CGC-AAPG Welcome New Students!

Welcome to Curtin University Sarawak Campus to new students! If you have decided to read geology in Curtin, i-Geology is here to help you. Curtin Geology Club and Curtin Sarawak American Association of Petroleum Geologist (AAPG) Student Chapter are the geology clubs to promote the interests of the field in Curtin Sarawak.

CGC has been in Curtin for quite some times and AAPG is a new student chapter which is still in the establishment process. 

CGC and AAPG are two separate geological clubs but both have i-Geology as its blog. We really hope new students coming to Curtin to study Geology will participate in all of our activities. As in AAPG, there will be an Introduction Session with one of our members for new students. The date and time will be informed later on. For any enquiries please contact Glaiza Marie Gagno through her Facebook.

Feature: Kuala Lumpur Karstic Limestones

This time around, i-Geology diverts its attention from Miri to Kuala Lumpur for a while. We'll be looking into the karstic features of Kuala Lumpur limestone. As what we have learnt in Geology 102 (it came out in last semester's exam question too!) karst is  is a geological formation shaped by the dissolution of a layer or layers of soluble bedrock, usually carbonate rock such as limestone or dolomite. 

Kuala Lumpur Limestone is well known for its highly erratic karstic features. With the exception of Batu Caves, exposures of Kuala Lumpur Limestone are mainly found in  tin mining areas.

Geology of Kuala Lumpur Area 

Figure 1: Geological section through KL. (Tan Siow Meng)

Published geological maps of Kuala Lumpur area show that Kuala Lumpur Limestone Formation dominates the majority area of KL. A geological section  through KL is shown in Fig. 1. The limestone is estimated to be about 1,850m thick, overlying graphitic  schist known as Hawthornden Schist. The top of the sequence is Kenny Hill formation which occupies the heartland of KL including areas at KLCC and Bukit Bintang. 

According to Gobbett & Hutchison (1973),  Kuala Lumpur Limestone is “Upper Silurian marble, finely crystalline grey to cream,  thickly bedded, variably dolomitic rock. Banded marble, saccharoidal dolomite, and pure calcitic limestone also occur”.

Karstic Features -- Development of Karsts  

Figure 2: Development of karsts

Karst topography in limestone is formed by a chemical dissolution process when groundwater  circulates through the limestone as illustrated in Fig. 2. Carbon dioxide from the atmosphere is fixed or converted in the soil in an aqueous state and combined with rainnwater to form carbonic  acid, which readily dissolves carbonate rocks. Karstic features develop from a self-accelerating process of water flow along well-defined pathways such as bedding planes, joints and faults

Jalan Cheras/Jalan Chan Sow Lin?

On a flat limestone terrain, steep depressions can occur. Such a feature was encountered in a deep excavation at a site near the junction of Jalan Cheras/Jalan Chan Sow Lin.  The depression was about 27m deep. Potholes as shown in Fig. 8 were exposed at an excavation site near Kg. Pandan Roundabout. The biggest pothole measured 11m in diameter and 8m deep. Another pothole was suspected 150m away as detected by boreholes supplemented by Mackintosh probing tests. The potholes at Sg. Besi Tin Mines observed by Ayob (1965) were 10m in diameter  and 25m deep. Similar features are described as ‘well like holes’ by Yeap (1986). Their sizes vary from  30m to 200m in diameter! 

Like limestone in other parts of the world, erratic karst topography commonly found in Kuala Lumpur Limestone is formed by a chemical dissolution process. The dissolution of limestone is a very slow process compared to human life span.  

The karsts consist of deep dissections, potholes, steep depressions and solution channels, resulting in erratic limestone rock bedrock profile that posts great uncertainties and challenges in foundation construction.

And this is where the role of a geologist is needed! 

Reference: Karstic Features of Kuala Lumpur Limestone. TAN Siow Meng, Simon, Committee Member, Geotechnical Engineering Technical Division 

Historical Highlight: Miri Field

By RASOUL SORKHABI

Miri is a major city in Sarawak, located on northwestern coast of Borneo. Its growth from a small fishery village in the late nineteenth century to a modern town with an airport and a population of over a quarter million is largely related to the oil industry.

