Geology is all around us, scarcely thought of as we go about our lives. Yet, it affects everything we do as a civilization, as a society and as individuals. While barely appearing to change from day to day, it works to alter the course of evolution. Preserving a record of creatures and landscapes both ancient and forgotten, the story of our past is written in stone and waiting to be read. I offer a view of how I see our world and its inhabitants, both past and present, as seen through my lens.
“Red sky at night,
Red sky at morning,
Sailor's take warning.”
Taken at 5:50 AM looking due east with the buildings of Boston's Back Bay 4.5 miles away. Notice the earliest indication of Irene's outer bands beginning to appear. They represent the outermost periphery of the hurricane.
Operating under the premise of this old English rhyme used by shepherds, sailors and farmers in the days before barometers when you watched the sky to forecast the weather, I waited with camera in hand at the crack of dawn on the morning of Hurricane Irene’s New England arrival on August 27th, 2011. Anticipating a colorful red sunrise, I was duly rewarded. Who ever said Arizona has the most spectacular first light?
Taken at 6:00 AM
Interestingly, the precise origin of the saying is unknown, although a form of it appears as early as the 14th century in the Wyclif Bible (Matthew 16:2-3). Apparently, the English form of the rhyme first applied to shepherds. Later, British and American maritime necessities modified the rhyme for usage by sailors.
WHY ARE SUNRISES AND SUNSETS RED IF THE SUN IS YELLOW?
Light bounces (reflects) off small dust particles in the atmosphere (called scattering). Lord Rayleigh, an English physicist in 1871, determined that shorter wavelength light is scattered more efficiently than light at longer wavelengths. The result is that blue light with a small wavelength is scattered 10 times more efficiently than red light with a larger wavelength. Light from the sun contains all the colors of the spectrum from red to blue. Because blue light is scattered significantly, we see a sky that’s blue. When the sun is low in the sky, such as at sunrise and sunset, scattering is much greater. Much more of the blue light coming from the sun is scattered away from the direct path towards our eyes. As a result, the sun will appear very red when it is low in the sky. Not surprisingly, the same phenomenon happens when the moon it is low in the sky.
SO WHAT'S THE RELATIONSHIP OF RED SKIES TO THE WEATHER FORECAST?
The weather in Britain (where the saying arose) largely comes from the west. So if the sky was red when the sun set (a clear sight of the red-setting sun), there was a good chance of a clear night and morning ahead with no storms to the west. But if the sky was red when the sun rose, it was likely there was a day of rain in store (with the sun casting its rays on storm clouds approaching from the west). Obviously, this was not a fool proof method of predicting the weather, but was fairly reliable for the immediately foreseeable future. It works best in the mid-latitudes of the Northern Hemisphere, where storm systems generally follow the jet stream from west to east.
When rhymes such as this arose in old England, the country had a primarily rural and maritime economy. Predicting the weather often was a matter of life and death. Before the invention of the barometer, there was no accurate means of anticipating changes in the weather other than reading the sky. Nowadays, with Doppler radar, satellite imagery, computer modeling and the Weather Channel, there doesn't seem to be much need for us to "look to the skies." Unless you see that it's raining when you walk out the door!
On a lighter note... "Weather forecast for tonight: dark. Continued dark overnight, with widely scattered light by morning." George Carlin
This is a follow up to my previous post where I mentioned that workers reported that a building on 111 Devonshire Street in the Financial District of Boston was leaning against the adjacent building immediately following an earthquake on August 23, 2011 at 1:15 PM with its epicenter in Mineral, Virginia.
I captured the above aerial view of the two buildings in question taken well before the quake from Google Earth, which do appear to touch. The captured view below is also from Google Earth taken with Street View. Although less clear, once again, the buildings do appear to touch, again before the quake.
The following photo was taken by me four hours after the earthquake, yesterday, August 24, 2011.
This appears to confirm that the quake did not significantly shift either building on its foundation. The official confirmation arrived with the morning's Boston Globe that reported "the structures were built that way, just three-fifths of an inch apart."
