www.elsevier.com/locate/epslEarth and Planetary Science Letters 223 (2004) 283–302

Delayed climate cooling in the Late Eocene caused by multiple

impacts: high-resolution geochemical studies at Massignano, Italy

Bernd Bodiselitscha, Alessandro Montanarib, Christian Koeberl a,b,*, Rodolfo Coccionic

aDepartment of Geological Sciences, University of Vienna, Althanstrasse 14, A-1090 Vienna, AustriabOsservatorio Geologico di Coldigioco, I-62020 Frontale di Apiro, Italy

c Istituto di Geologia e Centro di Palinologia dell’Universita, Campus Scientifico, Localita Crocicchia, 61209 Urbino, Italy

Received 24 September 2003; received in revised form 6 April 2004; accepted 19 April 2004

Available online 24 June 2004

Abstract

High-resolution studies (d13C, d18O, and elemental abundances) were done in rocks at and below the GSSP for the Eocene/

Oligocene (E/O) boundary at Massignano, Italy. In addition to an earlier known Ir anomaly at 5.61 m, which is possibly linked

to the Popigai impact event, we confirm the presence of two additional Ir anomalies in the intervals from 6.00 to 6.40 m and

from 10.00 to 10.50 m, with maximum values of 259F 32 ppt at 6.17 m, and 149F 24 ppt at 10.28 m, respectively. The lower

Ir anomaly might be derived from the Chesapeake Bay impact event, whereas for the other one no impact event is known.

Similar d13C and d18O trends related to the two Ir anomalies indicate that the Ir anomaly at 10.28 m might be also derived from

an impact into a continental shelf, similar to the Chesapeake Bay impact event. d18O values decrease in the high Ir layers to

� 1.16x and � 1.17x, respectively, which, together with the negative shifts in d13C in the Ir-rich levels, indicate a warm pulse

superimposed on a general Late Eocene cooling trend that is characterized by d18O values ranging between � 0.6x and

� 0.4x. The release of methane hydrate after an impact in a continental shelf or seafloor, or impacts of 12C-rich comets during

a 2.2-million-year-long comet shower, respectively, could produce these more negative carbon and oxygen excursions

compared to the continuously decreasing trend over the whole Late Eocene Massignano section.

D 2004 Elsevier B.V. All rights reserved.

Keywords: Chesapeake Bay crater; Popigai crater; Late Eocene impact ejecta; Massignano (Italy); global cooling

1. Introduction

The Late Eocene is a period of major changes,

characterized by an accelerated global cooling ([1,2]

and references therein), with a sharp temperature drop

of about 2 jC near the Eocene/Oligocene (E/O)

0012-821X/$ - see front matter D 2004 Elsevier B.V. All rights reserved.

doi:10.1016/j.epsl.2004.04.028

* Corresponding author. Department of Geological Sciences,

University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria.

E-mail addresses: bernd.bodiselitsch@univie.ac.at

(B. Bodiselitsch), sandro.ogc@fastnet.it (A. Montanari),

christian.koeberl@univie.ac.at (C. Koeberl).

boundary [3], and significant stepwise floral and

faunal turnovers ([1,4,5] and references therein). These

global climate changes, which are reflected by a

gradual increase of marine oxygen isotope values

(e.g., [6,7]) and biotic crises (e.g., [1,8,9]), are com-

monly attributed to the expansion of the Antarctic ice

cap following its gradual isolation from other conti-

nental masses [10,11]. However, multiple bolide im-

pact events ([12] and references therein), possibly

related to a comet shower over a duration of 2.2

million years [13,14], may have played an important

B. Bodiselitsch et al. / Earth and Planetary Science Letters 223 (2004) 283–302284

role related to the deterioration of the global climate at

the end of the Eocene Epoch.

The two large impact structures Popigai, Russia, and

ChesapeakeBay,USA,with respectivediametersof100

and 85 km, and respective ages of 35.7F 0.8 Ma [15],

and 35.3F 0.2 Ma [16–19], represent the largest post-

Cretaceous–Tertiary (K/T) boundary impact events.

Both have ages near the peak of the Late Eocene comet

shower that was proposed by Farley et al. [14] on the

basis of a marked enhancement of interplanetary dust

particle flux in marine sediments.

Three smaller impact craters of comparable age,

Mistastin, Canada (38F 4 Ma, 28 km; [14]), Wanapi-

tei, Canada (37F 2Ma, 7.5 km; [21,22]), and Logoisk,

Belarus (40F 5 Ma, 17 km; [23]), may be part of the

same event, supporting the scenario of a cometary

bombardment. The comet shower hypothesis predicts

an even larger occurrence of smaller impacts which

may have played a role in the alteration climate con-

ditions at a global scale, due to atmospheric blowout

and distribution of ejecta around the Earth [24].

At least two distinct, yet closely spaced, Late Eocene

impact spherule layers, the older containing microtek-

tites, and the younger microkrystites [25,26], have been

identified in ocean sediments from the Atlantic, Indian

and Pacific Oceans, the Caribbean Sea and theWeddell

Sea, offAntarctica [27]. These distal impact ejecta were

also found in Late Eocene sediments in Texas, Georgia,

Massachusetts, Barbados and Cuba [8,28–31]. The

North American tektites were proposed to be derived

from the Chesapeake Bay impact event [17,18,32],

whereastheclinopyroxene-bearingspherulestrewnfield

(i.e., the microkrystites) may be linked to the Popigai

crater [15,33]. Estimates of the time separating the two

layers rangefrom10to20ky[25],and3 to5ky[12],with

theChesapeakeBayimpactbeingtheyoungerevent.The

clinopyroxene-spherule layer contains an Ir anomaly,

shocked quartz, Ni-rich spinels, and impact spherules.

Here we present the results of the chemical composi-

tion, and oxygen and carbon isotope ratios of pelagic

marly limestones sampled in the Massignano section

(central Italy), which represents the Global Stratotype

SectionandPoint (GSSP)for theE/Oboundary.Samples

frommeter level6.00–6.40and10.00–10.50of theLate

Eocenewerestudied.Alsotheoxygenandcarbonisotope

variations over the wholeMassignano section from 0m

(Late Eocene) to 23 m (Early Oligocene) were investi-

gated indetail. Former studiesby [34] showprominent Ir

peaks at 5.61 (190 ppt), 6.19 (100 ppt) and 10.25m (330

ppt), respectively, in theMassignano section. The age of

the 5.61m Ir anomalywas determined at 35.7F 0.4Ma,

by interpolation fromseveraldatedvolcanicashes found

in the same section. The overlying peak at 6.19 m is

younger by ca. 0.15 Ma. Shocked quartz [35–37], Ni-

rich spinels, and microspherules [38] have been found

around 5.61 m, all indicating derivation from an impact

event. In the layer that containsshockedquartzat5.61m,

no high-pressure silica phaseswere detected, which are,

however, present in the Chesapeake Bay related micro-

tektite layer of DSDP 612 [39,40]. Langenhorst [37]

suggested that this shocked quartz was derived from the

nonporous, crystalline target rock at Popigai. That pro-

posal was recently supported by isotopic data ofWhite-

headetal. [33].Except theIranomalyat10.25m,noother

evidenceforanimpactwasfoundbyMontanarietal. [34]

at that level.

To determine whether these peaks are associated

with an impact event or not, we checked Ir/Fe ratios;

possible volcanic input is discussed using trace element

ratios. To investigate the influence of possible impact

events on seawater temperature we analyzed oxygen

and carbon isotopes from bulk-carbonates. It is well

known that weathering and/or diagenesis may affect

the original isotopic composition. In the case of the

Massignano section, being located on a relatively fresh

quarry cut, there are no indications of recent weather-

ing, and the section also is not disturbed by tectonics,

lacking faulting or folding. No recrystallization of the

carbonate phases were found, indicating that the car-

bonate phase is not diagenetically modified [41]. How-

ever, Vonhof et al. [42] have noted, from SEM analysis,

that the foraminifers in the Massignano section are

filled with secondary, blocky calcite.

In absence of well-preserved, species-determined

calcite tests or shells, and under certain diagenetic

conditions, bulk rock calcite may represent an accept-

able material for stable isotope analysis, particularly for

carbon [43,44]. Even compacted and cemented car-

bonate pelagic sediments may retain the original d13Csignal. On the other hand, oxygen isotopic ratios in

bulk-rock samples are generally much more suscepti-

ble to alteration during diagenesis than carbon isotopes

[45]. Oxygen isotopic fractionation is more affected by

temperature during recrystallization than carbon.

For the determination of the paleoceanographic and

paleoclimatic conditions, the usage of foraminiferal

B. Bodiselitsch et al. / Earth and Planetary Science Letters 223 (2004) 283–302 285

species is more common than bulk-carbonate analysis.

Bulk-carbonate samples represent a mixture of carbo-

nates from different sources, e.g., benthonic and plank-

tonic foraminifers and calcareous nannofossils. The

isotopic composition of bulk samples is a function of

the composition of these species—e.g., d18O of fora-

minifers—is a function of the seawater d18O value

where organism lived. Environmental changes could

be established if these changes have an effect on most

of the species. Under these circumstances, the isotopic

composition derived from bulk analyses resembles

closely the record derived from single foraminiferal

analyses [46,47].

Thus, d18O values could be used to infer changes in

water temperature through a given stratigraphic inter-

val, especially if such an interval is represented by

homogeneous pelagic sediments. Usually the d13Cvalues are not in equilibrium with seawater. However,

we can assume that, on average, the 13C/12C ratios are

invariant with time. Therefore, systematic variations of

Fig. 1. Tectonic sketch-map of the Umbria–Marche Apennines where the s

of the Massignano GSSP for the Eocene–Oligocene boundary is marked

this isotope ratiomay reflect variations in d13C contents

of ocean water [48]. A higher 13C/12C ratio can be

interpreted as a decrease in bio-productivity resulting in

a decrease in organic matter accumulation in the

sedimentary record. This can also be interpreted as

the consequence of a cooling event. Thus, we used the

d13C values, together with the d18O values, to derive

cooling or warming trends.

