microkrystites from the K/T boundary

here for Eocene microkrystites

Some links: badastronomy forum!

Burrow FurloBurrow in Maastrichtian sediments, just below the Ir-rich KT claylayer at Furlo, Italian Apennines

burrow Stevnss Spher Burrow in Maastrichtian chalk at stevns Klint, Denmark, filled with goethite spherules, some of which show a dendritic crystalline texture

Ejecta layer from Bco del Gredero, Caravaca, Spain, full of microkrystites, most Kspar (white)

sample Sm75-503

Zumaya Spherule layer Ejecta layer in the Zumaya section. Often the ejecta layer is hidden in white, calcitic slickensides, caused by bedding-plane slip. The ejecta layer is filled with crystalline spherules of arsenopyrite. The ejecta layer is underlain by light coloured Maastrichtian sediment, reduced (green) with abundant planktic foraminifers, and directly overlain by dark clay very poor in biota (see similar situation at Caravaca)

arsenopyriet Arsenopyrine spherule in reflected light, Zumaya, Spain. The dendritic crystals are most likely pseudomorph replacements after quench crystals of clinopyroxene

Ejecta layer of Agost, Spain, broken parallel to bedding. It can be clearly seen that the 3mm thick ejecta layer almost entirely consists of spherules. White is Kspar, greenish is smectite, and the black one is smectite covered with Cr-rich spinel crystals.

Sanidine Spher strooiselStrewnfield of sanidine (Kspar) spherules from the ejecta layer of Caravaca, Spain (see Caravaca)

sanidine quenchSanidine spherule in reflected light. Clearly visible are the two kind of quench crystals. On type has straight branches, the other type show curve crystal feathers. many aggregates started growing, nucleated on the outer surface of the spherule and have grown inwards. Caravaca, Spain

Thin section of Kspar spherule in transmitted light, displaying numerous dendritic crystallites

furlo strooiselStrewn of random spherules from the Furlo K/T boundary clay layer. Here the spherules are black (clay and spinel rich, enriched in Ir (33ng/g). green (glaucony and smectite) and white-reddish (Kspar)

spinel spherules Black spherules from Furlo in reflected light. the numerous Ni-rich spinel (magnesioferrite) crystal are abundant throughout the spherules

spinelFurloEnlarged portion of a Ni-rich spinal spherule from Furlo.

CPX577aCpx spherule from DSDP hole 577. Cpx crystals are both "barred" and dendritic.

cpx spher 577Cpx spherule from DSDP Hole 577, Shatsky rise. The spherule is filled with dendrites of cpx, floating in void that was originally filled with glass of unknown composition

cpx 577bEnlargement of cpx spherule at left, showing the well preserved cpx dendrites.

CPX577adetDSDP hole 577. enlargement of dendritic crystal of cpx from above.

cpx577Enlargement of cpx dendrites of spherule here above. DSDP 577, Shatsky rise, Pacific

Single dendrite of cpx. Hole 577, Shatsky rise.

smectite veerEdge of spherule with smectite dendrite, pseudomorph after cpx.Hole 577

smectite dendrite, pseudomorph after cpx. hole 577

dendrite of sanidine, Kspar, almost identical in shape as the cpx dendrites of Hole 577. Caravaca, Spain.

Series of enlargments of same spherule of Hole 577, showing the transition from smectite to sanidine

577

smecti-Kspa577 overviewidem

577

Enlarged, in the middle the sanidine crystals are visible in a matrix of host smectites.

577

even more enlarged, the rows of arranged sanidine is clearly visible against the wavy smectite crystals

577

kspar577 detailidem even more enlarged

577

backscatter image of smectite spherule from hole 577, core is full of magnesioferrite, rim is smectite.

photo: F. T. Kyte

backscatter image of smectite spherule from hole 577, core is full of magnesioferrite, rim is smectite.

photo: F. T. Kyte

backscatter image of smectite spherule from hole 577, sieve-like magnesioferrite.

photo: F. T. Kyte

backscatter image of smectite spherule from hole 577, core is full of magnesioferrite, rim is smectite.

photo: F. T. Kyte

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