of the Miocene Epoch. He named the period the Messinian, and salt-bearing and gypsum-bearing layers in many Mediterranean countries have been dated to that period.[1] It is not known if those layers were formed in the ocean basin.


 Discovery

In 1961, seismic surveying of the Mediterranean basin revealed a geological feature some 100-200 metres below the seafloor. This feature, dubbed the M reflector, closely followed the contours of the present seafloor, suggesting that it was laid down evenly and consistently at some point in the past. Drilling experiments, conducted a decade later from the Glomar Challenger under the supervision of head scientist Kenneth J. Hsu during Leg 13 of the Deep Sea Drilling Program, revealed the nature of the M reflector, a layer of evaporites up to 3 kilometres thick.


Evidence

Sediment samples from below the deep seafloor of the Mediterranean Sea, which include evaporite minerals, soils, and fossil plants, show that about 5.9 million years ago in the late Miocene period the precursors of the modern Strait of Gibraltar closed tight and the Mediterranean Sea evaporated into a deep dry basin with a bottom at some places 2 to 3 miles (3.2 to 4.9 km) below the world ocean level.[1] Even now the Mediterranean is saltier than the North Atlantic because of its near isolation by the Straits of Gibraltar and its high rate of evaporation.

If the Strait of Gibraltar closes again, which is likely to happen in the near geological future (though extremely distant on a human time scale), and the Suez Canal closes, the Mediterranean would evaporate dry in about a thousand years.[2]

The first solid evidence for the ancient desiccation of the Mediterranean Sea came in the summer of 1970, when geologists aboard the Deep Sea Drilling Program drillship Glomar Challenger brought up drill cores containing arroyo gravels and red and green floodplain silts; and gypsum, anhydrite, rock salt, and various other evaporite minerals that often form from drying of brine or seawater, including in a few places potash where the last bitter waters dried up. One drill core contained a wind-blown cross-bedded deposit of deep-sea foraminiferal ooze that had dried into dust and been blown about on the hot dry abyssal plain by sandstorms and ended up in a brine lake. These layers alternated with layers containing marine fossils, indicating a succession of drying and flooding periods. Other evidence of drying comes from the remains of many (now submerged) canyons that were cut into the sides of the dry Mediterranean basin by rivers flowing down to the abyssal plain. For example, the Nile cut its bed down to several hundred feet below sea level at Aswan and 8,000 feet (2,400 m) below sea level under Cairo. Fossilized cracks were found where muddy sediment had dried and cracked in the sunlight and drought. The area underwent repeated flooding and desiccation over 700,000 years. About 5.4 million years ago at the start of the Pliocene period the barrier at the Strait of Gibraltar broke, permanently reflooding the basin.

Some of these Messinian deposits have since been pushed up onto land during later orogenies in Messina (Sicily), northeast Libya, Italy, and southern Spain.




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ON THE ORIGIN OF THE STRAIT OF GIBRALTAR
 

Nicolas Loget, a,  and Jean Van Den Driesschea
aGéosciences Rennes, Université de Rennes 1, UMR 6118, Campus de Beaulieu, 35042 Rennes cedex, France

Available online 2 May 2006.





Abstract

Most interpretations of the Early Pliocene opening of the Strait of Gibraltar involve a tectonic process. However, no tectonic structure of this age has been unequivocally documented that could account for such a hypothesis. On the other hand, the sea-level drop of the Mediterranean during the Messinian Salinity Crisis has dramatically enhanced continental erosion and in particular regressive fluvial erosion. We show that such erosional process inevitably developed in the Gibraltar area. We finally propose that regressive fluvial erosion was at the origin of the opening of the Strait of Gibraltar.

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Several cycles

The enormous volume of extant Messinian evaporites could not have been deposited during a single event.[2] Furthermore, the nature of the strata points strongly to several cycles of the Mediterranean Sea completely drying up and being refilled. Each refilling was presumably caused by a seawater inlet opening either tectonically or by a river flowing eastwards below sea level into the "Mediterranean Sink" cutting its valley head back west until it let the sea in, similarly to a river capture. The last refilling was at the Miocene/Pliocene boundary when the Strait of Gibraltar broke wide open permanently. Upon closely examining the Hole 124 core, Kenneth J. Hsu found that:

"The oldest sediment of each cycle was either deposited in a deep sea or in a great brackish lake. The fine sediments deposited on a quiet or deep bottom had perfectly even lamination. As the basin was drying up and the water depth decreased, lamination became more irregular on account of increasing wave agitation. Stromatolite was formed then, when the site of deposition fell within an intertidal zone. The intertidal flat was eventually exposed by the final desiccation, at which time anhydrite was precipitated by saline ground water underlying sabkhas. Suddenly seawater would spill over the Strait of Gibraltar, or there would be an unusual influx of brackish water from the eastern European lake. The Balearic abyssal plain would then again be under water. The chicken-wire anhydrite would thus be abruptly buried under the fine muds brought in by the next deluge. The cycle repeated itself at least eight or ten times during the million years that constituted the late Miocene Messinian stage." (Kenneth J. Hsu, The Mediterranean Was a Desert, Princeton University Press, Princeton, New Jersey 1983. A Voyage of the Glomar Challenger.)


