Jan Smit Bibliography

Bibliography Jan Smit --CV and Bibliography (download EndNote file PC)(download EndNote file Mac)

Alvarez, W., J. M. Grajales N., et al. (1992). "The Cretaceous-Tertiary boundary impact-tsunami deposit in NE Mexico." Geological Society of America Abstracts with Programs 24(7): A331.

Alvarez, W., J. Smit, et al. (1991). "Impact-wave effects at the Cretaceous-Tertiary boundary in Gulf of Mexico DSDP cores." Lunar and Planetary Science Conference 22(1): 17-18.

Alvarez, W., J. Smit, et al. (1991). Proximal impact deposits at the Cretaceous Tertiary Boundary in the Gulf of Mexico: Re-interpreting DSDP sites 536 and 540. Geol. Soc. Am. Ann meeting, San Diego.

Alvarez, W., J. Smit, et al. (1991). "Proximal impact deposits at the Cretaceous-Tertiary boundary in the Gulf of Mexico: Reinterpreting DSDP sites 536 and 540." Geological Society of America Abstracts with Programs 23(5): A420.

Alvarez, W., J. Smit, et al. (1992). "Proximal impact deposits at the Cretaceous-Tertiary boundary in the gulf of Mexico: a restudy of DSDP leg 77 Sites 536 and 540." Geology 20: 697-700.

Brinkhuis, H., J. P. Bujak, et al. (1998). "Dinoflagellate-based sea surface temperature reconstructions across the Cretaceous-Tertiary boundary." Paleogeogr. Paleoclim. Paleoecol. 141: 67-83.

Brinkhuis, H., A. J. T. Romein, et al. (1994). "Danian Seelandian dinoflagellate cysts from lower latitudes with special referencce to the El Kef section, NW Tunisia." GFF 116: 46-47.

Brinkhuis, H. and J. Smit (1996). "The Geulhemmerberg Cretaceous/Tertiary boundary section (Maastrichtian type area, SE Netherlands); an introduction." The Geulhemmerberg Cretaceous/Tertiary boundary section (Maastrichtian type area, SE Netherlands) 75 (Special Issue Geol. & Mijnbouw): 101-106.

Brinkhuis, H., J. Smit, et al. (1995). The Geulhemmerberg K/T boundary section: a window on post-KT recovery in a shallow marine setting. EUG 8, Strasbourg, Fr.

Claeys, P., W. Alvarez, et al. (1993). "KT boundary impact glasses from the Gulf of Mexico region." Lunar and Planetary Science 24: 297-298.

Claeys, P., W. Alvarez, et al. (1996). "Shocked (?) limestone fragments- a new component of the proximal impact ejecta of the Chicxulub crater." Meteoritics & Planetary Science 31 supplement: A29.

Claeys, P., A. Montanari, et al. (1995). "KT boundary sections in southern Mexico,

closing in on Chicxulub." Geol. Soc. Abstr. Prog. xx: xx.

Claeys, P., J. Smit, et al. (1998). "L'impact de Chicxulub et la limite Cretace-Tertiaire dans la region du golfe du Mexique." Bull. Soc. Geol. France 169: 3-9.

Clercq, S. W. G. d., J. Smit, et al. (1975). "A marine tuffaceous sediment in the lower Miocene of the Velez-Rubio Lorca region." GUA papers of Geology 1: 105-114.

Coninck, J. D. and J. Smit (1982). "Marine organic-walled microfossils at the Cretaceous Tertiary boundary in the Barranco del Gredero (S.E. Spain)." Geologie en Mijnbouw 61: 173-178.

DePaolo, D. J., F. T. Kyte, et al. (1983). "Rb-Sr, Sm-Nd, K-Ca, O, and H isotopic study of Cretaceous-Tertiary boundary sediments, Caravaca, Spain: evidence for an oceanic impact site." Earth Planet.Sci. Lett. 64: 356-373.

DePaolo, D. J., F. T. Kyte, et al. (1982). Rb-Sr, Sm-Nd, and K-Ca studies of Cretaceous Tertiary boundary sediments: possible evidence for oceanic impact. Lun. planet. Sci. Conf., Houston, Tx.

Deutsch, A., C. Koeberl, et al. (1995). "The Impact-flood connection: Does it exist?" Terra Nova 6: 644-650.

