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Wyszukujesz frazę "Mahaney, W.C." wg kryterium: Autor


Wyświetlanie 1-2 z 2
Tytuł:
Weathering rind age assignment of neoglacial deposits in the okstindan mountains, northern Norway
Autorzy:
Mahaney, W.C.
Powiązania:
https://bibliotekanauki.pl/articles/2025298.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Little Ice Age
Okstindan Neoglacial record
weathering rinds
Opis:
Pre vi ous soil strati graphic anal y sis of soil morphogenesis in the Okstindan Moun tains es tab lished a Late Neoglacial soil evo lu tion ary se quence based on his tor i cally mon i tored and ra dio car bon-dated mo raine po si tions over the last ~3.0 cal yr BP. Thus pedon evo lu tion ranged from C/Cu®Ah/Cox/Cu®pedostratigraphic suc ces sion of Ah/C/Cu/Lb/Cub/Ahb/Coxb/Cub pro files with a max i mum rind weath er ing time of ~1.0 kyr. Fol low ing suc ces sive re treat phases of Neoglacial ice, weath er ing rind de vel op ment con tin ued apace on mo raines, each rind pop u la tion re cord ing weath ering time fol low ing suc ces sive gla cier stillstands. The age of the youn gest de pos its falls within the pe riod 1900–1910 AD, or the last 100 yrs, with vari able mo raine po si tions all doc u mented by his tor i cal de pic tions of the po si tion of the Austre Okstindan gla cial lobe prior re treat ing to its pres ent po si tion. The next older group of de pos its is con sid ered to have been emplaced near the end of the LIA or around ~1800 AD, with time of rind de vel op ment set at 200 yr, pos sibly older. The old est mo raine set within the late Neoglacial se quence lies atop a pedostratigraphic col umn, the up permost soil ra dio car bon dated at ~1.0 yr BP. Given the range of mean rind de vel op ment across this thresh old of de pos its, from 0.22 ±0.03 mm in the in ner group, 0.66 ±0.07mm in the mid dle group, to 1.38 ±0.15 mm in the outer, older group, it is clear that fi nite mea sure ments at sev eral sites within a suite of de pos its, some dated by ra dio car bon, can evenly dis crim i nate be tween de pos its in a gla cial suc ces sion.
Źródło:
Studia Quaternaria; 2016, 33; 131-138
1641-5558
2300-0384
Pojawia się w:
Studia Quaternaria
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Cosmic Airburst on Developing Allerød Substrates (Soils) in the Western Alps, Mt. Viso Area
Autorzy:
Mahaney, William C.
West, Allen
Milan, Alison
Krinsley, David H.
Somelar, Peeter
Schwartz, Stephane
Milner, Michael W.
Allen, Christopher C.R.
Powiązania:
https://bibliotekanauki.pl/articles/2025231.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Black Mat impact/airburst
Reconstructed soil at time of YDB
mid-LG-YD paleosol Sedimentary products of cosmic impact/glacial recession
Nauki o Ziemi
Opis:
Although much has been written about a cosmic impact event in the Western Alps of the Mt. Viso area, the event closely tied with the Younger Dryas Boundary (YDB) of 12.8 ka and onset of the Younger Dryas (YD), the affected land surface is considered to contain a similar black mat suite of sediment found on three continents. While work elsewhere has focused on recovered sediment from lake and ice cores, buried lacustrine/alluvial records, and surface glacial and paraglacial records, no one has traced a mountain morphosequence of deposits with the objective of investigating initial weathering/ soil morphogenesis that occurred in ice recessional deposits up to the YDB when the surface was subjected to intense heat, presumably, as hypothesized by Mahaney et al. (2016a) from a cosmic airburst. With the land surface rapidly free of ice following glacial retreat during the Bølling-Allerød interstadial, weathering processes ~13.5 to 12.8 ka led to weathering and soil morphogenesis in a slow progression as the land surface became free of ice. To determine the exposed land character in the mid- to late-Allerød, it is possible to utilize an inverted stratigraphic soil morphogenesis working backward in time, from known post-Little Ice Age (LIA) (i.e. time-zero) through LIA (~0.45 to ~0.10 ka), to at least the middle Neoglacial (~2 ka), to answer several questions. What were the likely soil profile states in existence at the end of the Allerød just prior to the cosmic impact/airburst (YDB)? Assuming these immature weathered regolith sections of the Late Allerød approximated the <1 ka old profiles seen today, and assuming the land surface was subjected to a hypothesized instant temperature burst from ambient to ~2200oC at ~12.8 ka, what would be the expected effect on the resident sediment? To test the mid-LG (YDB) to YD relationship we analyzed the paleosols in both suites of deposits – mid-LG to YD – to test that the airburst grains are restricted to Late Allerød paleosols and using relative-age-determination criteria, that the overlapping YD to mid-LG moraines are closely related in time. These are some of the questions about the black mat that we seek to answer with reference to sites in the upper Guil and Po rivers of the Mt. Viso area.
Źródło:
Studia Quaternaria; 2018, 35; 3-23
1641-5558
2300-0384
Pojawia się w:
Studia Quaternaria
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-2 z 2

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