Chronology

Based on palaeomagnetic datings of Messinian deposits tectonically brought above sea level, the salinity crisis started at the same time over all the Mediterranean basin, at 5.96 ± 0.02 million years ago. It was isolated from the Atlantic Ocean between 5.59 and 5.33 million years ago, resulting in a huge decrease in the Mediterranean sea level. During the initial stages (5.59 - 5.50 million years ago) was extreme erosion, creating several huge canyon systems (some similar in scale to the Grand Canyon) around the Mediterranean. Later stages (5.50 - 5.33 million years ago) are marked by cyclic evaporite deposition into a large "lake-sea" basin.

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Dehydrated geography

The notion of a completely waterless Mediterranean Sea has some corollaries.

The Strait of Gibraltar must have somehow reconfigured to disconnect the Mediterranean Sea from the Atlantic Ocean.
The high level of salinity would have precluded almost all plant life or, by extension, animal life, making much of the basin a wasteland.[citation needed] The basin's low altitude would have made it extremely hot during the summer through adiabatic heating, evidence supported by the presence of anhydrite, which is only deposited in water warmer than 35°C (95°F).
Rivers emptying into the basin would have cut their beds much deeper (at least a further 2,400 m or 8000 feet with the Nile, as the buried canyon under Cairo shows). This later caused some consternation for the construction of the Aswan Dam, with an original river bed filled with debris 750 meters = c.2,460 feet below sea level, although 1,200 km away from the coast.
2 to 3 miles below sea level at 35°C would have resulted in 1.43 to 1.71 atm (1,090 to 1,300 mmHg) of air pressure at the very bottom. A wind blowing into the dry Mediterranean hollow, assuming dry adiabatic warming, would be about 30°C - 50°C hotter at the bottom than it was at sea level.[citation needed]
Climates throughout the central and eastern basin of the Mediterranean and surrounding regions to the north and east would have been drier, even above modern sea level; today the evaporation from the Mediterranean Sea supplies moisture that falls in frontal storms, but without such moisture, the Mediterranean climate that we associate with Italy, Greece, and the Levant would be limited to the Iberian Peninsula and the western Maghreb. The eastern Alps, the Balkans, and the Hungarian plain would also be much drier than they are even if the westerlies prevailed as they do now. Civilizations characteristic of classical times would have been impossible in Egypt, Phoenicia, and Greece until the Mediterranean Sea filled.


Global effects

The water from the Mediterranean would have been redistributed in the world ocean, raising global sea level by anything up to 10 meters (~33 feet). The Mediterranean basin also sequestered below its seabed a significant percentage of the salt from Earth's oceans; this decreased the average salinity of seawater and raised its freezing point.


Cause

Although several possible causes have been considered, including tectonic uplift or sea level drop due to glaciation, evidence has been found of a crust-mantle interaction. Changes in volcanic rocks suggest subducted Tethys Sea crust may have moved westward and changed the chemistry and density in magma underlying the western Mediterranean. The less dense material under the area could have raised it sufficiently to close the Atlantic connection.

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Replenishment

When the Strait of Gibraltar was ultimately breached, the Atlantic Ocean would have poured a vast volume of water through what would have presumably been a relatively narrow channel. The resulting waterfall could have been higher than Angel Falls is today (979 meters), and far more powerful than either Niagara Falls or Victoria Falls.


In popular culture
 
1920s speculative map of 50,000 years agoEven before 1961, there had been speculations about a possible dehydration of the Mediterranean Sea in the distant past.

In 1920, H. G. Wells published a popular history book in which it was suspected that the Mediterranean basin had in the past been cut off from the Atlantic. One piece of physical evidence, a deep channel past Gibraltar, had been noticed. Wells estimated that the basin had refilled roughly between 30,000 and 10,000 B.C. The theory he printed was that:
 
In the last Ice Age, so much ocean water was taken into the icecaps that world ocean level dropped below the sill in the Strait of Gibraltar.

Without the inflow from the Atlantic the Mediterranean would evaporate much more water than it receives, and would evaporate down to two large lakes, one on the Balearic Abyssal Plain, the other further east.

The east lake would receive most of the incoming river water, and may have overflowed into the west lake.

All or some of this seabed may have had a human population, where it was watered from the incoming rivers.
There is a long deep submerged valley running from the Mediterranean out into the Atlantic.