Eijden, A. J. M. v. and J. Smit (1991). Eastern Indian Ocean Cretaceous and Paleogene quantitative biostratigraphy. Proc. ODP Sci. Results. J. Weissel, J. Peirce, E. Taylor and J. Alt. College Station (TX), Ocean Drilling Program. 121: 77-124.

Ficken, K. J., J. W. d. Leeuw, et al. (subm). "A biomarker for the Cretaceous/Tertiary boundary at Geulhem, the Netherlands." prep.

Groot, J. J., R. B. G. de Jonge, et al. (1989). "Magnetostratigraphy of the Cretaceous-Tertiary boundary at Agost (Spain)." Earth and Planetary Science Letters 94: 385-397.

Hermes, J. J. and J. Smit (1975). "New data on silexites of the west Mediterranean area." Proc. Kon Ned. Akad. Wet. seriesB, 79: 115-122.

Heymann, D., L. P. F. Chibante, et al. (1996). Fullerenes of possibe wildfire origin in Cretaceous-Tertiary boundary sediments. The Cretaceous-Tertiary Event and Other Catastrophes in Earth History. G. Ryder, D. Fastovski and S. Gartner. Boulder, Geol. Soc. of Amer. Sp. Pap. 307: 453-464.

Hildebrand, A. R., F. Asaro, et al. (1994). "The Chicxulub crater and its relation to the KT boundary ejecta and impact-wave deposits." LPI Contribution 825: 49-50.

Holst, H. K. H., J. Smit, et al. (1970). "Lacertoid footprints from the middle Triassic at Haarmuhle, near Alstatte, W. germany." Proc. Koninklijke Nederlandse Akademie van Wetenschappen 74: 157-165.

Kaars, W. A. v. d. and J. Smit (1985). "A palynological field preparation technique." Pollen et Spores 27: 495-496.

Klaus, A., R. Norris, et al. (1997). Impact- Induced K-T Boundary Mass Wasting Across the Blake Nose, W.

North Atlantic: Evidence From Seismic Reflection and Core Data. Am.Geophys.Un. Fall meeting, san francisco, Am. Geophys Union.

Klaus, A., R. D. Norris, et al. (2000). "Impact-induced mass wasting at the K-T boundary: Blake Nose, western North Atlantic." Geology 28: 319-322.

Kroon, D., R. D. Norris, et al. (1998). "Drilling Blake Nose: the search for evidence of extreme Palaeogene-Cretaceous climates and extraterrestrial events." Geology today 14: 222.

Kyte, F. T. and J. Smit (1986). "Regional variations in spinel compositions: An important key to the Cretaceous/Tertiary event." Geology 14: 485-487.

Kyte, F. T., J. Smit, et al. (1985). "Siderophile interelement variations in the Cretaceous Tertiary boundary sediments from Caravaca, Spain." Earth Planet. Sci. Lett. 73: 183-195.

Lowrie, W., W. Alvarez, et al. (1993). "Response to Comments by J. Urrutia-Fucugauchi:

Magnetic properties of Arroyo de Mimbral samples." Geology xx: xx.

Lowrie, W., W. Alvarez, et al. (1993). "Tektite-bearing, deep-water clastic unit at the Cretaceous-Tertiary boundary in northeastern Mexico: Reply." Geology 21(2): 191-192.

Margolis, S., P. Claeys, et al. (1992). Impact spherules from the Cretaceous-Tertiary boundary, NE Mexico. Abstracts with Programs - Geological Society of America, cincinnati, Geological Society of America, 1992 annual meeting.

Margolis, S. V., P. Claeys, et al. (1991). Tektite glass from the Cretaceous Tertiary boudary, Proximal to the proposed impact crater in Northern Yucatan, Mexico. Geol. Soc. Am. Ann meeting, San Diego.

Margolis, S. V., P. Claeys, et al. (1991). "Tektite glass from the Cretaceous-Tertiary boundary, proximal to the proposed impact crater in northern Yucatan, Mexico." Geol. Soc. Am. Abstr. Programs 23(5): A420.

Montanari, A., P. Claeys, et al. (1994). "Preliminary stratigraphy and iridium and other geochemical anomalies across the KT boundary in the Bochil section (Chiapas, southeastern Mexico)." LPI Contribution 825: 84=85.

Montanari, A., R. L. Hay, et al. (1984). "Spheroids at the Cretaceous-Tertiary boundary are altered impact droplets of basaltic composition: Reply." Geology 12(11): 696.