2. Location and stratigraphic documentation

The abandoned quarry of Massignano is located

along the provincial road of the Monte Conero Park,

about 4 km north of the town of Sirolo (Fig. 1). The 23-

m-thick section consists of a continuous and complete

sequence of pelagic marly limestone and calcareous

marls, which contain well-preserved planktonic and

benthonic foraminiferal tests suspended in a coccolith

and claymatrix, andwhich are interbeddedwith several

haded areas represent the Meso-Cenozoic orogenic belt. The location

by an asterisk.

B. Bodiselitsch et al. / Earth and Planetary Science Letters 223 (2004) 283–302286

biotite-rich volcano-sedimentary layers (Fig. 2). Strati-

graphically, the Massignano exposure covers the upper

part of the Eocene and the lowermost part of the

Oligocene. These characteristics make of the Mas-

signano section an ideal situation for the application

of an integrated stratigraphic approach aimed at the

precise and accurate calibration of the litho-, bio-,

magneto- and chemostratigraphic records with direct

radioisotopic datings. In 1993, the Massignano Global

Stratotype Section and Point (GSSP) for the E/O

boundary was formally established [49]. The integrated

stratigraphy of the section is described in [50]. Other

studies are reviewed in [51].

In particular, great attention has been given to a short

stratigraphic interval across a thin impactoclastic layer

located at 5.6 m in the section. In this layer, Montanari

et al. [34] detected an iridium anomaly of about 200

ppt. This prompted a number of detailed studies, which

resulted in the discovery, in the same Ir-rich layer, of

shocked quartz grains [36,37], Ni-rich spinel and

altered microkrystites [38], and a broad peak in extra-

terrestrial 3He content [14].

A high-resolution, microfloral and faunal investiga-

tion carried out in a 4-m-thick segment including the

impactoclastic layer at 5.6 m show that across this layer

the marine biota did not undergo abrupt, dramatic

effects in terms of extinction [52,53]. However, accord-

ing to these authors, significant quantitative changes in

the calcareous plankton and dinoflagellate cysts

assemblages indicates a cooling immediately after the

deposition of the impactoclastic layer. This cooling was

interrupted by a short-term warming episode and cool

conditions stabilized after about 60 ky.

Fig. 2. Wide-angle picture of the Massignano section. Numbers correspon

Eocene–Oligocene (E–O) boundary at meter level 19.

3. Sample preparation and analytical methods

For high-resolution studies, samples were taken at 1

cm intervals across the stratigraphic intervals from 6.0

to 6.4 m, and 10.0 to 10.5 m, respectively. Additional

samples at 0.25 cm intervals were taken between 6.0

and 6.1, 10.0 and 10.1, and 10.35 and 10.5 m, respec-

tively. In the whole Massignano section from 0 to 23 m

continuous 10 cm samples (except 5.60–5.65, 6.10–

6.25, 7.10–7.15 and 10.20–10.25 m are sampled in 5

cm intervals) were taken. The intervals 0 and 4 m, and

14 to 23 m were sampled in 20, 30 and 50 cm steps,

respectively.

Major element, V, Cu, Yand Nb analyses were done

on powdered samples, which were obtained with an

automatic agate ball mill, by standard X-ray fluores-

cence (XRF) procedure (see [54], for details on proce-

dures, precision and accuracy). All other trace elements

were analyzed by instrumental neutron activation anal-

ysis (INAA). For details of the procedures, see [55,56].

Eleven samples from each of the high-resolution parts

of the stratigraphic location across the 6.15–6.25 and

10.2–10.30 m intervals, respectively, were analyzed

with an iridium coincidence spectrometry system (ICS)

(see [57,58].

In this study, we have used the bulk-carbonate frac-

tion to determine the geochemical record. Under certain

circumstances, bulk-carbonate samples may give more

significant d13C values than isolated foraminiferal tests

(see Introduction). Details of analytical procedures are

given in [59]. Themean values and stan-dard deviations

of 10 analyzed NBS-19 standards are 1.95F0.03xfor y13C and � 2.21F 0.05x for y18O.

d to the meters of the measured sequence. Note the location of the

B. Bodiselitsch et al. / Earth and Planetary

4. Results and discussion

4.1. Major and trace element composition

The abundances of the measured elements and the

ratios K/U, La/Th, Th/U, LaCN/YbCN (CN= chondrite-

normalized), Eu/Eu* = ECN/M[(SmCN).(GdCN)] andCe/

Ce* = 3.CeCN/(2.LaCN +NdCN) [60] are listed inAppen-

dices A and B. Ratios among other elements, including

Fe/Cs, Sb/Cs, Co/Cs, Cr/Cs, Eu/Cs, Hf/Cs, Sc/Cs, Ta/

Cs, Th/Cs and Ce/Cs (Fig. 3), were used to distinguish

the characteristic background chemical profile of these

pelagic carbonates from possible biotite-rich volcanic

ashes. Biotite can be incorporated into the pelagic

sediment as airfall particles produced by volcanic activ-

ity.The lower stratigraphic interval,which contains an Ir

anomaly at 6.17 m (see [34], and below), show higher

Co/Cs, Hf/Cs and Th/Cs ratios, compared with the

background (Fig. 3). Fe/Cs and Sb/Cs ratios, however,

show values in the range of the background (Fig. 3). On

theotherhand,nounusualvalues inFe/Cs,Sb/Cs,Co/Cs,

Cr/Cs, Eu/Cs, Hf/Cs, Sc/Cs, Ta/Cs, Th/Cs and Ce/Cs

ratios, respectively (Fig.3), areevident in the Ir extended

region at 10.28m (see results below). This may indicate

that there are no influences from volcanic material, nor

were the iridium contents produced by diagenetic pro-

cesses and/or precipitation from seawater. These results

are consistent with those ofMontanari et al. [34]. Ni, Cr

andCoshowdistinctpeaksat6.17m(Fig.3).At10.28m,

only minor enhancements of these elements were ob-

served (Fig. 3).

The Fe/Mn ratio in carbonate rocks may be used as

an indicator for a marine versus detrital origin of the se-

diment. At 6.17 m, there is a sharp increase in Fe/Mn

ratio and magnesium content (Fig. 3). This could be

considered, at least locally, as a stratigraphically signi-

ficant event. A slight increase in the Fe/Mn ratio andMg

content (Fig. 3) was also found in the upper analyzed

interval at 10.27m.The peaks, however, are about a fac-

tor of 4 smaller than the distinct peak in the 6.0–6.4 m

section.

The REE patterns of the carbonates are similar to

each other. All samples in the two sections show high

abundance of the light REE, a negative Ce anomaly

(expressed as Ce/Ce*) and a small negative Eu anom-

aly (expressed as Eu/Eu*) with average values around

0.80 in both intervals, and a flat heavy REE distribution

pattern. The slopes are relatively constant.

4.2. Iridium anomalies

The Ir abundances are shown in Fig. 3 and listed

in Table 1. There are well-defined peaks extending

from 6.15 to 6.18 m, with a maximum of 259F32 ppt

at 6.17 m, at a background of V60 ppt and from 10.24

to 10.30 m, with a maximum of 149F24 ppt at

10.28 m, at a background of V40 ppt. The upper Ir-

enhanced region probably reaches beyond 10.30 m,

because Cr, Co and Ni abundances are increased at

10.31–10.33 m. However, no further samples were

analyzed for Ir analysis above this level. The contin-

uous increase of Ir at 10.24–10.28 m suddenly

decreases at 10.27 m to V44 ppt, which corresponds

approximately the background value. The interval at

6.15–6.18 m, with a maximum of 259F32 ppt at

6.17 m, corresponds to the peak of f100 ppt detected

by Montanari et al. [34] at 6.20 m.

The two closely spaced anomalies at 5.6 and 6.2 m

may correspond with two large impact events, Popigai

and Chesapeake Bay. In a 5-cm-thick layer containing

the main Ir peak at 5.6 m, additional evidence for an

impact were found, such as Ni-rich spinel and altered

microkrystites [38], and shocked quartz [36,37]. In the

region between 6.15 and 6.18 m, we found a few

possible spherules. We are not sure whether or not they

were derived from the main impactoclastic layer at 5.6

m, and were reworked upsection by bioturbation.

Huber et al. [58] reported, however, that bioturbation

at Massignano can disturb the iridium profile in the

sedimentary record, but only within about 20 cm.

Although impact spherules far below, and increased

abundance of Ni from possible Ni-rich spinel just

below the 5.6 m impactoclastic layer have been found,

it seems clear that the Ir anomaly at 6.2 m is a distinct

individual event, andwas not derived from the lower Ir-

rich layer at 5.6 m.

In this study, no elevated Se and Sb abundances

coincide with the Ir anomaly at 10.0 and 10.5 m, in

contrast to Montanari et al. [34]. A higher abundance

of Ir, Se and Sb could be the result of sulfide

precipitation in the sediment. No evidence for vol-

canic influences, but a very slight positive shift in

the Fe/Mn ratio (Fig. 3), was determined, which may

indicate a stratigraphically significant event. The

interesting aspect of the Ir anomaly at 10.28 m is

that there are no indications of a discontinuity in the

sedimentation. The average sedimentation rate for

Science Letters 223 (2004) 283–302 287

Fig. 3. High-resolution chemostratigraphy across Late Eocene, from 6.00 to 6.40 m, and 10.00 to 10.50 m, above the base of the GSSP for the E/O boundary at Massignano, Italy.

Grey bars show possible warm pulses with significantly lower d13CPDB and d18OPDB values compared with the generally third-order polynomial trend line. These pulses come along

with Ir-enhanced regions and are triggered due to impacts.

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Table 1

Ir contents for samples from Massignano, Italy, measured by

coincidence spectrometry after neutron activation

Stratigraphic level

(m)

Ir

(ppt)

6.15 135F 23

6.17 259F 32

6.18 180F 26

6.19 69F 16

6.20 71F17

6.21 V 52

6.22 V 37

6.23 87F 18

6.24 V 58

6.25 65F 16

Background V 60

10.20 V 52

10.21 32F 11

10.22 V 53

10.23 V 32

10.24 49F 14

10.25 92F 19

10.26 100F 20

10.27 V 44

10.28 149F 24

10.29 70F 16

10.30 90F 19

Background V 40

B. Bodiselitsch et al. / Earth and Planetary Science Letters 223 (2004) 283–302 289

the Massignano section, calculated from interpolation

of three radioisotopically dated biotite levels, is 5.8

m/Ma. A better estimate is not possible, considering

error levels. Moreover, in this alternation of marls

and marly limestones, we may expect that the marls

reflect slow sedimentation rate, whereas the lime-

stone high sedimentation rate (high productivity of

calcareous plankton). Of course, this assumption is

valid for volcano-sedimentary layers. However, in

the stratigraphic interval 10.0–10.5 m, with a fairly

constant CaCO3 content around 70%, prominent

marl or volcanic layers are lacking.

