This is an archive of CompuServe forum messages from 1985 to 1995, as saved in transcripts by John Foust.
Search Results (4,845 messages)
Hi, Kamron– The article on large igneous provinces implied that they had tentatively identified many (all?) of these plateaus as basaltic masses based on seismic data; then expeditions went out to check, and verified it at Ontong-Java, Vorland (N. Atlantic), and Kerguelen. Cores or surface samples? I do not recall.…
hot springs
Message #175301
I am interested in finding information about hot springs. How they are formed, types, etc… . If anyone has information about where to find the information it would be of great help. internet sources are a plus. Thanks, tom ohs@teleport.com
Hi Doug, You know fluorescence is not my strong point but I thought this might be a good point to pipe up about fluorescent color standardization. Remember Ron Pellar? His main employement these days is Color Scientist and he has been asked to assist on the technical color end of…
Sorry Doug, this list is entirely snail mail addresses…
NEW WEB SERVER
Message #175215
We have a new WebServer for treasure hunting, metal detecting, and prospecting. Although there is not a complete overlap, if you are interested, check it out. It includes articles from Treasure Quest magazine and elsewhere, current news articles, newsgroups for detecting and treasure huntng, online research guides, online shopping, etc.…
Hi Lanny, No problem. I had a copy of the latest Mineral News at my computer when John's query came up. So I just copied the info to him. Rod
#Meteorite Group
Message #175123
To anyone that is interested, there is a group of us that are forming a meteorite group or sort of an cyberspace club and we encourage anyone else that is interested in this area to join us. I am now sending out question aires for the group and will send…
My thanks to those who helped John locate the Mineral News. Lanny Mineral News
#Database
Message #175066
No, it isn't the same. I just got a call from the author of the new MINCAT, soon to have a new name, because he just discovered that the name was in use. Apparently the MINCAT program is primarily for X-ray work and to search for minerals with certain elements–find…
Hi, Doug– >> Hydrocarbon inclusions in minerals often fluoresce a bright yellowish-white…> Are we talking radioactive like granite, or radioactive like high-grade uranium ore here? > Can you describe the brightness and precise color in terms of any "commonplace" (to fluorescent colors) mineral specimens?
#Antartica
Message #174995
Hello Doug Here comes the focus of the plate motion controversy (converging impossibilities) The motion of the Antarctic plate is demonstrated by the features present in the Mid Ocean Ridge that we find around it. We agree that the motion is directly away from the Australian continent on that side.…
Doug — The news group is only about 3 weeks old and may not be carried by most servers. My internet provider didn't start carring it till I asked. I wouldn't have even known about it had I not participated in getting it started. — Bill
Doug >> As stated before, I am aware of no motions that require a dramatic amount of plate compression to fit through a narrow "exit". In the Indonesian case we are talking about different subducting plates approaching from different directions – each plate is traveling in a mostly unified direction…
Doug >>If a ridge is active, I presume it has oriented itself to cut across the tension (if I pull cloth apart, the rip tends to cut across the pull), for the most part. That means there is little sideways tension to make the plates slide along the length of…
Doug >>The Scientific American of Oct 1993 article on large igneous provinces shows the Broken Ridge plateau and the 90-East ridge as being such. It implies the Kerguelen plateau and the Broken Ridge plateau formed from a single mantle plume. I take this to mean the plume formed a hot…
Don If all the sections of crust in the pacific are from separations of crust due to rifting then each in sequence was cut away by a different older rift from an earlier time. Any part carved off would be equidistant from the parent continent like the Cook Islands Manihiki…
Doug >>Another mechanism is described in the Scientific American of July 1989. After India rifted away from Africa and Antarctica, at the end of the Cretaceous it was blown apart by the arrival of a hotspot that announced itself by erupting the tremendous Deccan traps. A rift formed there and…
>>>Until, of course, there is deposition on top of the stubs, as there is already in GA and AL where the southern range disappears under the Mesozoic. Should that area ever be uplifted and subsequently eroded, newly re-exposed faults and folds will once again provide relief.