Montanari, A., R. L. Hay, et al. (1983). "Spheroids at the Cretaceous-Tertiary boundary are altered impact droplets of basaltic composition." Geology 11: 668-671.

Geen reprints

Montanari, A. and J. Smit, Eds. (1993). Post Nordlingen Newsletter of the The Scientific network of ESF: Impact craterimg and Evolution of Planet earth". Coldigioco, Italy, ESF.

Ocampo, A., K. Pope, et al. (1997). Chicxulub impact ejecta in Belize. Conference on Large Meteorite Impacts and Planetary Evolution., Sudbury, Canada, JPL Nasa.

Pope, K. O., A. C. Ocampo, et al. (1999). "Chicxulub impact ejecta from Albion Island, Belize." EPSL 170: 351-364.

Abstract

Impact ejecta from the Albion Formation are exposed in northern Belize. The ejecta come from the outer portion of the continuous ejecta

blanket of the Chicxulub crater, which is located 360 km to the northwest. The basal unit of the Albion Formation is a ~1-m-thick clay and

dolomite spheroid bed composed of up to four discrete flows. The clay spheroids are altered impact glass, and the dolomite spheroids are

accretionary lapilli. The upper unit is a ~15-m-thick coarse diamictite bed containing altered glass, large accretionary blocks, striated, polished,

and impacted cobbles, and rare shocked quartz. The abundance of accretionary clasts, evidence for atmospheric drag sorting, and the presence

of multiple flows in the Albion Formation indicate that atmospheres play an important role in the formation of the outer portions of continuous

ejecta blankets of large craters.

Rigby, J., J. K., K. R. Newman, et al. (1987). "Dinosaurs from the Paleocene part of the Hell Creek Formation, McCone County, Montana." Palaios 2: 296-302.

Roep, T. B. and J. Smit (1996). Sedimentological aspects of the K/T boundary at Geulhemmerbarg, Zuid Limburg, Netherlands. The Geulhemmerberg Cretaceous/Tertiary boundary section (Maastrichtian type area, SE Netherlands). H. Brinkhuis and J. Smit. Dordrecht, Kluwer Academic Publishers. 75 (Special Issue Geol. & Mijnbouw): 119-131.

Romein, A. J. T. and J. Smit (1981). "Carbon-Oxygen isotope stratigraphy of the Cretaceous-Tertiary boundary interval: data from the Biarritz section (SW France)." Geol. en Mijnbouw 60: 541-544.

Romein, A. J. T. and J. Smit (1981). "The Cretaceous-Tertiary boundary: calcareous nannofossils and stable isotopes." Proc. Koninklijke Nederlandse Akademie van Wetenschappen 84: 295-314.

Romein, A. J. T., J. Smit, et al. (1983). "Calcareous nannoplankton from the western Gaj river section (Pakistan)." Proc. Kon. Akad. van Wetenschappen 86: 393-400.

Smit, J. (1977). "Discovery of a planktonic foraminiferal association between the Abathomphalus mayaroensis zone and the "Globigerina" eugubina zone at the Cretaceous/Tertiary boundary in the Barranco del Gredero (Caravaca, SE Spain): a preliminary report." Proc. Koninklijke Nederlandse Akademie van Wetenschappen 80: 280-301.

Smit, J. (1979). The Cretaceous/Tertiary transition in the Barranco Del Gredero, Spain. Cretaceous-Tertiary Boundary Events Symposium; II. Proceedings. W. K. Christensen and T. Birkelund. Copenhagen: 156-163.

Smit, J. (1979). "Microcodium, its earliest occurrence and other considerations." Revue de micropaleontologie 22: 44-50.

Smit, J. (1980). "Reply to "Terminal Cretaceous catastrophe"." Nature 287: 760.

Smit, J. (1981). "Anomalous trace element concentrations and K-spar spherules from the base of the Cretaceous Tertiary boundary clay." (abstract) Terra Cognita Special Issue: 117.

Smit, J. (1981). A catastrophic event at the Cretaceous Tertiary boundary, Univ. of Amsterdam.

Smit, J. (1981). Synthesis of trace element, sanidine and sedimentological KT boundary data, evidence for cometary impact? Snowbird conference on larege body impacts and terrestrial evolution, Snowbird, Utah.