"Did it used to touch?" is the big question everyone in this office building was asking after rushing out into the street when it began to quiver and shake. Many workers in the Financial District of Boston are certain that the building on the right never used to touch the building on the left, that is until 1:15 PM yesterday.
USGS REPORTS A SIZABLE EARTHQUAKE ON THE EASTERN SEABOARD
Yesterday, August 23, 2011 at 1:15 PM (EST), a 5.8 magnitude earthquake rocked the Mid-Atlantic East Coast. On the Richter Scale, 5.8 connotes a quake that is in the high intermediate range; 6.0 is considered to be noteworthy. The USGS reported that the quake occurred at a shallow depth of 3.7 miles with its epicenter at Mineral, Virginia, 40 miles northwest of Richmond. The movement apparently lasted for no more than 30 seconds. The quake sent shock waves up and down the East Coast to a third of the U.S. and was reported to have been felt in at least 22 states and northward into Canada. The coordinates of the epicenter (the position of the quake on the surface of the Earth) in units of latitude and longitude were 37.936°N, 77.933°W. The source of this information is the Southeast U.S. Seismic Network.
Mineral, Virginia, the epicenter of the quake, is located about 75 miles southwest of Washington, D.C. The town is situated within the Piedmont physiographic zone of the Appalachian Mountain chain.
JITTERS AND RATTLED NERVES BUT NO LOSS OF LIFE
About 12 million people living close to the epicenter reported intense shaking as powerful as that of a freight train. An overall feeling of jitters and rattled nerves prevailed for many of those that had never experienced an earthquake before, including myself. Reports of people running into the streets abound. Early reports of damage, which appears to have been minimal, include collapsed walls, snapped church steeples, damaged roofs and dismantled chimneys. Communication system phones were briefly overwhelmed. Numerous airports on the East Coast were temporarily closed, while flights were diverted. But overall, the damage appears to have been minimal with few reports of injuries and without any loss of life; however, the quake was disruptive in that buildings up and down the East Coast were immediately evacuated, including National Monuments in D.C., the Pentagon, and even the White House. Chivers ran high with the approach of 911's ten-year anniversary.
The epicenter was not far from Dominian Virginia Power’s North Anna nuclear plant. Its two reactors were protectively shut down without incident and power was lost, but its diesel generators were up and running. As an interesting twist of events, people on the west coast were calling friends and family on the east coast asking if they were all right.
The USGS 2008 hazards map The seismic zones in central Virginia are in the low mid-range for hazard potential.
THE SEISMIC ZONE
According to the USGS, the earthquake occurred as reverse faulting on a north or northeast-striking plane within a previously recognized seismic zone, the Central Virginia Seismic Zone. The CVSZ has produced small and moderate earthquakes since at least the 18th century. The previous largest historical shock from the Zone occurred in 1875. The 1875 shock occurred before the invention of effective seismographs, but the felt area of the shock suggests that it had a magnitude of about 4.8. A magnitude 4.5 earthquake on 2003, December 9, also produced minor damage.
Previous seismicity in the CVSZ has not been causally associated with mapped geologic faults. Analyses of past seismicity includes diverse focal mechanisms over a wide swath of land. This means that the seismicity is likely caused by several smaller faults instead of one general, causative fault such as the San Andreas Fault System.
The locale of the Central Virginia Seismic Zone: The underlying bedrock is composed of a variety of igneous and metamorphic rocks that range in age from Proterozoic (~1,100 Ma) to Paleozoic. These rocks form the internal core of the Appalachian Mountain belt.
Previous, smaller, instrumentally-recorded earthquakes from the CVSZ have had shallow focal depths (average depth about 8 km). They have had diverse focal mechanisms and have occurred over an area with length and width of about 120 km, rather than being aligned in a pattern that might suggest that they occurred on a single causative fault.
Individual earthquakes within the CVSZ occur as the result of slip on faults that are much smaller than the overall dimensions of the zone. The dimensions of the individual fault that produced the earthquake will not be known until longer-term studies are done, but other earthquakes of similar magnitude typically involve slippage along fault segments that are 5-15 km long.
