ChemSemBlog

ChemSem 07

Rates and rate-determining processes in natural weathering of rock-forming minerals: linking microscopy and the major-element geochemistry of natural waters

by jongho on Nov.04, 2009, under ChemSem 07

Professor Michael A. Velbel’s presentation about the rates and rate-determining processes in natural weathering of rock-forming minerals was overall easy to follow and understandable. He is a Professor of Geological Sciences at Michigan State University, and he is also currently an associate editor of the American Journal of Science. During Dr. Murray’s speaker introduction, I was impressed to hear about him being an editor of a reknowned scientific journal.

Three new ‘things’ I learned include 1) feldspar reaction he proposed is 2-step process, instead of 1-step process as many textbooks say, and those 2-step process includes dissolving the molecules completely and forming clay afterwards, 2) Biotite Mica is a natural K source for vegetation, and it has completely different mechanism from pelspar which requires one to do matrix algebra, and 3) studying minerals and their reactions with aqueous solutions improves understanding of many phenomena on earth and elsewhere in the solar system and beyond. I also learned that

I think the presentation was pretty interesting as he focused on presenting the information that can be understood by us, instead of presenting many detailed and abstract informations about his research that can only be understood by those who have studied or researched in the same area. During the seminar, I have felt that the presenter was very experienced with his area of research and presenting scientific information to the student body.

I would describe the presentation in one short sentence to my ‘non-science’ friend or family as the following: “The presentation by Michael A. Velbel discussed about how microscopes are connected to geochemistry.”

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Rates and rate-determining processes in natural weathering of rock-forming minerals: Linking microscopy and the major-element geochemistry of natural waters

by Troy on Nov.04, 2009, under ChemSem 07

This week in seminar we were all given a very special treat: variety. Barring dentistry, mineral chemistry and geochemistry are virtually nonexistent in general, organic and biochemistry. Dr. Michael Velbel, a geochemist from Michigan State University, talked to us about different patterns of mineral erosion and other physical and molecular characteristics of minerals.

Dr. Velbel was given the challenge to connect with students who, for the most part, have not had an environmental chemistry or a geochemistry class. Some had probably never even had a lecture on the subject. I half-expected people to raise their hands and ask if this applied to Grignard reagents. Obviously, they wouldn’t do that. Dr. Velbel had a very intellectual yet friendly and approachable demeanor about him, so he easily bridged the gap of familiarity with the students. He spoke of his treks up into the hills and mountains to fetch additional data supporting the cycling of minerals in surface and ground water.

As part of his presentation, Dr. Velbel showed TEM slides demonstrating a pattern of “holes” in the solid mineral structure, indicating the location that Feldspar used to be located. He mentioned that his research included no cleaning of the samples and that they were essentially examining mud. Perhaps what Dr. Velbel will be most remembered for, however, is the slide he showed of actual atoms. Not cells, not organelles, not masses of collagenous protein, but atoms. I found this to be the most exciting part of the lecture for me. I can see why he is so fond of his beloved TEM.

Dr. Velbel stands out to me as one of the best lecturers we’ve had so far. He seemed very excited about his material and very saddened when time was up and he had to let everybody go. My judgment is as follows: 10/10 for professionalism, 10/10 for chemistry content and 8.5/10 for student engagement. The odds were out of his favor to get real stimulation in a group devoid of geochemical foundations.

To the lay person, this seminar was all about how rocks, in their small form, are affected by water in their natural environment.

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Review of Velbel’s Presentation on Rate and Rate-Determining Processes in Minerals

by quines on Nov.04, 2009, under ChemSem 07

Michael Velbel gave a rather unique presentation by giving a geologist’s perspective on chemistry with his presentation, “Rate and Rate-Determining processes in natural weathering of rock forming minerals”. I was pretty interested throughout the presentation, though the dimming of the lights did have a negative effect on my ability to stay awake. But, from what I was able to remember and stay awake for, it really did seem like an engaging presentation. It was also nice during the end of the presentation how he was able to thoroughly answer all the questions that we had for him, and from the end discussion I was able to learn about how geochemistry can play a role not only in our planet, but elsewhere like the moon or even mars.