Smit, J. (1982). "Extinction and evolution of planktonic foraminifera after a major impact at the Cretaceous/Tertiary boundary." Geological Society of America Special Paper 190: 329-352.

Smit, J. (1982). Stratigraphy and sedimentology of the Cretaceous Tertiary boundary. 3rd European Regional Meeting IAS, Copenhagen, Denmark.

Smit, J. (1985). "Catastrophic events at the terrestrial Cretaceous-Tertiary (K/T) boundary." Geological Society of America Abstracts with Programs 17: 720.

Smit, J. (1985). Fine tuning the Cretaceous Tertiary boundary in pelagic facies. "Rare Events in Geology", Gwatt, Switserland.

Smit, J. (1987). The Cretaceous Tertiary boundary: Surprisingly? uneventful sedimentation for a convulsive event. 8th IAS Regional Meeting of Sedimentology, Tunis.

Turbidite Mesa de Llera, tsunamite at brazos

Smit, J. (1988). Clinopyroxene in microtektite-like spherules from the Cretaceous/Tertiary boundary(KT) boundary. Geol. Soc. Am. Ann. Meeting, Denver.

Smit, J. (1989). "High-resolution stratigraphy at Cretaceous-Tertiary boundary." International Geological Congress, Washington, Abstracts 3: 136-137.

Smit, J. (1990). "Meteorite impact, extinctions and the Cretaceous-Tertiary boundary." Geologie en Mijnbouw 69: 187-204.

Smit, J. (1990). "Verdwijnen en opnieuw beginnen: het verhaal van het uitsterven op de Krijt Tertiair grens." GEA 23: 80-85.

Smit, J. (1991). "Cretaceous/Tertiary extinction: where did it happen?" Nature 349: 461-462.

Smit, J. (1991). The Geological record of Mass-extinctions. Symposium on the Frontiers of Science, Irvine, California.

Smit, J. (1991). Op een mooie Zomerdag... NRC Handelsblad. Amsterdam: W&O 1-2.

Smit, J. (1993). El Impacto de un Meteorito en Chicxulub (Yucatan) hace 65 milliones de anos: datos procedentes de Espana y consequencias para la vida terrestre. Tierra Y Technologia. 4: 78-85.

Smit, J. (1994). "Blind tests and muddy waters." Nature 368: 809-810.

Smit, J. (1994). Extinctions at the Cretaceous Tertiary boundary: The link to the Chicxulub impact. Hazards due to comets and asteroids. T. Gehrels. Tucson, University of Arizona press. 24: 859-878.

1994i

Smit, J. (1996). "Un épisode tragique: "L'Ocean Folamour"." La Recherche 293: 62-64.

Smit, J. (1997). "Extraterrestrial Impacts: The Big Splash." Nature 390: 340-342.

Smit, J. (1997). "Predictive elements of large-body impacts in geologic history." Geol. Rundschau 86: 464-470.

Smit, J. (1998). "Dinosauriers: Het debat over het massaal uitsterven." Amsterdamse Boekengids 10: 10-14.

Smit, J. (1998). Het Ocean Drilling Program speurt naar meteorietinslagen. Oceaandag metropolis. Metropolis Amsterdam, NWO.

Smit, J. (1998). Uitsterven door een meteorietinslag. Natuurkundige Voordrachten. P. N. J. Wisse. Den Haag, Diligentia. 75: 61-66.

Smit, J. (1999). Ejecta deposits of the Chicxulub impact, In: Berichte zur Polarforschung. ESF IMPACT workshop Oceanic impacts: Mechanisms and perturbations, Bremerhaven, AWI.

Smit, J. (1999). "The global stratigraphy of the Cretaceous Tertiary boundary impact ejecta." Annual Review of Earth and Planetary Sciences 27: 75-113.

Smit, J. (2000). The Fate of planktic foraminifera crossing the K/T boundary (or not): a Review. Catastrophic events & mass-extinctions, Impacts and beyond, Vienna, ESF/LPSC.

Smit, J. and W. Alvarez (1991). "Is the "Mid-Cretaceous Unconformity" in the Gulf of Mexico a Cretaceous-Tertiary boundary impact-wave erosion surface?" Lunar and Planetary Science Conference 22: 1275.

