The town of Urubamba is nestled in the Sacred Valley, about 33 miles northwest of Cusco.
Most people traverse Peru’s Sacred Valley quickly on their way from Cusco to Machu Picchu. But this stretch of countryside is an area well worth staying around in for awhile, both for getting to know Andean culture and understanding some of its history.
Farming methods in the Sacred Valley are still non-mechanized. Eight varieties of corn are grown in the Sacred Valley, several of which are shown above, on the drying tarps.
The Sacred Valley is considered the heartland of the Inca Empire (1438 to 1533 CE), linking Cusco, the once capital of the Inca Empire, to the world renowned ruins of Machu Picchu. The rich history of this area is evidenced by numerous archaeological sites and a multitude of agricultural terraces that date back to the Inca era. But the region is also a place where contemporary culture mixes with tradition. Quechua-speaking people still farm using non-mechanized techniques and Quecha is often overheard at the numerous markets in the valley’s villages. Yet it is not unusual to see a market vendor using a cell phone or hear someone talking about cable TV.
Hats are a good seller at the Pisac market.
Sacred Valley Markets and the Chinchero Weaving Co-op
– Pisac
Village markets in the Sacred Valley are really a treat. One of the largest markets is in downtown Pisac. It is a daily market, with the busier days typically being Tuesdays, Thursdays, and Sundays. The market vendors sell all kinds of items ranging from handmade goods to traditional Peruvian foods.
My guides, Teddy and Ayul, and even I couldn’t pass up buying a hat at the Pisac market!Textile colors at the Pisac market are amazing.
Chinchero Market and Textile Center
The Chinchero market, with a vendor selling produce and flowers.
The market at Chinchero is smaller that the Pisac market, but it is still worth a visit. Although it is typically a daily market, the busiest day is Sunday. But by far the most interesting place to visit in Chinchero is the Textile Center where traditional weaving demonstrations are on-going throughout the day. The weavers use alpaca and sheep wool in their textiles. The demonstrations include much of the textile-making process from wool dyeing to the actual weaving.
Several local, natural ingredients are used for dyeing wools at the Chincheros weaving co-op.The preservation of traditional weaving using alpaca and sheep wool is the focus of the Chinchero weaving co-op.
Ruins and Their Geologic Context
The archaeological sites in the Sacred Valley are so numerous (and many are so well known) that I’ll just highlight a few that have some interesting geologic context.
The Maras salt pans have been used for salt production since at least the Inca era.
— Maras Salt Pans
The Maras salt pans are located less than a mile west of the town of Maras (Maras itself is about 25 miles north of Cusco). The salt pans have been used for salt production since at least Inca times. Maturrano and others (2006) note:
“Maras salterns are located over the Maras Formation in the Cusco Department (13°18′10″S, 72°09′21″W) in southern Peru at an altitude of 3,380 m in the Andes, and they are 1,000 km from the coast. These salterns have been used for salt production since the time of the Incas. Salt is produced mostly during the dry season from May to November. The salterns consist of more than 3,000 small shallow ponds which are not interconnected, so there is no spatial salinity gradient as there is in multipond marine solar salterns. Each pond is filled with hypersaline water from a spring feeding the saltern and empties after salt precipitation, so the ponds act directly as crystallizers. …The origin could be related to the presence in the Maras Formation of underground halite deposits dating to 110 million years ago.”
The salt pans are available to anyone from the community to use for salt production. Once salt is collected, it is physically packed up-slope several hundred feet where it then is distributed to market.
— Moray
Moray is comprised of concentric agricultural terraces that are built in a carbonate sink hole (doline).
The concentric terraces at the Moray archaeological site are of Inca construction. The terraces are thought to have been built as an agricultural experiment site with each level corresponding to a different microclimate. The hottest microclimate occurs in the deepest part of the terrace construction and temperatures on the terraces decrease upwards. Interestingly, the agricultural terraces are built in a sink hole (doline) that developed in the area’s carbonate rocks. Satukunas and others (2002) say:
“…where the rings of Inca and pre-Inca terraces (the Incas agricultural experiment) are constructed in a karstic doline of some 150 m depth. Active landslide destroyed rings of the 7th-8th terraces and these are currently under reconstruction. The site demonstrates excellent Inca knowledge of management of dolines. ”
— Ollantaytambo
Terraces and stairways that climb the ruins of Ollantaytambo.
