May 28, 2014

Melanterite Stalactite with possible Szomolnokita and Copiapite minerals oxidizing with the iron Sulfates. Cueva de los Minerales, Volcano Irazu, Costa Rica. 

After hours of scrambling down a semi active volcano around loose volcanic rock, we arrived at a ledge where the clouds started to ascend above the elevation barrier they previously held on to before. As the minutes inched their way towards noon, the sun burned away the remaining rogue clouds as an eerie and mysterious crack in the sheer cliff started to expose it's red, orange, and yellow minerals  that have been expelled from the volcano into this cave. What we were about to discover inside these caves on Irazu volcano have scientists questioning the origins of the metamorphic mineral development and the geothermal relationships going on with this volcanspelological region in Costa Rica. All these pictures are true to color

Melanterite Stalactite with possible Szomolnokita and Copiapite minerals oxidizing with the iron Sulfates. Cuevas de los Minerales Volcano Irazu, Costa Rica. 

From Tres Rios Costa Rica, we left around 5am for the drive up to the top of Irazu volcano in Costa Rica. This volcano is a semi active volcano with a bit of history that occurred back in the 1960s which left some people believing that the volcano had erupted or a massive landslide occurred which might have revealed these cave entrances. The caves we first noticed in 1994 and expeditions have been conducted previously to study the caves mineral deposits.

Irazu volcano from the top

Andres and Anthros were able to receive scientific access to navigate around the volcano past the designated trails so we could reach the other side of the main crater and descend down into the volcanos cave system on the northwest corner.
Another volcano that is active. We could smell the sulfur from this volcano.

We started our traverse descent early to avoid the rainfall which could have made difficult conditions even worse due to the slippery conditions and landslides that frequently occur here.

Andres, pointing out the exposed walk across the lip of Irazu Volcano to get to the descent traverse, Costa Rica

We worked our way around the crater to a section where we had to traverse a trail that was just a couple of feet wide on each side that either dropped hundreds of feet into the volcano on one side or down the other side into the jungle below.

Descending down Irazu Volcano to the Mineral Cave in Costa Rica
 Eventually we made it to a place where we had to descend down the volcano and around a ledge-landslide area full of loose talus and scree that could have tumbled down below and accidently hit someone lower than us but thankfully that never happened. We continued to descend down the loose volcanic talus until we got to a vegetation patch that had thick roots, vines, and leaves which reminded me of the type of flora I have seen in other Central American cloud forests.  At this elevation of over 10,000 feet, sustaining high winds are quite common as it was on the day that we were there so if any plant life wanted to survive this environment, it would have to be able to evolve to accommodate to these conditions.
Flora on Irazu Volcano Costa Rica

It was also quite cold at this elevation in Costa Rica...45 degrees Fahrenheit.  We worked our way through the thick brush avoiding rocks that were being accidentally kicked down towards us and we started to work our way down to the volcanos draw and spur section.  We traversed around these draws and spurs of sharp loose rocks and eventually started to see minerals exposed out in the open along with a strange black moss that covered some of the rocks and plants.

Flora with black film on the branches, Irazu Volcano Costa Rica

 Shortly after, the group was called to a halt from above and Andres was called to come back up to the back of the group. One of the members of the expedition was suffering from altitude sickness so another member had to take him back to the car to get him transported to medical.  We were all assured that he will be taken care of and treated well so the expedition continued down and around the volcano.  We had to make sure that we were taking note of our route so we can return back if the clouds started to roll in and limit our visibility, which they did!
Clouds passing through above and around us on Irazu Volcano Costa Rica

After taking a break we continued on a horizontal traverse at the elevation we were at to the large landslide of exposed minerals and volcanic rock.  This is where the clouds started to cover our visibility and soon after burn away as the sunlight worked its way through.  As we made it closer to the ledge, more rogue clouds started to drift through elevation line where they previously were floating at as we looked over the final ledge for the first time.  Cloud cover followed by moments of clarity and sun gave this 400ft cliff an eerie appearance but it was what was at the bottom of this cliff that we had our eyes on.  It was a distinguished horizontal crack at the bottom of a 400 ft. cliff. This is the entrance to the cave of the minerals, Cuevas De Los Minerales. Wow we finally made it here!  

Cueva Mineral, Irazu Volcano, Costa Rica
There are three caves in this area which are situated on the northwest side of the main crater of Irazu volcano. The intense hydrothermal alternation that this section has gone through has exposed some of the most mysterious and abnormal volcanspeleological and mineralogenic interactions known throughout this region and maybe the planet as more questions have been left unanswered. 
Large Sulfur Crystals Cueva De Los Minerales Irazu Volcano Costa Rica
Samples were collected by Anthros from previosu expeditions adn diffractometry studies were conducted which rendered twenty one different minerals relating to sulfates and one native element (Sulfur). There were at least five of these minerals that were reported to be found for the first time inside of a cave that have never been previously found on any other cave in the world which are Aplowite CoSO4•4H2O, boyleite ( Zn,Mg) SO4•4H2O , ferrinatrite Na3Fe(SO4)3•3H2O, magnesiocopiapite MgFe+34 (SO4)6(OH)2•20H2O , and wupatkiitea (Co,Mg,Ni)Al2(SO4)4•22H2O).

