Evelyn Mervine @emervine ?

active 3 days, 19 hours ago
  • This week’s Monday Geology Picture was taken during my recent vacation in Australia. One day my husband and I drove outside of Sydney to spend some time exploring the Blue Mountains. One of the tourist […]

  • [caption id="attachment_6477" align="aligncenter" width="650"]A wind farm near Jeffrey's Bay, South Africa. A wind farm near Jeffrey’s Bay, South Africa.[/caption]

    South Africa is currently facing a significant shortage of electricity. Recently, there have been regular periods of “load shedding” or planned power outages. Basically, there is often not enough power to go around, so the power is purposely turned off on a rotating schedule. In the neighborhood where I live and work in Cape Town, the power is regularly turned off for two hours a day or sometimes for four or more hours per day. As you can imagine, these regular power outages are quite disruptive to work and home life and certainly have a negative impact on the economy.

    There is a great need for more power sources here in South Africa. Thus, I was quite pleased when I recently drove past a relatively new wind farm near Jeffrey’s Bay, South Africa. As the wind turbines spun, I smiled thinking about the power that they are diligently producing. Although wind farms will probably only play a small role in solving South Africa’s energy crisis, every little bit helps. Also, every megawatt of power produced by a wind farm is one less megawatt of power than needs to be produced by “dirtier” carbon emitting power plants, such as coal plants.

  • I’m not an expert on the geology of the Oudtshoorn region, but I believe that the basin in which these conglomerates/breccias were deposited formed as a result of stretching due to the final separation of Africa from Gondwana… there are also some large faults in the area…

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  • Yes, I believe that they are related to Enon… see my latest post!

    I was just in PE! I’ll let you know next time I’m there…

    In reply to - · View
  • [caption id="attachment_6454" align="aligncenter" width="650"]Red conglomerate hills with a rock arch. Red conglomerate hills with a rock arch.[/caption]

    On Monday I shared a picture of a pretty conglomerate that I recently walked across. Today I thought that I would share a few more pictures of this conglomerate formation and also tell you a little more about it. Although in Monday’s picture the conglomerate looks somewhat dull-colored, the conglomerate formation is actually impressively red in color in many places, so much so that hills made of the conglomerate are known as “the red hills” or “the red stone hills”.

    My husband and I hiked amongst the red conglomerate rocks during a recent stay at a wonderful holiday farm known as the Red Stone Hills, named in honor of the local geology, of course! The farm is located a few miles outside of Oudtshoorn, South Africa, a town known for ostrich breeding… so you pass fields of ostriches on your way to the farm! We also stayed at the farm a couple of years ago although I neglected to share pictures of that visit here on Georneys. Around the farm there are several hills of the striking red conglomerate rock. On some of the hills, impressive rock arches have formed. During our previous visit, we hiked up to one of the rock arches and took some pictures. The climb was quite strenuous, however. We only had a few hours for hiking on our recent visit, so we kept mostly to the valleys and observed the rock arches from a distance.

    Geologically, the red conglomerates are part of the Buffelskloof Formation. This formation has also been called Enon in the past, so some people still refer to the red rocks as the Enon Conglomerates. The Buffelskloof Formation also contains breccias. The conglomerates and breccias were deposited in a large, land-locked basin in the early Cretaceous. The conglomerates were deposited by rivers and streams while the breccias represent scree deposits. The precise age of the Buffelskloof Formation is not known very well because of poor fossil preservation, most likely due to the sediments being emplaced in an oxidizing environment. Oxidation is also responsible for the reddish color of the rocks. The red color results from oxidation of iron in the matrix of the conglomerate/breccia rocks.

