Those old rocks

"In Glittering Gems, Reading Earth’s Story"

by

Carl Zimmer

June 13th, 2013

The New York Times

A jewelry store is an archive of the Earth. Every gem fixed to every ring or necklace was forged deep inside our planet, according to its own recipe of elements, temperature and pressure.

But it has taken a while for geologists to decode the cookbook for gems. Jade, for example, puzzled geologists for decades. “For a long time people looked at this crazy rock, and it didn’t make any sense,” said George Harlow, a geologist at the American Museum of Natural History. But thanks to the research of Dr. Harlow and other geologists, jade now has a back story: It formed in dying oceans.

The discovery of gems like rubies and jade thus signifies more than just a new supply of bling in jewelry stores. It tells geologists some important things about the planet.

If rocks contain jade, the scientists can be fairly sure those rocks are a vestige of an ocean buried underground. Rubies, on the other hand, appear in places where mountains formed from continental collisions, even if those mountains were eroded away millions of years ago.

Gems may thus preserve precious clues to some of the most profound questions about the life of our planet.

The Earth is covered with tectonic plates. In some places, like off the coast of the northwestern United States, ocean plates are getting pushed underneath continental ones. As the plates sink, they are squeezed to titanic pressures. They also get cooked. Under these extreme conditions, their atoms are combined into new molecular arrangements that would never emerge anywhere else on Earth. Hot jets of mineral-rich fluid rise from the plates, pushing up into the overlying rock. Among the things that emerge from that fluid is a mixture of sodium, aluminum, silicon and oxygen known as jadeite — a form of jade.

In the current issue of the journal Earth and Planetary Science Letters, Dr. Harlow and his colleagues report new findings that support this chain of events. At the bottom of the Caribbean Sea, they found jade-bearing deposits that are 30 million years older than the surrounding rock. That’s what you would expect if jade-producing fluid rose up from sinking oceanic crust long before other material from a sinking ocean plate.

In the journal Geology, Dr. Harlow — writing with Robert J. Stern of the University of Texas at Dallas, Tatsuki Tsujimori of Okayama University in Japan and Lee A. Groat of the University of British Columbia — explores some stories that gems like jade can tell. Each is different. While jade is produced from dying oceans, for example, rubies are forged in newborn mountains.

Some mountain ranges, like the Himalayas, were formed when two continental plates collided. Fifty million years ago, the Indian subcontinent was an isolated island. In a slow-motion crash, it plowed into Asia. The force of the impact crumpled rocks for hundreds of miles inland, producing mountains.

As mountains rose overhead, the Indian plate slid underneath Asia. Once again, the rock was squeezed and heated. Continents are ringed by rocks like shale, formed from sediments washing off of land. When crushed in this subterranean forge, shale can produce crystals of aluminum and oxygen.

If these crystals stop developing, they become sapphires. But the crystals may instead get pushed up toward the surface of the Earth. The overlying rock they move into is rich in chromium. The chromium atoms push the aluminum atoms out of the crystals and take their place, giving them a red color. “When they get a little chromium in them, we call them rubies,” Dr. Stern said.

The oldest deposits of jade and rubies date to only about 600 million years ago. The Earth itself is more than 4.5 billion years old, which naturally raises the question of why there aren’t any jade stones or rubies from the first nearly four billion years of the planet’s existence.

Dr. Stern, for one, thinks the answer is that plate tectonics — the stirring of the planet’s interior that drives plates around its surface — didn’t exist for most of Earth’s history. “I would say it started less than a billion years ago,” he said.

That’s a controversial idea in the geological community. Perhaps gems may someday resolve it.

Nicolas Steno and a Google Doodle

"Nicolas Steno, 17th century myth buster, gets Google Doodle"

January 11th, 2012

Los Angeles Times

Nicolas Steno, recipient of a Google Doodle on Wednesday, was a 17th century brainiac with the type of weird genius that led to his discovery of the human salivary duct and a made him a pioneer in geology. But in the end, he threw it all over for God.

It was Steno, born this day in 1638, who slapped his forehead and said: "Hey, you can see history in these layered rocks." That simple yet profound observation was at the core of a 1669 treatise with a long and windy name: "The Prodromus of Nicolaus Steno's Dissertation Concerning a Solid Body Enclosed by Process of Nature Within a Solid."

Because of "Prodromus," many now see Steno as the "father of geology," according to James Aber, geology professor at Kansas' Emporia State University. But Steno's geology career lasted all of three years. And at the time, his contemporaries pooh-poohed him.

Steno was born in Copenhagen into a family of well-to-do Lutheran goldsmiths. His later fame was perhaps fated: "Sten" in Danish is "rock." So his surname (Stensen, to the Danes) means "Son of Rocky," Aber notes.