Smit, J. and W. Alvarez (1991). "Is the "Mid-Cretaceous Unconformity" in the Gulf of Mexico a Cretaceous-Tertiary boundary impact-wave erosion surface?" Lunar and Planetary Science Conference 22.

Smit, J., W. Alvarez, et al. (1994). Misunderstandings regarding the KT boundary deposits in the Gulf of Mexico. New developments regarding the KT event and other catastrophes in Earth History, Houston, Texas.

Smit, J., W. Alvarez, et al. (1992). ""Tektites" and microkrystites at the Cretaceous Tertiary boundary: Two strewnfields, one crater?" Proc. Lun. Planet. Science conf. 22: 87-100.

Smit, J. and H. Brinkhuis (1996). The Geulhemmerberg Cretaceous/Tertiary boundary section (Maastrichtian type area, SE Netherlands); summary of results and and a scenario of events. The Geulhemmerberg Cretaceous/Tertiary boundary section (Maastrichtian type area, SE Netherlands). H. Brinkhuis and J. Smit. Dordrecht, Kluwer Academic Publishers. 75 (Special Issue Geol. & Mijnbouw): 283-293.

Smit, J. and P. Claeys (2000). Chicxulub impact ejecta stratigraphy. 31st Int. Geol. Congress, Rio de Janeiro.

1 SMIT, J & 2CLAEYS, P. 1 Aardwetenschappen, Vrije Universiteit, Amsterdam,

Neth. 2Institute fur Mineralogie, Berlin, Germany

The Chicxulub ejecta become more and more complex, when moving in towards

the crater from (global) distal sites to the direct surroundings of the crater. The

distal sites are characterized by 1-2 mm thick lamina, enriched in pge elements,

microkrystites and shocked minerals, often diagenetically altered to smectite or

goethite. This lamina is occurs on top of homogenous top Maastrichtian sediments,

showing no progressive trend in facies of paleoenvironment. The lamina is

covered by a thin dark layer (P0 zone) marking the environmental crisis following

the impact event. A thin, dual, 1-2cm thick ejecta layer marks sites at intermediate

distances (-2500 - 4000km). Likewise these are underlain by non-changing top

Cretaceous sequences, and overlain by a 'crisis' layer. Proximal sites 2500km

invariably comprise 1 to 11m thick complex clastic deposits, mixtures of proximal

ejecta (tektites) and locally derived material, transported by gravity flows,

landslides and tsunami waves. These deposits are wedged between homogenous

hemipelagic Maastrichtian sequences, and dark marls of the P0 zone. The clastic

deposits show often a complex structure, consisting of multiple, amalgamated,

channeled often-graded layers of sand. The coarser basal layers are rich in ejecta

(e.g. tektites), the middle units are rippled sandstone layers, consisting of locally

and distal derived biogenic and lithic clastic debris. The top units consist of fine

grained sandstone ripples, alternating with Ir and spinel rich thin silt layers.In

southern Yucatan and Belize, the outermost ejecta blanket deposits are found,

resting on Maastrichtian platform carbonates, and overlain by Paleocene lagoonal

deposits.

Smit, J., A. J. v. Eijden, et al. (1991). Analysis of the Australasian microtektite event, the Toba lake event, and the Cretaceous/Paleogene boundary, Eastern Indian Ocean. Proc. ODP. Sci. Results. J. Weissel, J. Peirce, E. Taylor and J. Alt. College Station, Tx, Ocean Drilling Program. 121: 489-506.

Smit, J., M. Grajales, et al. (1992). "Sedimentology and biostratigraphy of Cretaceous-Tertiary impact-tsunami wave deposits in NE Mexico and Texas." Geological Society of America Abstracts with Programs 24(7): A355.

Smit, J., H. Groot, et al. (1988). Impact and extinction signatures in complete Cretaceous Tertiary (KT) boundary sections. Global catastrophes in Earth history, Snowbird, Utah.

G. cretacea in the boundary clay but Glo'nella and g'oides still common

Smit, J. and J. Hertogen (1980). "An extraterrestrial event at the Cretaceous-Tertiary boundary." Nature 285: 198-200.

Smit, J. and J. Hertogen (1980). "Terminal Cretaceous catastrophe." Nature 287: 760.

Smit, J., J. K. R. jr., et al. (1984). Terrestrial extinctions in Montana: out with a bang, not a whimper. Soc. Geol. Fr. Extinctions in vertegrate history, Paris.