If current trends continue, in a few tens of millions of years there will be a 2000 km long Island Arc in the North Pacific — the present California Coast from Drake's Bay South plus Baja California. It will contain some Paleozoic rocks — much metamorphised and hard to date…
> I see what you're saying here, and I think you're basically right, but I don't see your "roots" going down very far. Remember, these are sediments which have overflowed the edge of the continental craton being pushed back by the plate collision like you'd push back the cuticle of…
I am interested in your geiger counter offer. – George
#Mineral News back issues
Message #174757
Hi John, Sure, back issues of the Mineral News are available from the Mineral News publication. It says here in a recent copy: Mineral News – Back Issues are available for only $1.75 ea. (Out-of-Print will be photocopied): Vol. 1, Nos. 1-7; Vols 2-9, Nos. 1-12. (Vol. 10 issues only…
#Internet
Message #174756
Hi, Bill– Thanks for the word on the new alt.mining.recreational newsgroup. I was able to read it using CompuServe in a manner like that described in SCIGEO.SCR in the library. It looks quite young; I found only 7 topics, where 100 would be normal for sci.geo.geology. –Doug
#Fold mountains
Message #174752
Hi, Kamron– As noted in another message, I blooped in speaking of a root as deep as the mountain is high – I should have multiplied root depths by 5 or 10, since the air/rock density ration is much greater than crust/mantle density. The Scientific American of Oct 1993 article…
Volcanic Formation Rules
Message #174748
Hi, Michael– I forgot to mention that the Scientific American of Oct. 1993 has an article on large igneous provinces, which gives both reasons and possible global consequences of huge volcanic outpourings such as the Deccan Traps I mentioned. –Doug
Rock Clubs On-Line
Message #174709
The club's snail mail address is : The Rhode Island Mineral Hunters, Inc. c/o H. Duane Evans 28 Ash Street Portsmouth, RI 02871 Regarding other members interested to receive e-mail, I'll check at our next meeting and get back to you. thanks JT
Hi, Howard– At last, a new fluorescent mystery! The brightest longwave-UV yellow fluorescences I know of come from scapolite (meionite, generally) from Ontario/Quebec. Wollastonite and pectolite are also notable for this. Hydrocarbon inclusions in minerals often fluoresce a bright yellowish-white, as do hydrocarbon minerals such as idrialite (which also tends…
Hi, Ed– The picture I am forming in my mind is of a great range of fold mountains (as big as the Himalayas?) forming during the collisions as/before Pangaea formed, with correspondingly great roots below them. Then, sort of like I explained to Kamron, as the tops wore down, the…
Hi, Howard– The mineralogical density difference is indeed a reason I had not mentioned why if either subducts in a collision, it will be seafloor rather than continent. Kamron and I have discussed it before, thus I sort of assumed it, but it is best to spell it out when…
Hi, Don and Jon– I remember reading about those water gaps. I cannot find the article in question at the moment, but it offered several theories about how they could have been formed. One has the river establish its course on flattish land, then uplift and differential weathering of folded…
Hi, Jon– >> My text says that Gondwanaland was assembled from continents and microcontinents very early in the Paleozoic, or even in the late Proterozoic, and stayed pretty well in one piece until it broke up in the mid-Mesozoic. In Dalziel's reconstruction in the Sci Am article, the pieces of…
Hi, Kamron– >> If the basin is only 200 million years old how can there be crustal sections out in the Pacific that have lower Paleozoic layers in them? Note in my reply to Don in this thread the discussion on the separations of Japan and New Zealand from their…
Hi, Russ– Do you have any E-addresses in that list? I expect it would be a welcome upload; I know I would find it handy in answering queries about clubs that pop up from time to time. I suspect the AFMS and/or regional FMS'es must be keeping their lists on…
Don, >> On both sides we have these tidy folded mountains that are purported to have eroded only a little — only a few thousand feet of sediment missing — in 300,000,000 years. I don't have any problem with localized uplifts, but I have a lot of trouble with the…
>>>True, it is. All I know is that three different texts in my library agree that the modern Appalachians are the roots of the ancient mountain ranges, mildly uplifted in the Cenozoic by isostatic adjustment and/or epeirogeny.