Melanterite Stalagmite with Alunógeno minerals in Cueva De Los Minerales Irazu Volcano

Cueva De Los Minerales, Irazu Volcano
The research from local and International Universities have been conducting sample studies in these caves have come up with some rare mineral discoveries and one mineral that my have never been documented before.  Updated test results will come out soon but overall, the mineralogenic mechanisms happening in these caves have been the purpose for propelling this expedition which was to produce samples and survey maps of these cave systems. This will hopefully explain the formation of these features along with the biogenic activity in the acidic precipitation, solubilization alteration, and dehydration of these volcano cave mineral properties. A lot of this work is from Andres and Anthros.  
Melanterite with yellow minerals on the ceiling, Cueva De Los Minerales, Irazu Volcano, Costa Rica
We are here today to answer some more of these questions but as you will see, we were left with more questions than answers.  

Melonterite with possible epsonite in Cueva de los Minerales, Irazu Volcano, Costa Rica

We sat down on the ledge and rigged a hand line so everyone can safely climb down this ledge. At the bottom of this ledge is another small fissure crack cave called cueva mucolitos.  We eventually   surveyed this cave but our scope was on the main attraction.  We started our climb down from the ledge and eventually over the breakdown and up to the entrance of the cave. As I made my final climb over and onto the lip of the cave I looked above me from a safe distance and I could see the clouds rolling up the cliff that gave the topography above a steaming volcanic look like this volcano was about to go....AMAZING!!!

Cueva De Los Minerales Irazu Volcano

Here I am in Costa Rica, a bit cold, over 9,000 feet above sea level, above the clouds, about to enter a cave raining a sulfuric acid compound where I have to wear a gas mask to view some of the rarest minerals in the world....does it get more exotic than this?!? 

Melanterite Stalagtite Cueva de Los Minerales Costa Rica

 Below me are piles of breakdown and minerals that caked the landslide below which tampered off   into a thick cloud line and vanished. We are around nine thousand feet up above the clouds on a semi active volcano and about to enter a cave no foreigner outside of Costa Rica has entered.   I turn around into the cave and take my first steps as I step forward into this hostile environment. 

At the Entrance Of Cueva Minerales Irazu Volcano Costa Rica
My mask made it a little more difficult to breath at this altitude and with the layers I had on and the 90+ temps inside the cave, it made taking pictures a bit more challenging for me.
A Sulfuric Acid Compound dripping down over the entrance of the Mineral Cave Cueva de Los Minerales
DON'T LOOK UP!!, I was told as a diluted form of sulfuric acid dropped from the ceiling onto the breakdown digging holes into the trail and rocks below.  A previous scientist got some in his eye and apparently he did not have a "good result" as I was told.  This precipitation was leaving trace elements around the rim of acid burned holes and even building stalagmites left hollowed out from the solution.

Sulfate Geysermite with a teal interior releasing hot sulfur gas and a sulfuric acid compound dripping into the formation from the ceiling down into the formation.  Cueva de Los Minerales, Irazu Volcano, Costa Rica.
The ground was covered with various colors of yellow sulfur in curds piled on top of layers of pink, light green and white minerals. I noticed a fumarole vent exhaling hot sulfur air with white and teal circular crystals coating the inner layer inside the thermal.  Some of the minerals identified here include Aplowita, Alunógeno, Coquimbita, Halotriquita, Copiapite.  Some of these minerals were found in clusters in other various themal places on the floor and walls of the cave and some of these crystals inside the fumarole formations were growing out and downward toward the center of the fumarole.   Sulfur seemed to be in abundance here especially near the vents as it appears to need a temperature of at least 30 degree Celsius to generate..
Sulfur and other composite minerals at the base of a thermal volcanic vent inside the Cueva De Los Minerales Irazu Volcano Costa Rica.

Surrounding this and other similar fumarole thermals were Geysermites made of various mineral sulfate composites of yellows and whites around the outside and a teal and white color on the inside which I am considering to be Melanterite along with some other oxidized sulfates.  The Solution dripping from above hollowed out these formations to create what we are looking at below.

 Sulfate Geysermite with a teal interior releasing hot sulfur gas and a sulfuric acid compound dripping into the formation from the ceiling down into the formation.  Cueva De Los Minerales, Irazu Volcano, Costa Rica.

I briefly removed my mask and can feel a slow and subtle burning sensation starting to develop in my throat so I put my mask back on realizing the air quality is a caustic blend of gasses mixed into the air. I continue inside and down a breakdown pile full of shattered minerals with colors ranging from teal, pink, red, and some greens. I look down at the bottom where I followed a crawl passage leading to one of the most amazing speleological features I have and might ever see, an aqua marine stalagmite made out of an oxiding sulfate element called Melanterite. This formation was aqua marine in color, translucent, and sprinkled with bright yellow mineral deposits. This mineral can be found in some mines but What I found even more fascinating is that the stalactite was active and continuing to develop.
melanterite Stagalatite sprinkled with Copiapite minerals, Cueva De Los Minerales, Irazu Volcano Costa Rica

 I had to crawl and get a picture of this active formation which was still dripping at the time I was there. Furthermore, there was a previous formation that appeared to have broken off and a whole new formation has grown since than which I have been told is rather quick so there is more going on in the ceiling than we understand. 