Ollantaytambo (located about 37 miles northwest of Cusco) is both an archaeological ruins site and a town. The area was a royal estate of Inca Pachacuti and is also a ceremonial site where Incas resisted Spanish conquest. Of interest to me is that Ollantaytambo contains stone from multiple quarries (Protzen, 1985; Hunt, 1990; Tipcevich, N and Vaughn, K.J., eds., 2012, Mining and Quarrying in the Ancient Andes). It appears that the various successions of builders had their own stone preference ranging from biotite andesite, to granitoid rocks, to the youngest construction phase by Inca Pachacuti of arkose from the nearby Ollantaytambo Formation.
In summary, the Sacred Valley is an area not to be skipped through quickly on the way to Machu Picchu!
The entrance to the smokejumper ready room at the McCall, ID, smokejumper base. The tower for hanging parachutes is the tall structure attached to the ready room.
The McCall Smokejumper Base, in west-central Idaho, has 70 wildland firefighters on staff. McCall’s Smokejumper program was established in 1943, and since then has continually providing fire management personnel to wildland fires throughout the nation. As noted on the McCall Smokejumper website:
“Today, the McCall Smokejumper Unit is an interagency resource providing highly trained, experienced firefighters and leadership for quick, wide-ranging, self-sufficient initial attack, extended attack, Incident Command System (ICS) fire teams, and prescribed fire operations throughout the country. Three Twin Otters comprise the fixed-wing aircraft fleet which enables this unit to provide firefighters, paracargo, and supplies to literally anywhere in the country.”
McCall smokejumpers doing a refresher jump from a Sherpa aircraft.Almost down and ready for the ground roll. Note the yellow and pink crepe streamers in the trees in the background. Typically 2 sets of streamers are dropped prior to the jumps so that the pilot and spotter can determine wind speed and direction.
I visited the McCall Smokejumper Base a few days ago and was lucky enough to not only have a detailed base tour, but to watch some of the refresher jump training for the experienced smokejumpers. The jumps that I saw were made both from a Shorts Sherpa C-23 (which flew down from the Missoula, Montana smokejumper base for the refresher training) and from a Twin Otter, which is an aircraft in the McCall base fleet. The ground crew for the jumps gave me a detailed explanation of the drop procedures as they monitored the jumps via radio and video. The refresher jumps are critiqued for each person. The exit door on each plane has a video device to capture aircraft exiting procedures and the ground crew video parachute maneuvering, parachute landing rolls and talk with each stick of two jumpers to make sure jump communications were good. I even was able to watch a couple cargo drops and a drill of emergency medical procedures.
The parachute tower where chutes are dried and inspected for damage.
The base tour included being able to see the parachute loft tower (where parachutes are hoisted up in order to dry them and inspect them), the sewing repair room, the parachute folding room, and the ready room. Because this is the start of the season and the refresher jump training time, it was a very busy place.
The parachute folding room. It takes experienced folders from 45 minutes to an hour to fold a chute.Smokejumpers hang their jumpsuit gear on speed racks in the ready room so they can quickly suit up for fire deployment.
To get a better idea of what it’s like to be a smokejumper at the McCall Base, watch the following Youtube video that was done by a group of McCall smokejumpers:
During the 14th century, the Inca ruler Inca Pachacuteq (Tito Cusi Inca Yupanqui) transformed the central Andean area of present-day Cusco, Peru into a major urban center. The city became the capital of the Inca empire, containing religious and administrative areas that were surrounded by fertile agricultural expanses. In the 16th century, the Spanish conquered Cusco, building their Baroque churches and palaces atop the remnants of the Inca city. Today about half a million people live in Cusco. The city is now known for its amazing indigenous population and as a mecca for tourists that travel on to the Sacred Valley and Machu Picchu.
The Plaza de Armas in the UNESCO World Heritage site of Cusco. Our guide told me that there is a celebration in the square 360 days of each year! I actually saw three different events there during my first afternoon in Cusco, so needless to say, the Plaza de Armas is a busy place.
Cusco Historic District
Cusco was declared a UNESCO World Heritage site in 1983 and the boundary for the site is mostly what is known as the Historic District (link here for a map of the UNESCO inscribed property). I did tour some of the buildings within the Historic District, my favorite being the Convent of Santo Domingo. The Spanish built this church on the remains of Qurikancha, a revered Incan temple for the Sun God Inti. The Inca stonework is the foundation for the cathedral and it is truly enthralling to see. Interestingly, numerous earthquakes have extensively damaged the cathedral, but the Inca stone walls still stand largely undamaged.