But the Strait of Gibraltar is 320 m deep, and global sea levels during the most recent Ice Age are believed to have lowered sea levels by only about 100 m, so the basin was not dry during this recent period. That there had been an extreme drying event in the region, was to be discovered forty years later.

Had the breach in the Strait of Gibraltar not occurred, as it did not with the land around the Suez Canal, the course of human history could have been very different.

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Footnotes

^ Kenneth J. Hsu, The Mediterranean Was a Desert, Princeton University Press, Princeton, New Jersey 1983. A Voyage of the Glomar Challenger.
^ "Only the inflow of Atlantic water maintains the present Mediterranean level. When that was shut off sometime between 6.5 to 6 MYBP, net evaporative loss set in at the rate of around 3,300 cubic kilometers yearly. At that rate, the 3.7 million cubic kilometers of water in the basin would dry up in scarcely more than a thousand years, leaving an extensive layer of salt some tens of meters thick and raising global sea level about 12 meters." Cloud, P. (1988). Oasis in space. Earth history from the beginning, New York: W.W. Norton & Co. Inc., 440. ISBN 0-393-01952-7
^ a b Wells, H. G. (1920). The Outline of History. Garden City, New York: Garden City Publishing Co., Inc..
 

References

^  Clauzon, Georges, Suc, Jean-Pierre, Gautier, François, Berger, André, Loutre, Marie-France (1996). "Alternate interpretation of the Messinian salinity crisis: Controversy resolved?". Geology 24 (4): 363–366.  DOI:<0363:AIOTMS>2.3.CO;2 10.1130/0091-7613(1996)024<0363:AIOTMS>2.3.CO;2
^  Svend Duggen, Kaj Hoernle, Paul van den Bogaard, Lars Rüpke and Jason Phipps Morgan (2003). "Deep roots of the Messinian salinity crisis". Nature 422 (6932): 602–6.  DOI:10.1038/nature01553
Geology 212, Lecture 17: "When the Mediterranean Dried Up". (Accessed 7/16/06)
W. KRIJGSMAN et al., "Chronology, causes and progression of the Messinian salinity crisis" Nature 400, 652 - 655


Bibliography

Kenneth J. Hsu, The Mediterranean Was a Desert: A Voyage of the Glomar Challenger, Princeton University Press, ISBN 0-691-02406-5


External links

http://www.soton.ac.uk/~imw/messin.htm
http://earth.leeds.ac.uk/tectonics/messinian/
http://www.messinianonline.it/
Retrieved from "http://en.wikipedia.org/wiki/Messinian_salinity_crisis"
Categories: Articles with unsourced statements since February 2007 | All articles with unsourced statements | Regional geology | Mediterranean | Paleogeography





SPACE VIEW OF STRAIT OF GIBRALTAR 

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Strait of Gibraltar


Orbit 35519 Frame 2885 4 February 2002 11:3:41 GM

Internal waves in the Strait imaged on 4th February 2002 by the ERS SAR.

Through the Strait, a continuous current enters the Mediterranean Sea from the Atlantic Ocean, and tidal currents ebb and flow along the European and African shores. A westerly flowing undercurrent carries off the surplus waters of the Mediterranean.

Upper right corner: To the left, Algeciras, a port and industrial centre in the Bay of Gibraltar. To the right: on top, La Linea de la Concepción, in the neutral zone that separates Spain from the British dependency of Gibraltar; below it, the free port of Gibraltar.

Throughout, in the ocean: intense ship traffic and plenty of oil slicks.

Bottom part of the image: Northwestern Morocco with the town of Tangier facing the Strait. Broad coastal plains can be detected along the Atlantic Ocean. To the right: the Rif mountains.

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Strait of Gibraltar



The Strait of Gibraltar connects the Atlantic Ocean with the Mediterranean Sea. The water body in the Strait of Gibraltar and its approaches consists of a deep layer of salty Mediterranean water (salinity approximately 38 psu) and an upper layer of less salty Atlantic water (salinity approximately 36 psu). The mean flow is composed of two counter-flowing layers: an upper layer of Atlantic water flowing into the Mediterranean Sea and a lower layer of Mediterranean water flowing into the Atlantic Ocean. The mean depth of the interface between these two layers slopes down from about 80 m at the Mediterranean side of the strait to about 800 m at the Atlantic side. The relative change of density across this interface, which is mainly determined by the salinity difference and is therefore called a halocline, is 0.002. For a comprehensive summary of the oceanography of the Strait of Gibraltar the reader is referred to the paper of Lacombe and Richez (1982). The Strait of Gibraltar has a complex bottom topography containing several ridges as depicted in the topographic map shown in Fig. 1. The shallowest section in the Strait of Gibraltar is at the Camarinal Sill where the maxium water depth is 290 m. The interaction of the predominantly semidiurnal tidal flow with the sills inside the strait, in particular with the Camarinal Sill, gives rise to periodic deformations of the halocline in the sill regions which then give birth to internal solitary waves. The ERS SAR images have revealed that the internal solitary waves only propagate eastwards into the Mediterranean Sea and not westwards into the Atlantic. By model calculations Brandt et al. (1996) have shown that this asymmetry of the internal wave field in the Strait of Gibraltar and its adjacent waters results from the east-west asymmetry of the mean flow in the upper and lower layer of the strait.