Michel et al. [61] used the Ir/Fe ratio to distinguish

between an Ir enhancement from an impact fallout, and

variations in accumulation rate, which, in the case of

Massignano, is controlled by the primary productivity

of biogenic CaCO3 versus the input of detrital clay.

Thus, changes in CaCO3 production affect the relative

abundances of clay and iridium, but not their ratio. Fig.

3 shows that the Ir abundance and Ir/Fe ratio patterns

are similar, indicating no change in the deposition rate

of CaCO3, as otherwise the high Ir/Fe ratios would be at

background levels at 7� 10� 9 in the interval 6.0–6.4

m, and 4� 10� 9 in the interval 10.0–10.5 m, which is

not the case.

Therefore, a change in sedimentation rate in the

interval between 10.0 and 10.5 m cannot explain the

higher Ir content. Therefore, we agree with Montanari

et al. [34] that the Ir anomaly in this case is due to an

extraterrestrial event. However, the absence of impac-

toclastic evidence in the 10–10.5 m interval, such as

microspherules, Ni-rich spinel, and shock metamor-

phosed quartz grains, may be indicative of a localized

event, possibly a small object that exploded at sea

surface without producing a crater and/or detectable

impact debris.

Farley et al. [14] reported an increase in extraterres-

trial 3He in this region, which was interpreted as a

signature of increased influx of interplanetary dust

particles during a comet shower. Remarkably, all three

impactoclastic layers at 5.61, 6.17 and 10.28 m, coin-

cide with two narrow peaks superimposed on the very

broad peak of enhanced 3He flux (Fig. 4).

4.3. Oxygen and carbon isotope ratios

4.3.1. Complete section

The d13C values range between + 0.84x and

+ 2.17x (Appendix C); values decreases from f 7

tof16.5 m and increase from f16.5 to 23 m (Fig. 4).

The d18O values are in the range of � 1.60% and

� 0.59x (Appendix C), but there is no obvious trend

as for d13C, with only a slight decrease from 0 to 23 m

being recognizable (Fig. 4). The greater fluctuations in

the d18O values against the d13C values could be due

to the fact that oxygen isotopes ratios in bulk samples

are more sensitive against diagenetic alteration than

carbon isotopes.

Beginning at 16.5 m d13C values increase and

comes along with the onset of increasing 187Os/188Os

ratios [62] after a sharp minimum between f 13.5 and

f 16 m. This excursion in seawater Os isotope com-

position lag the time of maximum 3He flux by roughly

1.5 Ma. If this sharp minimum in Os isotope compo-

sition would be attributed to an increased influx of

extraterrestrial material, this time lag between the 3He

flux maximum and the 187Os/188Os ratio minimum

could be caused by Poynting–Robertson drag [62].

So the turning point of the d13C curve from lower to

higher d13C values at f 16.5 m might indicate the last

e

Fig. 4. Integrated litho-, chemo-, bio- and magnetostratigraphic model of the GSSP of the Late Eocene/Early Oligocene boundary at Massignano. Also shown are the impact events

that occurred during this period. (Data from: [6,14–17,20–23,34,36–38,42,58,62,63,71,75–78] and this work.)

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B. Bodiselitsch et al. / Earth and Planetary Science Letters 223 (2004) 283–302 291

influence of the 2.2 Ma lasting comet shower whose

duration is derived from the 3He curve from the

Massignano section [14].Weathering of Os-rich ophio-

lite sequences, uplifted by closure of the Tethys, has

been proposed for the abrupt drop in seawater187Os/188Os ratios ([62], but see also [63]).

Between 12.70 and 12.90 m, there is a spike in the

d13C curve with very low d13C values, including the

lowest d13C value of + 0.84x over the complete

section. This spike coincides with two biotite-rich

volcaniclastic layers in this region [34] and with the

onset of the 187Os/188Os ratio minimum. A second,

smaller, spike between 14.50 and 14.70 m also coin-

cides with a biotite-rich volcaniclastic layer [34] and is

located in the middle of the 187Os/188Os ratio mini-

mum. Moreover, lower d18O values are also found at

these levels. This effect is rather due to preferential

alteration of material in the volcaniclastic layer and not

an effect from the local volcanic conditions that causes

a warmer ocean with higher bio-productivity. Between

5.50 and 5.65 m, there is another d13C (maximum

+ 2.09x) and d18O (maximum � 0.81x) spike, agree-

ing with the impactoclastic layer at 5.61 m, and

indicating a possible cooling period with decreased

bio-productivity.

4.3.2. High-resolution parts

In our work, the d13C values in the two high-

resolution parts are in the range of +1.59x to +

2.08x through the 6.0–6.4 m interval and +1.28xto + 1.60x in the 10.0–10.5 m interval. The d18Ovalues range between � 1.76x and � 0.60x and

from � 1.94x to � 0.66x. (Fig. 3; Appendix D).

The d13C and d18O values for all two levels essen-

tially show covariant trends. At 6.17 m, the lowest

d13C and d18O values were found, followed by a

continuous increase uptometerlevel6.20.Inaddition,the

third-order poly-nomial trend line, which is superim-

posed to indicate the general trend more clearly, shows

an increase of d13C and d18O after the Ir-enhanced

region. Lowest d13C and d18O values at in the 10.0–

10.5 m interval were found at 10.25 m followed by a

continuous increase up to 10.27 m., which coincides

with the Ir enrichment discussed above. After this point,

a continuous decrease up to meter level 10.30 was

detected. A general increase of isotopic values, starting

in the Ir-enriched region, is indicated by the third-order

polynominal trend line.

At 6.17 m, with the highest Ir content, we found the

lowest d13C and d18O values. The negative shift in d13Cand d18O can be interpreted as a consequence of sudden

warming of ocean water. From 6.20 m on, a rapid

increase of d13C and d18O values indicates a return to

the general seawater cooling trend that characterizes

the terminal Eocene. For comparison, in the Quaternary

record, there are also present climate short-lived

changes, especially more frequent fluctuations in sea-

surface temperature associated with changes in bio-

productivity within 2.5 ky and shorter (e.g., [64,65])

(Note: 1 cmuf 1.7 ky in the Massignano section).

Thus, it seems that short-lived changes in bio-producti-

vity and sea temperature changes are not extraordinary.

The warm pulse that we can infer from the d13C and

d18O negative shifts at 6.17 m (Fig. 3) may have been

triggered by a meteoritic impact, which would have

released greenhouse gases into the atmosphere. Poag et

al. [66] suggested that the general cooling trend from

the middle Eocene to the lowermost Oligocene is

interrupted by a warm pulse in the upper Eocene, which

may have been triggered by the Popigai and Chesa-

peake Bay impact events, and may have been pro-

longed by subsequent impacts during the peak of a

comet shower (Fig. 5). In addition, in the Ir-enhanced

region in the 10.0–10.5 interval, we found a warm

pulse with lower d13C and d18O values. The general

trend of our isotopic records from the two levels shows

a warm pulse followed by a continuous cooling period

at this point with higher Ir concentration. d18O plots in

Fig. 3 indicate similar d18O values in the two levels.

The last value in 6 m section at 6.4 m is d18O� 0.89F 0.08x and at the beginning at the 10 m

section d18O � 0.80F0.03x. The average d18O val-

ues are very similar with � 1.16x and � 1.17x,

respectively. It seems that seawater temperature did

not change appreciable during this period of about 700

ky. The average d13C values differ somewhat between

the two levels. The average value in the lower

section is d13C + 1.79x, and in the upper section

d13C + 1.60x, respectively. This could indicate an

incursion of colder, more vigorous bottom waters

[67] and an increase of biomass and productivity

[68] during this time span.

If we compare the carbon and oxygen isotope data in

the three Ir anomaly regions at 5.61, 6.17 and 10.28m, it

is particularly striking that in the region of 5.61 m the

carbon andoxygen isotopedata showhigher values than

Fig. 5. Integrated stratigraphic model shows relationship of Popigai and Chesapeake Bay impacts to calcareous nannofossil (NP14–NP21),

foraminiferal biozones (P10–P19), extraterrestrial 3He curve [14], Ir peaks (this work; [58]) and oxygen isotope curve [6]. Modified from Poag

et al. [18]. The zoomed part shows foraminiferal biozones (Fo), magnetostratigraphy (MagC; for details, see Fig. 4), extraterrestrial 3He curve

and three subpulses of climatic warmth hypothesized by Poag et al. [71].

B. Bodiselitsch et al. / Earth and Planetary Science Letters 223 (2004) 283–302292

the dominant downward trend and in the two other

regions the d13C and d18Ovalues are significantly lower

than this trend. It seems that the event that produced

the Ir anomaly at 5.61 m caused a cooling period,

whereas the two other events caused some warming.

The target rocks of the 100-km-diameter Popigai

structure are generally granitic gneisses overlain by

f 1.25 km of sandstone and carbonates [15] produced

by the impact of an ordinary chondrite body [69]. If the

Ir anomaly at 5.61 m is related to the Popigai impact

event, this kind of impact causes a following cooling

period with a decrease in bio-productivity. If we relate

the Ir anomaly at 6.17 m to the Chesapeake Bay impact

event, this kind of impact triggers a warming period

with increased bio-productivity. The 85-km-diameter

Chesapeake Bay impact structure on the coastal plain

of Virginia is developed in a mixed-target substrate

composed of granitoids and metasedimentary rocks

overlain by dominantly siliciclastic, sedimentary rocks

[17,18]. The reason for the different climatic effects

might be due to the locations where the impacts

occurred. The Popigai impact event occurred on the

continent, whereas the Chesapeake Bay impact event

took place on the continental shelf. Kent et al. [70]

suggested that release of methane hydrates from me-

chanical disruption of sediments as a result of an impact

could cause a greenhouse effect, which is shown by the

negative shift in the carbon and oxygen isotope record.

