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Compositions of coexisting amphiboles in sample 1382.36 m from microprobe analyses . (a) (Ca+Na) in M4 vs. [6] coordinated (Al+Fe 3+ +Cr+Ti). (b) (Ca+Na) in M4 vs. (Fe 2+ +Mn) /(Mg+Fe 2+ +Mn).  

Compositions of coexisting amphiboles in sample 1382.36 m from microprobe analyses . (a) (Ca+Na) in M4 vs. [6] coordinated (Al+Fe 3+ +Cr+Ti). (b) (Ca+Na) in M4 vs. (Fe 2+ +Mn) /(Mg+Fe 2+ +Mn).  

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A metamorphosed ultramafic rock, penetrated by the KTB pilot hole at a depth of 1382.36 m, contains the assemblage Caamphibole - anthophyllite - chlorite - talc, formed at about 630degreesC/10 kbar under conditions of the high-P amphibolite facies. EMP analyses of the Ca-amphibole yielded magnesiohastingsite (to pargasite) compositions with (Al+Fe3...

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Context 1
... microprobe analyses of coexisting amphiboles from sample 1382.36 m are listed in Table 1 and graphically presented in Fig. 2 and 3. In the discrimination diagram of Leake et al. (1997), all Ca-amphiboles intergrown with an- thophyllite plot in the field of pargasite and magnesioha- stingsite (Fig. 2b); in most cases, the Fe 3+ /Al ratios are > 1, thus conforming to the magnesiohastingsite composition. Chemical characteristics (in cations p.f.u.) are Si 6.09-6.35, ...
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... (Fig. 2b); in most cases, the Fe 3+ /Al ratios are > 1, thus conforming to the magnesiohastingsite composition. Chemical characteristics (in cations p.f.u.) are Si 6.09-6.35, octahedral (Al+Fe 3+ +Cr+Ti) 1.01-1.18, (Ca+Na) in M4 1.88-1.92, (Na+K) A 0.70-0.78, Ti 0.050-0.075; the (Fe 2+ +Mn)/(Mg+Fe 2+ +Mn) ratios range between 0.10 and 0.16 (Fig. 3). In one of the two areas analyzed, the Ca-am- phibole displays Cr 2 O 3 contents of 0.16-0.29 wt.%, well Table 1. Selected microprobe annalyses (wt.%) and structural formulae of coexisting Ca-amphibole, anthophyllite and chlorite. (Fig. 3a), whereas the (Fe 2+ +Mn)/ (Fe 2+ +Mn+Mg) ratios (0.21-0.29 p.f.u) are higher (Fig. 3b), which ...
Context 3
... (Na+K) A 0.70-0.78, Ti 0.050-0.075; the (Fe 2+ +Mn)/(Mg+Fe 2+ +Mn) ratios range between 0.10 and 0.16 (Fig. 3). In one of the two areas analyzed, the Ca-am- phibole displays Cr 2 O 3 contents of 0.16-0.29 wt.%, well Table 1. Selected microprobe annalyses (wt.%) and structural formulae of coexisting Ca-amphibole, anthophyllite and chlorite. (Fig. 3a), whereas the (Fe 2+ +Mn)/ (Fe 2+ +Mn+Mg) ratios (0.21-0.29 p.f.u) are higher (Fig. 3b), which is commonly the case in anthophyllite-Ca-amphibole assemblages (e.g. Robinson et al., 1982). In contrast to the Ca-amphiboles analyzed, anthophyllite did not reveal any titanium and chromium contents above the detection ...
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... between 0.10 and 0.16 (Fig. 3). In one of the two areas analyzed, the Ca-am- phibole displays Cr 2 O 3 contents of 0.16-0.29 wt.%, well Table 1. Selected microprobe annalyses (wt.%) and structural formulae of coexisting Ca-amphibole, anthophyllite and chlorite. (Fig. 3a), whereas the (Fe 2+ +Mn)/ (Fe 2+ +Mn+Mg) ratios (0.21-0.29 p.f.u) are higher (Fig. 3b), which is commonly the case in anthophyllite-Ca-amphibole assemblages (e.g. Robinson et al., 1982). In contrast to the Ca-amphiboles analyzed, anthophyllite did not reveal any titanium and chromium contents above the detection ...

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... The most common source of such intergrowths has frequently been stated in courts across our country by lawyers and their expert witnesses that suggest the only source of these intergrowths occur where anthophyllite veins meet with talc deposits. This can be true, but more commonly talc is an integral component of anthophyllite all the time [29]. If a mineralogist looks at anthophyllite fibers by what has been termed zone-axis analyses where the anthophyllite is analyzed by tilting and rotating to find possible co-mingling of some talc with the anthophyllite and therefore making the false claim that it is an intergrowth making the fiber non-asbestos. ...
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: and . John C. Schumacher Dept. of Earth Sciences, University of Bristol, Bristol, BS8