Convent of Santo Domingo built over the Qurikancha.My guide, Ayul Acuna Cardenas, explaining the Incan stonework that was part of Qurikancha and now forms the foundation for the Convent of Santo Domingo.The trapezoidal windows that are characteristic of Inca architecture.
All kinds of goods are sold at the Vino Canchón market!The chili selection at Vino Canchón is simply superb.Vino Canchón’s fruit aisle is paradise for fruit lovers.What a selection of cheese!Many hotels get their fresh flowers daily from the Vino Canchón market.The prepared food at Vino Canchón is a must to try!The many varieties of Peruvian potatoes are overwhelming.
The Vino Canchón Market
The markets of Cusco – now they are an experience that can’t be missed. If you love food, Vino Canchón in the district of San Geronimo, is the place to go. This is the largest market in Cusco, supplying families as well as businesses with all kinds of produce, hardware, flowers, and many other items. It is also a market where the traditional Quechua language dominates the conversations. The Vino Canchón market is open daily and vendors are happy to talk with customers and the inquiring tourist.
Saqsaywaman and Its Geologic Puzzle
Saqsaywaman is the ruins of a fortified complex located at the northern edge of Cusco, on a hilltop that overlooks the city. As briefly summarized by Lake and others (2012):
“Most of the complex was demolished by Spanish settlers, who used the Incan stone to rebuild Cusco into a Spanish colonial town. What remains of the Saqsaywaman complex are large limestone blocks along with some shales, plasters and limonites which were too large for the Spanish settlers to easily remove. Some of these blocks are over 125 tonnes. Chroniclers state, that the construction ofSaqsaywaman was initiated by the ninth Inca, Pachacutec and was continued by his son Tupac Yupanqui Inca, between 1431 and 1508. The construction of Saqsaywaman is testament to the stonework engineering ability of its builder architects: Huallpa Rimachi Inca, the first and main Builder, followed by Maricachi Inca, Acahuanca Inca and Calla Cunchuy Inca. The remaining walls lean inward, which according to current theory allowed the Inca to create a more earthquake resistant structure, and are comprised of mortar-less joints so closely interlocked that even a single sheet of paper cannot fit between the blocks.”
Remnants of fortress walls at Saqsaywaman include large limestone slabs, some weighing over 125 tons.A close view of the rock slabs at Saqsaywaman showing indentations at slab bottoms which may have been used in a leverage process during fortress construction.
The Geologic Puzzle at Saqsaywaman
On the north side of the Saqsaywaman Archeological Park is a strange outcrop. The outcrop is andesite, but it is marked with north-east trending grooves. It is so deeply grooved in fact, that it’s known as “El Rodadero” – the roller coaster.
Close-up view of “El Rodadero” grooves in andesite.
In a quick scan of the geologic literature, it appears that ideas for groove formation have ranged from glacial grooves, to faulting, and to the andesite being plastic to partially molten as it was extruded and basically corrugated due to the overlying wallrock. The consensus on groove formation appears to be that of the viscous flow model, but here are links to the references I found, so decide for yourself:
This is one of the best visualizations for global temperature change that I’ve seen. It’s created by Ed Hawkins, a climate scientist in the National Centre for Atmospheric Science at the University of Reading. As noted by Ed Hawkins:
“The animated spiral presents global temperature change in a visually appealing and straightforward way. The pace of change is immediately obvious, especially over the past few decades. The relationship between current global temperatures and the internationally discussed target limits are also clear without much complex interpretation needed.” – Ed Hawkins, Climate Lab Book
Lima, Peru is fast becoming a preeminent food hotspot with traditional Peruvian foods and various fusion cuisines that I found extremely delicious. And of course it is also internationally known for extraordinarily magnificent museums such as the Museo Larco with its collection of pre-Columbian art.