    Without further ado, here are some more pictures of the pretty red conglomerates:

    [caption id="attachment_6455" align="aligncenter" width="650"]The lovely guest cottage where we stayed, nestled at the foot of one of the red conglomerate hills. The lovely guest cottage where we stayed, nestled at the foot of one of the red conglomerate hills.[/caption]

    [caption id="attachment_6456" align="aligncenter" width="650"]Another one of the lovely guest cottages on the farm. Another one of the lovely guest cottages on the farm.[/caption]

    [caption id="attachment_6457" align="aligncenter" width="650"]The start to our walk amongst the red conglomerate hills. The start to our walk amongst the red conglomerate hills.[/caption]

    [caption id="attachment_6458" align="aligncenter" width="650"]Red conglomerate hills in the late afternoon sun. Red conglomerate hills with intriguing weathering patterns.[/caption]

    [caption id="attachment_6459" align="aligncenter" width="650"]Red conglomerate hills in the foreground and distance. Red conglomerate hills in the foreground and distance.[/caption]

    [caption id="attachment_6460" align="aligncenter" width="650"]A closer view of the conglomerate texture. A closer view of the conglomerate texture.[/caption]

    [caption id="attachment_6461" align="aligncenter" width="650"]Hiking across a conglomerate path. Hiking across a conglomerate path.[/caption]

    [caption id="attachment_6462" align="aligncenter" width="650"]Red conglomerate hills and impressive aloe. Red conglomerate hills and impressive aloes.[/caption]

    I managed to find my pictures from our last visit to the Red Stone Hills farm, so here are some closer images of one of the impressive rock arches:

    [caption id="attachment_6463" align="aligncenter" width="650"]Conglomerate rock arch. Conglomerate rock arch.[/caption]

    [caption id="attachment_6464" align="aligncenter" width="650"]Standing in the conglomerate rock arch. Standing in the conglomerate rock arch. For scale, my husband is about 6’2″ tall.[/caption]

    [caption id="attachment_6465" align="aligncenter" width="650"]Another view through the arch. Another view through the arch.[/caption]

    [caption id="attachment_6466" align="aligncenter" width="650"]Looking through the arch to more conglomerate hills. Looking through the arch to more conglomerate hills.[/caption]

    [caption id="attachment_6467" align="aligncenter" width="650"]A close-up view of some conglomerate texture near the arch. A close-up view of some conglomerate texture near the arch.[/caption]

    [caption id="attachment_6468" align="aligncenter" width="650"]One last view of conglomerate texture. Another view of conglomerate texture.[/caption]

    [caption id="attachment_6469" align="aligncenter" width="650"]Conglomerate texture, with husband for scale. Conglomerate texture, with husband for scale.[/caption]

    If you ever find yourself near Oudtshoorn, be sure to visit these impressive red conglomerate rocks!

    • Do you know if there’s a tectonic event responsible for the uplift that presumably accompanies the deposition of these conglomerates?

      • I’m not an expert on the geology of the Oudtshoorn region, but I believe that the basin in which these conglomerates/breccias were deposited formed as a result of stretching due to the final separation of Africa from Gondwana… there are also some large faults in the area…

  • [caption id="attachment_6450" align="aligncenter" width="500"]Pretty red conglomerate, with my foot for scale. Pretty conglomerate, with my foot for scale.[/caption]

    A couple of weeks ago I spent part of a weekend staying near Oudtshoorn, South Africa. During a hike, I walked by and, at times, across a beautiful Cretaceous age conglomerate. Here’s one image of the conglomerate, taken when I hiked across it. I’ll share some more pictures in another post.

    • Nice. There is some fantastic stuff around Oudtshoorn.
      Are those conglomerates related to the Enon Formation further east?

      Let me know if/when you are ever around Port Elizabeth btw.

      • Yes, I believe that they are related to Enon… see my latest post!

        I was just in PE! I’ll let you know next time I’m there…

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    During my recent travels in Australia, I noticed quite a bit of sandstone around Sydney. Therefore, I was not particularly surprised to also see quite a few sandstone building stones around the city. For […]

    • Although I find sandstone to be particularly beautiful, I can’t help but wonder if it isn’t dangerous to build with it. Considering that it allows percolation to take place due to its large grain sizes, won’t there be allot of water damage to the structure?