Most earthquakes that occur on the Eastern Seaboard of North America are the result of movement on ancient faults due to the relief of stress. Unlike West Coast quakes where one plate (the North American Plate) is pushing under or sliding past the other (the Pacific Plate or remnants of the extinct Farallon Plate), slippage in a "hidden" fault occurred near the surface at a relatively shallow depth.
EAST COAST QUAKES ARE FELT MORE WIDELY THAN WEST COAST QUAKES Fractured bedrock on the West Coast dampens a quake's energy, while East Coast quakes are often felt widely because the bedrock is more solid. This dissipates the quake's energy over a longer distance.
Earthquakes in the central and eastern U.S., although less frequent than in the western U.S., are typically felt over a much broader region. East of the Rockies, an earthquake can be felt over an area as much as ten times larger than a similar magnitude earthquake on the west coast. A magnitude 4.0 eastern U.S. earthquake typically can be felt at many places as far as 100 km (60 mi) from where it occurred, and it infrequently causes damage near its source. A magnitude 5.5 eastern U.S. earthquake usually can be felt as far as 300 miles from where it occurred (Boston, my hometown, is 470 miles from the epicenter), and sometimes causes damage as far away as 25 miles.
"PASSIVE" AND "ATLANTIC-STYLE" MARGINS
The continental margin present on the east coast of North America, in fact on both sides of the Atlantic Ocean, is an “Atlantic-style” margin. It is considered to be "passive" in that regionally there are no plate collisions, no subduction zones, no volcanic activity, no mountain-building and no earthquakes (well, sort of). In contrast, “active” margins, such as those that surround the Ring of Fire around the Pacific Ocean, are zones of plate collision, and therefore possess all those things that a passive margin typically doesn't have. That isn't to say that the East Coast's passive, Atlantic margin possesses no activity. Active processes certainly are present in the form of active subsidence, sedimentation, growth faulting and migration.
Passive margins develop as continents rift apart to form new ocean basins, which is exactly what happened when the supercontinent of Pangaea began to break apart during the Late Triassic. The splitting initially occurs at a divergent plate boundary, but as spreading proceeds with the ocean basin widening, the active boundary remians in a mid-plate position at the center of the new ocean basin. That leaves the Atlantic margins passive in the sense that they are no longer active.
TECTONICS The tectonic framework in the vicinity of the seismic zone is extremely complex. The precise location of the pre-Rodinian (pre-Grenville) continental margin is unknown (although much of it can be assumed) and is thought to be west (using contemporary perspectives) of the seismic zone. Subsequent accretionary events such as the Grenville Orogeny, the closing of the Iapetus Ocean, the formation and subsequent rifting of Pangaea, etc. have cumulatively imprinted the Eastern Seaboard. Therefore, assigning the Central Virginia Seismic Zone to a particular tectonic event is difficult at this time, and will surely be a subject of discussion at an upcoming meeting of the Geological Society of America.
Map showing the complex tectonic framework in eastern North America. Color-coded are the assembly of Rodinia, opening of the Iapetus Ocean, assembly of Pangaea and the opening of the Atlantic Ocean. (From Tectonic Inheritance at a Continental Margin, William A. Thomas, 2005 GSA Presidential Address)
FORESHOCK, MAINSHOCK OR AFTERSHOCK?
The USGS cautioned that a concern is that the quake represents a foreshock, implying that the worst is to come. If not, then perhaps aftershocks will follow. At least one is reported to have occurred. The following days will provide additional information, this report being posted the morning after the quake.
It all reminds me of two quotations. Will Durant, a U.S. historian, writer and philospher, once said "Civilization lives by geological consent, subject to change without notice." And, the poet Ralph Waldo Emerson who said "We learn geology the day after the earthquake." How apropos!
"Because it's there." George Mallory, 1923 English mountaineer
This July I had the pleasure of backpacking in the Adirondack Mountains of New York State with my daughter. It was actually our first, extended excursion together without the rest of the family. We went to the GreatRange, an 11-mile chain of a dozen or more contiguous mountains in the HighPeaks region with names such as the Wolf Jaws, Armstrong, Saddleback, Gothics, Haystack, Big Slide, and of course Mt. Marcy, the highest peak in the state at 5,344 feet. Summer haze can obscure visibility from the summits due to heat and humidity, but our climbing conditions were picture perfect. We had warm and dry weather with deep blue skies and big white clouds.