Steno started out studying medicine, which took him to Amsterdam for a study of human anatomy. There, the Son of Rocky had his first eureka moment when he discovered the parotid salivary duct -- also called the Stensen's duct. Obviously. At least he was appreciated as a physician -- he was appointed personal doctor to Grand Duke Ferdinand II in 1665.

For reasons not quite clear, the duke requested in 1666 that Steno dissect the head of a large shark.

The good doctor concluded that shark teeth were identical to "glossopetrae" found in rocks.

To put this in perspective, glossopetrae -- fossilized shark teeth -- were at one time believed to have magical properties. In the Middle Ages, it was thought they were tongues of serpents that Saint Paul had turned to stone while visiting the islands of Malta. Thus they were called glossopetrae or "tongue stones." Roman naturalist Pliny the Elder (AD 23-79) thought they fell from the sky during lunar eclipses.

From sharks' teeth, Steno went on to other solid objects found inside other solid objects -- i.e. a layer of rock. His reasoning came to be known as "Steno's law of superposition," according to the University of California Museum of Paleontology -- layers of rock are arranged in a time sequence from oldest to youngest with youngest on the top "unless later processes disturb this arrangement."

After making such scientific observations -- at the time underappreciated -- Steno got religion.

He became Roman Catholic in 1667 and tossed aside science. In 1675, he became a priest and in 1677 a bishop. He was apostolic vicar of northern Germany and Scandinavia and spent the remainder of his life -- which wasn't that long -- doing missionary work. He died at age 48.

Nicolaus Steno [Wikipedia]

The Prodromus of Nicolaus Steno's Dissertation Concerning a Solid Body Enclosed by Process of Nature Within a Solid

Geology and the Civil War

"Impact Of Geology On The U.S. Civil War: War From The Ground Up"

October 7th, 2008

ScienceDaily

The connection between geology and the history of the Civil War has fascinated Robert Whisonant since his undergraduate days, and now Whisonant has teamed up with geomorphologist Judy Ehlen, both of Radford University, to take history, military history in particular, a step deeper -- into the geology beneath the soldiers' feet.

Whisonant and Ehlen examined the geomorphology of several battlefields and compared the terrain to known casualties for each day of fighting. The question, says Whisonant, is whether a correlation exists between the geology of the battlefield and casualties taken there. For some battles in the Civil War, the story told by the shape of the land is clear: soldiers were at greater risk in some areas because the underlying geology created a more dangerous terrain.

"Gettysburg is a good example where the Union had the high ground, but one disadvantage was the hard rock that forms that high ground is so close to the surface that the soldiers couldn’t dig trenches." They were open targets for artillery assault by the Confederates. But the disadvantage didn’t just go one way: "Those Confederate soldiers had to go up an open slope formed on more erodible rock with nothing to get behind when they finally had to attack." That's what Whisonant and Ehlen mean by their presentation title, "No Place to Run, No Place to Hide."

Whisonant and Ehlen also studied the terrain at Antietam, the site of the bloodiest battle in the Civil War, where on 17 September 1862 up to 23,100 soldiers were killed, wounded, or declared missing. "What’s so striking at Antietam," says Whisonant, is that "two geologic units underlie [that area]. One is a very, very pure limestone that as it erodes it literally melts. Mostly what you get with that is a very even, level, open surface -- there just aren’t a lot of deep holes and high hills that give soldiers a place to hide." On one area of this flat surface, known as Miller's Cornfield, "armies just shot each other to pieces until absolute exhaustion set in."

Nearby, however, a different formation lies beneath the terrain, made up of limestone and dolomite with some shale. "It makes for a very different kind of topography -- dissected topography" that provides good cover and concealment, and according to this study, "the casualties are much lower on that part of the battlefield."

In their talk on 5 October at the 2008 Joint Meeting of The Geological Society of America, Soil Science Society of America-American Society of Agronomy-Crop Science Society of America, Gulf Coast Association of Geological Societies, in Houston, Texas, Whisonant and Ehlen will present details of their of Civil War geomorphology and casualties, linking history and geology in a very striking way.

When asked why this topic creates such a draw for people, Whisonant says, "I just think there's an innate interest in the wars that we've been involved in -- especially the Civil War -- that's just a part of our national 'who we are.' I think we've got a built in audience. … Using geology to connect to something people understand is really gratifying -- I love to talk to my students about the planet they live on and make connections to something they would know something about".