    • Although I find sandstone to be particularly beautiful, I can’t help but wonder if it isn’t dangerous to build with it. Considering that it allows percolation to take place due to its large grain sizes, won’t there be allot of water damage to the structure? 15056971

  • [caption id="attachment_6429" align="aligncenter" width="500"]A statue from Nimrud on display at The British Museum, November 2014. A statue from Nimrud on display at The British Museum, November 2014.[/caption]

    I was very upset to learn that a few days ago ISIS looted and bulldozed the ancient Assyrian city of Nimrud in Iraq. This war crime is a terrible tragedy, and I hope that not all of the city’s treasures were destroyed. Fortunately, many artefacts from Nimrud are preserved in various museums around the world. In a way, that is bittersweet. I really wish that artefacts from Nimrud could primarily be displayed in Iraq rather than in foreign museums. However, considering the present political situation, I am relieved that many artefacts have survived overseas. A few months ago, I saw some spectacular artefacts from Nimrud in The British Museum.  For this week’s “Monday Geology Picture” I am sharing a picture of one of the very impressive statues from Nimrud that I saw at The British Museum. While I am happy that this statue has survived, I mourn the other statues and artefacts that were recently destroyed.

  • [caption id="attachment_6401" align="aligncenter" width="650"]Silvermine #1. Silvermine #1.[/caption]

    Earlier today I wrote up a post about the recent fire on the Cape Peninsula, nearby my home city of Cape Town, South Africa. I also shared some pictures of the fire raging near the town of Hout Bay. In this post, I’d like to share some pictures of the landscape that the fire left behind. This afternoon my husband and I spent a few hours hiking in the Silvermine Nature Reserve, which was burned by the fire just a few days ago. Before the fire, Silvermine was covered in fairly thick, lush, green fynbos vegetation, sprinkled here and there with colorful flowers. However, when we walked through Silvermine today the landscape was barely recognizable. Much of the vegetation had been burned away completely, and many of the plants and trees that remained had been charred black. In between the roasted remains of the vegetation, we saw bare soil, often singed black, or accumulations of white ash. Remarkably, every now and then we would pass a patch of vegetation that had been largely spared from the fire. For example, we occasionally passed patches of bright green succulents or brilliant protea bushes, remnants of the landscape that existed before the fire. When we hiked down a small valley, we reached the edge of the fire damage. For awhile, we followed the sharp boundary that separated charred soil from vibrant vegetation. The difference between the two sides – one burned, one green – was remarkable. It was fascinating wandering through the recently-burned landscape, which at times felt like a moonscape or perhaps a view from Mars or some other planet.

    Without further ado, here are some pictures of the recently-burned Silvermine landscape:

    [caption id="attachment_6402" align="aligncenter" width="500"]Silvermine #2. Silvermine #2.[/caption]

    [caption id="attachment_6403" align="aligncenter" width="500"]Silvermine #3. Silvermine #3.[/caption]

    [caption id="attachment_6404" align="aligncenter" width="500"]Silvermine #4. Silvermine #4.[/caption]

    [caption id="attachment_6405" align="aligncenter" width="650"]Silvermine #5. Silvermine #5.[/caption]

    [caption id="attachment_6406" align="aligncenter" width="650"]Silvermine #6. Silvermine #6.[/caption]

    [caption id="attachment_6407" align="aligncenter" width="650"]Silvermine #7. Silvermine #7.[/caption]

    [caption id="attachment_6408" align="aligncenter" width="500"]Silvermine #9. Silvermine #8.[/caption]

    [caption id="attachment_6409" align="aligncenter" width="500"]Silvermine #9. Silvermine #9.[/caption]

    [caption id="attachment_6410" align="aligncenter" width="650"]Silvermine #10. Silvermine #10.[/caption]

    [caption id="attachment_6411" align="aligncenter" width="500"]Silvermine #11. Silvermine #11.[/caption]

    [caption id="attachment_6412" align="aligncenter" width="500"]Silvermine #12. Silvermine #12.[/caption]

    [caption id="attachment_6413" align="aligncenter" width="500"]Silvermine #14. Silvermine #13.[/caption]

    [caption id="attachment_6414" align="aligncenter" width="500"]Silvermine #14. Silvermine #14.[/caption]

    Those are all of the pictures that I’ll share today. In my next post, I’ll share a few more pictures of the recently-burned landscape, including some pictures showing brand new green growths of fynbos vegetation.