Bottom topography of the Strait of Gibraltar. The shallowest section is at the Camarinal Sill. (Figure reproduced from Brandt, P., Alpers, W. & Backhaus, J. O., Study of the generation and propagation of internal waves in the Strait of Gibraltar using a numerical model and synthetic aperture radar images of the European ERS 1 satellite, J. Geophys. Res., 101, 14237-14252 (1996).)

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                                      Neanderthals at Gorham's Cave, Gibraltar





Researchers working on the Gibraltar promontory have amassed a suite of about 30 AMS radiocarbon dates from stacked Neanderthal occupations at Gorham's Cave that suggest Neanderthals were still living on Gibraltar at about 25,000 years ago, fully 5,000 years after they have been thought to be gone from the world. Clive Finlayson of the Gibraltar Museum and colleagues report on their findings in an online article made available on September 13, 2006 and to appear in a future issue of Nature.

The archaeological site of Gorham's Cave is located on the British territory of Gibraltar, that rocky narrow strip of land that extends off Spain and points towards Morocco. Gibraltar overlooks the Strait of Gibraltar, a 14-kilometer wide stretch of open water connecting the Mediterranean Sea with the Atlantic Ocean, and separating Europe from northern Africa. Gorham's Cave was discovered in 1907 and first excavated in the 1950s by John Waechter of the Institute of Archaeology in London. In addition to Phoenician, Carthegenian and Neolithic occupations in the cave, there are 16 meters of Pleistocene deposits. The top part of the Pleistocene consists of two Upper Paleolithic deposits, identified as Solutrean and Magdelenian and used by what archaeologists now call Anatomically Modern Humans (AMH). Below that, and reported to be separated by five thousand years is a level of pure Mousterian, and, according to the latest AMS radiocarbon dates, was occupied beween 23,000 and 33,000 years ago.


The cave backdrop is Gorham's Cave, Gibraltar (S. Finlayson). The skull is a CT reconstruction of the Gibraltar Devil's Tower Neanderthal child done by C. Zollikofer and M. Ponce de Leon, Anthropology Dept of the University of Zurich

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Mousterian Occupations at Gorham's Cave



Mousterian is the name given to a lithic industry that in Europe is always associated with Neanderthals; in parts of Africa, the Mousterian is found with both Neanderthals and Anatomically Modern Humans (AMH), at sites such as Haua Fteah in Libya and Djebel Irhoud in Morocco. The Mousterian occupation has been known since the 1940s and the fossil remains of Neanderthals have been found on Gibraltar before. There are eight other Mousterian sites including Forbes Quarry and Devil's Tower, where Neanderthal remains were recovered. Recent work at Gorham's Cave is headed by Clive Finlayson of the Gibraltar Museum and has concentrated on the Mousterian parts of the cave deposits.

What Finlayson and his crew have found to date include three superimposed Mousterian hearths, which all contained charcoal, and are now dated to 24,010 (+/-320), 26,400 (+/-440), and 30,560(+/-720) years before the present. Other materials in these occupation layers include cut (probably butchered) animal bone and classic Levallois blade-like flakes. The team has also conducted environmental research, and they argue that as climatic conditions worsened in Europe, the last small group of Neanderthals retreated as far as they could, finding refuge on Gibraltar.

Is this the last stand of the Neanderthals? It's hard to say. It's a pretty compelling story, but there are no fossil remains of Neanderthals in the cave and it's possible this is an AMH site (14 kilometers of sea separates Gibraltar from Morocco, after all). Nevertheless, Gorham's Cave is one of the sites to keep your eyes on.




References
Clive Finlayson et al. 2006. Late survival of Neanderthals at the southernmost extreme of Europe. Published online at Nature on September 13, 2006.
Eric Delson and Katerina Harvati. 2006. Return of the last Neanderthal. Published online at Nature on September 13, 2006.
Haua Fteah, Australian National University
Djebel Irhoud, Ma Prehistoire (in French)
Gorham's Cave, Gibraltar, the Gibraltar Museum


http://archaeology.about.com/od/neanderthals/a/gorhams_cave.htm

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GORHAM CAVE - GIBRALTAR