So, the warm pulse at 6.17 m could be due to release of

large amounts of seafloor methane hydrate during and

after the Chesapeake impact event.

No impact event that could be related to the Ir

anomaly at 10.28 m is known so far. This anomaly,

correlated with a negative carbon and oxygen excur-

sion, could have been triggered by an impact in an

area of gas hydrate accumulation on the seafloor.

B. Bodiselitsch et al. / Earth and Planetary Science Letters 223 (2004) 283–302 293

Poag et al. [71] proposed threefold subdivision of

the inferred Late Eocene warm pulse. Negative d13Cand d18O excursions in the Ir-enhanced regions from

this study correspond with two of the three subpulses.

The oldest warm subdivision, W-1, in C16n.2n and the

lower part of C16r.1r correlates with Ir anomaly at 6.17

m. The Ir anomaly at 10.28 m correlates with the warm

subpulse, W-2, coincides with C16n.1n and the lower

two-thirds of C15r (Fig. 5).

5. Summary and conclusions

Two Ir anomalies at 6.17 and 10.28 m were

investigated in the Massignano, Italy, E/O section;

these can be attributed to impact events in the Late

Eocene. They are precisely placed within magneto-

and biostratigra-phic sequences, and were radioisoto-

pically dated using volcanic ash layers [34]. These Ir

anomalies are found in a 700 ky time interval from

35.7 and 35.0 Ma. This confirms preliminary Ir data at

6.19 and 10.25 m reported by Montanari et al. [34].

We found maximum Ir abundances of 259F 32 ppt at

6.17 m and of 149F 24 ppt at 10.28 m. The former

anomaly is still within the lowermost part of P16

zone, and within a short reversed interval in the upper

part of C16n. The other one is loca-ted in mid-C15n,

mid-P16 and upper CP15b (Fig. 4).

Another Ir anomaly, associated with an impacto-

clastic layer at 5.61 m, has been known before, and

may be associated with the Popigai impact event,

whereas the newly confirmed Ir anomaly at 6.17 m

may be related to the Chesapeake Bay impact event

(or another so far unknown impact event). Evidence

for impact materials, such as Ni-rich spinels, clino-

pyroxene-microspherules, shocked quartz were found

at 5.61 m, but not in the 6.17 m region. However,

shocked quartz at 5.61 m shows no high-pressure

silica phases, which are present in the North American

strewn field microtektites related to the Chesapeake

Bay impact event, but are not present in the clinopyr-

oxene-bearing spherules strewn field related to the

Popigai impact event.

In the region of the Ir anomaly at 10.28 m, no

further evidence for an impact event was found. Our

study shows, however, strong evidence for an extra-

terrestrial source, rather in the form of an impact

than slow accumulation of extraterrestrial dust. So

far, no particular impact event can be assigned to this

layer. There are some possible impact events which

might be correlated with this layer: Mistastin, Can-

ada (38F 4 Ma, 28 km; [20]), Wanapitei, Canada

(37F 2 Ma, 7.5 km; [21,22]), Logoisk, Belarus

(40F 5 Ma, 17 km; [23]), or even badly dated

impact events, like Beenchime-Salaaty, Russia

(40F 20 Ma, 8 km; [72]) and Longancha, Russia

(40F 20 Ma, 20 km; [72]).

Carbon and oxygen isotope ratios data show

significant anomalies in both Ir-enhanced regions at

6.17 and 10.28 m. There is no significant extinction

event directly after the closely spaced Popigai and

Chesapeake Bay impact event. However, data from

calcareous nannoplankton show fluctuations, which

coincide with the initiated warm pulse followed by a

cooling period after these events in the 6.0–6.4 m

section. Possible causes of these negative isotope

excursions could be due to the release of large

amounts of methane hydrate during and after an

impact in the continental shelf (like the Chesapeake

Bay impact) or seafloor, or the input of 12C-rich

carbon due to a cometary impact—cometary material

is rich in carbon [73] with measured 12C/13C ratios

as high as 5000 compared to terrestrial values of

about 89 [74], respectively.

The d18O values are not different between the 6.0

and 6.4 m section and the about 700 ky younger section

at 10.0–10.5 m. This is also reflected by oxygen iso-

tope data over the complete Massignano section that

show only a slight downward trend over the whole

Massignano section. Despite the fact that oxygen

isotope values measured in this study were clearly

diagenetically influenced, the general trend of the

d18O values might provide evidence that a continuous

cooling from the middle Eocene to Oligocene is inter-

rupted by warm pulses triggered by multiple impact

events during a comet shower lasting 2.2 Ma in the

Late Eocene.

Acknowledgements

C.K. and B.B. were supported by the Austrian

Science Foundation (grant Y58-GEO) and the research

of R.C. by MIUR 60% and CNR (grant

97.00242CT05). We thank C. Wylie Poag, Ken Farley

and an anonymous reviewer for their constructive and

critical reviews. Special thanks go to Dieter Mader for

useful comments and discussion. [KF]

Appendix A. Major and trace element contents in carbonates, in the 6.0–6.4 m section, above the base of GSSP for the E/O boundary at

Massignano, Italy

Stratigraphic

level

(m)

6.000 6.025 6.050 6.075 6.100 6.110 6.120 6.130 6.140 6.150 6.160 6.170 6.180 6.190 6.200 6.210 6.220 6.230 6.240 6.250 6.260 6.270 6.280 6.290 6.300 6.325 6.350 6.375 6.400

wt.%

SiO2 10.23 10.44 10.82 11.02 12.77 10.66 10.90 10.98 12.81 11.92 13.09 18.46 15.74 11.90 10.14 9.51 9.20 9.44 9.61 9.34 9.34 9.61 8.94 8.65 9.10 8.96 8.95 8.81 9.04

TiO2 0.18 0.18 0.19 0.19 0.21 0.19 0.19 0.21 0.19 0.19 0.21 0.27 0.25 0.21 0.18 0.17 0.16 0.18 0.17 0.17 0.16 0.17 0.16 0.16 0.17 0.16 0.17 0.16 0.17

Al2O3 3.00 3.06 3.18 3.27 3.95 3.16 3.18 3.21 3.87 3.57 3.97 5.69 4.71 3.79 3.01 2.81 2.66 2.83 2.85 2.73 2.79 2.80 2.59 2.50 2.67 2.65 2.64 2.62 2.69

Fe2O3 1.30 1.30 1.37 1.39 1.54 1.39 1.34 1.36 1.56 1.46 1.54 2.27 1.89 1.50 1.37 1.24 1.24 1.26 1.23 1.20 1.17 1.26 1.14 1.14 1.29 1.16 1.14 1.07 1.14

MnO 0.16 0.16 0.16 0.16 0.15 0.16 0.16 0.16 0.15 0.16 0.15 0.12 0.14 0.15 0.16 0.16 0.16 0.18 0.18 0.18 0.18 0.17 0.17 0.17 0.17 0.17 0.17 0.17 0.17

MgO 0.90 0.87 0.89 0.89 1.04 0.89 0.90 0.86 1.00 1.00 1.06 1.34 1.19 0.95 0.85 0.82 0.77 0.84 0.83 0.84 0.83 0.84 0.80 0.80 0.83 0.82 0.83 0.78 0.80

CaO 46.55 46.33 46.20 45.83 43.76 46.04 46.24 45.96 43.87 44.35 43.40 36.53 39.67 43.82 45.86 46.46 47.09 48.85 48.55 49.17 48.42 49.38 49.48 49.60 48.94 48.13 48.88 49.19 48.87

Na2O 0.10 0.10 0.10 0.11 0.12 0.11 0.11 0.10 0.11 0.13 0.13 0.19 0.15 0.13 0.12 0.11 0.11 0.11 0.11 0.10 0.10 0.11 0.10 0.10 0.10 0.10 0.10 0.10 0.10

K2O < 0.01 0.01 < 0.01 0.01 0.02 < 0.01 0.01 < 0.01 0.04 < 0.01 0.01 0.17 0.11 0.07 < 0.01 0.01 < 0.01 0.02 0.02 0.02 0.02 0.02 0.01 0.01 0.04 0.04 0.06 0.02 0.05

P2O5 0.08 0.08 0.07 0.08 0.09 0.08 0.08 0.08 0.08 0.08 0.10 0.11 0.10 0.08 0.06 0.06 0.07 0.07 0.07 0.07 0.07 0.07 0.07 0.07 0.08 0.07 0.07 0.08 0.08

L.O.I. 37.42 37.34 37.12 37.00 36.25 37.16 37.08 37.15 36.32 36.66 36.17 33.81 34.80 36.37 37.00 37.39 37.54 34.90 35.33 35.15 35.55 35.31 35.60 35.58 35.29 35.44 35.60 35.14 35.13

Total 99.87 99.83 100.04 99.87 99.80 99.81 100.12 100.03 99.99 99.40 99.81 98.81 98.61 98.80 98.60 98.63 98.92 98.60 98.87 98.87 98.57 99.67 98.98 98.70 98.59 97.61 98.60 98.08 98.15

ppm (except where noted)

Sc 3.39 3.39 3.48 3.74 4.21 3.65 3.59 3.57 4.00 4.18 4.15 6.20 5.28 4.33 3.75 3.34 3.22 3.32 3.17 3.01 2.97 3.28 3.10 3.01 3.15 3.19 2.90 2.50 3.14

V 22 23 27 25 31 27 27 24 30 28 30 40 31 27 22 20 20 21 21 19 22 19 21 18 21 20 20 19 19

Cr 29.9 29.9 30.7 33.6 37.4 32.8 32.1 31.8 35.6 38.7 36.6 54.1 44.1 36.4 33.8 31.3 30.3 29.3 30 28.3 28.1 30.8 28.8 28.2 28.2 29.4 29.9 27.1 29

Co 8.9 8.5 10.1 9.84 13 9.72 9.75 9.74 11.9 12.3 12.3 20.7 16.4 12.7 8.98 8.71 8.11 9.59 8.35 7.96 7.53 8.25 7.6 6.9 7.32 8.22 7.99 7.88 7.86

