The Historical Importance Of Jerusalem's Geology

A view of the Old City in Jerusalem. (Credit: iStockphoto/Ash Laidlaw)

------------------------------------------------------------------------------------------------------------------------------------------

Bedrock Of A Holy City: The Historical Importance Of Jerusalem's Geology

Jerusalem's geology has been crucial in molding it into one of the most religiously important cities on the planet, according to a new study.

It started in the year 1000 BCE, when the Jebusite city's water system proved to be its undoing. The Spring of Gihon sat just outside the city walls, a vital resource in the otherwise parched region. But King David, in tent on taking the city, sent an elite group of his soldiers into a karst limestone tunnel that fed the spring. His men climbed up through a cave system hollowed out by flowing water, infiltrated beneath the city walls, and attacked from the inside. David made the city the capital of his new kingdom, and Israel was born.

In a new analysis of historical documents and detailed geological maps, Michael Bramnik of Northern Illinois University will add new geological accents to this pivotal moment in human history in a presentation October 20 at the annual meeting of the Geological Society of America in Portland, Oregon.

"The karst geology played a major role in the city's selection by David for his capital," Bramnik said.

It proved to be a wise decision. One of David's successors, King Hezekiah watched as the warlike Assyrian horde, a group of vastly superior warriors toppled city after city in the region. Fearing that they'd soon come for Jerusalem, he too took advantage of the limestone bedrock and dug a 550 meter-long (1804 feet) tunnel that rerouted the spring's water inside the city's fortified walls.

The Assyrians laid siege to the city in 701 BCE, but failed to conquer it. It was the only city in history to successfully fend them off.

"Surviving the Assyrian siege put it into the people's minds that it was because of their faith that they survived," Bramnik said. "So when they were captured by the Babylonians in 587, they felt it was because their faith had faltered."

Until then, the Jewish religion had been loosely associated. But that conviction united the Jews through the Babylonian Captivity, "and so began modern congregational religion," Bramnik said.

In an arid region rife with conflict, water security is as important today as it was during biblical times. While the groundwater for Jerusalem is recharged surface waters in central Israel, other settlements' water sources are not publicly available for research. Bramnik's efforts to find detailed hydrological maps were often rebuffed, or the maps were said to be non-existent.

"I think Jerusalem's geology and the geology of Israel is still significant to life in the region, perhaps even reaching into the political arena," he said.

The talk, The Bedrock of Monotheism: The Geology of Jerusalem and Its Historical and Religious Implications, is to be presented on October 20, 2009, at the Oregon Convention Center.
Adapted from materials provided by Geological Society of America, via EurekAlert!, a service of AAAS.

Geologists Point To Outer Space As Source Of The Earth's Mineral Riches

New research suggests that the wealth of some minerals that lie in the rock beneath the Earth's surface may be extraterrestrial in origin. (Credit: iStockphoto)

------------------------------------------------------------------------------------------------------------------------------------------

According to a new study by geologists at the University of Toronto and the University of Maryland, the wealth of some minerals that lie in the rock beneath the Earth's surface may be extraterrestrial in origin.

"The extreme temperature at which the Earth's core formed more than four billion years ago would have completely stripped any precious metals from the rocky crust and deposited them in the core," says James Brenan of the Department of Geology at the University of Toronto and co-author of the study published in Nature Geoscience on October 18.

"So, the next question is why are there detectable, even mineable, concentrations of precious metals such as platinum and rhodium in the rock portion of the Earth today? Our results indicate that they could not have ended up there by any known internal process, and instead must have been added back, likely by a 'rain' of extraterrestrial debris, such as comets and meteorites."

Geologists have long speculated that four and a half billion years ago, the Earth was a cold mass of rock mixed with iron metal which was melted by the heat generated from the impact of massive planet-sized objects, allowing the iron to separate from the rock and form the Earth's core. Brenan and colleague William McDonough of the University of Maryland recreated the extreme pressure and temperature of this process, subjecting a similar mixture to temperatures above 2,000 degrees Celsius, and measured the composition of the resulting rock and iron.

Because the rock became void of the metal in the process, the scientists speculate that the same would have occurred when the Earth was formed, and that some sort of external source – such as a rain of extraterrestrial material – contributed to the presence of some precious metals in Earth's outer rocky portion today.

"The notion of extraterrestrial rain my also explain another mystery, which is how the rock portion of the Earth came to have hydrogen, carbon and phosphorous – the essential components for life, which were likely lost during Earth's violent beginning."

The research was funded with the support of the Natural Sciences and Engineering Research Council of Canada and a NASA Cosmochemistry grant.
Adapted from materials provided by University of Toronto, via EurekAlert!, a service of AAAS.