I was able to learn several other things from throughout this lecture. First of all, how feldspar dissolves its products and precipitates after. Furthermore i learned that the microscopy constrains how reaction should be written, and studying minerals and their reactions with aqueous solutions improves understanding of the many phenomena on earth and elsewhere in the solar system and beyond. He also explained his SEM techniques and what he was looking for throughout his research. I was also able to learn more about the many things he did during his research.

Overall I thought the presentation was interesting given his clear presentation style and the unique topic being discussed. I would describe this presentation to my non-science friend by saying that through observing minerals and their reactions with aqueous solutions, we can gain further understanding that can help us in our explanations of certain phenomena.

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Linking Microscopy to the Geochemisty of Natural Waters

by choig on Oct.30, 2009, under ChemSem 07

Most people think that the geology has little relationship with chemistry and some would think that geology and chemistry are totally different subjects. However, there is geochemistry and it actually contains information about geology and chemistry together. The seminar that was held in October 22, 2009 was “Rates and rate-determining process in natural weathering of rock-forming minerals: Linking microscopy is the major element geochemistry of natural waters. “

The speaker was Michael A. Velbel who is currently Professor of Geological Sciences in Michigan State University. He received his Bachelor degree at Northwestern University followed by a Ph.D. from Yale University. An interesting fact about this speaker was that he held a NASA/ASEE Summer Faculty Fellowship and moreover, he was a member of the Mineralogy-Petrology subteam of the NASA Stardust mission Preliminary Examination Team.

Michael Velbel discussed weathering rates of rock forming minerals in the Blue Ridge Mountain where there are some watersheds.  The purpose and approach for his research was to examine weathering rates of primary silicate minerals in metamorphic bedrock to saprolite.  The specific area that he has studied  is the Cosweeta Watersheds.

During the presentation, he mentioned that by entering density levels of the water into a computer program, the amount of mineral can be determined. Also it will let you know what kinds of minerals have been lost from the rock.

This presentation was very interesting because I learned about geochemistry, a field of science I do not think about often. As compared to previous presentation which showed lots of mechanisms, it was really different and unique. I wanted to ask if he has researched other places rather than Blue Ridge Mountain or if there are any other research groups that are studying the same subjects but in different places. I learned that the minerals are named based on names of people who found the mineral or the place where the mineral was found. Furthermore, it will help to study minerals on other planets. If I can sum up this presentation in one sentence then it will be the examining weathering rates of minerals in rock at Coweeta Watershed.

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Rates and rate-determining processes in natural weathering of Rock-forming minerals: Linking microscopy and te major-element geochemistry of natural waters

by brummett on Oct.29, 2009, under ChemSem 07

On October 22, 2009 Dr. Michael A. Velbel came to Andrews University to speak about his research in the Southern Appalachian Blue Ridge Mountains.  Dr. Velbel came to us from Michigan State University, East Lansing.  He is currently working in the Department of Geological Sciences and has been a part of Michigan State University since 1983.  Dr. Velbel received his BA from Northwestern University in 1978 and his Ph.D from Yale in 1984.  He previously worked as an Intern at NASA/ASEE.

As previously stated Dr. Velbel is working on research of the Southern Appalachian Blue Ridge Mountains.  He makes a trip to these mountains about every 2 years to gather more rock and mineral pieces, which he studies and analyzes in his labs at Michigan State University.  One thing that I learned and found very interesting was that there are actually rotten rocks and the name of it is saprolitic.  Another aspect that I learned from the speaker was that the feldspar can remove itself from rock formations creating deep groves in the rock by way of Na, Ca, Al, and O.  One thing that I really didn’t understand was the fact that when feldspar dissolves, its products precipitates after mobilization of solutes.  I don’t really understand how it dissolves but yet it creates a precipitate with its product.

Dr. Velbel was a great speaker; he has tons of information about the topic that he presented.  Even making comments like ‘I better quiet himself’ so that he would stay within the time restraints.  I really liked that he did stay within the time restraints.  He had a booming voice that made it extremely easy to hear and understand.  He shared his topic with passion and excitement.   Only downside is that I wish we would have had more time so that we didn’t have to rush through some of the material.  Other than that I thoroughly enjoyed his presentation and would even like to hear him speak on another occasion if possible.

