2,794 research outputs found
Behaviour of Li isotopes during continental weathering: the Bidar laterite profile, India
No full textWeathering of large basaltic provinces is a major sink of atmospheric carbon dioxide, and is also an important part of the geochemical cycle of many other elements. This study aims to improve our understanding of basaltic weathering by analysis of trace elements and Li isotopes in a lateritic profile developed upon the Deccan Traps flood basalt. At its base, the profile consists of unaltered basalt that has a Li concentration and ?7Li value of ?5 ppm and +2.5‰, respectively, which is upwards progressively altered to a highly weathered laterite (iron-rich) residuum at the surface. High concentrations of Fe2O3 (85 wt.%) at 11 m depth indicate the presence of a palaeowatertable; the transition metals, the rare earth elements (REEs) and U are also strongly enriched in this horizon, whereas fluid mobile elements, such as Li and Rb, are depleted relative to the precursor basalt, and the bulk ?7Li value is very low (?5.5‰). A high proportion of leachable Li is found in this horizon, and this is enriched in 6Li relative to the bulk. We suggest that leaching extracts the labile weathering products, and these have high 6Li as 7Li has been preferentially mobilised during basalt weathering. Throughout the rest of the profile, Li concentrations and Li isotope values are best explained by two-component mixing between the precursor basalt and aeolian material with high Li and low ?7Li. Mass balance calculations show that at least 50% of the Li present in the profile could have been supplied by a mineral aerosol that has a ?7Li value between 0‰ and +1.3‰. The depth-integrated ?7Li value of the profile is ?0.6‰, which suggests that 7Li has been preferentially leached from the aerosol after its deposition. The source of this aeolian material is most likely to be ancient continental crust. It is possibly derived from Archaen/Proterozoic terrain to the south and southeast of the Deccan, and/or material from central Asia, similar to that which forms Chinese loess and which is supplied to the North Pacific basin
Mike Olszewski Interview, 2009
No full textMike Olszewski is a newscaster for WKSU-FM and a professor of communications at Kent State University and the University of Akron, as well as the author of several books. He was born in Cleveland in 1953. The interview discusses his childhood, racial issues, music, and the media
Mike Olszewski Interview, 2009
No full textMike Olszewski is a newscaster for WKSU-FM and a professor of communications at Kent State University and the University of Akron, as well as the author of several books. He was born in Cleveland in 1953. The interview discusses his childhood, racial issues, music, and the media
Dr. Mike Davison – Faculty Author Interview
No full textDr. Mike Davison, Professor of Music, discusses his documentary film, Cuba: Rhythm in Motion. This dynamic film captures the joy of making music in Cuba, an island that Dr. Davison has visited numerous times with his students. The contrasting yet intertwined histories of Cuban and American music are traced and illustrated with extensive performance footage. A DVD of Cuba: Rhythm in Motion is available in Parsons Music Library
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Discussion: Sheth, H.C. Plume-related regional pre-volcanic uplift in the Deccan Traps: Absence of evidence, evidence of absence
No full textSheth misreads key aspects of my earlier comment. For the record: I consider ‘uplift’ an issue central to the plume debate. I reiterate; uplift ‘remains a polemic issue’, (i.e. worthy of discussion). Word limits preclude the desired detailed dialogue, but some important issues are raised below.
I entirely agree that concerted field work is necessary, but both this paper and Sheth (2005) offer little new field data, and instead rely largely upon an interpretation of previous authors’ information. Such retrospectives do not permit the reader to evaluate the relative merits of plume versus non-plume models, and so cannot materially progress debate.
The argument regarding southward (not eastward, as suggested by Sheth) younging of the main Deccan edifice remains robust. Three independent lines of geological evidence support this interpretation: Two independent lines are usually deemed sufficient to indicate a scientific ‘truth’.
Sheth concludes, logically, that Western Ghats is the product of post-Deccan denudational processes. This particular interpretation has long been available (e.g. Widdowson and Cox, 1996; Widdowson, 1997; Gunnell and Fleitout, 1998; Widdowson and Mitchell, 1999). Given this issue is not in dispute, why raise it here?
Sheth asserts that Cox’s (1989) plume-head drainage idea is problematic. Perhaps, but the fact that radial drainage patterns do occur in key CFBPs remains a valid, if inexplicable (?) observation. Cox’s idea was superseded by arguments provided in Widdowson and Cox (1996), Widdowson (1997; see fig. 14), and AFTA data (Gunnell et al., 2003), and so becomes irrelevant for contending pre-eruptive uplift.
Sheth argues, correctly, that the nature of the pre-Deccan palaeosurface holds important clues regarding pre-eruptive uplift in the DVP (Jerram and Widdowson, 2005). Much of this surface remains buried by the Deccan lavas, and is both inaccessible and unknowable. It only becomes exposed around the northern and eastern periphery of the main lava pile. Such peripheral localities, including many of those described by Sheth, were hundreds of kilometres from the Deccan eruptive loci. If any uplift did occur here, it would have been minimal at such large distances from the focus of putative plume head uplift, and thus consistent with that affecting the Dongargaon basin, for example (Tandon, 2002; Samant and Mohabey 2005).