  • [caption id="attachment_6381" align="aligncenter" width="650"]The fire raging in Hout Bay at night. Picture courtesy of Nils Backeberg. Hout Bay Fire #1. Picture courtesy of Nils Backeberg.[/caption]

    For nearly a week, a forest fire raged through much of the Cape Peninsula region of South Africa. On Sunday, March 1st the fire began on the hills above the seaside town of Muizenberg, a popular destination for surfers and other beach visitors. Over the next few days, aided by strong winds, the fire spread across the mountains to the towns of Hout Bay, Tokai, and Noordhoek. These towns are all suburbs of the city of Cape Town, where I live and work. For a time, the normally busy mountain roads Ou Kaapse Weg (Afrikaans for “Old Cape Road”) and Chapman’s Peak were closed to traffic as the fire raged along them. For five days, professional firefighters and many volunteers battled the raging fire, which threatened many homes and other structures and which, unfortunately, engulfed a few buildings, reducing them to charred pieces of wood. Many people, including some of my friends and work colleagues, were evacuated from their homes when the flames ranged dangerously close. Emotions ran high as people wondered if they would still have homes by the weekend. Some of the Cape region’s famous vineyards were burned, and some historical buildings were threatened. For example, as a precaution antiques from the famous Groot Constantia Manor were removed although, thankfully, the flames on the farm were put out before the manor house burned down. The fire was mostly fought on the ground, but helicopters and airplanes fought the fire in places where ground crews could not reach, or could not reach quickly enough. Helicopters equipped with giant buckets scooped up water from the sea and from lakes and dropped the water on the flames. Crop-dusting type airplanes spread water rather than pesticides. Thankfully, the fire was finally brought under control yesterday, and the last of the flames were extinguished today.

    Although forest fires commonly occur in the greater Cape Town area during the hot and dry summer months, the fire that raged this past week was unusually extensive and destructive. Here’s an infographic from News24 that summarizes the recent Cape fire:

    [caption id="attachment_6380" align="aligncenter" width="500"]Infographic on the recent Cape Town fire. Taken from the News24 website. Infographic on the recent Cape fire. Taken from the News24 website.[/caption]

    The fire has had a dramatic effect on the peninsula landscape. Normally fairly green, much of the mountain range now seems an alien landscape, reminiscent of Mars or the moon, perhaps. Ecologically, the fire will have a big impact on the animals, such as the baboon troops, and the vegetation of the forest. For the local fynbos vegetation, the recent fire is actually a good thing, in many ways. Many fynbos plants actually thrive after forest fires, taking advantage of the sudden room. Some fynbos plants even depend upon regular fires in order to be able to reproduce because their seeds germinate as a result of heat from the fire and chemical compounds from the fire smoke. Many fynbos plants can re-sprout after a fire. Mere hours after a fire sweeps through, the vegetation begins to grow again. All that said, fynbos does not thrive if fires occur too often, so it is still important for humans to be vigilant and not start fires accidentally. Potentially, a single carelessly tossed cigarette may have started the recent fire.

    Today, my husband and I went hiking in the Silvermine Nature Reserve off of the Ou Kaapse Weg road. We often hike at Silvermine, which is usually covered in thick green vegetation. However, today we hiked in amazement through the sparse charred remains of trees and other vegetation, which were sticking up out of bare reddish brown soil and white ash. We took quite a few pictures of the recently-burned landscape, and I’ll share some of those pictures in my next post. Today, I’d like to share some pictures of the fire itself. All of the pictures in this post were kindly sent to me by Nils Backeberg, a geologist friend of mine who lives in Hout Bay. The pictures show the fire raging in Hout Bay. Thanks very much to Nils for allowing me to share these pictures here on Georneys.