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Review of Michael A. Velbel’s Rates and rate-determining processes in natural weathering of rock-forming minerals: Linking microscopy and the major-element geochemistry of natural waters

by shieun on Oct.26, 2009, under ChemSem 07

Today’s speaker is from a different breed of chemists in the field of science. His research isn’t likely to stumble upon a compound to cure diseases or develop materials that will be manufactured and integrated into everyday-items. Acknowledging the unique perspective that he was bringing to us, Michael A. Velbel admitted that while he is trained as a “low temperature” geochemist (working with the surface material of the Earth), most of the analytical work done is reminiscent of geology and mineralogy. After the previous chemistry heavy seminars, Velbel’s mathematical basis of analysis made me feel out of place (am I in the right amphitheater?).

Although Velbel is the Professor of Geological Sciences at Michigan State University, his research requires a bit of traveling. Samples from watersheds in the southern Appalachian Blue Ridge of North Carolina are collected to calculate rates of silicate minerals. Velbel introduced many new terms to our vocabulary such as saprolite, feldspar, and lamellar bands (rocky words!). From the amount of minerals captured in the watersheds, the rate of weathering can be determined. Simply, as Velbel put it, some of it plus the rest of it makes all of it. However, it seemed other factors had to be taken into account, such as minerals like potassium which are absorbed by plants.

At the end, some of the questions led to some interesting information about geochemistry. When acid rains were causing havoc, geochemists determined the disintegration of different compounds in reaction to the harmful rain. Also, Velbel spoke about the “philosophy of science” in answer to a question about the determination of data with work from NASA. From whatever data obtained, scientists make deductions, but when proven wrong they must start over, knowing that either their deductions or hypothesis were in fault. Since the cheapest way of gathering data on extraterrestrial bodies is taking pictures of the planet’s surface, wildly incorrect deductions are more than common.

Unfortunately, the speaker did not speak more on his extraterrestrial work. The part of his biography on the seminar fliers that drew my eye was his time with NASA. This seemed to be the case with other individuals as well, looking at the amount of time spent on the subject during the Q-and-A. Although I found most of the seminar boring (I’m not too crazy about rocks, so I found the Q-and-A section more exciting) Velbel spoke clearly and seemed quite comfortable in the environment.

Laymen’s Summary of Chemistry Seminar: Chemists work with rocks too, and Velbel determines the rate of their weathering by measuring the mineral concentrations in collected water in the area. Even cooler, geochemists help out NASA with their rocks from outside our atmosphere.

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Rate and rate-determining processes in natural weathering of rock-forming minerals linking microscopy and the major-element geochemistry of natural waters by Michael Velbel

by seonui on Oct.26, 2009, under ChemSem 07

This week’s talk was on Rate and rate-determining processes in natural weathering of rock-forming minerals linking microscopy and the major-element geochemistry of natural waters by Michael Velbel.

Our guest speaker for this week’s presentation was Michael Velbel, who is a professor of Geological Sciences at Michigan State University. I think the presentation was good and easy to follow, and he was very enthusiastic to tell students about his research.

I was very interested in Velbel’s presentation because the topic of the presentation regarding geological science is a completely new field for me. I learned that mineralogy–studying formation, distribution, and utilization of mineral groups — is closely related to chemistry.

Velbel usually works at Coweeta watershed to study silicate minerals which are the largest and most important component of rock-forming minerals and to examine weathering rates of primary silicate minerals. I also learned about some names of silicate minerals like Feldspar, Micas, Garnets, and so on.

The most interesting thing that I learned during his presentation is that the reaction of Na-Feldsper weathering that occurs in nature is different from the reaction equation that is described in the textbook.

On the other hand, I had a question about what kind of other factors such as temperature in groundwater environments can also influence the weathering rate of rock-forming minerals.

For a non-science friend, I would say that Geological science, the study of the solid and liquid matter that constitutes the Earth, helps us understand phenomena on Earth and its systems from microscopic to global scales, specifically, studying minerals and their reactions within natural waters.