Ni 6 7 11 14 23 10 10 14 21 19 23 51 35 22 10 9 8 < 6 < 6 < 6 < 6 < 6 < 6 < 6 6 < 6 < 6 < 6 < 6

Cu 6 9 9 < 6 < 6 < 6 < 6 < 6 < 6 < 6 < 6 13 6 < 6 < 6 < 6 < 6 < 6 < 6 < 6 < 6 < 6 < 6 < 6 < 6 < 6 < 6 < 6 < 6

Zn 32 40 40 38 40 37 37 35 37 41 39 56 49 36 40 33 30 31 30 30 30 33 30 29 31 31 31 31 28

As 0.47 0.41 0.38 0.46 0.50 0.26 0.35 0.33 0.54 0.28 0.33 0.34 0.41 0.33 0.34 0.29 0.12 0.28 0.20 0.18 0.25 0.27 0.27 0.23 0.31 0.22 0.30 0.24 0.27

Se 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.2 0.1 0.2 0.2 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1

Br 0.43 0.49 0.45 0.46 0.37 0.33 0.37 0.32 0.45 0.39 0.43 0.33 0.32 0.32 0.51 0.53 0.45 0.50 0.39 0.49 0.49 0.32 0.42 0.43 0.43 0.40 0.31 0.30 0.47

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Rb 30.6 29.0 28.8 33.4 36.4 31.6 32.2 30.5 34.1 33.0 32.7 51.0 42.2 36.9 31.1 27.0 27.5 27.7 27.1 26.4 27.5 28.2 20.4 24.4 23.3 27.1 26.2 24.6 26.6

Sr 931 942 955 959 972 959 989 960 964 959 959 940 926 941 918 899 901 906 902 903 902 897 884 904 901 898 895 895 862

Y 13 14 14 14 14 14 14 14 14 15 14 16 17 16 14 13 14 13 14 13 13 13 13 13 13 14 13 15 13

Zr 25 28 30 28 29 30 28 26 29 29 31 51 41 35 34 20 21 20 22 21 23 23 30 25 25 21 25 20 24

Nb 6 6 6 6 6 6 6 6 7 6 7 7 8 8 6 6 7 5 6 6 5 6 6 6 6 5 5 6 6

Sb 0.18 0.17 0.16 0.16 0.2 0.15 0.16 0.15 0.18 0.16 0.19 0.29 0.24 0.17 0.16 0.14 0.13 0.14 0.15 0.12 0.18 0.14 0.14 0.13 0.17 0.14 0.17 0.14 0.15

Cs 2.11 2.07 2.15 2.43 2.66 2.32 2.38 2.33 2.39 2.40 2.16 3.27 2.59 2.20 2.05 1.83 1.81 1.65 1.85 1.89 1.67 1.93 1.93 1.59 1.62 1.85 1.74 1.70 1.83

Ba 507 498 450 514 576 514 1460 526 553 563 537 814 661 535 561 596 573 578 556 626 599 583 532 686 535 511 482 468 490

La 12.5 11.7 11.6 12.6 13.7 13.0 12.2 12.3 12.5 13.6 13.5 16.7 16.0 13.8 12.9 11.7 12.6 12.0 12.3 14.3 12.0 12.5 13.0 11.7 11.8 12.2 12.2 11.5 12.8

Ce 17.2 17.1 17.2 18.4 19.6 18.6 17.8 17.5 19.1 21.0 19.0 27.3 25.0 19.1 19.2 17.3 16.0 15.6 16.7 14.9 15.0 17.4 17.0 16.7 15.5 17.2 15.9 16.8 17.5

Nd 10.2 9.8 9.06 10.8 11.1 11.1 10.6 10.8 11.7 10.1 9.6 15.6 12.9 12.4 8.51 7.85 8.3 8.99 7.53 9.12 7.19 9.45 9.3 7.73 9.55 9.32 8.5 8.33 8.52

Sm 1.99 1.85 1.81 2.09 2.16 2.12 2.00 2.01 1.99 1.99 1.96 2.75 2.02 2.15 1.83 1.63 1.77 1.72 1.75 1.81 1.67 1.86 1.86 1.60 1.67 1.82 1.75 1.77 1.98

Eu 0.45 0.43 0.45 0.49 0.50 0.49 0.47 0.44 0.48 0.51 0.48 0.65 0.62 0.51 0.46 0.44 0.44 0.42 0.42 0.39 0.38 0.45 0.43 0.41 0.40 0.42 0.41 0.43 0.44

Gd 1.57 1.55 1.45 1.61 1.65 2.02 1.60 1.50 1.95 1.62 1.58 2.49 2.11 < 1.90 1.73 1.45 1.38 1.30 1.45 1.32 1.45 1.59 1.61 1.44 < 1.30 1.45 1.52 1.49 1.53

Tb 0.28 0.29 0.27 0.30 0.30 0.34 0.30 0.28 0.30 0.28 0.29 0.40 0.40 0.34 0.31 0.27 0.26 0.20 0.25 0.25 0.27 0.29 0.27 0.27 0.25 0.26 0.28 0.28 0.28

Tm 0.15 0.17 0.17 0.16 0.16 0.16 0.16 0.16 0.16 0.17 0.17 0.23 0.19 0.18 0.18 0.16 0.16 0.15 0.15 0.15 0.16 0.17 0.16 0.16 0.15 0.16 0.16 0.16 0.16

Yb 1.04 1.09 1.05 1.11 1.10 1.10 1.10 1.08 1.10 1.18 1.18 1.43 1.29 1.24 1.18 1.10 1.11 1.05 1.05 1.04 1.08 1.11 1.08 1.06 1.05 1.10 1.09 1.07 1.07

Lu 0.15 0.15 0.15 0.16 0.16 0.16 0.16 0.16 0.16 0.17 0.16 0.21 0.18 0.18 0.18 0.16 0.16 0.16 0.16 0.16 0.16 0.16 0.16 0.16 0.16 0.16 0.15 0.15 0.16

Hf 0.69 0.63 0.66 0.65 0.75 0.63 0.61 0.64 0.70 0.75 0.71 1.32 1.15 0.84 0.73 0.66 0.53 0.53 0.59 0.59 0.55 0.65 0.57 0.56 0.54 0.60 0.54 0.52 0.54

Ta 0.18 0.17 0.17 0.19 0.20 0.18 0.20 0.19 0.22 0.21 0.14 0.29 0.25 0.18 0.21 0.15 0.14 0.15 0.18 0.12 0.14 0.16 0.14 0.14 0.14 0.17 0.15 0.13 0.17

W 1.1 1.1 1.7 1.2 1.4 1.2 1.1 1.5 1.1 < 0.9 0.6 0.7 0.5 0.8 < 0.7 0.4 < 0.7 0.6 0.6 0.6 1.1 0.5 0.5 0.6 0.3 0.5 0.5 0.4 0.3

Au (ppb) 0.3 0.3 0.1 0.4 0.1 0.6 0.5 0.5 0.6 0.5 0.5 1.3 < 0.5 0.9 0.5 0.6 < 0.5 0.4 0.3 1.1 0.3 < 0.5 0.4 < 0.5 0.4 0.3 0.3 0.4 0.3

Th 2.25 2.17 2.15 2.41 2.61 2.27 2.30 2.30 2.60 2.47 2.38 4.47 3.54 2.62 2.36 2.00 1.84 1.91 1.96 1.73 1.83 2.11 1.87 1.76 1.87 2.01 1.86 1.82 1.95

U 0.48 0.39 0.46 0.45 0.64 0.55 0.52 0.58 0.45 0.52 0.66 0.96 0.72 0.72 0.70 0.42 0.51 0.55 0.46 0.60 0.64 0.52 0.53 0.64 0.65 0.59 0.55 0.56 0.71

K/U n.d. 256 n.d. 222 312 n.d. 192 n.d. 667 n.d. 152 1458 1250 833 n.d. 238 n.d. 363 434 333 312 385 189 156 461 509 909 357 563

La/Th 5.56 5.39 5.40 5.23 5.25 5.73 5.30 5.35 4.81 5.51 5.67 3.74 4.52 5.27 5.47 5.85 6.85 6.28 6.28 8.27 6.56 5.92 6.95 6.65 6.31 6.07 6.56 6.32 6.56

Th/U 4.69 5.56 4.67 5.36 4.08 4.13 4.42 3.97 5.78 4.75 3.61 4.66 4.92 3.64 3.37 4.76 3.61 3.47 4.26 2.88 2.86 4.06 3.53 2.75 2.88 3.41 3.38 3.25 2.75

Ce/Ce* 0.65 0.69 0.71 0.69 0.68 0.67 0.69 0.67 0.71 0.75 0.68 0.76 0.74 0.65 0.73 0.73 0.63 0.63 0.67 0.52 0.62 0.67 0.64 0.70 0.63 0.68 0.64 0.71 0.67

LaCN/YbCN 8.12 7.25 7.47 7.67 8.42 7.99 7.49 7.70 7.68 7.79 7.73 7.89 8.38 7.52 7.39 7.19 7.67 7.72 7.92 9.29 7.51 7.61 8.13 7.46 7.59 7.49 7.56 7.26 8.08

Eu/Eu* 0.78 0.78 0.85 0.82 0.81 0.72 0.80 0.77 0.74 0.87 0.83 0.76 0.92 n.d. 0.79 0.87 0.86 0.86 0.81 0.77 0.75 0.80 0.76 0.83 n.d. 0.79 0.77 0.81 0.77

Total iron as Fe2O3.