Indeed, it was in Miri in 1910 that the first oil field on Borneo (the world’s third largest island) was discovered, and the following year (now one hundred years ago) 1,950 barrels of oil were produced from the discovery well, Miri No. 1.

Looking for Seeps

Charles Hose & Dr. Josef Theodor Erb

Charles Hose & Dr. Josef Theodor Erb

Human settlement in the Miri area is thousands of years old. The modern history of Sarawak, began in the mid-nineteenth century when an Englishman, James Brooke, gradually but steadily brought the region under his control.

During the rule of the so-called White Rajahs of Sarawak, European scientists began to map the region. Thus, in 1892 Dr. T. Posewitz published “Borneo: Its Geology and Mineral Resources.”

As in the world’s other oil regions, oil seeps first attracted oilmen to explore and drill in Sarawak. Indeed, local inhabitants had extracted oil from hand-dug wells for centuries and used what they called minyak tanah (“earth oil”) as medicine or for waterproofing boats and lighting lamps.

In the 1880s, Claude Champion de Crespigny, an officer working for the White Rajah Charles Brooke, listed 18 hand-dug oil wells in the Miri area and recommended “the oil district near the mouth of the Miri River should be thoroughly searched and reported on.”

This task was pursued by de Crespigny’s successor, Charles Hose (1863-1929), an Englishman who rose to be an eminent author and authority on the natural history of Sarawak.

Hose prepared a map of 30 oil seeps around Miri, and to do so, he even offered awards to the locals who would show him an oil seep.

After retiring from service and returning to England in 1907, Hose contacted the aging Charles Brooke, who happened to be living in England that year. Hose requested the Rajah’s permission to show his map and samples of oil seeps from Miri to an oil company in London.

The Rajah gave his permission, and the oil company that Hose contacted was Royal Dutch Shell Company, which had just merged.

Surprise!

H.N. Benjamin, a branch manager in the company, was enthusiastic about exploring for oil in Miri, and the Rajah personally came to London to sign the first Sarawak Oil Mining Lease in 1909.

Royal Dutch Shell dispatched its senior geologist Josef Theodor Erb (1888?-1934) along with Charles Hose to Miri. From August 1909 to July 1910 (except for a leave in December-January), Erb mapped the Miri area and identified the Miri Hill (about 150 meters above sea level) as an anticline and a favorable site for drilling.

This surprised the local people, who had anticipated the well to be drilled in an oil seep like the hand-dug wells before. Before the drilling could begin, Erb and Hose had to convince the people that the well would not open the underground cave that was, according to a local legend, home for two evil tigers.

The well was spudded in on August 10, 1910, using a rig composed of wooden derricks and cable tool drilling.

The rig was engineered by a Canadian named “Mr. McAlpine”; therefore, the hill has been historically called the “Canada Hill.”

On Dec. 22, 1910, the well struck light crude at 425 feet (130 meters) depth in the Upper Miocene deltaic sandstone. The discovery must have been a Christmas present for Hose and Erb.

Royal Dutch Shell then founded a subsidiary in Miri, the Sarawak Oil Field Ltd., which still operates today as Sarawak Shell Berhard.

Incidentally, the Miri field has so far been the only onshore oil field in Sarawak – exploration and production went offshore in the late 1950s, and that is where oil operations still are.

On Oct. 31, 1972, the Miri field was closed in.

‘The Grand Old Lady’

During the six decades of operation, 624 wells had been drilled in the field and about 80 million barrels of oil had been produced. Miri No. 1 had faithfully produced over 0.65 million barrels and was still yielding several barrels a day in October 1972. But it was probably time for retirement.

Although oil seeps are still notable in and around Miri, urbanization has discouraged further drilling.

Today, the 30-meter high Miri Well No. 1 derrick, affectionately called “The Grand Old Lady,” sits on top of the Canada Hill (renamed Bukit Telaga Minyak in Malay in 2005), next to the Petroleum Museum that was opened in 2005.

If you happen to be in Miri, a visit to this museum is worth the effort.

This article was first published here.