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Linking Microscopy to the Geochemisty of Natural Waters

by chem nerd on Oct.26, 2009, under ChemSem 07

Last Thursday I discovered a field of chemistry I had never known about: geochemistry. Because I haven’t had any previous exposure to this subject matter, almost everything presented to me was something new. Our presenter was Michael A. Velbel, professor of geological studies at Michigan University. I enjoyed his presentation; however, because he is a geologist and not a chemist, his presentation was a little lacking in the chemistry aspect. This is not to say that he did not show us the chemical aspect of his research, just that I would have liked to have heard a more in depth discussion about its chemistry. Nevertheless, Velbel did a great job at setting up the background and foundation of his research, and presenting it in a way that was easy to understand.

In a nut shell, Velbel examines the weathering rates of primary silicate minerals in metamorphic bedrock located in the Blue Ridge Mountains of Otto, North Carolina. His primary focus is to control south hardwood forest water sheds. He does this by measuring the amount of the water that goes over the veer, and analyzes that water every week. With this information, Velbel and his team are trying to find a system of equations that will tell them the input and output of minerals in a given area so that they can know how weather affects the natural minerals in a rock. One of their main focuses is on aluminum, present in feldspar, which is the most abundant and reasonably reactive mineral found in the Saprolite Regolith hill slope where their watershed is based. Through SEM and TEM analyses of the rock, they have discovered that weathering causes the feldspar to leave the environment in a dissolved form, thus leaving pits in the rock where the elements used to be.

Although Velbel spent a considerable amount of time discussing feldspar, other similar compounds, and mass balance equations. What I found most interesting was brought up in the last five minutes as he spoke about his partnership with NASA research on Mars. From Velbel I learned that NASA is quick to pass judgment, which becomes embarrassing five years later, that often part of this misjudgment is due to the fact that NASA compares footage of Mars to pictures that only look similar to what they have seen, and finally that we will never know for certain if water did exist on Mar because there is not one ounce of anything resembling water left on that planet, just ground formations.

Overall I like the presentation, the only questions I have are: what is the maximum distance minerals can migrate from the rock to make a reasonable difference in life of the surrounding environment? How much of their conclusions apply to other watersheds around the US? And finally, if interpreting data on Mars will help in his research on Earth in the Blue Ridge Mountains.

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How Nature Erodes

by shulla on Oct.26, 2009, under ChemSem 07

This installment of ChemSem featured Michael A. Velbel of Michigan State University’s Geological Sciences department. He discussed his PhD and ongoing research work involving mineral erosion and solubility from rain in the Blue Ridge Mountains. Evidently, on an annual or semi-annual basis, Dr. Velbel ventures south to collect samples of rock from the Blue Ridge Mountain National Park and analyzes them under an electron microscope in order to see the pores and fissures in the surface and determine what, if any, mineral substances have been washed out by the action of water erosion.

Much of this presentation was interesting, though the true applications of all of it was not clear. To begin with, Velbel mentioned that one could see the erosion of alumina out of the holes in feldspar samples. This is interesting considering that alumina is one of the seven most abundant elements on earth, but is almost entirely insoluble. Though most of the solutes in these samples were only washed a few millimeters at most from their pores down the face of the feldspar sample, over time this erosion can be significant. In the Blue Ridge Mountains National Park, there are weekly studies of the water supply leaving the park taken which record dissolved solutes and calculate mass loss based upon flow speeds through a sluice. This data, kept for many years by the park, was invaluable in understanding the effects over time of this erosion of feldspar and other minerals from the ground structure.

Velbel’s research falls into the category of Watershed studies. I found it interesting when Velbel pointed out that most of the impetus for this study came at the same time many other watershed studies were undertaken and for the same reason. Specifically, when the first occurrences of acid rain came in the 1980’s, many different groups began studying common erosion features in order to better understand the effect sulfuric acid would have on erosion of the landscape and the rates of material loss to water. Finally, though not specifically educational, Velbel did share an interesting bit of trivia when he admitted that mineralogy involves some of the worst nomenclature around since every mineral is named randomly after its place, its appearance, its discoverer, latin, greek, or a variety of these to distinguish it.