Smit, J., W. A. v. d. Kaars, et al. (1987). "Stratigraphic aspects of the Cretaceous-Tertiary boundary in the Bug Creek area of eastern Montana, USA." Mem. Soc. Geol. France 150: 53-73.

Smit, J., W. G. T. Kate, et al. (1990). New aspects of the Cretaceous Paleogene boundary in Pelagic sediments. 4th ECOD workshop, Terassini, Terassini, Sicily.

Smit, J., W. G. T. Kate, et al. (1992). Sequence stratigraphy and cyclostatigraphy of the Cretaceous Tertiary boundary in the Biscaye Basin. CNRS-IFP Int. Symp. on Mesozoic and Cenozoic Sequence stratigraphy of European basins, Dyon.

Smit, J., G. Keller, et al. (1997). "The El Kef sections and sampling procedures." Marine Micropaleontology 29: 69-72.

Smit, J. and T. M. G. v. Kempen (1987). Planktonic foraminifers from the Cretaceous/Tertiary boundary at Deep Sea Drilling Project site 605, North Atlantic. Init. Repts. DSDP. J. E. Van Hinte, Wise, W et al.,. Washington, U.S. Govt. Printing Office. 92: 549-553.

Smit, J. and G. Klaver (1981). "Sanidine spherules at the Cretaceous-Tertiary boundary indicate a large impact event." Nature 292: 47-49.

Smit, J., G. Klaver, et al. (1987). Three unusually complete spanish K/T boundary sections: Caravaca, Agost, Zumaya. III Jornadas de Paleontologia: Paleontologia Y Evolution: Fenomenos de Extinction, Bilbao.

Smit, J. and G. T. Klaver (1989). "Multiple impacts at the Cretaceous Tertiary (KT) boundary?" Terra Abstracts 1(1): 421.

Smit, J. and F. T. Kyte (1983). "Siderophile-rich magnetic spheroids from the Cretaceous-Tertiary boundary in Umbria, Italy." Nature 310: 403-405.

Smit, J. and F. T. Kyte (1984). Evidence for a worldwide strewnfield of microtektites at the Cretaceous-Tertiary boundary. Geol. Soc. Am Annual Meeting, Reno, GSA.

Smit, J. and F. T. Kyte (1985). "Cretaceous-Tertiary extinctions: Alternative models." Science 230: 1292-1293.

Smit, J. and A. Montanari (1996). Effects of Impacts on the Atmosphere and Biosphere in regards to short- and Long-term changes. Newsletters of the ESF Network Impact cratering and the evolution of planet Earth, ESF.

Smit, J., A. Montanari, et al. (1991). Microkristites and (micro)tektites at the KT boundary: two different sources or one? Lunar and Planetary Science XXII, Houston, Lunar and Planetary Institute.

Smit, J., A. Montanari, et al. (1991). "Microkristites and (micro)tektites at the KT boundary: two different sources or one?" Lunar and Planetary Science Conference 22: 1277-1278.

Smit, J., A. Montanari, et al. (1994). Tsunami-generated beds at the KT boundary in Northeastern Mexico. Field Guide to Cretaceous Tertiary boundary sections in Northeastern Mexico. G. Keller, W. Stinnesbeck, T. Adatte, N. MacLeod and D. R. Lowe. Houston, LPI Contribution. 827: 95-101.

Smit, J., A. Montanari, et al. (1994). Tsunami-generated beds at the KT boundary in northeastern Mexico. Field guide to Cretaceous-Tertiary boundary sections in northeastern Mexico. G. Keller, W. Stinnesbeck, T. Adatte, N. MacLeod and D. R. Lowe. Houston, Lunar and Planetary Institute. 827: 95-101.

Smit, J., A. Montanari, et al. (1992). "Tektite-bearing, deep-water clastic unit at the Cretaceous-Tertiary boundary in northeastern Mexico." Geology 20: 99-103.

Smit, J., A. Montanari, et al. (2000). Impact spherules: The K/T boundary and late Eocene compared. 31st Int. Geol. Congress, Rio de Janeiro.

Impact Spherules: The K/T Boundary and Late Eocene

Compared

1 SMIT, J., 2 MONTANARI, A., 1 VONHOF, H., 3 ROBIN, E. 1 Vrije

Universiteit, Amsterdam, Netherlands; 2 Osservatorio Coldigioco,

Apiro, Italy; 3 CNRS/CEA Gif-sur Yvette, France.