Feature: Crystal Palace

Have you ever wondered living in a crystal palace? No, it is not even close to the man-made Crystal Mosque of Terengganu. This crystal cave is found in a remote part of Mexico. 

Nothing compares with the giants found in Cueva de los Cristales, or Cave of Crystals. The limestone cavern and its glittering beams were discovered in 2000 by a pair of brothers drilling nearly a thousand feet below ground in the Naica mine, one of Mexico's most productive, yielding tons of lead and silver each year. The brothers were astonished by their find, but it was not without precedent. The geologic processes that create lead and silver also provide raw materials for crystals, and at Naica, miners had hammered into chambers of impressive, though much smaller, crystals before. But as news spread of the massive crystals' discovery, the question confronting scientists became: How did they grow so big?

Processes

In their architecture crystals embody law and order, stacks of molecules assembled according to rigid rules. But crystals also reflect their environment. Spanish crystallographer Juan Manuel García-Ruiz was one of the first to study the Naica crystals beginning in 2001. More familiar with microscopic crystals, García was dizzied by the proportions of the Naica giants. By examining bubbles of liquid trapped inside the crystals, García and his colleagues pieced together the story of the crystals' growth. For hundreds of thousands of years, groundwater saturated with calcium sulfate filtered through the many caves at Naica, warmed by heat from the magma below. As the magma cooled, water temperature inside the cave eventually stabilized at about 136°F. At this temperature minerals in the water began converting to selenite, molecules of which were laid down like tiny bricks to form crystals. In other caves under the mountain, the temperature fluctuated or the environment was somehow disturbed, resulting in different and smaller crystals. But inside the Cave of Crystals, conditions remained unchanged for millennia. Above ground, volcanoes exploded and ice sheets pulverized the continents. Human generations came and went. Below, enwombed in silence and near complete stasis, the crystals steadily grew. Only around 1985, when miners using massive pumps lowered the water table and unknowingly drained the cave, did the process of accretion stop.

Research and discovery

Now, in the cave, a team of scientists and explorers is conducting research and working on a documentary. Stein-Erik Lauritzen, a professor of geology at the University of Bergen in Norway, is retrieving samples for uranium-thorium dating. His preliminary research suggests the largest of the crystals are about 600,000 years old. Penelope Boston, an associate professor of cave and karst science at New Mexico Tech, searches for microbes that might live among the crystals. In some of them, tiny bubbles of suspended fluid—the kind García studied—sparkle in our lights. They are little time capsules: Italian scientists led by Anna Maria Mercuri extracted pollen that may have been trapped within these inclusions. The grains appear to be 30,000 years old and suggest that this part of Mexico was once covered not by desert but by forest.

NEOShield to assess Earth defence

NEOShield is a new international project that will assess the threat posed by Near Earth Objects (NEO) and look at the best possible solutions for dealing with a big asteroid or comet on a collision path with our planet.

The effort is being led from the German space agency's (DLR) Institute of Planetary Research in Berlin, and had its kick-off meeting this week.

It will draw on expertise from across Europe, Russia and the US.

It's a major EU-funded initiative that will pull together all the latest science, initiate a fair few laboratory experiments and new modelling work, and then try to come to some definitive positions.

Industrial partners, which include the German, British and French divisions of the big Astrium space company, will consider the engineering architecture required to deflect one of these bodies out of our path.

Should we kick it, try to tug it, or even blast it off its trajectory?

"We're going to collate all the scientific information with a view to mitigation," explains project leader Prof Alan Harris at DLR.

"What do you need to know about an asteroid in order to be able to change its course - to deflect it from a catastrophic course with the Earth?"

It's likely that NEOShield will, at the end of its three-and-a-half-year study period, propose to the politicians that they launch a mission to demonstrate the necessary technology.

The NEO threat may seem rather distant, but the geological and observational records tell us it is real.

About every 2,000 years or so, an object the size of a football field will impact the Earth, causing significant local damage.On average, an object about the size of car will enter the Earth's atmosphere once a year, producing a spectacular fireball in the sky.

And then, every few million years, a rock turns up that has a girth measured in kilometres. An impact from one of these will produce global effects.