Lima, the capital city of Peru, has a population of almost 10 million people that is dispersed among its 43 districts. Known as the “City of Kings”, Lima was founded by the Spanish conqueror Francisco Pizarro in January 1535 when Pizarro confiscated land on the south bank of the Rimac River where the Inca curaca (local ruler), Taulichusco, had his palace. Lima then became the most important city and capital of the Spanish holdings in South America until the mid 1700’s. Lima’s supremacy later diminished as northern South America became a part of the Spanish Empire (known as the Viceroyalty of New Granada and established in 1717) and with the creation in 1777 of the Viceroyalty of La Plata, which encompassed the present-day territories of Argentina, Bolivia, Paraguay.
“The authenticity of the Historic Centre of Lima is intact as it largely preserves the original features of its urban foundation design, as a checkerboard, and the expansion area from the XVI to the XIX century, including old pre-Hispanic paths heading North (Chinchaysuyo) and East (Antisuyo).”
The Plaza de Armas in the Historic Centre of Lima. The bronze fountain, erected in 1650, sits in the Plaza’s center. The Cathedral of Lima is seen here directly in back of the fountain.
The Plaza de Armas is near the center of the Historic District and thought of as the birthplace of the city. There is no original building remaining adjacent to the plaza, but the bronze fountain in the Plaza’s center was erected in 1650. Some of the more significant buildings now surrounding the Plaza include the Cathedral of Lima, the Government Palace, and the Archbishop’s Palace of Lima.
The construction for the first church on the Cathedral of Lima site was completed in 1538. The present cathedral is the result of many renovations and rebuildings and is largely based on the original plans of the Cathedral that was devastated in 1746.
The Government Palace houses the official residence of Peru’s President and executive branch. The palace’s original construction began in 1535 over the residence of Taulichusco, the then Inca curaca. Similar to the Lima Cathedral, the Government Palace has been extensively rebuilt over the years.
The Archbishop’s Palace is sited on land that Pizarro designated for the head priest of Lima’s residence shortly after the city’s foundation in 1535. The present Archbishop’s Palace was built in 1924 and is well known for its ornate Moorish-style balconies.
The San Francisco Monastery in Lima’s Historic Centre. The Monastery is well-known for its catacombs.
Two of the other places that I visited – and I think are well worth going to – in the Historic Centre are the San Francisco Monastery and the Plaza San Martin. The San Francisco Monastery (Convento de San Francisco) is one block northeast from the Plaza de Armas. The Monastery was consecrated in 1673 and completed in 1774, although it has been extensively repeatedly rebuilt. Of note are its famous catacombs where a series of underground burial vaults were used until the mid 1800’s.
Plaza San Martin was dedicated on July 27, 1921 to honor the 100th anniversary of Peru’s independence. The statue of Jose de San Martin is central to the Plaza.
The Plaza San Martín is located about 5 blocks southwest of the Plaza de Armas. The Plaza was dedicated on July 27, 1921 to honor the 100th anniversary of Peru’s independence. An equestrian statue of José de San Martín is the Plaza’s central statue.
A video of Lima’s Historic Centre, done by UNESCO/NHK, gives a good overview of this area:
Lima Area Earthquakes – the Forces Behind the Rebuilding of the City
As noted several times in the text above regarding Lima’s Historic Centre, no wholly original buildings exist today, and those that do stand today have usually been repeatedly rebuilt. The continued destruction to Lima’s architecture is due primarily to several strong earthquakes in the Lima region that have occurred periodically.
“Peru is located on the western edge of the South American crustal plate, one of several large lithospheric plates that comprise the Earth’s crust and slowly move with respect to one another. The boundary between the South American plate and the Nazca plate to the west is one of the most seismically active areas of the world. The Nazca plate is being overridden and driven beneath the westward-moving South American plate. This collision between two large segments of the lithosphere is the source of most of Peru’s earthquakes. Offshore, where the two plates meet, the shocks occur at shallow depth. To the east, as the Nazca plate is pushed downward, the earthquakes occur at progressively greater depth – to as much as 600 kilometers near the Peru-Brazil border. … Shallow earthquakes are potentially more destructive than deep shocks of the same magnitude because they generate stronger surface waves.”
Although earthquakes are common in Peru, there have been several significant quakes in the Lima region since its founding. Much of the city was destroyed because of earthquakes in 1586, 1687, and 1746 (Philibosian, 2001) that had magnitudes from 8.6 to 8.7. More recent, large magnitude earthquakes (8.1 to 8.2) in the Lima area occurred in 1940, 1966, 1974 (Dorbath and others, 1990) and also caused substantial building structural damage and loss of life.
