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Table 4 Isotopic analysis of samples in the concretion

From: 3-D orientation and distribution of ammonites in a concretion from the Upper Cretaceous Pierre Shale of Montana

Sample type

Sample no.a

Lab no.b

AMNH no.c

ΡΙd

Locatione

δ18O (‰)

Mean δ18Of (‰)

δ13C (‰)

Mean δ13Cf (‰)

Comments

OS

1B-1

69

85490

2.5

West end

−1.20

−2.06

From shell in mold

OS

1B-1a

70

85490

2.5

West end

−1.29

−1.25

−1.15

−1.61

As above

OS

14A-1

11

85461

2.0

East end

−1.49

−2.20

At apt, mid-venter

OS

14A-1a

57

85461

 

East end

−1.27

−1.38

−2.04

−2.12

As above

OS

8A-1

29

85450

2.5

Center

−3.94

1.70

From apt, mold

OS

8A-1a

59

85450

 

Center

−4.08

−4.01

1.14

1.42

As above

OS

10A-1

36

85444

2.5

Center

−2.35

−2.05

From apt

OS

10A-1a

41

85444

1.5

Center

−2.32

−2.34

0.01

−1.02

Near above but…g

OS

16-5

30

85473

3.0

Top

−2.28

1.31

From shell in mold

OS

16-5a

38

85473

3.5

Top

−2.46

−2.37

1.47

1.39

As above

OS

5B-1

14

85484

 

Low center

−1.70

−0.93

From phrag, lat

OS

5B-1a

58

85484

4.0

Low center

−2.03

−1.86

0.04

−0.44

As above

CC

1B-1

5

85490

 

West end

−1.23

−3.11

Last ch, along siph

CC

14A-1

65

85461

 

East end

−1.80

−1.73

Near bc, but ch

CC

8A-1

52

85450

 

Center

−1.28

−4.17

Near bc, but ch

CC

16-5

10

85473

 

Top

−2.01

−2.87

1/3 back from bc

CC

16-5a

32

85473

 

Top

−1.90

−1.96

−2.46

−2.67

As above

CC

5B-1

68

85484

 

Low center

−0.68

−12.63

Broken chamberh

VC

3A

81

85558

 

Bottom

−11.90

−25.54

VC

8B

44

n85450

 

Center

−3.49

−7.01

VC

10A

62

n85444

 

Center

−12.08

−25.74

MX

1B-1

1

85490

 

West end

−1.49

−15.48

From infilled bc

MX

14A-1

17

n85461

 

East end

−1.51

−9.66

Near apt, 14A-1

MX

8A-1

40

n85450

 

Center

−1.44

−13.38

Near mold, 8A-1

MX

10A-1

47

n85444

 

Center

−1.33

−13.42

Near venter, 10A-1

MX

16-5

7

85473

 

Top

−1.36

−13.11

MX in bite mark

MX

5B-1

66

n85484

 

Low center

−1.39

−13.40

Near 5B-1

CR

1B

55

n85490

 

West end

−1.27

−17.44

Exposed surface crust

CR

14A

24

n85461

 

East end

−1.65

−17.95

As above

CR

3B

77

85560

 

Bottom

−1.21

−17.01

As above

  1. OS outer shell, CC chamber calcite (from inside phragmocone), chambers intact except as noted in footnote h, VC vein carbonate, MX concretion matrix (carbonate), CR concretion outer crust (carbonate)
  2. apt aperture; bc body chamber; ch chamber; phrag lat phragmocone, lateral region; siph siphuncle
  3. aIndicates samples submitted as replicates to assess measurement consistency; samples with a number (and letter) followed by a dash and another number are from the outer shell or the chamber of the ammonite specimen indicated; others were not on or in an ammonite (but may have been near one, see also footnote c)
  4. bRandomly assigned number for purposes of blind measurements, i.e., the laboratory doing the measurements did not know the source of the sample
  5. cn” before number indicates that the sample is derived from matrix or crust of a specimen without an AMNH number, but near the indicated AMNH specimen
  6. dPI = Preservation index as defined by Cochran et al. (2010)
  7. eLocation within the concretion
  8. fMean values calculated for duplicate analyses; these were the values used for analyses and plotting (Fig. 11) in the case of duplicate samples, otherwise the original sample value was used
  9. g(Sample 41) from venter of body chamber adapical of the point of recurvature, close enough to sample 36 and from the same region of the ammonite to be considered as a duplicate
  10. hSample from a broken phragmocone chamber that was open to an open space in the adjoining body chamber that was not completely filled with matrix; all other chamber samples were from intact phragmocone chambers that were bored into by the investigators to obtain samples from inside