Howard… While I have no help with identification I saw your comment about not having access to a Geiger counter. I can't resist jumping in to mention I have a geiger counter obtained in a rockhound's garage sale. I was never able to get it to respond properly although I…
#Rock Clubs On-Line
Message #174414
Doug fwiw, I have about 150, maybe 200, club addresses in the database for the Opal Society. Got most of them out of Lapidary Journal and Rock & Gem. Nearly all are in the southwestern US. I set this list up for the purpose of contacting clubs when the AOS…
Don, >> All of what you said seems reasonable to me except the erosion of the Applachians. The modern Applachian chain is very clearly a folded structure.
All of what you said seems reasonable to me except the erosion of the Applachians. The modern Applachian chain is very clearly a folded structure. The Easternmost fold — Blue Mountain — stretches for many hundreds of kilometers broken only by the occasional water gap. To further complicate things, one…
Fluor. Mystery mineral
Message #174237
Here's one for you fluorescent-mineral hounds: I have a sample of rock from an oil-well core cut in the Jurassic Nordegg Member of the Fernie Formation in Alberta, Canada. The main lithology of the Nordegg member is dark brown to black, calcareous, very organic/petroliferous marine shale. The shale is locally…
Hi, Doug and Kamron! >> The lithosphere is colder than the mantle below it because it is more able to lose its heat to the surface. This makes it denser, and given any opportunity, it will sink …> (Kamron): Greenland looks like it drifted north while Iceland drifted south. >…
Doug, Mr. Dalziel may well have the right of it. I don't know. I only know that my text describes exotic terranes that don't clearly match either Laurentia or Baltica as being involved in the Taconic orogeny. >> In the next late-Devonian map they are more firmly connected and the…
Kamron, Sorry, I don't know. The references I have don't say anything about that, or if they do, I haven't found it yet. Jon W.
I agree with you, Doug. As deep and complete as the erosion of a faulted and folded region could ever be, it would still be differential between layers. Resilient beds, and/or inclined beds, will always produce relief. Nothing in the Central Appalachians, at least, has been eroded flat. The inverted…
Don >> As I understand it, continental rock is very light and doesn't get sucked into subduction zones. That's how all those exotic terrannes John McPhee )"Assembling California") writes about got tacked onto the West side of Northern California.
Sorry — don't know a thing about the Pacific plateaus. As I understand it, continental rock is very light and doesn't get sucked into subduction zones. That's how all those exotic terrannes John McPhee )"Assembling California") writes about got tacked onto the West side of Northern California.
Hi, Michael– Welcome to the forum! The pros who hang out here may have something to tell you if you keep watching. If we leave you thirsty for more, you might want to try the volcanoes mail-list discussed in INTERN.TXT in this forum's library. Near crustal collisions and hot spots…
Hi, Kamron– >>I see the entire continental crust as about 5 miles thick on top of a base that is more like 10 or 12 miles thick. At collision zones like the Himalayas, the crust must be at its thickest, which is more like 70 km, according to my notes.…
Hi, Jon– The author of the article (Ian W. D. Dalziel) seemed to have the strongest conviction that Antarctica was connected to Laurentia before the Cambrian; the various collisions of Laurentia (proto-N.America) with the S. American part of Gondwana seemed to be worded as more speculative, or perhaps that was…
Hi, Don– The Scientific American of Sept. 1983 has an article that says "Behind the volcanic arc the overriding plate may be extended or compressed. … If the extension of continental crust behind the arc proceeds until new oceanic crust is formed, a marginal sea will result. …just as the…
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