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Appendix B. Major and trace element contents in carbonates, in the 10.0–10.5 m section, above the base of

GSSP for the E/O boundary at Massignano, Italy

Stratigraphic

level

(m)

10.000 10.025 10.050 10.075 10.100 10.125 10.150 10.160 10.170 10.180 10.190 10.200 10.210 10.220 10.230 10.240

wt.%

SiO2 12.49 11.49 12.07 11.80 10.93 11.02 11.19 11.67 11.55 11.69 11.38 11.18 11.50 11.20 11.27 11.56

TiO2 0.22 0.20 0.22 0.20 0.18 0.20 0.19 0.20 0.20 0.19 0.20 0.19 0.20 0.19 0.19 0.19

Al2O3 3.73 3.40 3.52 3.42 3.21 3.28 3.34 3.55 3.46 3.44 3.39 3.26 3.42 3.35 3.28 3.40

Fe2O3 1.72 1.59 1.72 1.66 1.60 1.57 1.54 1.59 1.59 1.67 1.56 1.54 1.60 1.64 1.50 1.53

MnO 0.16 0.16 0.16 0.16 0.15 0.16 0.16 0.16 0.16 0.16 0.16 0.16 0.16 0.16 0.14 0.15

MgO 1.04 0.99 1.02 0.97 0.92 0.95 0.98 1.03 1.01 1.02 0.99 0.93 1.00 0.96 0.90 0.96

CaO 44.69 45.65 44.93 45.30 48.26 46.87 46.17 45.27 45.84 45.44 45.77 46.05 45.63 46.09 46.09 45.84

Na2O 0.13 0.11 0.11 0.11 0.12 0.12 0.11 0.12 0.13 0.13 0.12 0.13 0.13 0.13 0.12 0.12

K2O 0.22 0.14 0.20 0.14 0.10 0.12 0.14 0.11 0.08 0.08 0.05 0.05 0.06 0.04 0.07 0.08

P2O5 0.08 0.08 0.08 0.07 0.07 0.08 0.07 0.07 0.08 0.08 0.09 0.08 0.08 0.08 0.07 0.09

L.O.I. 34.37 34.84 34.62 35.02 34.90 34.56 34.76 34.78 34.57 34.93 35.25 35.36 34.89 35.03 35.20 35.08

Total 98.74 98.63 98.59 98.76 100.35 98.86 98.59 98.50 98.57 98.73 98.94 98.82 98.60 98.76 98.81 98.94

ppm (except where noted)

Sc 4.37 3.82 4.17 3.98 3.89 3.82 3.94 3.80 4.02 4.18 3.76 3.96 4.04 4.03 3.86 4.05

V 26 25 22 26 26 27 25 26 26 28 28 27 27 28 31 27

Cr 38.3 34.5 39.3 34.2 34.3 35.2 35.6 32.9 36.9 37.7 33.5 34.6 35.5 34.8 34.5 35.6

Co 11.3 9.63 11.1 9.61 9.61 9.11 9.91 9.42 9.84 10.5 9.51 9.90 9.78 9.60 9.75 10.3

Ni 21 16 < 6 16 16 10 14 15 16 20 18 16 17 15 20 18

Cu < 6 < 6 < 6 < 6 < 6 < 6 < 6 < 6 < 6 < 6 < 6 < 6 < 6 < 6 8 < 6

Zn 38 38 35 37 37 38 36 40 33 41 40 39 40 36 40 39

As 0.58 0.38 0.48 0.43 0.45 0.45 0.49 0.34 0.49 0.52 0.35 0.40 0.38 0.41 0.40 0.38

Se 0.2 < 0.1 0.1 < 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 < 0.1 0.2 < 0.1 0.1 0.1

Br 0.35 0.36 0.38 0.35 0.40 0.37 0.25 0.34 0.29 0.35 0.27 0.25 0.40 0.40 0.33 0.39

Rb 36.9 30.5 39.3 33.5 35.8 31.1 32.4 35.3 34.8 36.1 31.0 33.7 34.6 33.4 31.8 33.3

Sr 1120 1140 1130 1180 1200 1210 1130 1240 1200 1170 1290 1160 1220 1200 1140 1100

Y 13 13 13 13 12 12 13 12 13 13 13 14 13 13 13 14

Zr 30 29 33 27 26 28 26 25 26 26 24 25 30 29 23 27

Nb 6 6 6 7 6 6 6 4 5 6 5 6 6 6 5 6

Sb 0.18 0.12 0.19 0.14 0.15 0.16 0.57 0.18 0.15 0.15 0.14 0.16 0.15 0.14 0.13 0.13

Cs 2.31 1.96 2.59 1.94 2.08 1.96 2.04 2.17 2.24 2.33 2.00 2.07 2.17 2.16 2.04 2.15

Ba 441 431 426 410 380 378 402 422 398 424 409 422 420 435 387 382

La 13.4 12.2 12.6 12.6 12.5 11.9 12.7 11.7 11.9 12.8 11.4 12.7 12.2 11.7 11.5 12.4

Ce 19.8 17.6 21.0 19.2 18.8 18.2 18.7 17.7 18.6 19.4 17.6 18.7 19.1 18.3 17.7 19.5

Nd 10.3 10.2 9.91 11.1 9.76 11.0 10.0 10.2 9.68 10.7 10.0 10.3 11.0 8.55 10.1 10.1

Sm 2.00 1.67 1.90 1.81 1.89 1.80 1.87 1.94 1.89 1.94 1.69 1.88 1.86 1.88 1.73 1.96

Eu 0.50 0.47 0.51 0.49 0.46 0.46 0.47 0.45 0.48 0.48 0.45 0.48 0.47 0.44 0.44 0.49

Gd 1.74 1.96 1.91 1.27 1.98 1.47 2.08 1.70 2.00 2.11 1.40 1.60 1.56 1.74 1.52 1.55

Tb 0.32 0.29 0.35 0.30 0.33 0.26 0.30 0.32 0.27 0.32 0.26 0.31 0.31 0.33 0.28 0.27

Tm 0.19 0.17 0.21 0.16 0.16 0.17 0.17 0.18 0.16 0.16 0.16 0.16 0.18 0.15 0.16 0.17

Yb 1.10 0.99 1.02 1.01 1.02 1.03 1.03 1.00 1.05 1.06 0.97 1.08 1.07 1.00 1.05 1.05

Lu 0.16 0.15 0.15 0.15 0.15 0.15 0.15 0.15 0.17 0.16 0.15 0.16 0.15 0.15 0.15 0.16

Hf 0.78 0.64 0.78 0.80 0.75 0.66 0.68 0.68 0.71 0.71 0.61 0.67 0.68 0.61 0.62 0.69

Ta 0.20 0.17 0.22 0.18 0.19 0.17 0.18 0.19 0.19 0.19 0.17 0.19 0.18 0.14 0.16 0.17

W 1.2 0.1 0.7 0.6 0.6 0.6 0.8 1.0 0.7 0.8 < 0.5 0.9 1.0 0.8 0.6 0.6

Au [ppb] 4.3 0.5 1.0 0.3 0.5 0.8 0.5 0.8 0.3 1.0 0.3 0.3 0.8 0.8 1.0 1.8

Th 2.66 2.20 2.75 2.41 2.48 2.34 2.38 2.51 2.44 2.53 2.18 2.37 2.43 2.42 2.30 2.45

U 0.47 0.43 0.51 0.40 0.53 0.26 0.43 0.46 0.37 0.56 0.51 0.41 0.37 0.42 0.42 0.41

K/U 3830 2791 3333 3000 1509 3846 2791 1957 1892 1250 784 976 1351 714 1429 1707

La/Th 5.04 5.55 4.58 5.23 5.04 5.09 5.34 4.66 4.88 5.06 5.23 5.36 5.02 4.83 5.00 5.06

Th/U 5.66 5.12 5.39 6.03 4.68 9.00 5.53 5.46 6.59 4.52 4.27 5.78 6.57 5.76 5.48 5.98

Ce/Ce* 0.71 0.68 0.80 0.71 0.72 0.71 0.70 0.74 0.72 0.72 0.70 0.70 0.73 0.76 0.72 0.75

LaCN/YbCN 8.23 8.33 8.35 8.43 8.28 7.81 8.33 7.91 7.66 8.16 7.94 7.95 7.70 7.91 7.40 7.98

Eu/Eu* 0.82 0.79 0.82 0.99 0.73 0.86 0.73 0.76 0.75 0.73 0.89 0.85 0.84 0.74 0.83 0.86

Total iron as Fe2O3.

B. Bodiselitsch et al. / Earth and Planetary Science Letters 223 (2004) 283–302296

10.250 10.260 10.270 10.280 10.290 10.300 10.310 10.320 10.330 10.340 10.350 10.375 10.400 10.425 10.450 10.475 10.500

12.23 11.45 13.11 12.61 11.86 11.98 12.22 13.28 13.47 12.06 12.71 12.19 12.70 12.84 11.59 11.02 10.44

0.21 0.20 0.22 0.21 0.21 0.20 0.21 0.22 0.22 0.20 0.21 0.21 0.21 0.21 0.20 0.18 0.19

3.70 3.43 3.90 3.74 3.51 3.53 3.63 3.96 3.90 3.51 3.74 3.57 3.78 3.80 3.47 3.26 3.09

1.57 1.53 1.76 1.70 1.60 1.66 1.69 1.76 1.80 1.66 1.74 1.74 1.72 1.69 1.67 1.67 1.50

0.15 0.15 0.15 0.16 0.17 0.15 0.15 0.15 0.16 0.16 0.16 0.16 0.15 0.15 0.16 0.16 0.16

1.01 0.99 1.06 1.05 1.00 0.98 1.02 1.04 1.04 1.00 1.03 1.01 1.06 1.10 1.10 1.11 1.03

45.21 45.55 43.99 44.34 45.41 45.12 45.01 42.46 43.39 44.48 42.70 44.62 41.84 43.58 45.25 45.96 46.84

0.13 0.13 0.13 0.12 0.12 0.11 0.13 0.13 0.12 0.11 0.12 0.11 1.25 0.12 0.00 0.00 0.00

0.08 0.07 0.14 0.14 0.13 0.13 0.14 0.20 0.29 0.13 0.20 0.29 0.19 0.11 0.009 0.16 0.14

0.09 0.08 0.09 0.08 0.08 0.08 0.08 0.08 0.09 0.07 0.09 0.08 0.10 0.09 0.08 0.08 0.07

34.85 35.42 34.95 34.94 34.86 34.80 34.66 35.55 34.75 35.19 36.46 34.86 37.15 35.41 35.84 35.11 35.24

99.16 98.82 99.38 99.10 98.85 98.73 98.84 98.74 99.21 98.55 99.09 98.82 98.95 99.13 99.40 98.61 98.65