This four-photo panorama of the Great Range extends from the southeast to the west. It was taken from the summit of Big Slide Mountain (4,240 feet) which we climbed the following day. Johns Brook Valley lies in the foreground of the range with Johns Brook Lodge basically in the center. From the far left the peaks include Giant, the Rooster Comb, Lower Wolf Jaw, Upper Wolf Jaw, Armstrong, Gothics (with the big slide), Saddleback (two summits), Basin, Haystack, Marcy (the pointed peak right of center), Gray (tucked behind Marcy), Colden (pointed peak), Phelps (small), Algonquin (also a pointed peak) and Wright. Click for a larger view.
I've backpacked the GreatRange four times over the years, having first done it back in high school with a very close friend, a good 45 years ago. Equipment in those days was heavy and cumbersome, and qualified as being called "no-tech." Backpacks were made out of heavy, green canvas that got even heavier when wet, and stayed that way. There was no such thing as "cotton kills." Wool and down worked fairly well back then before being replaced by fleece and other breathable-microfibers. And certainly, there was nothing like DEET, which works well against the Adirondack's notorious blackflies. I remember a big frying pan dangling from my backpack that banged against my legs! Things have definitely changed for the better.
Fortunately, to my great delight, everything looked just as I remembered: the scenic drive up the Adirondack Northway (I-87), the majestic stretch to KeeneValley on NY 73, the quaint, little town of Keene Valley, the better-get-there-early car-park in the Garden, the 3.5 mile hike into the valley of Johns Brook, and finally, the lodge of the same name, maintained by the Adirondack Mountain Club (a.k.a. ADK). The excitement hadn't changed either! I hoped my daughter would experience the same.
This old man and his young daughter are looking "ready, willing and able" at the Garden car-park.
Johns Brook Lodge, known to many as JBL (but with the "J" written backwards stemming from an old tradition), is an unforgettable oasis in the woods. It’s the perfect base from which to initiate hikes into "some of the best hiking in the northeast." It’s rustic (c. 1925) and isolated (over an hour from the car), but clean as a whistle and very well-maintained. A veritable haven of peace, quiet and tranquility. You'll feel the stress flow from your body as you approach it. There’s no electricity, just a solar-powered refrigerator and a propane-powered stove. Even the lights are propane-fueled. By the way, all the food is backpacked in three times a week by the dedicated JBL crew. The lodge has a great porch-deck with chairs for hanging out. And what a view of the tops of the HighPeaks through the trees!
The lodge has high ceilings inside with big beams and a massive, stone hearth. There are long, wooden tables for dining family-style. Listen for the dinner bell! There's hearty, home cooking with great deserts. How about some hand-churned ice cream? There’s lots of socializing. “What did you climb today?” "What's the condition of the trail?" “What’s the forecast for tomorrow?” Guest-lectures are in the evening after dinner. Scrabble. UNO. Monopoly. Bunk beds for 28 guests. Quiet time after 10. Even earplugs for non-snorers! Hot coffee and oatmeal are served in the morning when the breakfast bell rings. Pancakes too, with real maple syrup. My daughter absolutely raved about the lodge and can’t wait to come back next summer.
Johns Brook Lodge
View of one of the range's peaks from the deck of the lodge
The Adirondacks have a distinctive look and addicting appeal. Hiking them is very different from my experiences in New England, and certainly out West. All the repeated ups and downs. The high water-bars made of logs that test the merit of your tendons and ligaments. The gnarled, exposed tree roots that offer a step-up to the next level, as well as a chance to trip your gait. The huge steps of rounded, glaciated-stones. Ascend and work your heart and lungs; descend and blast your knees and quads! And of course, there’s the wet, black muck. Step in it and risk pulling the hiking boot right off your foot. By the end of your trip, you will have acquired the balance of the Flying Wallendas by walking on all the narrow bridges made of wooden planks and logs.