The latest estimates indicate that we've probably found a little over 90% of the true monsters out there and none look like they'll hit us.

It is that second category that merits further investigation.

Data from Nasa's Wise telescope suggests there are likely to be about 19,500 NEOs in the 100-1,000m size range, and the vast majority of these have yet to be identified and tracked.

New telescopes are coming that will significantly improve detection success. In the meantime, the prudent course would be to develop a strategy for the inevitable.

The strongest mitigation candidates currently would appear to be:

Kinetic impactor: This mission might look like Nasa's Deep Impact mission of 2005, or the Don Quijote mission that Europe designed but never launched. It involves perhaps a shepherding spacecraft releasing an impactor to strike the big rock or comet. This gentle nudge, depending when and how it's done, could change the velocity of the rock ever so slightly to make it arrive "at the crossroads" sufficiently early or late to miss Earth.

"The amount of debris, or ejecta, produced in the impact would affect the momentum of the NEO," says Prof Harris.

"Of course, that will depend on what sort of asteroid it is - its physical characteristics. What's its surface like; how porous or dense it is? This is really something you would want to test with a demonstration mission."

"Gravity tractor": This involves positioning a spacecraft close to a target object and using long-lived ion thrusters to maintain the separation between the two. Because of gravitational attraction between the spacecraft and the NEO, it is possible to pull the asteroid or comet off its trajectory. "It's like using gravity as a tow-rope," says Prof Harris. "It's not straightforward of course. Can you be sure those thrusters will keep working for the time they're needed - a decade or more? Do you have confidence that the spacecraft can look after itself autonomously all that time? These are the sorts of technical problems we will look at."

In both scenarios, the effects are small, but if initiated years - even decades - in advance should prove effective enough.

What we've learnt about asteroids, however, is that they are not all the same. Different rocks are likely to need different approaches.

One method often discussed but about which there is great uncertainty is "blast deflection" - the idea that you would detonate a nuclear device close to, or on the surface of (even buried under the surface), an incoming rock.

The Russian members of the NEOShield consortium will take a close look at the option.

At present, I detect a lot of scepticism out there about this approach. Delivering the device to just the right place would prove very difficult, and the outcomes, depending on the composition and construction of the NEO, would be very hard to predict. But some better numbers than we have currently are required and TsNIIMash, the engineering arm of the Russian space agency (Roscosmos), will gather all the available data.

"What we want to do is take a comprehensive view, to try to draw everything we know together, with the right expertise so that this thing has momentum," commented Dr Ralph Cordey, from Astrium UK.

"We will look at the spectrum of techniques, trying to see which ones might be applicable in different cases. And then taking it to a level where we do some detailed design work on a possible mission to demonstrate one or more of these techniques."

And Prof Harris added: "At the end of this, we want to be able to say to the space agencies 'if you're interested in asteroid mitigation, this is what we think. We have six countries represented in our consortium and we're all agreed this is the way to go'.

"The politicians would then have everything on a plate. All they have to do is decide whether or not to execute the mission."

Next Supercontinent Will Form in Arctic, Geologists Say

Geologists have long predicted that North and South America will eventually fuse together and merge with Asia, forming a new supercontinent along the lines of the ancient Pangea — the precursor to today’s great land masses, which separated about 200 million years ago.

In the past, researchers had guessed that the new continent, often called Amasia, would form either in the same location as Pangea, closing over the Atlantic near present-day Africa, or 180 degrees away, on the other side of the world.

But a new study predicts that Amasia will form over the Arctic Ocean.

“The fusion of North and South America together will close the Caribbean Sea and meet Eurasia at the present-day North Pole,” said Ross Nelson Mitchell, a geologist at Yale University, who worked on the study as part of his doctoral research.

“And Australia is moving north, and would probably snuggle to join Asia somewhere between India and Japan,” he added.

Mr. Mitchell and colleagues from Yale, who discuss their theory in the current issue of the journal Nature, modeled the movement of supercontinents of the past using paleomagnetic data, a measurement of the force between the earth’s rocks.