All in all the presentation was well prepared and effectively explained both the process of the research and it’s purpose. Velbel was a good speaker and amusing at times, offering quite a bit of knowledge about mineralogy, though not all of it could be clear from the common chemist’s perspective. Velbel sees his efforts as forwarding knowledge in general claiming that the studies of minerals in solutions helps scientists better understand the world and the cosmos in general. While this is true, the specific applications of the ongoing research is not entirely clear. It would have been nice if some measure of application was more understood and seen so that the research could be viewed as moving in a discernible, definable, and effective direction.

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Microscopy & Geochemistry of Natural Waters

by Danuel on Oct.26, 2009, under ChemSem 07

This week’s seminar was presented by Dr. Michael A. Velbel.  Dr. Velbel works for the  Department of Geological Sciences at Michigan State University.  Velbel is scientifically trained as a low-temperature aqueous geochemist.  Most of  his research took place at the Coweeta Watershed in the southern Appalachian Blue Ridge.  Dr. Velbel examined the weathering rates of primary silicate minerals in metamorphic bedrock to saprolite.  Mass balance was used to calculate the destruction rates.  Reaction stoichiometries had to be determined by optical petrography, scanning electron microscopy, ICP-MS, and various other methods.

There were a few interesting things presented in this seminar that personally caught my attention.  These points had to deal with hillslope hydrology, coweeta water sheds, Na-feldspar weathering, and the role of microscopy with these reactions.  Hillslope hydrology deals with the role and function of watersheds at the plot-hillslope catchment scale.  It helps scientists discover where the water goes when it rain, how long it residues in a watershed, and what pathway the water takes to the stream channel.  Using this method, Dr. Velbel was able to see that the water flowed down through mineral and geologic material and then came out as stream water.  Through extensive research of the watersheds, Dr. Velbel’s research group was able to combine and balance the stoichiometric weathering reactions. With Na-feldspar weathering the feldspar would turn into kaolinite plus dissolved materials known as ions. All occurred in the solid form and none in the liquid form. If the feldspar came in contact with acid and water it would readily turn into clay. The reaction can be sped up with an increase in temperature and an acid. The role of microscopy was to constrain how reactions should be written and it showed how the feldspar dissolved into its other states.   Dr.Velbel also stressed that studying materials and their reactions with aqueous solutions improves the understanding of many phenomena on earth and elsewhere in the solar system and beyond.

In conclusion, I truly can say that I enjoyed this seminar.  The information shared was very interesting and relevant to the environmental mindset of todays society.  Dr. Velbel humorous style of speaking and presentation, just added a positive vibe throughout the entire seminar.  I definately wouldn’t mind having Dr. Velbel speak again at a future seminar session.

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Rates and Rate-Determining Processes in Natural Weathering of Rock-Forming Minerals: Linking Microscopy and the Major-Element Geochemistry of Natural Waters

by young on Oct.25, 2009, under ChemSem 07

On October 22nd, there was a presentation about geological science given by Michael A. Velbel, who is from Michigan State University. His presentation title was “Rate and Rate-determining Processes in Natural Weathering of Rock-forming minerals.” It was very interesting that the theme of his seminar had not been presented during past seminars. Also, he used a lot of visual data, like SEM or TEM pictures, which attracted my attention.

The purpose of his research was to examine the weathering rates of minerals in metamorphic bedrock in the southern Appalachian Blue Ridge, specifically in Coweeta watershed. He said that he collected the data once a week and analyzed it to make a model and related molecular distribution ratio. From his seminar, I learned that the reaction formula which the textbook presents does not fit well in real reaction for Na-feldspar weathering. Also, he said that nomenclature for geological compounds is from the name of a place which they are found, or a person who discovers the compound. Lastly, he explained the applications of geologically analyzed data. For example, we might be able to say that there was water on Mars because the marks on the surface of Mars are similar to the water marks on the soil of the Earth.

I would tell my friends that the seminar was about researching which molecules consist of mineral, and which facts affect the forming rates of minerals. This helps us easily understand the mysteries occurring on the Earth and other planets in the Solar system.