High above, the leafy tree-canopy sways in the breeze. Down below, the ever-present fallen trees are rotting and decomposing, covered with fungus, mushrooms and moss. Butterflies are everywhere, and unfortunately, blackflies and mosquitoes are too (mainly in the low wooded sections). Great smells, sights and sounds. Sensory overload. It all comes back to you, almost fifty years later. Tremendous!
Typical appearance of gnarled roots, exposed on the woodland floor
The infamous, Adirondack, boot-sucking, black muck has devoured my right foot.
This massive erratic in Johns Brook Valley was carried and deposited by glacial ice. In North America, the Laurentide continental ice sheet covered the uppermost half of North America during the Pleistocene, beginning 1.6 million years ago. It was characterized by several glacial advances and retreats, the most recent surge of which was the Wisconsin, ending about 10,000 years ago. Continental and later alpine glacial ice covered Mt. Marcy and the other peaks of the Adirondacks, as evidenced by glacial polish, glacial striations, and erratics such as this.
On our first full day of hiking, my daughter and I plunged right in. We climbed remote Mt.Marcy at 5,344 feet. Starting at an elevation of 2,316 feet from the lodge, the distance to the summit of Marcy (my daughter and I still disagree on the mileage), is a total of 11.5 miles round trip (her figure is 13). The exact number matters little. It’s not a difficult climb to Marcy’s summit, but taking into account the distance from the lodge, and the elevation gain and loss of over 6,000 feet, it was a loooong day. Trust me. Our round trip was nine hours. Drink lots of water!
Our hike to the base of Mt. Marcy began from Johns Brook Lodge; our hike to the summit began about 3 hours later. Heading southwest along the Phelps Trail (yellow markers) that essentially follows the brook, we then skirted past Slant Rock (red markers) to summit from Marcy's northeast slope. Notice the contiguous peaks of the Great Range that parallel our trail to the east. You can climb them all in a Grand Traverse.
On our trek through the valley to Marcy, we've transitioned from the Northern hardwood forest zone (of maple, beech, birch and hemlock) at the car-park and lodge to the coniferous spruce-fir forest zone (of spruce, fir and balsam) at about 2,500 feet. A bridge of logs traverses a low, wet section of the boreal forest covered with Sphagnum moss, sedge and liverworts. As we gain altitude, the environment changes as well. The growing season is shorter. The temperatures are colder, and the effective precipitation is higher. Notice our entry into a section of thinning, mature growth with a new, evergreen understory.
Sphagnum moss and Leather-leaf are right at home on the wet, boggy forest floor.
Decomposition is vital to renewal. This gill fungus is probably Pluteus admirabilis that fruits on well-rotted wood.
Someday this rotting stump will be "borne-again", when its organic, nutritional components provide the fuel for new growth.
Ganoderma applanatum forms large, bracketed fruitbodies with distinctive concentric grooves. It is also known as Artist's Conk, since it can be used for etched designs when fresh. It turns dark brown when bruised. It occurs on living trees as well as recently cut stumps and logs. There is some scientific evidence that indicates this mushroom has some antibacterial properties.
This epiphytic (tree) lichen (possibly Evernia prunastri or "Oakmoss lichen") is thriving an a decomposing limb. Lichens are actually complex organisms, the result of a relationship between a fungus and alga. In an alpine ecosystem such as this, the lichen functions as a soil-former by converting atmospheric nitrogen into a utilizable form for other plants.
After a while, it became a joke between my daughter and me. All the butterflies landed on me, while all the mosquitoes landed on her. I actually had one beautiful butterfly that I was trying to photograph, land on my hand that was holding my camera! This is a White Admiral (Limenitis arthemis). It has a prominent white band across its wings making it readily recognizable on forest trails.
The well-camouflaged American toad (Bufo americanus) is a common trailside-insectivore. The bracket fungus is Trametes versicolor with its characteristic shelving and overlapping of its fruitbodies. Also known as "TurkeyTail," it's commonly found on downed logs and rotting stumps. There has been recent research done on this fungus for its medicinal value as an adjunct treatment for colorectal cancer and leukemia.
What at first appeared to be the top of Marcy is actually the summit of Little Marcy at 4,765 feet. Many of the Adirondack's mountains have false summits and dual peaks. Read those maps!