Once each supercontinent is assembled, it undergoes back-and-forth rotations about a stable axis on the Equator, Mr. Mitchell said. This motion is called true polar wander. Using this, the researchers determined the center of each of the previous supercontinents — Pangea (often spelled Pangaea), Rodinia and Nuna.

There was a clear pattern. In each case, the centers of the supercontinents were separated by 90 degrees.

Scientists to Drill Earth's Mantle, Retrieve First Sample?

It may not be a journey to the center of the Earth, but it could be the closest thing yet.

Scientists are planning to drill all the way through the planet's miles-thick crust to Earth's deep, hot mantle and retrieve samples for the first time. The samples, they say, would rival moon rocks for sheer scientific import—and be nearly as hard to get.

"That has been a long-term ambition of earth scientists," geologist Damon Teagle told National Geographic News.

But a lack of suitable technology and insufficient understanding of the crust have long tempered that ambition. (Get an overview of Earth's magma and other layers).

Now, better knowledge of the Earth's shell and technological advances—for example, a Japanese drill ship equipped with six miles (ten kilometers) of drilling pipe—have put the goal within reach, according to a commentary in this week's issue of the journal Nature, co-written by Teagle, a geologist at the U.K.'s University of Southampton.

Even so, drilling into the mantle would be "very expensive" and would require new drillbit and lubricant designs, among other things, according to the paper.

But if all goes as planned, drilling could begin by 2020, Teagle said. As soon as next month, the team will begin exploratory missions in the Pacific, where crews will "bore further into the oceanic crust than ever before," the paper says.

(Related: Find out how Earth's mantle once housed a magma "ocean.")

Mantle Holds Clues to Quakes and Earth Origins

Between Earth's molten core and hard, thin crust, the roughly 2,000-mile-thick (3,200-kilometer-thick) mantle contains the vast bulk of Earth's rocks. But we don't know much about them, because all we have are bits that have come to the surface via volcanoes or been trapped in ancient mountain belts.

But all these mantle samples no longer really represent mantle conditions and makeup, since they've been altered in the long process of coming to the surface, so they providing only tantalizing glimpses of what lies below, scientists say.

Drilling would tell scientists not only what the mantle is like, but also reveal the nature of the Moho layer, a shadowy transitional layer at the base of the crust.

"We know what the happens to seismic waves as they cross the Moho, but we don't know what it is," Teagle said.

Scientists would also be able to look for signs of life in the deep crustal rocks.

"Wherever we've looked, up to 120 °C (248 °F), we've seen evidence of microbial activity," Teagle said. "We would certainly test that on the way to the mantle."

But the big prize is the mantle itself.

Getting a sample, he said, would tell us much about the Earth's origins and history.

Mantle rocks would also provide insight into how current mantle processes operate—highly important in understanding the plate tectonics that drive many earthquakes, tsunamis, and eruptions, he added.

(Related: "Infant, Magma-Ball Earth Glimpsed Via Newfound Rocks.")

Deep Ocean, Shallow Crust

The best place to drill, Teagle said, is in the mid-ocean, because that's where Earth's crust is thinnest—only about four miles (six kilometers) thick, versus tens of miles deep in continental regions.

But the mid-ocean, is, of course, still deep—about 2.5 miles (4 kilometers) in the targeted areas. That's nearly twice the depth reachable by today's offshore drilling techniques, Teagle said. So far, drills have penetrated only about 1.2 miles (2 kilometers) into undersea crust.

(Also see: "'First Contact With Inner Earth': Drillers Strike Magma.")

And while the seabed is cold, the drill would have to be able to reach into a zone where temperatures would hit 570°F (300°C) and pressures would mount to 2,000 atmospheres—equivalent to more than 4 million pounds per square foot (21 million kilograms per square meter).

"There are deeper drill holes than this," Teagle said, "but they have been done on land or into relatively soft sediments."

There's no danger of a blowout, such as the Gulf oil spill, because there are no oil and gas deposits in the mid-ocean for the drill to accidentally penetrate, he added.

Nor would the mantle rocks suddenly erupt out of the hole, since the channel would be narrow and mantle rocks aren't molten.

"There is a risk of failure in that the hole could collapse," he said, "but there is no perceived environmental risk."