    [caption id="attachment_6382" align="aligncenter" width="650"]Hout Bay Fire #2. Picture courtesy of Nils Backeberg. Hout Bay Fire #2. Picture courtesy of Nils Backeberg.[/caption]

    [caption id="attachment_6383" align="aligncenter" width="650"]IMG_0055 Hout Bay Fire #3. Picture courtesy of Nils Backeberg.[/caption]

    [caption id="attachment_6384" align="aligncenter" width="650"]Hout Bay Fire #4. Picture courtesy of Nils Backeberg. Hout Bay Fire #4. Picture courtesy of Nils Backeberg.[/caption]

    [caption id="attachment_6385" align="aligncenter" width="650"]Hout Bay Fire #5. Picture courtesy of Nils Backeberg. Hout Bay Fire #5. Picture courtesy of Nils Backeberg.[/caption]

    [caption id="attachment_6386" align="aligncenter" width="650"]Hout Bay Fire #6. Picture courtesy of Nils Backeberg. Hout Bay Fire #6. Picture courtesy of Nils Backeberg.[/caption]

    [caption id="attachment_6387" align="aligncenter" width="650"]Hout Bay Fire #7. Picture courtesy of Nils Backeberg. Hout Bay Fire #7. Picture courtesy of Nils Backeberg.[/caption]

    Here are some pictures of the fire being fought by a helicopter:

    [caption id="attachment_6388" align="aligncenter" width="650"]Helicopter #1. Picture courtesy of Nils Backeberg. Helicopter #1. Picture courtesy of Nils Backeberg.[/caption]

    [caption id="attachment_6389" align="aligncenter" width="650"]Helicopter #2. Picture courtesy of Nils Backeberg. Helicopter #2. Picture courtesy of Nils Backeberg.[/caption]

    [caption id="attachment_6390" align="aligncenter" width="650"]Helicopter #3. Picture courtesy of Nils Backeberg. Helicopter #3. Picture courtesy of Nils Backeberg.[/caption]

    [caption id="attachment_6391" align="aligncenter" width="650"]Helicopter #4. Picture courtesy of Nils Backeberg. Helicopter #4. Picture courtesy of Nils Backeberg.[/caption]

    [caption id="attachment_6392" align="aligncenter" width="650"]Helicopter #5. Picture courtesy of Nils Backeberg. Helicopter #5. Picture courtesy of Nils Backeberg.[/caption]

    [caption id="attachment_6393" align="aligncenter" width="650"]Helicopter #6. Picture courtesy of Nils Backeberg. Helicopter #6. Picture courtesy of Nils Backeberg.[/caption]

    [caption id="attachment_6394" align="aligncenter" width="650"]Helicopter #7. Picture courtesy of Nils Backeberg. Helicopter #7. Picture courtesy of Nils Backeberg.[/caption]

    [caption id="attachment_6395" align="aligncenter" width="650"]Helicopter #8. Picture courtesy of Nils Backeberg. Helicopter #8. Picture courtesy of Nils Backeberg.[/caption]

    So, those are some pictures of the flames. Stay tuned for some pictures of the ashes in the next post!

    • A salt pan is formed when the rate of evaporation exceeds the rate of precipitation near a lake or river. Usually when this occurs in nature the salt pan should be white or pearly. What caused this one to be pink? 15056971

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    Over the past few weeks, I’ve been sharing pictures of ancient Egyptian artefacts from the British Museum for my “Monday Geology Picture” posts. Here’s one last picture from the British Museum: a rock […]

    • How did the ancient Egyptian’s manage to carve their hieroglyphics into granite when granite is shown to have a hardness between 6-7 on the Mohs hardness scale? 15056971

  • [caption id="attachment_6333" align="aligncenter" width="500"]A jasper-rich rock from Minnesota. Picture courtesy of Ben Chorn. A jasper-rich rock from Minnesota. Picture courtesy of Ben Chorn.[/caption]

    def. Jasper:
    A dense, opaque variety of chalcedony. Jasper is most often red in color but can also be yellow, brown, green, or gray.