And it is not just the ground movement generated by earthquakes that have been devastating for Peru:
“Records indicate that since the late sixteenth century, large earthquakes centered off the Peruvian coast have generated several destructive tsunamis (1586, 1604, 1647, 1687, 1746, 1865, 1868, 1914, 1942, 1960, 1966, 1996). Of those listed, five were particularly destructive. These include the 1586, 1604, 1687 and 1746 tsunamis, as well as the 1868 Arica tsunami.” (USC Tsunami Research Center, 2005)
Probably the most extensive tsunami in the Lima area occurred in association with the 1746 Lima–Callao earthquake (with a moment magnitude recently estimated at 9.0 – Jimenez and others, 2013). Not only did this earthquake cause considerable damage and loss of life in Lima, but the ensuing tsunami basically wiped out the nearby port of Callao:
“On the evening of 28 October 1746, Lima was shaken by a violent earthquake. Out of a population of 50,000, only about 1,000 people died. But at about 11 pm, a tsunami devastated the neighbouring port of Callao, destroying the port itself and sweeping miles inland. In contrast to Lima, only a handful of Callao’s 6,000 inhabitants survived. Lima was then the most important city in South America, and the port of Callao exported gold and silver to Spain. The disaster was unprecedented for the Spanish in the region, and posed a critical economic threat to the colonial power.” (GAR, 2011)
Given the geologic setting of the Lima, Peru area, it’s a reasonable assumption that earthquake activity is and will be a part of life here.
I just returned from travels in Peru, which took me from Lima to Cusco, to the Sacred Valley, and eventually to Machu Picchu. It was a spectacular trip! Adventure Life, a company from Missoula, Montana, did the trip travel logistics for our group of University of Montana Alumni. They did an amazing job, starting with providing two incredible local guides, Ayul and Teddy. And the Peruvian food that I ate during the trip – it was delicious! Our group size was small with 19 people in total, which for me was a plus, rather than traveling with a huge bus-load of people. We covered a lot of ground during our Peruvian travels and this is the first of several blogs on the trip, starting with Miraflores, a truly captivating part of Lima.
Green Spaces
Parque Kennedy, located in the heart of Miraflores, is well known for its abundance of cats.
Miraflores is well known for its green spaces. We stayed in the heart of Miraflores near Parque Kennedy, which is named after John F. Kennedy because of the aid he gave to Peru during his presidency. Although artisans, food vendors, and a free wifi hotspot are draws to the parque, probably its best known aspect is that it is home to many stray cats. No one apparently knows for sure where the cats came from. Some say that a pregnant cat was abandoned in the park about 25 years ago and that event started the parque’s cat population. In any event, today there are by best estimates, probably somewhere around 80-100 cats living in the parque that are cared for by its visitors.
The Miraflores Malecón is a six-mile expanse of parks atop the cliffs that fringe
Víctor Delfín’s large carving of a couple in a deep embrace is the centerpiece of the Miraflores Malecon’s Parque del Amor.
the Pacific Ocean. The Malecón is a great place for walking, bike riding, and sea-scape viewing. We spent time walking through a part of the Malecón known as Parque del Amor (Love Park) where Víctor Delfín’s large carving of a couple in a deep embrace is its centerpiece.
Mosaics along the Parque del Amor, whose designs are reminiscent of work by Antoni Gaudí.
Alluvial Fans
Cliffs that abut the ocean in the Miraflores District contain the alluvial fan sediments of the Lima Conglomerate.
The cliffs that abut the Pacific Ocean in the Miraflores area are made up of alluvial fan sediments that comprise the Plio-Pleistocene Lima Conglomerate. This geologic unit contains sediments ranging in size from cobbles to clay that were sourced in the Cordillera east of Lima and eventually deposited by the shifting Rimac and Chillon rivers in the greater Lima area. As noted by Roux, J.P. and others (2000: Sedimentology of the Rimac-Chillon alluvial fan at Lima, Peru, as related to Plio-Pleistocene sea-level changes, glacial cycles and tectonics, Journal of South American Earth Sciences 13, 499 – 510), and summarized by Koster (2008), the
“clasts are mostly granites, diorites, gabbros and Mesozoic to Cenozoic volcanic rocks. The Lima Conglomerate has a thickness of up to 86 m. It is interrupted in parts by lenticular sand and siltstone lenses that likely represent estuarine incursions caused by sea-level variations”.