Adam Haydock inside Cueva de Los Minerales, Irazu Volcano, Costa Rica.

The colors within these volcanospeleotherms went from a solid green to a aquamarine to a bright electric blue. Surrounding this formation were gypsum and Halotrichite needles along with other aqua marine formations, maroon, and yellow colored minerals on the ceiling.  On the walls there was coatings of pink and yellow crystals.
 I was surrounded by a room covered in crystal and mineral formations which were clustered on the walls, floor, and ceiling. The smell of sulfur was strong as I got deeper into the cave and the temperature must have been around 90 degrees at I got to the end of the cave.

Halotrichite needles Cueva Mineral, Irazu Cave, Costa Rica

The passages were not to long but the mineralogy and volcanology of this feature was something I and everyone else on the expedition have never seen. I exited the cave to go to the fissure crack Cueva Mucolitos next to the hand line. Inside this cave, there was sulfur on the walls similar to the mineral cave but this cave had Snottites or "snotties" which are soda straw looking formations.
Snottites inside Cueva Mucolitos Irazu Volcano Costa Rica 
Unknown Insects crawling around where the Snottites were located.
Read more about this cave here:
 After exiting Cueva Mucolitos Scott He went back up to the main cave and I told him I was going to go down and check out this cave to photo document the discovery. The Third Cave is named Cueva del Pizote Espantado.  I descended down over loose breakdown and encountered a very talus slope until I reached a bend in the cliff.  The clouds start to roll back in creating that eerie haze that added the mysterious ambiance of what I was about to encounter.  As I walked closer, the silhouette of a dark opening within the rock face appeared more defined as the closer I got.

Unknown sulfur like formation with snottite or spider webbing material retaining an unknown liquid in Cueva Del Pizote Espantado  Irazu Volcano Costa Rica

La Cueva del Pizote Espantado Irazu Volcano Costa Rica

Read more about La Cueva del Pizote Espantado, click here :

 I came back to the base camp where the hand line was rigged after climbing up a very brittle and exposed climb and found that everyone was still inside the mineral cave.  I took break and made my ascent up to the top of the ledge.  That's when I heard two thunderous booms!!!! It came from inside the mineral cave!  Thankfully nobody was inside but I looked around the ledge and saw two people running down the hill and away from the cave!! It appears that material from the ceiling fell which might have been due to the heat of the sun and the moist cool clouds that rolled in shortly after but I can not confirm that.  Nobody really knows what happened in the cave but we were glad everyone was safe.  That was a close call.  We were in the cave for a few hours and something just happens to fall right at the time the last person has exited the cave? That just leaves even more mystery to this place. We each work our way up the ledge and start our journey back around the volcano with limited visibility.
Andres addressing the group as we prepare to ascend Irazu Cave Costa Rica Photo taken by Scott Trescott

Now that's a happy caver

 With a few mis orientations, we were able to find ourselves around the landslide and out of harms way when we entered into the vegetation.
Coming out of the clouds on Irazu Volcano Costa Rica

As we pop out of the vegetation, we made our final ascent out of the cloud line and the sun was shining which reflected upon the jungle below on the windward side and a dense cloud overcast on the leeward side raining down upon the jungle canopy below.

The Expedition Climbing up the volcano, Photo Taken By Scott Trescott, Irazu Volcano, Costa Rica. 

Eventually we made it back to the summit lip of the volcano just in time for one of the most spectacular sunsets over the clouds I have ever seen.  12hrs after starting the trip we made it back to our cars. Another member caught some gravel in his eye so with that and the altitude sickness condition we did not suffer any broken bones or life threatening injuries which I consider a success. I want to thank the Grupo Espeleologico Anthros and everyone involved in making this expedition a success. 
Currently research is being conducted on the samples we brought back and more updates will follow as I become aware of the information.  

Sunset over Irazu Volcano Costa Rica

click on this link to watch a video on this project

More information regarding previous research on the caves:



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  1. It was nice expedition and nice pics. There is the link of one publication of the minerals in the cave.

  2. Thank you Andres, I will read up on this link as well.

  3. Adam,
    Oh my goodness! Those are the most beautiful pictures I have ever seen. What a legendary journey. I am captivated by the titian and celeste lustrous hues. I'm not going to lie, after reading this article, I earnestly considered returning to university for a geology degree so that one day I may have a opportunity to study mysterious minerals and divine formations that the world keeps under the layers of time. These experiences must be your holy grail.

    1. Yes and thank you, this was a fantastic place and has been quite inspiring to all of us. I am glad it has had the same effect on you. Thanks for sharing !!



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