More Mr. Wizard TV...geology

"Types of Rocks"


Mr. Wizard and "electricity"

Not Chicago, not New York but ancient "sin cities": Sodom and Gomorrah

"Then the Lord rained on Sodom and Gomorrah brimstone and fire from the Lord out of heaven; and he overthrew those cities, and all of the valley, and all the inhabitants of the cities, and what grew on the ground."

Okay, that's the mythical Biblical version and carries some weight for the fundamentally religious but from a scientific perspective it isn't that simple and over the years conjectures have been varied: Massive flooding, volcanic, an asteroid, and earthquake [Great Rift Valley].

"Searching for Sodom and Gomorrah"

by

Joey Corbett

Biblical Archaeology Review

Sodom and Gomorrah. They are perhaps the most infamous cities of the Bible, inhabited by men and women so vile and wicked that only their utter annihilation could appease God’s wrath (Genesis 19).

But where does the Bible locate these legendary dens of iniquity, and does any trace of them still exist?

It is clear from various Biblical passages that Sodom and Gomorrah should be located in the Dead Sea region. When Abraham and his nephew Lot part ways (Genesis 13:8-13), Lot chooses to settle in the Jordan valley "in the direction of Zoar" and moves his tents to "the cities of the plain" as far as Sodom. According to Genesis 14, the "cities of the plain," which include Sodom, Gomorrah, Zoar, Zeboiim and Admah, join forces to battle a coalition of Mesopotamian kings in the "Valley of Siddim (that is, the Salt Sea)," a clear reference to the Dead Sea region. Another clue is found in Genesis 10:19, which describes the southern border of Canaan as extending east from Gaza "in the direction of Sodom, Gomorrah, Admah, and Zeboiim," again placing the cities in the vicinity of the Dead Sea.

But Biblical scholars have long been divided about where exactly around the Dead Sea the cities were located. Most traditional theories place the cities at the southern end of the Dead Sea, in and around the well-watered and fertile plains and valleys south of the Lisan peninsula. At the southern end of this region, the Bible and other sources, including the first-century A.D. historian Josephus and the sixth-century A.D. Madaba Map, locate Zoar, one of the cities of the plain and the place to which Lot and his daughters fled following the destruction of Sodom (Genesis 19:22-23).*

Finding no clear archaeological evidence for Sodom and Gomorrah in the vicinity of Zoar, however, W.F. Albright and others conjectured that the remaining cities of the plain lay submerged beneath the shallow waters of the Dead Sea's southern basin. They argued that during the time of Abraham, when the level of the Dead Sea was possibly much lower, the entire southern basin would have been a lush valley watered by rivers flowing down from the highlands of Moab.

By the late 1970s, when the level of the Dead Sea had begun to drop considerably due to industrial exploitation and damming projects, archaeologists had an unprecedented opportunity to search the now mostly dry southern basin for remains of the lost cities. But alas, not a sherd was found; there was no evidence that the cities had been submerged beneath the salt sea.

While exploring the high fertile banks along the southeastern shore of the Dead Sea, however, the same archaeological expedition discovered the ruins of four towns that had been inhabited during the Early Bronze Age (3300-2000 B.C.).** Some scholars, though certainly not all,*** date the origins of the stories of Abraham and Lot to the end of this period. The expedition, headed by archaeologists Thomas Schaub of Indiana University of Pennsylvania and Walter Rast of Valparaiso University, excavated two of the largest sites in the plain—Bab edh-Dhra and Numeira—and discovered that both had been thriving Bronze Age cities that were destroyed at almost exactly the same time, about 2350 B.C. Rast proposed that the Biblical story of the destruction of Sodom and Gomorrah originated from ancient traditions surrounding the near-simultaneous demise of these once-prosperous twin cities.1

Although many have adopted Rast's view of the southern provenance of the Sodom and Gomorrah tradition, others have proposed that the Bible actually locates the fabled cities at the northern end of the Dead Sea. The most vocal proponent of the northern theory is Dr. Steven Collins of Trinity Southwest University, who argues that Lot’s apportioned territory and all the "cities of the plain" (Genesis 13:8-13) should be located in the broad circular plain where the Jordan River meets the Dead Sea. First, according to Collins, Genesis 13 places the separation scene between Abraham and Lot somewhere around Ai and Bethel, an area that has commanding views over the northern Dead Sea and southern Jordan valley, not the southern Dead Sea region. Second, the passage describes Lot’s territory as the "circular" or "disc-shaped" plain (Heb. kikkar) of the Jordan, a term which Collins argues refers specifically to the broad alluvial plain of the southern Jordan valley just north of the Dead Sea.