     

    For this week’s Geology Word of the Week post, we’re going to learn a little about silica, aka silicon dioxide or SiO2. More specifically, we’re going to learn about silica minerals. Silicon and oxygen are the two most common elements in the Earth’s crust and are found in many, many minerals. In fact, silicate minerals comprise ~90% of Earth’s crust. Silica minerals are silicate minerals with the chemical formula SiO2.

    The most common silica mineral (and the second most common mineral in Earth’s crust, after feldspar) is quartz. Quartz is most commonly clear or opaque white in color but can also be purple (amethyst), pink (rose quartz), yellow (citrine), and brown or black (smoky quartz). The different colors of quartz are caused by impurities and crystal defects. Quartz is one of a few varities of crystalline SiO2. Under most pressure and temperature conditions present at Earth’s surface and in Earth’s crust, quartz will crystallize as the SiO2 mineral. However, under different temperature and pressure conditions, such as deep in Earth’s mantle or at a meteorite impact site,  SiO2 can form as other minerals, such as cristobalite, coesite, tridymite, or stishovite.

    When  SiO2 does not form with a large crystal structure but rather forms with a microcrystalline or cryptocrystalline structure, a mineral known as chalcedony forms. Like quartz, chalcedony comes in different varieties. Jasper is one common type of chalcedony. Another common type of chalcedony is agate, which has alternating clear and opaque banding. Other types of chalcedony include carnelian, chrysoprase, heliotrope, and onyx.

    Here are a few more pictures of jasper rocks, courtesy of Ben Chorn:

    [caption id="attachment_6334" align="aligncenter" width="500"]Another jasper rock from Minnesota. Picture courtesy of Ben Chorn. Another jasper rock from Minnesota. Picture courtesy of Ben Chorn.[/caption]

    [caption id="attachment_6335" align="aligncenter" width="500"]Another Jasper rock from Minnesota. Picture courtesy of Ben Chorn. Yet another Jasper rock from Minnesota. Picture courtesy of Ben Chorn.[/caption]

    [caption id="attachment_6332" align="aligncenter" width="500"]Jasper cobbles from Minnesota. Picture courtesy of Ben Chorn. Jasper cobbles from Minnesota. Picture courtesy of Ben Chorn.[/caption]

    [caption id="attachment_6336" align="aligncenter" width="500"]Two jasper cobbles from Minnesota. Picture courtesy of Ben Chorn. Two jasper cobbles from Minnesota. Picture courtesy of Ben Chorn.[/caption]

    And here’s a pretty agate that’s sitting on a shelf in my living room:

    [caption id="attachment_6337" align="aligncenter" width="500"]Agate rock. Agate rock.[/caption]

    And here’s some quartz crystals on a rock that I picked up during a recent hike in South Africa:

    [caption id="attachment_6339" align="aligncenter" width="500"]A closer view of the vein of quartz crystals. A rock with a vein of quartz crystals.[/caption]

    • If Jasper is an SiO2 rich mineral what causes the red color? I know red usually comes from the oxidation of iron in a rock or mineral but I can’t think of what could cause this color? 15056971

  • [caption id="attachment_6308" align="aligncenter" width="500"]Ice on a partially-frozen wetland pond, New Hampshire, November 2014. Ice on a partially-frozen wetland pond, New Hampshire, November 2014.[/caption]

    def. Ice:
    Water (H2O) in a solid state. When naturally occurring, ice is considered a mineral. There are many forms of ice: lake ice, river ice, sea ice, snow, glaciers, ice caps, ice sheets, and frozen ground (such as permafrost).