4.08 4.22 4.57 4.19 4.12 3.98 4.21 4.33 4.21 3.93 4.24 3.97 4.10 3.90 3.58 3.53 3.32

30 24 28 28 28 26 31 29 27 27 25 28 30 24 26 25 24

37.1 36.5 40.9 35.8 35.2 36.4 40.9 42.8 40.4 36.4 39.7 36.9 40.1 38.2 35.1 34.2 33.2

9.93 10.5 11.9 11.5 10.8 10.6 11.0 11.9 11.8 10.5 11.6 10.2 10.8 10.0 9.52 9.33 8.88

22 22 23 25 21 20 22 24 26 21 21 14 23 20 18 13 12

< 6 < 6 11 8 6 7 < 6 8 < 6 < 6 < 6 < 6 6 < 6 < 6 < 6 < 6

43 41 43 40 41 39 42 41 41 37 39 41 42 42 41 41 37

0.38 0.39 0.46 0.41 0.41 0.47 0.46 0.59 0.47 0.59 0.47 0.61 0.47 0.38 0.48 0.49 0.44

< 0.1 < 0.1 0.1 0.2 0.2 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1

0.37 0.32 0.22 0.31 0.30 0.41 0.40 0.43 0.34 0.42 0.40 0.43 0.38 0.36 0.35 0.41 0.30

34.7 36.3 39.9 38.5 36.4 33.9 37.8 40.7 40.0 37.4 36.8 36.6 38.3 35.1 36.6 35.9 31.4

1120 1120 1130 1140 1100 1100 1100 1200 1190 1090 1130 1160 1150 1140 1110 1140 1190

14 13 13 14 13 14 12 13 14 13 15 13 14 15 14 13 13

28 26 30 29 28 32 28 41 38 30 34 34 29 26 28 26 24

5 6 6 6 7 6 5 7 6 7 7 6 6 6 5 5 6

0.12 0.16 0.18 0.16 0.12 0.15 0.18 0.16 0.14 0.16 0.15 0.17 0.17 0.12 0.15 0.15 0.13

2.16 2.29 2.48 2.40 2.13 2.33 2.77 2.73 2.72 2.55 2.57 2.43 2.56 2.41 2.47 2.46 2.20

410 446 490 478 452 437 450 471 496 477 458 388 387 361 379 413 355

12.0 13.0 13.7 12.6 12.9 11.6 12.6 13.1 12.5 12.0 12.7 12.7 13.1 12.3 11.1 11.5 11.6

19.0 19.6 21.1 18.8 18.9 18.2 19.9 20.5 19.7 18.7 20.5 19.2 19.8 19.0 17.1 17.4 17.3

10.0 10.7 11.7 9.96 9.66 10.1 10.5 10.4 10.5 10.4 11.0 10.8 10.4 10.2 9.91 9.82 10.1

1.81 1.99 2.12 2.00 1.86 1.88 2.17 2.19 2.12 2.08 2.09 2.02 2.09 2.00 1.92 1.94 1.87

0.46 0.49 0.52 0.47 0.47 0.45 0.49 0.50 0.48 0.46 0.50 0.47 0.49 0.46 0.43 0.42 0.42

1.55 1.69 1.80 1.64 1.42 1.62 1.86 1.70 1.70 1.65 1.60 1.70 1.70 1.93 1.53 1.50 1.45

0.28 0.32 0.34 0.31 0.25 0.29 0.35 0.30 0.32 0.31 0.30 0.32 0.32 0.30 0.29 0.28 0.27

0.16 0.16 0.18 0.18 0.15 0.17 0.17 0.16 0.15 0.16 0.18 0.16 0.19 0.15 0.14 0.17 0.15

1.05 1.08 1.08 1.01 0.98 1.02 1.17 1.08 1.04 1.07 1.17 1.13 1.14 1.10 0.96 1.07 1.03

0.15 0.16 0.16 0.15 0.15 0.15 0.16 0.16 0.15 0.16 0.16 0.17 0.15 0.15 0.14 0.14 0.14

0.70 0.70 0.82 0.78 0.70 0.73 0.70 0.92 0.85 0.75 0.83 0.82 0.76 0.74 0.66 0.66 0.59

0.18 0.19 0.24 0.21 0.17 0.19 0.20 0.23 0.24 0.22 0.25 0.32 0.20 0.19 0.21 0.22 0.19

0.5 < 0.3 1.1 0.6 0.6 1.7 2.15 1.15 1.30 1.51 1.10 1.00 0.90 1.50 2.00 1.50 1.00

1.8 1.8 2.0 1.0 0.6 0.2 1.3 1.2 1.0 0.3 0.5 1.1 0.5 0.9 0.4 0.8 0.3

2.45 2.60 2.96 2.69 2.43 2.34 2.62 2.81 2.77 2.48 2.66 2.50 2.64 2.46 2.37 2.45 2.26

0.49 0.44 0.57 0.55 0.53 0.49 0.57 0.58 0.66 0.68 0.52 0.59 0.56 0.51 0.59 0.53 0.46

1429 1364 2105 2182 2075 2245 2105 2931 3636 1618 3269 4068 2857 1765 1266 2506 2527

4.90 5.00 4.63 4.68 5.31 4.96 4.81 4.66 4.51 4.84 4.77 5.08 4.96 5.00 4.68 4.69 5.13

5.00 5.91 5.19 4.89 4.58 4.78 4.60 4.84 4.20 3.65 5.12 4.24 4.71 4.82 4.02 4.62 4.91

0.75 0.72 0.73 0.71 0.71 0.74 0.75 0.75 0.75 0.73 0.76 0.71 0.72 0.73 0.72 0.71 0.70

7.72 8.13 8.57 8.43 8.90 7.68 7.28 8.20 8.12 7.58 7.34 7.59 7.77 7.56 7.81 7.26 7.61

0.84 0.82 0.81 0.79 0.88 0.79 0.75 0.79 0.77 0.76 0.84 0.78 0.79 0.72 0.77 0.75 0.78

B. Bodiselitsch et al. / Earth and Planetary Science Letters 223 (2004) 283–302 297

Appendix C (continued)

Stratigraphic level

(m)

d13CV-PDB

(x)

d 18OV-PDB

(x)

B. Bodiselitsch et al. / Earth and Planetary Science Letters 223 (2004) 283–302298

Appendix C. Carbon and oxygen isotope data

from samples of the complete Massignano GSSP,

Italy

Stratigraphic level

(m)

d13CV-PDB

(x)

d 18OV-PDB

(x)