A closer view of the sediments of the Lima Conglomerate.
The larger clasts from the Lima Conglomerate form the beach pavement, making for a very rubbly beach surface.
Huaca Pucllana
Huaca Pucllana, a pre-Inca ruins dating from about 400-700 CE, lies in the midst of a Miraflores residential neighborhood. The ruins encompass about 5 hectares and most prominently consist of a 22-meter high pyramid with 7 levels presently identified that was built by the Lima culture.
Pyramid structure at Huaca Pucllana located in the midst of Miraflores.
The pyramid is made of adobe bricks stacked like books on shelves; fill for the structure mainly consists of sand and gravel from the surrounding area. This building technique is thought to minimize damage caused by earthquakes, perhaps lending to the complex’s remarkable preservation.
Bookshelf construction using adobe bricks probably made the structures at Huaca Pucllana somewhat earthquake resistant. Note the fingermarks on the individual bricks.
The pyramid part of the complex was most likely used as a ceremonial sector. Clay huts and structures that probably functioned as administrative buildings surround the pyramid.
The Lima culture abandoned Huaca Pucllana about 700 CE. From about 800 CE until 1000 CE, the Wari culture occupied Huaca Pucllana, using it mainly as a burial site for the nobility. In 2008, archaeologists uncovered the intact remains of three people from the Wari culture– two adults that were wearing masks and a child that appears to have been sacrificed.
Sand and gravel fill exposed beneath overlying adobe pyramid tier at Huaca Pucllana.
A later social group, the Ychsma (inhabiting the site from about 1000-1450 CE), appear to have reused some of the adobe bricks from the ruins to build what look like temporary shelters on-site and to use the site for offerings and as a cemetery. In 2015, archaeologists found four Ychsma culture mummies (three women and one man) at the complex.
To add to the mystique of Huaca Pucllana, is the presence of a very fine restaurant where we dined during our evening in Miraflores. The food is wonderful and it was equally fun to see Huaca Pucllana in lights as we ate.
Huaca Pucllana pyramid construction in a closer view. Car in upper left for scale.
Dr. James Hansen (Director of Climate Science, Awareness and Solutions Program Earth Institute, Columbia University) and 18 co-authors just published an article – Ice melt, sea level rise and superstorms: evidence from paleoclimate data, climate modeling, and modern observations that 2 °C global warming could be dangerous – in the journal AtmosphericChemistry & Physics. Their article is significant because not only does it raise the issues of superstorms and sea level rise that are associated with human forcing of climate change, but their research also suggests that current climate models do not adequately gauge the effects of ice melt runoff from the Antarctic and Greenland ice sheets. The video embeded below is done by Dr. Hansen and his co-authors and is a good abstract of their recent research findings.
Montana Forest Legacy article in the March-April issue of Montana Outdoors: Keeping Forests Forested – a worthy read.
Montana Outdoors just published an article on two Forest Legacy projects that I’m very proud to have worked on – the Haskill Basin and Trumbull Creek projects, which are both located near Whitefish, MT. Both are projects where varied interests have come together for a common goal. As well stated by the article’s author, Allen Morris Jones,
That’s the concept behind the Forest Legacy Program, a little-known conservation workhorse administered by the U.S. Forest Service. Forest Legacy was created in 1990 in response to widespread development turning the nation’s privately owned forests into “nonforest uses”—housing estates, golf courses, and other commercial sites. The conversion of timberland hurt logging and sawmill businesses, cut off recreational access, fragmented critical wildlife habitat, and degraded streams with sedimentation and leaching septic systems.
These projects are also a great tribute to a late colleague of mine from the Trust for Public Lands, Alex Diekmann, who passed in early February. Alex’s hard work and perseverance on these projects makes them a success.
Siccar Point, located on the southeast coast of Scotland, is well revered in the geological community. Outcrops at this locale display ‘Hutton’s Unconformity’. This is an angular unconformity where tilted rock units of about 370 million years in age called the Old Red Sandstone (with a basal layer of conglomerate) lie atop nearly vertical strata of greywacke that are approximately 435 million years in age. James Hutton observed these rock juxtapositions while on a boat trip past Siccar Point in 1788 with James Hall and John Playfair. His observations and contemplation of this unconformity formed a basis for his theory of repeated cycles of deposition, uplift, and erosion, which was later known as uniformitarianism.