     

    If you ask a geologist what he or she considers to be Earth’s most important mineral, you will probably hear many different answers, depending on the person. Some might choose a common mineral, perhaps olivine or quartz or feldspar. Others might choose a rare, economically valuable mineral, perhaps gold or tantalite or monazite. Others might choose a mineral that is important for understanding the geological history of the Earth, perhaps zircon or spinel or serpentine or maybe even jimthompsonite. However, if you ask me what I consider to be Earth’s most important mineral, I think that I would reply that it is ice.

    After all, how many minerals have an entire field of geology devoted to them? Glaciology is a very important field of geology that is devoted to the study of glaciers and, more generally, ice in all its forms.

    And how many minerals cover vast expanses of the Earth? Sure, much of the mantle consists of olivine and much of the core consists of metal alloys, but no other mineral can compete with ice when it comes to Earth’s surface. Ice covers much of the Earth’s land and ocean surface, and the portions of the Earth that are covered with ice comprise the cryosphere. Some scientists even believe that during particularly cold time periods in the past, the entire Earth, a so-called “Snowball Earth”, was covered with ice, an all-encompassing cryosphere.

    And how many minerals play such an important role in Earth’s climate? The formation of ice is a key aspect of Earth’s climate system. Very simply, there is more ice when Earth is colder and there is less ice when Earth is warmer. However, the transition from water to ice and ice to water can be complex. For example, the light color of ice creates an ice-albedo feedback loop. Climatologists are still working to unravel the details of the roles that ice plays in global climate.

    And how many minerals are less dense than their liquid counterparts? The lower density of ice relative to water enables it to float on top of water, and this physical arrangement has a profound impact on the nature of the hydrosphere and biosphere. If ice did not float on top of water, then many natural bodies of water might freeze completely, never fully thawing in the heat of summer. The lower density and greater volume of ice (compared to water) also plays a role in geomorphology. The expansion of water when it freezes into ice contributes to the physical weathering of rocks. The freezing and thawing of water breaks up rocks and is also responsible for other geomoprhological processes, such as solifluction.

    I’m sure that there are many other reasons why ice is an important mineral. However, I think that the ones I’ve listed above are sufficient to convince me. If anyone asks me what I consider to be Earth’s most important mineral, I will answer ice… although since I currently work as a diamond geologist I might broaden the definition to include both frozen water and the sparkly gemstones I study at work.

    But what would you answer? What is Earth’s most important mineral? What about Earth’s second most important mineral?

    I have to admit, until I gave some thought to this week’s geology word I don’t think that I would have answered ice. I probably would have answered olivine, since I like mantle geology. However, that’s because I don’t generally think of ice when I think of minerals. I guess that ice is so common, and also so unusual (compared to other minerals), that it doesn’t fit into my standard “this is a mineral” box. There’s no doubt about it, though: ice is a mineral, and it is an important one.

    Of course, not all ice is a mineral. The ice that you find in ice cubes in your drink is technically not a mineral since minerals must be naturally occurring by definition. My husband, who grew up in South Africa and only saw snow for the first time in his 20s, has a nice way of categorizing ice: he calls the ice that you find in your refrigerator “domesticated ice” and ice that you find out in nature “wild ice”. Growing up in a landscape without ice, my husband finds the “wild ice” of New Hampshire, where I come from, fascinating. And I suppose he should. For while a frozen puddle on the street, a line of icicles on a rooftop, and a dusting of snow on the driveway may seem quite ordinary to someone who grew up in a cold climate, they are small pieces of a quite extraordinary cryosphere that is an integral part of the planet we call home.

    [caption id="attachment_6309" align="aligncenter" width="500"]Snowy New Hampshire scenery, November 2014. Snowy New Hampshire scenery, November 2014.[/caption]

    [caption id="attachment_6311" align="aligncenter" width="500"]A glacier on Denali in Alaska, 2013. Snow and glacier covered Denali in Alaska, 2013.[/caption]

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