0.00 2.00F 0.10 � 0.95F 0.17

0.30 1.96F 0.00 � 1.01F 0.00

0.50 2.06F 0.01 � 0.87F 0.06

0.60 2.01F 0.06 � 0.93F 0.13

1.00 1.93F 0.01 � 0.92F 0.04

1.20 1.99F 0.03 � 0.89F 0.05

1.50 1.87F 0.02 � 1.08F 0.00

1.80 1.88F 0.07 � 0.96F 0.12

2.00 1.83F 0.00 � 0.96F 0.00

2.50 1.94F 0.03 � 0.86F 0.04

3.00 1.85F 0.00 � 0.81F 0.00

3.50 1.82F 0.01 � 0.96F 0.04

4.00 1.94F 0.04 � 1.03F 0.10

4.10 2.06F 0.08 � 0.80F 0.11

4.20 1.96F 0.00 � 0.97F 0.00

4.30 1.93F 0.01 � 1.13F 0.01

4.40 2.06F 0.05 � 0.92F 0.11

4.50 1.92F 0.08 � 1.07F 0.15

4.60 1.94F 0.00 � 0.94F 0.00

4.70 2.17F 0.04 � 0.59F 0.06

4.80 1.93F 0.01 � 1.11F 0.08

4.90 1.91F 0.06 � 0.98F 0.11

5.00 1.73F 0.03 � 1.17F 0.04

5.10 2.07F 0.02 � 0.75F 0.08

5.20 1.88F 0.00 � 1.11F 0.00

5.25 1.68F 0.02 � 1.29F 0.01

5.30 1.76F 0.08 � 1.26F 0.11

5.40 1.66F 0.02 � 1.56F 0.08

5.50 2.09F 0.02 � 0.81F 0.07

5.60 1.90F 0.04 � 0.96F 0.05

5.65 1.88F 0.06 � 0.92F 0.13

5.70 1.69F 0.01 � 1.35F 0.01

5.80 1.91F 0.01 � 0.77F 0.08

5.90 2.06F 0.07 � 0.69F 0.14

6.00 1.90F 0.01 � 0.83F 0.01

6.10 1.76F 0.03 � 1.23F 0.05

6.15 1.74F 0.00 � 1.12F 0.00

6.20 1.95F 0.00 � 0.93F 0.00

6.25 1.75F 0.00 � 1.22F 0.00

6.30 2.06F 0.00 � 0.85F 0.05

6.40 1.76F 0.04 � 1.37F 0.07

6.45 1.81F 0.06 � 0.97F 0.13

6.50 1.72F 0.02 � 1.24F 0.06

6.60 1.93F 0.03 � 0.85F 0.06

6.70 1.98F 0.06 � 0.91F 0.07

6.80 2.05F 0.01 � 0.82F 0.00

6.90 1.87F 0.02 � 1.16F 0.02

7.00 1.92F 0.09 � 1.02F 0.15

7.10 1.88F 0.11 � 1.04F 0.20

7.15 1.99F 0.03 � 0.86F 0.06

7.20 1.88F 0.00 � 1.05F 0.00

7.30 1.73F 0.00 � 1.32F 0.00

7.35 1.87F 0.06 � 1.18F 0.11

7.40 1.91F 0.02 � 0.81F 0.03

7.50 1.61F 0.01 � 1.55F 0.02

7.60 1.96F 0.08 � 0.94F 0.13

7.70 1.80F 0.00 � 0.89F 0.00

7.80 1.75F 0.09 � 1.04F 0.04

8.00 1.64F 0.03 � 1.30F 0.06

8.10 1.78F 0.03 � 1.03F 0.05

8.20 1.56F 0.01 � 1.58F 0.05

8.30 1.73F 0.05 � 0.96F 0.08

8.40 1.76F 0.05 � 0.91F 0.11

8.50 1.88F 0.09 � 0.72F 0.14

8.60 1.81F 0.01 � 0.77F 0.01

8.70 1.62F 0.06 � 1.30F 0.06

8.80 1.76F 0.05 � 1.17F 0.11

8.90 1.83F 0.00 � 1.01F 0.00

9.00 1.83F 0.08 � 0.80F 0.05

9.10 1.64F 0.06 � 1.10F 0.13

9.20 1.55F 0.02 � 1.31F 0.02

9.30 1.58F 0.03 � 1.32F 0.08

9.40 1.84F 0.05 � 0.80F 0.12

9.50 1.74F 0.00 � 1.15F 0.00

9.60 1.66F 0.05 � 1.32F 0.12

9.70 1.63F 0.03 � 1.40F 0.03

9.80 1.56F 0.08 � 1.45F 0.06

9.90 1.68F 0.09 � 1.26F 0.16

10.00 1.90F 0.08 � 0.77F 0.12

10.10 1.63F 0.06 � 1.09F 0.12

10.20 1.87F 0.02 � 0.84F 0.10

10.25 1.64F 0.06 � 1.22F 0.10

10.30 1.65F 0.02 � 1.27F 0.04

10.40 1.50F 0.00 � 1.15F 0.01

10.50 1.66F 0.00 � 1.04F 0.00

10.60 1.63F 0.01 � 1.09F 0.02

10.70 1.60F 0.00 � 1.12F 0.01

10.80 1.53F 0.08 � 1.12F 0.14

10.90 1.70F 0.02 � 0.84F 0.03

11.00 1.53F 0.04 � 1.17F 0.11

11.10 1.52F 0.01 � 1.15F 0.02

11.20 1.32F 0.02 � 1.60F 0.01

11.30 1.57F 0.09 � 1.14F 0.22

11.40 1.35F 0.08 � 1.56F 0.06

11.50 1.55F 0.08 � 1.15F 0.16

11.60 1.46F 0.06 � 1.12F 0.06

11.70 1.28F 0.05 � 1.51F 0.11

11.80 1.45F 0.00 � 0.93F 0.00

11.90 1.42F 0.00 � 1.20F 0.01

12.00 1.43F 0.09 � 1.32F 0.05

12.20 1.52F 0.02 � 1.03F 0.08

Appendix C (continued)

Stratigraphic level

(m)

d13CV-PDB

(x)

d 18OV-PDB

(x)

12.30 1.35F 0.09 � 1.34F 0.12

12.40 1.43F 0.08 � 1.30F 0.14

12.50 1.45F 0.04 � 1.10F 0.06

12.60 1.65F 0.04 � 0.69F 0.08

12.70 1.09F 0.05 � 1.19F 0.04

12.80 1.01F 0.02 � 1.33F 0.04

12.90 0.84F 0.10 � 1.55F 0.08

13.00 1.48F 0.05 � 0.84F 0.01

13.10 1.30F 0.01 � 1.26F 0.04

13.20 1.39F 0.00 � 1.16F 0.00

13.30 1.45F 0.03 � 1.04F 0.10

13.40 1.43F 0.03 � 0.99F 0.01

13.50 1.26F 0.01 � 1.26F 0.04

13.60 1.20F 0.04 � 1.28F 0.13

13.70 1.22F 0.05 � 1.24F 0.09

13.80 1.23F 0.02 � 1.24F 0.04

13.90 1.26F 0.08 � 0.97F 0.16

14.00 1.37F 0.02 � 1.12F 0.06

14.10 1.24F 0.06 � 1.05F 0.11

14.40 1.14F 0.08 � 1.49F 0.07

14.50 1.06F 0.07 � 1.57F 0.19

14.70 1.07F 0.05 � 1.14F 0.10

15.00 1.16F 0.06 � 1.14F 0.13

15.30 1.22F 0.03 � 0.93F 0.08

15.50 1.27F 0.02 � 0.80F 0.07

16.00 1.27F 0.01 � 1.10F 0.06

16.20 1.04F 0.06 � 1.17F 0.11

16.50 1.01F 0.08 � 1.15F 0.18

16.80 1.07F 0.02 � 1.11F 0.01

17.00 1.05F 0.04 � 1.35F 0.09

17.10 1.27F 0.06 � 1.00F 0.02

17.50 1.29F 0.14 � 0.97F 0.17

17.70 1.52F 0.05 � 0.90F 0.04

18.00 1.53F 0.02 � 1.16F 0.02

18.30 1.49F 0.02 � 1.26F 0.04

18.50 1.65F 0.04 � 0.95F 0.05

18.60 1.47F 0.11 � 1.28F 0.17

18.75 1.47F 0.01 � 1.09F 0.06

18.85 1.42F 0.02 � 1.14F 0.10

18.90 1.65F 0.12 � 1.02F 0.12

19.00 1.39F 0.00 � 1.58F 0.01

19.50 1.54F 0.01 � 1.24F 0.05

19.80 1.55F 0.02 � 1.29F 0.00

20.00 1.87F 0.01 � 0.83F 0.03

20.40 1.41F 0.03 � 1.38F 0.09

20.50 1.56F 0.00 � 1.20F 0.04

20.70 1.61F 0.03 � 1.26F 0.09

21.00 1.61F 0.08 � 1.31F 0.09

21.30 1.78F 0.08 � 1.23F 0.15

21.40 1.78F 0.01 � 1.24F 0.08

21.60 1.76F 0.00 � 1.32F 0.10

21.90 1.81F 0.01 � 1.26F 0.02

22.00 1.92F 0.07 � 0.87F 0.07

Appendix C (continued)

Stratigraphic level

(m)

d13CV-PDB

(x)

d 18OV-PDB

(x)

22.20 1.69F 0.04 � 1.29F 0.12

22.40 1.79F 0.08 � 0.96F 0.18

22.50 1.77F 0.03 � 1.04F 0.08

23.00 1.98F 0.01 � 0.95F 0.03

Errors are 1r for d 13C and d 18O.

B. Bodiselitsch et al. / Earth and Planetary Science Letters 223 (2004) 283–302 299

Appendix D. Carbon and oxygen isotope data

from samples of the high-resolution part from

Massignano, Italy

Stratigraphic level

(m)

d 13CV-PDB

(x)

d 18OV-PDB

(x)

6.000 1.94F 0.00 � 0.80F 0.00

6.025 2.08F 0.07 � 0.60F 0.06

6.050 1.95F 0.02 � 0.84F 0.01

6.075 1.91F 0.01 � 1.07F 0.01

6.100 1.85F 0.07 � 1.18F 0.09

6.110 1.92F 0.06 � 1.12F 0.02

6.120 1.67F 0.00 � 1.62F 0.04

6.130 1.68F 0.00 � 1.61F 0.00

6.140 1.98F 0.03 � 0.98F 0.08

6.150 1.83F 0.01 � 1.34F 0.05

6.160 1.95F 0.03 � 1.06F 0.00

6.170 1.62F 0.02 � 1.76F 0.01

6.180 1.70F 0.06 � 1.49F 0.07

6.190 1.78F 0.02 � 1.20F 0.01

6.200 1.85F 0.06 � 0.98F 0.08

6.210 1.79F 0.00 � 1.07F 0.00

6.220 1.61F 0.04 � 1.29F 0.07

6.230 1.76F 0.02 � 1.00F 0.01

6.240 1.61F 0.03 � 1.37F 0.05

6.250 1.59F 0.08 � 1.34F 0.13

6.260 1.60F 0.04 � 1.35F 0.03

6.270 1.71F 0.00 � 1.19F 0.02

6.280 1.61F 0.04 � 1.33F 0.07

6.290 1.85F 0.01 � 0.90F 0.03

6.300 1.65F 0.03 � 1.36F 0.06

6.325 1.90F 0.03 � 0.85F 0.04

6.350 1.82F 0.02 � 1.06F 0.03

6.375 1.77F 0.04 � 1.12F 0.03

6.400 1.92F 0.01 � 0.89F 0.08

10.000 1.79F 0.01 � 0.80F 0.03

10.025 1.65F 0.00 � 1.19F 0.06

10.050 1.79F 0.02 � 0.66F 0.02

10.075 1.66F 0.02 � 1.00F 0.07

10.100 1.74F 0.01 � 0.86F 0.06

10.125 1.61F 0.07 � 1.12F 0.12

10.150 1.56F 0.04 � 1.24F 0.01

Appendix D (continued )

Stratigraphic level

(m)

d 13CV-PDB

(x)

d 18OV-PDB

(x)

10.160 1.59F 0.00 � 1.20F 0.01

10.170 1.64F 0.05 � 1.13F 0.15

10.180 1.69F 0.01 � 1.05F 0.03

10.190 1.51F 0.02 � 1.46F 0.10

10.200 1.67F 0.00 � 1.07F 0.00

10.210 1.74F 0.03 � 0.96F 0.11

10.220 1.64F 0.01 � 1.17F 0.01

10.230 1.59F 0.04 � 1.35F 0.03

10.240 1.61F 0.00 � 1.24F 0.00

10.250 1.28F 0.04 � 1.94F 0.11

10.260 1.61F 0.00 � 1.25F 0.00

10.270 1.80F 0.07 � 0.80F 0.07

10.280 1.54F 0.04 � 1.28F 0.04

10.290 1.37F 0.01 � 1.77F 0.07

10.300 1.57F 0.00 � 1.21F 0.00

10.310 1.45F 0.02 � 1.68F 0.04

10.320 1.50F 0.05 � 1.47F 0.07

10.330 1.52F 0.00 � 1.33F 0.00

10.340 1.51F 0.00 � 1.45F 0.08

10.350 1.60F 0.01 � 1.16F 0.00

10.375 1.66F 0.02 � 0.82F 0.04

10.400 1.58F 0.02 � 0.96F 0.00

10.425 1.46F 0.01 � 1.24F 0.04

10.450 1.68F 0.05 � 0.86F 0.06

10.475 1.63F 0.04 � 0.88F 0.10

10.500 1.61F 0.01 � 0.99F 0.02

Errors are 1r for d 13C and d 18O.

B. Bodiselitsch et al. / Earth and Planetary Science Letters 223 (2004) 283–302300

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