The pre-eruptive palaeosurface has been significantly modified by the crustal loading of the Deccan edifice, and in its western extensions suppressed far below datum. Thus, the gross form and elevation of this basement – basalt contact is largely an artefact of post-eruptive flexural adjustment. Nevertheless, Sheth argues that this highly modified surface reveals a ‘peneplain’, and that its preservation as such precludes significant fluvial incision. Possibly: But peneplains are the consequence of erosion, and the classical, albeit obsolete, Davisian model requires regional uplift as a trigger for peneplanation to proceed. Etchplanation is more appropriate to the development of the pre-Deccan surface (e.g. Büdel, 1982). Here, thick alteration mantles accumulate through tropical weathering of surfaces exposed during prolonged periods of tectonic stability. If, as Sheth requires, such conditions had characterised the pre-Deccan land surface, then the widespread absence of deep weathering mantle preserved beneath the lava units may instead indicate that this landscape had been thoroughly stripped prior to DVP eruptions. Etchplain stripping may be achieved through widespread fluvial erosion induced by regional uplift (Borger and Widdowson, 2001).
Offshore sedimentary records in the Krishna, Godavari, and Narmada-Tapti basins, all reveal significant increases in Late Cretaceous depositional flux (Halkett et al. 2001): these data are consistent with pre-eruptive regional erosion of peninsular India – starting with the stripping of an easily erodable weathering mantle perhaps?
If pre-eruptive (plume-driven?) uplift had occurred in pre-Deccan peninsular India, what might then be recorded in the erosional and sedimentary chronologies of the DVP peripheral regions? Removal of any easily erodable weathering mantle, perhaps; minimal changes in elevation, possibly; development of shallow basins receiving fine clastic input from the plume-uplift effects hundreds of kilometres away - may be. This interpretation of the available infra- and intra-trappean sedimentary (i.e. Lameta Beds) data is equally plausible using the same compendium of field evidence provided by Sheth. Accordingly, I offer a modified, précis version of Sheth’s own summary:
‘Any original flatness and elevation of the pre-Deccan landscape has been significantly modified by syn- and post-eruptive isostatic adjustment deriving, initially, from the loading of the DVP edifice, and subsequently by denudational unloading. The occurrence of a stripped, pre-eruptive etchplain, together with associated offshore sedimentological data, are consistent with those phenomena predicted had a large plume head upwelled beneath India during the Late Cretaceous.
Post-Deccan uplift has elevated both the pre-Deccan, and post-Deccan surfaces. This uplift of the Western Ghats is not related to a putative Deccan plume: it is not domal, occurs beyond the limits off the Deccan lava cover, and represents a later, denudationally-driven, uplift (Widdowson, 1997). Thus, the easterly drainage of the Indian peninsula is not plume-related dome flank drainage, and is largely antecedent to denudational uplift effects’.
To summarise, of those observations described by Sheth, most, if not all, can equally and adequately be explained by the passage of India over a static, spatially restricted, mantle melting anomaly during the Late Cretaceous: For want of a better term, and until consensus offers me a better alternative, I will continue to call this anomaly, sensu lato, a ‘mantle plume’. I end by reiterating the rationale to my initial comment: The challenge to Sheth remains to deliver us an alternative, ‘non plume’, model that can better explain the Deccan CFBP
Mike Nichols Oral History
No full textOral histories created by University of Kansas students, staff and faculty as part of the Religion in Kansas Project are archived at http://hdl.handle.net/1808/12524 in KU ScholarWorks, the digital repository of the University of Kansas.Oral history interview with Mike Nichols conducted by Diana Brown at the Latte Land coffee shop in Kansas City, Kansas, on July 6, 2014. Mike is the author of The Witches’ Sabbats, taught classes on Paganism for decades, and owned The Magic Lantern occult book shop in Kansas City in the 1980s; this interview discusses those experiences. This interview was conducted for the Religion in Kansas Project as part of a summer fieldwork internship funded by the Friends of the Department of Religious Studies.Friends of the Department of Religious Studie
Mike Ladd: Invisible mending
No full textAn Author event presented by The Friends of the University of Adelaide Library, recorded in the Ira Raymond Room, Barr Smith Library, 18 May 2017.Mike Ladd's new collection, Invisible Mending ranges across genres including essay, memoir, short story and poetry. Based loosely on the ideas of scarring and healing, Invisible Mending extends from family intimacies to connection and disconnection in the Australian community, environmental damage and repair. It also has an international view. Parts of it were written at an artist's residency in Malaysia and while travelling through South America
Portrait of Australian theatre expert, Mr David Addenbrooke [picture] /
No full textTitle from inscription on reverse.; Condition good.; Inscriptions: "Australian theatre expert Mr David Addenbrooke readily admits that he is an author by accident. A thesis he wrote for amaster's degree is now a book, 'The Royal Shakespeare Company' ... Mr Addenbrooke at his home in Perth, Western Australia. Australian Information Service photograph by Mike Brown, 24/7/75/6, P75/591" --printed on reverse
Jere Nash Interview with Mike Moore
No full textInterview conducted by author Jere Nash with former Mississippi Attorney General Mike Moore in the process of writing Mississippi Politics: The Struggle for Power, 1976-2006. Topics discussed include Moore as District Attorney and investigation of Board of Supervisors in Jackson County; Eddie Khayat; FBI\u27s Operation Pretense investigating political corruption in Mississippi; campaign for Mississippi Attorney General in 1987; Richard Scruggs; background on tobacco litigation in the state; Kirk Fordice; negotiating national and Mississippi tobacco settlement; and Bill Clinton
Interview with Dr. Mike Austin [video]
No full textDr. Mike Austin is an Associate Professor in the Department of Philosophy and Religion, and author of two recent books, Wise Stewards: Philosophical Foundations for Christian Parenting and Football and Philosophy: Going Deep . He enjoys approaching practical topics like parenting and sports through a philosopher\u27s lens
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