Word of the Week - 4-7-2008

Word of the Week
INOSCULATE
Pronunciation: \i-ˈnäs-kyə-ˌlāt\
Function: verb
Inflected Form(s): in·os·cu·lat·ed; in·os·cu·lat·ing
Date: 1671
: join, unite


Interesting Fact
Diamonds are formed and brought to the surface by volcanoes.

The formation of natural diamond requires very specific conditions. Diamond formation requires exposure of carbon-bearing materials to high pressure, ranging approximately between 45 and 60 kilobars, but at a comparatively low temperature range between approximately 1652–2372 °F (900–1300 °C). These conditions are known to be met in two places on Earth; in the lithospheric mantle below relatively stable continental plates, and at the site of a meteorite strike.

The conditions for diamond formation to happen in the lithospheric mantle occur at considerable depth corresponding to the aforementioned requirements of temperature and pressure. These depths are estimated to be in between 140–190 kilometers (90–120 miles) though occasionally diamonds have crystallized at depths of 300-400 km (180-250 miles) as well. The rate at which temperature changes with increasing depth into the Earth varies greatly in different parts of the Earth. In particular, under oceanic plates the temperature rises more quickly with depth, beyond the range required for diamond formation at the depth required. The correct combination of temperature and pressure is only found in the thick, ancient, and stable parts of continental plates where regions of lithosphere known as cratons exist. Long residence in the cratonic lithosphere allows diamond crystals to grow larger.

Diamonds that have come to the Earth's surface are generally very old, ranging from under 1 billion to 3.3 billion years old.

Diamonds can also form in other natural high-pressure events. Very small diamonds, known as microdiamonds or nanodiamonds, have been found in meteorite impact craters. Such impact events create shock zones of high pressure and temperature suitable for diamond formation.

Not all diamonds found on earth originated here. A type of diamond called carbonado diamond that is found in South America and Africa was deposited there via an asteroid impact (not formed from the impact) about 3 billion years ago. These diamonds formed in the intrastellar environment. Presolar grains in many meteorites found on earth contain nanodiamonds of extraterrestrial origin, probably formed in supernovas.

Diamond-bearing rock is brought close to the surface through deep-origin volcanic eruptions. The magma for such a volcano must originate at a depth where diamonds can be formed, 150 km (90 miles) deep or more (three times or more the depth of source magma for most volcanoes); this is a relatively rare occurrence. These typically small surface volcanic craters extend downward in formations known as volcanic pipes. Diamond-bearing volcanic pipes are closely related to the oldest, coolest regions of continental crust (cratons). Not all pipes contain diamonds, and even fewer contain enough diamonds to make mining economically viable. The magma in volcanic pipes is usually one of two characteristic types, which cool into igneous rock known as either kimberlite or lamproite. The magma itself does not contain diamond; instead, it acts as an elevator that carries deep-formed rocks (xenoliths), minerals (xenocrysts), and fluids upward. Once diamonds have been transported to the surface by magma in a volcanic pipe, they may erode out and be distributed over a large area. A volcanic pipe containing diamonds is known as a primary source of diamonds. Secondary sources of diamonds include all areas where a significant number of diamonds, eroded out of their kimberlite or lamproite matrix, accumulate because of water or wind action. These include alluvial deposits and deposits along existing and ancient shorelines, where loose diamonds tend to accumulate because of their approximate size and density. Diamonds have also rarely been found in deposits left behind by glaciers (notably in Wisconsin and Indiana); however, in contrast to alluvial deposits, glacial deposits are not known to be of significant concentration and are therefore not viable commercial sources of diamond.


Trivial Pursuit
Here are the questions:
Global View (Geography):
What Asian island nation lets citizens criticize the state only from a tiny corner of Hong Lim Park?

Entertainment:
What TV host removed a pair of loafers on camera every weekday for 34 years?

News:
What credit card company was sued in 2001 by two baseball fans for plagiarizing their documentary of a cross-country pilgrimage?

Written Word:
How many people other than Oprah Winfrey appeared on the cover of O in its first year?

Life & Science: What did veterinarian Robert Lopez purposely drop in his own ear, to earn an Ig Nobel Prize – chili extract, his cat’s ear mites or Krazy Glue?

Games & Sports:
What eastern U.S. city catches sports fans in the net of its Lacrosse Museum and Hall of Fame?


Here are last week’s answers:
Global View (Geography):
What nation soberly reported treating 5,945 people in its hospitals for “trouser accidents” in 1999? Britain

Entertainment:
What human informed the world: “I’m the Doggfather – nobody bites my style”? Snoop Dogg

News:
Who are the only two men in history to get more popular votes in a U.S. presedential election than George W. Bush, through 2001? Ronald Reagan and Al Gore

Written Word:
What did Time magazine call its “Man of the Year” award when it picked Corazon Aquino? Person of the Year

Life & Science: What nation’s Ministry of Public Security released “Internet Police 110”, software designed to block access to cults, sex or violence, in 2001? China

Games & Sports:
What do hunters hope to attract by rattling and grunting like Hunter “The Gruntmaster” Powers? deer