The British Geological Survey posted a new video on Siccar Point a few days ago. Their video features amazing drone video of the locale and good accompanying audio. It is well worth a view!
Spending time in Puerto Rico is a fantastic experience. The beaches are wonderful, the rain forest of El Yunque National Forest is unique in the U.S. Forest Service’s holdings, the bio-bays are enchanting, and of course there are intriguing rocks that underlie all these natural wonders.
Geologic Setting
Puerto Rico is the eastern-most island of the Greater Antilles, which is a group of islands in the Caribbean Sea that includes the countries of Cuba, Hispaniola (Haiti and the Dominican Republic), Jamaica, and the U.S. territory – the Commonwealth of Puerto Rico. Puerto Rico (and its outlying islands of Culebra and Vieques), along with the U.S and British Virgin Islands are the subaerial form of a microplate that exists at a seismically active plate boundary between the North American plate and the northeast margin of the Caribbean plate. Because of the tectonically-active location, this area has experienced large magnitude earthquakes and destructive tsunamis.
“Map of the North American – Caribbean tectonic plate boundary. Colors denote depth below sea level and elevation on land. Bold numbers are the years of moderately large (larger than about M7) historical earthquakes written next to their approximate location. Asterisk – Location of the January 12, 2010 earthquake. Barbed lines- boundary where one plate or block plunges under the other one. Heavy lines with half arrows – faults along which two blocks pass each other laterally”. From: http://woodshole.er.usgs.gov/project-pages/caribbean/
The rock record of Puerto Rico covers about 150 million years and contains rocks of a volcanic island-arc terrane. As noted in the U.S Geological Survey Open-File Report 98-
Tsunami evacuation sign in San Juan underscoring the tsunami potential for the area.
38 on Puerto Rico’s Geology, Geochemistry, Geophysics, Mineral Occurrences:
The island consists of volcaniclastic and epiclastic rocks of volcanic origin as well as other sedimentary rocks of Late Jurassic to Paleocene and Eocene age and intrusive mafic and felsic plutonic rocks of Late Cretaceous and early Tertiary age. These rocks are overlain unconformably by Oligocene and younger sedimentary rocks and sediments.
Touring Puerto Rico’s North-Northeast Area
I flew into San Juan, but as soon as I picked up a rental car, I headed to the beaches in the Piñones area. This area is about 10 miles east of San Juan, located along Route 187, which skirts Puerto Rico’s north coast, linking San Juan and Loíza. Route 187 is a scenic drive and there are many places to pull off the road and enjoy the beaches. The beaches of Pinoñes fringe a mangrove forest and large sand dunes. The beach areas are further enhanced by eolianites and beachrock creating a relatively continuous barrier that protects the shore and make for a relaxing swim.
Eolianites and beachrock on Pinoñes beaches create a relatively continuous barrier that protects the shore and make for relaxing swims.
Further east along Puerto Rico’s northern coast, the beaches of the Luquillo area provide better access to some surf. La Pared, the Wall, is one of these surf beaches and is located nearest to downtown Luquillo. Its western end is a narrow stretch of sand shaded by palm trees where there is easy access to set up beach chairs and enjoy life. East from here, the surf increases and this is where most surfing action occurs.
La Pared, the Wall, is a main spot for surfing in the Luquillo area.
El Yunque
The El Yunque National Forest is the only tropical rain forest in the U.S. National Forest system. Although it is one of the smallest of the national forests (approximately 28,000 acres), its biological diversity is immense. The US Forest Service provides an excellent description of El Yunque:
The rugged Luquillo Mountains that rise to 3,533 ft. above sea level comprise most of the forest land. Their steep slopes can sometimes receive rainfall of over 200 inches (508 centimeters) per year at higher elevations. Caressed by gentle easterly winds the forest has an average temperature of 73° F (21° C), and seasonal changes are almost imperceptible. It is the ideal climate for exuberant tropical vegetation. The rain forest is noted for its biodiversity; it is “home” to thousands of native plants including 150 fern species, 240 tree species (88 of these are endemic or rare and 23 are exclusively found in this forest). The El Yunque National Forest has no large wildlife species, but hundreds of smaller animals abound in this gentle forest, many of which exist nowhere else on the planet.