Impact spherules of the K/T boundary are highly variable in

texture and composition. At distal sites the 3mm thick impact layer

consists of microkrystites, at a density of ~7000/cm2).

The Late Eocene has two impact layers. The upper layer

contains microtektites and can be traced to the Chesapeake

crater. The lower contains mostly microkrystites, is enriched in Ir,

while the upper is not. The microkrystites could be derived from

the Popigai crater.

The microkrystites at the K/T boundary fall into three groups: 1)

with Ca-rich clinopyroxene2) Glassy with clusters of cpx, 3) with

Ni-rich spinels and olivine crystals. At site 577 the original cpx is

preserved, otherwise only the inherited crystal texture. Ni-rich

spinel crystals are almost globally preserved, except in strongly

reduced environments. Groups 1 and 2 intermix, but group 3

shows little mixing 1and2.

Eocene microkrystites contain Ca-rich cpx and spinels. There are

Cr-rich and Cr-poor spinels, and microkrystalline or crystalline

endmembers. At Massignano Cr-rich spinel spherules exist next

to green (cpx) spherules.

Both Eocene and K/T microkrystite strewnfields are global and

associated with an iridium anomaly. Therefore, the impacts should

be similar. That could imply a similar impactor type, a

carbonaceous chondrite according to Cr isotope systematics, or a

similar composition of target rocks of Popigai and Chicxulub. Both

are excavated on continental crust, covered with carbonate

platformrocks (3000m resp 800m). Vaporisation and mixing of the

carbonate cover and basement and subsequent condensation in

the hot vapor cloud may explain the origin of these microkrystites.

Smit, J., A. Nederbragt, et al. (1992). The first 50000 years after the KT boundary impact event: Immigration or innovation of new planktic foraminiferal faunas. EUG VI, Strasbourg.

Smit, J. and A. J. Nederbragt (1997). "Analysis of the El Kef Blind test II." Marine Micropaleontology 29: 94-100.

Smit, J., A. J. Nederbragt, et al. (1992). The Cretaceous Tertiary boundary (K/Pg) boundary type section of El Kef, Tunisia, compared with proximal K/Pg transitions from the Gulf of Mexico. Inernational workshop on Cretaceous Tertiary transitions (El Kef Section), Tunis, Tunisia.

Smit, J., A. J. Nederbragt, et al. (1991). Milankovitch cyclicity and foraminiferal abundance at the Cretaceous Tertiary Boundary. Geol. Soc. Am. Ann meeting, San Diego.

Smit, J. and R. Rocchia (1996). Neutron Activation analysis of trace elements in the Geulhemmerberg Cretaceous/Tertiary boundary section, SE Netherlands. The Geulhemmerberg Cretaceous/Tertiary boundary section (Maastrichtian type area, SE Netherlands). H. Brinkhuis and J. Smit. Dordrecht, Kluwer Academic Publishers. 75 (Special Issue Geol. & Mijnbouw): 269-274.

Smit, J., T. B. Roep, et al. (1995). Tsunami Induced sandstone beds at the Cretaceous Tertiary boundary around the Gulf of Mexico: Consequences of the Chicxulub Impact. Geol. Soc. Am. Ann. Meeting, New Orleans, Geol. Soc Am.

Smit, J., T. B. Roep, et al. (1994). "Comment: Deposition of channel deposits near the Cretaceous-Tertiary boundary in noprtheastern Mexico: catastrophic or "normal" sedimentary deposits? and Is there evidence for cretaceous-Tertiary boundary age deep-water deposits in the Caribbean and Gulf of Mexico?" Geology 22: 953-959.

Smit, J., T. B. Roep, et al. (1994). "Deposition of channel deposits near the Cretaceous-Tertiary boundary in northeastern Mexico: Catastrophic or "normal" sedimentary deposits?: Comment; and Is there evidence for Cretaceous-Tertiary boundary-age deep-water deposits in the Caribbean and Gulf of Mexico?: Comment." Geology 22(10): 953-954.

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Vonhof, H. B. and J. Smit (1999). "Late Eocene microkrystites and microtektites at Maud Rise (Ocean Drilling Project Hole 689B; Southern Ocean) suggest a global extension of the approximately 35.5 Ma Pacific impact ejecta strewn field." meteoritics 34(5): 747-756.

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