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Rates and Rate-Determining Processes in Natural Weathering of Rock-Forming Minerals: Linking Microscopy and the Major-Element Geochemistry of Natural Waters

by mastera on Oct.25, 2009, under ChemSem 07

The lecture this week was very intriguing and informative, and I found it to be very interesting. The reason for this is not only did it deviate from the topics of the past few lectures, but it also reminded me of the reservoir engineering class I took last semester at Penn State University. It was a nice mixture of chemistry and geology, a refreshing break from straight synthesis every week.

One thing that I learned was that when a rock has empty holes in it that means that the rock had elements that were dissolved in solution. One thing that I want to know more about is why the sections of the forest in the watersheds are replanted. The speaker mentioned that the main reason is to study how different trees affect the erosion and other stuff like that, but it would be interesting to learn more about it. Another thing that I would like to know about is why aluminum is the least soluble element in its class. Also, it was interesting to note that sand on regular beaches, that is, beaches on the ocean, are composed of about ninety-nine percent quartz.

In explaining what this lecture was about to one of my non-science friends, I would tell them that the lecture was about how the flow of water, mixed with certain natural chemicals, affects rocks in some areas of the country. As for the guest speaker, Dr. Michael A. Velbel works at the Department of Geological Sciences at Michigan State University. He has been working with the area of the Blue Ridge Mountains in the southern Appalachians of North Carolina since his years in graduate school. His speaking style is professional, a steady but understandable pace, and it shows his experience in teaching.

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Microscopy and Geochemistry of Natural Waters

by Celena on Oct.25, 2009, under ChemSem 07

Michael Velbel is a professor of geological sciences at Michigan State University. Velbel presented on the microscopy and geochemistry of natural waters. Under this topic he, informed us about some reactions that take place during the weathering of the rocks. Velbel kept students interested by adding humor to his presentation and relating with the audience. The presentation was understandable and very interesting. Velbel also made eye contact and did not hesitate to answer the questions of the students in the end.

Some interesting points learned during this presentation dealt with hillslope hydrology, coweeta water sheds, Na-feldspar weathering, and the role of microscopy with these reactions. Hillslope hydrology addresses the role and function of watersheds at the plot-hillslope catchment scale. It helps scientists discover where the water goes when it rain, how long it residues in a watershed, and what pathway the water takes to the stream channel. Using this method Velbel was able to see that the water flowed down through mineral and geologic material and then came out as stream water. The Coweeta watersheds measured the flux of elements going in the rain and the amount was able to be determined by removing it from the rain water. With the watersheds Velbel’s group was able to combine and balance the stoichiometric weathering reactions. With Na-feldspar weathering the feldspar would turn into kaolinite plus dissolved materials (ions). All occurred in the solid form and none in the liquid form. If the feldspar came in contact with acid and water it would readily turn into clay. The reaction can be sped up with an increase in temperature and an acid. The role of microscopy was to constrain how reactions should be written and it showed how the feldspar dissolved into its other states.

The conclusion that Velbel stressed at the end was, studying materials and their reactions with aqueous solutions improves the understanding of many phenomena on earth and elsewhere in the solar system and beyond. I thought this to be very interesting and many students were engaged especially when Velbel brought up the subject of NASA, and the work that Velbel’s group would like to see done on Mars. The overall presentation was satisfactory, and it would be interesting if they found out about pyroxene corrosion being present on Mars.

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Using Mass Balance in Geochemistry

by ckrym on Oct.25, 2009, under ChemSem 07

The Chemistry Seminar Speaker on October 22, 2009 was Dr. Michael A. Velbel. Dr. Velbel is in the Department of Geological Sciences at Michigan State University. His presentation was about microscopy and geochemistry of natural waters. I found his presentation very interesting. The use of images and explanations of the practical use of this chemistry made it easy to understand.

Dr. Velbel worked in a field area in the Southern Appalachian Blue Ridge in North Carolina. He collected water samples from water sheds and analyzed them for elements coming off the mountain. Field work, especially outdoors, really interests me. I enjoy the fact that you can be outside, physically go somewhere and collect something and then go back to the lab and do your chemistry. This addition to research would prevent me from feeling like a lab rat.