We're now in the Krummholz or "crooked wood" zone at about 4,500 feet. The trees have become shorter and are almost impenetrable with thick stands of balsam, fir and black spruce. The inhospitably harsh climate here dwarfs the trees. The growing season is barely two months. Along with the thin soil, extreme temperatures, winter winds, and reduced sunlight due to clouding and fog, the flora appears in a miniaturized form.
That's Marcy's treeless dome, almost shrouded in the clouds, looming in the distance. Trees there can't survive the harsh summit conditions of its alpine climate zone. In the foreground, a poorly-drained depression has developed into a small alpine bog. My experience with bogs thus far has only included rather large, lowland bogs. Typically, the bog's tundral flora includes Sphagnum moss, sedge, leatherleaf, cottongrass and even carnivorous plants. Notice also the dwarf spruce and fir trees. Final push for the summit! Please visit my three posts on woodland bogs starting at:
While buffeting over 50 mile in hour gusts of wind at Marcy's summit, my daughter proudly exalts in the fact that she's the most elevated person in the State of New York, both geographically and emotionally. Marcy's treeless and glaciated summit of exfoliating metanorthosite is speckled with lichen and moss, the indigenous tundra-vegetation. Fragile patches of alpine soil are protected from the unsuspected trampling of hikers by rows of rocks. Non-native sedge has been planted to stabilize the sites so that native mosses can gradually revegetate the area. Johns Brook Valley, from whence we cometh, is in the distance and far below. Many of the plants in the alpine zone are rare, threatened or endangered, but all are protected.
My turn on top!
The plaque at the summit officiates our presence.
Back at the lodge nine hours later, the cold Johns Brook is a sure-cure for tired, aching, blistered feet.
The brook is choked with large cobbles of rounded metanorthosite, also in gneissic and gabbroic forms. In fact the entire Great Range is underlain with this ancient, Precambrian rock. A compositionally similar version of metanorthosite is actually found on the Moon. The mysteries of the tectonic genesis of the Adirondacks as well as its curious, more recent doming, which accounts for up to 3mm of rise per year, remains a subject of heated debate and research. Thus, the Adirondacks are considered to be "new mountains from old rocks." It is a common misconception that the Adirondacks are merely old, eroded mountains. Another misconception is that the Adirondacks are geologically related to the Appalachians. In actuality, they are the only mountains in the eastern U.S. that aren't geologically Appalachian. The Adirondacks are related to a terrane called the Grenville Province and a mountain-building event called the Grenville Orogeny that far predates the formation of the Catskills, theTaconics, and the Green and White Mountains of New York and New England. I plan to address these issues in a future post.
Taken near the summit of Big Slide Mountain, climbed the following day, we were afforded an impressive view of of Big Slides' sheer slope, the Johns Brook Valley, the Upper Great Range and Mt. Marcy (to the right). On many steep slopes such as Big Slide and Gothic (seen in the distance), slides are common where a thin, soil cover over the basement of metaplutonic anorthosite has slid off. The groundwork for such slides was probably laid during the last ice age at elevations up to 2,000 feet or so. Clay and silts were deposited in large deep lakes in advance of the glaciers. Their deposition facilitates the conveyance of groundwater that contributes to slope instability especially on steep inclines. Heavy snowpacks, melting snow and rainfall over the millenia infiltrates the subsurface. At higher elevations, the soils that cling to the slopes are thinner making them less stable, especially when steep. Interestingly, talus at the base of the slopes is minimal.
Back at the lodge at night and reflecting on the day's trek to Marcy and back, my daughter proclaimed “I’m really proud of myself!” And I, of her! There's an organization amongst climbers called the Forty-Sixers which recognizes those who have ascended the 46 High Peaks in the Adirondack Mountains. My daughter says she's interested.
Summiting Marcy was the second best part of the trip. The best part was doing it with her. Call it “quality time.” And, that it was.
P.S. I highly recommend the pocketsize Adirondack Alpine Summits by Nancy Slack and Allison Bell, as an ecological field guide with wonderful photos and concise descriptions.