Driving south on Highway 191 from Palmer into El Yunque, there is a progression in forest types as elevation increases. Forest growth changes from Tabonuco (tall trees and low light intensities at ground level), to Palo Colorado (upland swamp of short-statured trees with shallow root systems), to Sierra Palm Forest (overall smaller vegetation of the two previous forest types found on steep slopes, unstable soils and streambeds). There is one
Mt. Britton trail head sign in El Yunque.
last forest type – the cloud forest (upper edges of the Palo Colorado and Sierra Palm Forest types with water-saturated soils), but to see this, you need to hike. A good hike to get to the cloud forest is to do the climb to the Mt. Britton Tower. The trail takes off from Highway 191, but you have to walk up the road from the last parking area to get to the trail head. It’s a 0.8 mile, one-way hike and climbs 594 feet in this short distance. The trail head is well signed and the trail is paved and maintained.
On the trail to the Mt. Britton Tower, hiking through the cloud forest.Mt. Britton Tower in El Yunque.Mt. Britton Tower stands tall on a peak comprised of rocks from the Cretaceous Tabunuco Formation.
Highway 191 winds its way through El Yunque National Forest within the Cretaceous Tabonuco Formation. The Tabonuco Formation is marine in origin and contains andesitic
The waters of La Coca Falls drop 85 feet onto the volcaniclastic sandstones of the Tabonuco Formation.
to basaltic volcaniclastic sandstone, mudstone, volcanic breccia, and conglomerate. One of the best places in El Yunque to see the Tabonuco Formation is at La Coca Falls. La Coca Falls is easily accessible and is one of the first spectacular features to be seen along Highway 191 as one travels up into the forest.
About 0.5 miles north of Mt. Britton lies El Yunque, a towering peak that has been iconic in Puerto Rican history since pre-Columbian times. El Yunque (Spanish for anvil) is 3,412 feet high, breaking through the old growth forest where it is covered by clouds. The topographic prominence of El Yunque has recently caught the attention of geologists who wondered why the peak is not covered with vegetation and eroding rapidly given the area’s humid tropical climate. Their research indicates that El Yunque is part of an ancient supervolcano named Hato Puerco that was active about 145-66 million years ago. The hardness and chemical properties of the rocks that form El Yunque and deter rapid erosion came from being cooked in the chamber of the supervolcano.
Puerto Mosquito and the Bio-Bay of Vieques
The island of Vieques lies about 8 miles east of Puerto Rico. Vieques is an island
The ferry from Fajardo to Vieques is a fun ride. Be prepared for unexpected delays!
municipality of Puerto Rico and was home to a major naval base until 2003. Consequently, much of the island escaped intense development. The easiest way to get to Vieques is on the ferry that leaves from the town of Fajardo. The ferry trip is probably usually uneventful, but on the way back from Vieques to Farardo, there was a multiple vehicle smash-up during loading time. Just a couple hour delay, which wasn’t too bad, considering all the damage.
Of particular interest to me was the bio-luminescent bay, Puerto Mosquito, found in the southern part of the island and considered to be the largest and brightest of Puerto Rico’s bio-bays. The luminescence in the bay is caused by a dinoflagellate, Pyrodinium
Touring Mosquito Bay’s Bio-bay with JAK Water Sports was amazing.
bahamense, which glows whenever the water is disturbed, leaving a trail of light. A combination of factors results in ideal conditions for the growth of Pyrodinium bahamense and hence thebioluminescent bay. These factors include red mangroves that surround the bay adding vitamin B-rich bacteria to the water, the restricted outlet to the Caribbean, the shallow water depth, water temperature and salinity, and little variation in atmospheric conditions. All this combines to give an amazing light show!
I kayaked Mosquito Bay with one of the local tour companies, JAK Water Sports. My kayak had a clear bottom which really enhanced the streaming of the bio luminescence, I also did the tour during the dark of the moon – another plus for maximum viewing and definetly a bucket-list event.
And of course the beaches of Vieques are excellent. I stayed in Esperanza, on the south side of the island. Even within walking distance, there is no lack of desirable beach. The nearby beach locally known as Coconut Beach
Coconut beach near Esperanza is well within walking distance from the local lodgings.
even had rock exposed. The exposed rock is a Cretaceous granodiorite that is, needless to say, extensively weathered.
Granodiorite exposed on the locally known “Coconut Beach” near Esperanza.