What is more, Collins believes he has located the actual site of Biblical Sodom on a high bank overlooking the valley. The site, Tell el-Hammam, is one of the largest mounds in the plain and supported almost continuous occupation from the Chalcolithic to the Byzantine period. Although the site has substantial Early Bronze Age remains (as at Bab edh-Dhra and Numeira), Collins believes that the extensive and well-fortified Middle Bronze Age city (c. 2000-1550 B.C.) represents the Sodom known to Lot and Abraham, Biblical figures that he and many others believe should be dated to the first half of the second millennium B.C. In one area of the Middle Bronze Age city, Collins located a massive destruction layer over 3 feet thick. Could this layer be the archaeological residue of God’s infamous judgment on Sodom? Whatever the case, Collins hopes to uncover even more evidence of the Biblical story in future seasons of excavations at the site.

But whether one locates Sodom and Gomorrah south or north of the Dead Sea, there is plenty of reason to suspect that the Biblical tradition surrounding the doomed cities of the plain was more than just fanciful legend. As suggested by Amos Frumkin in his May/June 2009 BAR article on the salt pillar known as Lot's Wife, the Sodom story told in the Bible likely represents an ancient memory of a single catastrophic event that affected the cities and peoples of the Dead Sea region nearly 4,000 years ago.

Notes:

*Konstantinos Politis, "Where Lot's Daughters Seduced their Father," BAR, January/February 2004.
**"Have Sodom and Gomorrah Been Found," BAR, September/October 1980.
***Kenneth Kitchen, "The Patriarchal Age: Myth or History?" BAR, March/April 1995.

1 See Walter E. Rast, "Bab edh-Dhra and the Origin of the Sodom Saga", in Leo Perdue, Lawrence Toombs and Gary Johnson, eds., Archaeology and Biblical Interpretation: Essays in Memory of D. Glenn Rose (Atlanta: John Knox Press, 1987), pp. 185-202.

Sodom and Gomorrah

Deceased--Dwight R. Crandell

Dwight R. Crandell
January 25th, 1923 to April 6th, 2009

"Dwight R. Crandell dies at 86; volcanologist helped predict 1980 eruption of Mt. St. Helens"

April 19TH, 2009

Los Angeles Times

Dwight R. "Rocky" Crandell, a U.S. Geological Survey volcanologist whose persistent tracking of deep layers of mud led to a pioneering reassessment of volcano hazards in the Pacific Northwest, died April 6 at a hospice in Wheat Ridge, Colo., from a heart attack. He was 86.

His death was confirmed by James W. Vallance, a research geologist and friend of Crandell at the USGS Cascades Volcano Observatory in Vancouver, Wash.

In 1978, Crandell and his longtime scientific partner, Donal R. Mullineaux, warned in a report that the Mt. St. Helens volcano 150 miles southeast of Seattle could erupt within 20 years. It did, in a furious blast in May 1980, resulting in 57 deaths.

Crandell and Mullineaux's studies began in the early 1950s, while assigned to map the Puget Sound lowlands southeast of Seattle, where the men overturned what was then the conventional wisdom that the area's landscape had been shaped mainly by glaciers.

Filling notebooks with observations of deep layers of mud beneath the surface in Washington state, then tracing the mud for years, they eventually found it had come from high on the slopes of 14,411-foot Mt. Rainier, the tallest volcano in the 48 contiguous states, previously thought to pose little danger.

They proved that about 5,600 years earlier, the summit of Mt. Rainier had collapsed in an eruption that caused a landslide massive enough to reach Puget Sound near Tacoma, filling some valleys up to 400 feet deep. That awakened the recognition that a similar event could endanger hundreds of thousands of people living atop the ancient mudflows.

The approach used by Crandell and Mullineaux formed the basis of today's volcano hazard assessment methodology and led to discoveries of the violent past and danger posed by Mt. St. Helens. Since the volcano's 1980 eruption, mudflow warning systems have been installed nearby and evacuation drills are held.

Crandell was born Jan. 25, 1923, in Galesburg, Ill., and earned his "Rocky" nickname while studying geology in college. He received a bachelor's from Knox College in Galesburg and a doctorate from Yale University. In between, he served in the Army during World War II, fighting in Germany as a lieutenant in a mortar platoon.

He began working for the USGS in 1951 and for most of his career was based near Denver. He did most of his fieldwork on Pacific Northwest ash falls, mudflows and lava extrusions in the summer, then spent winters analyzing the rock and soil samples gathered earlier.

"Rocky was a consummate field geologist," Dan Miller, a USGS volcanologist, told the Seattle Times. "He was willing to hike miles and miles to get to an outcrop, and go back day after day."

Crandell retired from the USGS in the mid-1980s but continued to study Mt. St. Helens.

Survivors include two daughters, three grandchildren and a great-grandchild. His wife, Marion, died in 2004. A son died in 1965.