I learned in studying his samples Dr. Velbel did not prepare or wash them in anyway before analyzing them with the scanning electron microscope. This allows him to see any erosion or sediments in his sample. I was informed that studying minerals and their reactions with aqueous solution can help us explain many geological forms on Earth and in the solar system. The most informative part of this presentation for me was about mass balance. I am currently learning about this in my Quantitative Chemical Analysis class and I was glad to see a practical case for using this equation. Dr. Velbel derived mass balance equations from differential equations to re-explain steady state. This allows him to solve for the weather rate of the mineral.

In describing this presentation to family members or friends I would say that Dr.Velbel described how analyzing erosion can help us determine how fast other materials will weather in different conditions.

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October 22 Seminar

by fletchek on Oct.24, 2009, under ChemSem 07

This week’s speaker was Michael Velbel from Michigan State University.  It was nice to finally get someone from Michigan State after having so many speakers from the University of Michigan.  Velbel is trained as a low-temperature aqueous geochemist.  His research took place at the Coweeta Watershed in the southern Appalachian Blue Ridge.  Velbel examined the weathering rates of primary silicate minerals in metamorphic bedrock to saprolite.  Mass balance was used to calculate the destruction rates.  Reaction stoichiometries had to be determined by optical petrography, scanning electron microscopy, ICP-MS, and other methods.

In calculating mass balance, Velbel used this equality: “Some of it plus the rest of it equals all of it.”  There were different input and output factors that had to be considered.  Precipitation and weathering added input.  Some of the material was lost to biomass, streams, and clay mineral formation.  Biomass removal, in particular, complicated the mass balance.  A system of four equations needed to be used to calculate the mass balance.  In addition, there were some assumptions that Velbel made that turned out to be false.  In conversion of Na-feldspar to kaolinite, aluminum was assumed to be entirely solid, since it is the least soluble of the major rock forming elements.  But, scanning electron microscopy of samples showed holes where feldspar was located.  This implied that all of feldspar’s elements, even aluminum, were left in solution.  Velbel figured out that .75 units of Na+ go into solution for every unit of dissolved feldspar.  This was used to determine the weathering rate of plagioclase feldspar.

This presentation was very interesting, because  I learned about how a quantitative analysis concept, mass balance, was used to investigate mineral composition in nature.  Velbel mentioned some of the difficulties of geochemistry.  For example, mineral names are not systematic, unlike organic naming.  Minerals are usually named for their discoverers and locations, while organic compounds are named for their functional groups.  I learned that mineral chemistry will be needed to study other planets such as Mars, since there is no water on them.  There were some terms used in the presentation that I did not understand, and the calculations were quite complicated as well.  But, Velbel did a very good job of presenting the main highlights of his research.  If I had to sum up his presentation for a layperson, I would say that compositions of mineral samples were investigated at the Coweeta watershed.

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Microscopy and Geochemistry of Natural Waters

by kgardner on Oct.23, 2009, under ChemSem 07

Today Dr. Michael Velbel came to talk to us about Microscopy and Geochemistry of Natural Waters from Michigan State University where he is a Professor of Geological Sciences. Most of the research he discussed was for weathering rates of rock forming minerals in the Southern Appalachian Blue Ridge where there are several watersheds. His specific study area was the Coweeta Watershed, where he takes samples and analyzes them for different mineral contents. The Southern Blue Ridge area has been split into portions for different tests, some being filled with pine trees and others with other types of trees, and then there are the control sections with the trees that were originally there. There are dams at the bottom of these watersheds where they can keep track of the amount of water leaving the area. They use computers to test how many and what kind of minerals are leaving them and in this way can tell what minerals are being lost from the rocks.

In this seminar I learned about geochemists, a career that I did not even know existed. I learned some of the interesting things that they can be involved with regarding outer space and planet composition. I also learned some interesting things regarding the mineral feldspar and its properties with dissolving and products precipitating. I found this seminar to be very interesting, Dr. Velbel was very good about explaining the different things and had many visual aids in the form of pictures and the chemical crystalline structure of a couple of the minerals he discussed. I would explain this seminar to a non scientific person as finding the rates of weathering on rocks in the Southern Appalachian Blue Ridge.

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testing chemsem 7

by dmurray on Oct.18, 2009, under ChemSem 07

this is a test.

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