12-meter-long man made monolith discovered off Italian coast [View all]
A massive monolith over 10,000 years old has been found in the Mediterranean Sea near Italy, scientists say. The block, which was apparently constructed by humans, bears traces of prehistoric civilization.
The 12-meter-long monolith resting on the sea-floor was located at a depth of 40 meters, in a shallow bank of the Sicilian Channel, says the report by ocean scientists from Italy and Israel published in July.
It is broken into two parts, and has three regular holes: one at its end which passes through from part to part, the others in two of its sides.
According to the study, the site was abandoned at about 9,350 ± 200 years BP (Before Present) and the morphological evidence, underwater observations and results of petrographic analysis suggest that the monolith was made by humans.
This discovery provides evidence for a significant Mesolithic human activity in the Sicilian Channel region.
The scientists say the block was cut and extracted as a single stone from the outer rectilinear ridge which was about 300 meters to the south, and then transported and possibly erected.
From the size of the monolith, we may presume that it weighs about 15 tons, the study says, adding that its function hasnt been specified yet.

http://www.rt.com/news/311675-mediterranean-human-made-monolith/
Science Abstract from another source.
Abstract
The ancient geography of the Mediterranean Basin was profoundly changed by the increase in sea level following the Last Glacial Maximum. This global event has led to the retreat of the coastlines, especially in lowland areas and shallow shelves, such as the Sicilian Channel.
The NW sector of this shelf, known as Adventure Plateau, is studded by isolated shoals mostly composed of Late Miocene carbonate rocks and by some volcanic edifices. These shoals, until at least the Early Holocene, formed an archipelago of several islands separated by stretches of extremely shallow sea. One of these submerged features the Pantelleria Vecchia Bank located 60 km south of Sicily, has been extensively surveyed using geophysical and geological methods.
It is composed of two main shoals, connected seaward by a rectilinear ridge which encloses an embayment. Here we present morphological evidence, underwater observations, and results of petrographic analysis of a man-made, 12 m long monolith resting on the sea-floor of the embayment at a water depth of 40 m. It is broken into two parts, and has three regular holes: one at its end which passes through from part to part, the others in two of its sides.
The monolith is composed of calcirudites of Late Pleistocene age, as determined from radiocarbon measurements conducted on several shell fragments extracted from the rock samples. The same age and composition characterize the metre-size blocks forming the rectilinear ridge. The rest of the rocks composing the shoals are mostly Tortonian limestonessandstones, as revealed by their fossil content.
Extrapolating ages from the local sea level curve, we infer that seawater inundated the inner lands at 9350 ± 200 year B.P., the upper limit which can be reasonably taken for the site abandonment. This discovery provides evidence for a significant Mesolithic human activity in the Sicilian Channel region.
http://www.sciencedirect.com/science/article/pii/S2352409X15300535
So really what it says is that the object is at least 11 thousand years old and could be older, this is the dating of when the area was flooded not when it was constructed. Also interesting is that the Ancient stone structures of Malta lies in this area too.

posted in Anthropology forum also; http://www.democraticunderground.com/12292233