Table 1 Eggshell and sediment geochemical analyses.

From: A new Argentinean nesting site showing neosauropod dinosaur reproduction in a Cretaceous hydrothermal environment

 

Samples

 

Eggshell fragments

Sediments sub-site H

Sediments sub-site F

Sediments Los Barquitos

 

Sub-site A (clutch 10)

Sub-site E (clutch 4)

Sub-site F (clutch 11)

SAN 1 *

SAN 2 †

SAN 6 ‡

SAN 3 *

SAN 4 †

SAN 5 ‡

SAN 7 *

SAN 8 †

SAN 9 ‡

Oxides (wt%)

 SiO2

40.15

80.61

36.76

70.05

85.51

31.81

74.20

64.27

75.71

82.88

54.56

59.00

 TiO2

0.01

0.01

0.01

0.38

0.11

0.09

0.10

0.02

0.06

0.10

0.03

0.08

 Al2O3

0.23

0.19

0.24

8.46

4.59

2.42

3.02

2.48

2.34

7.63

6.57

3.90

 Fe2O3

0.16

0.28

0.15

2.64

1.27

0.61

1.22

0.53

0.66

1.00

0.05

0.64

 MnO

0.01

0.01

0.01

0.08

0.25

0.03

0.03

0.02

0.01

0.02

0.01

0.01

 MgO

0.04

0.03

0.04

0.81

0.24

0.21

0.27

0.07

0.11

0.24

0.10

0.30

 CaO

32.49

7.09

30.84

1.15

1.06

35.83

9.14

15.81

8.82

0.90

17.34

16.61

 Na2O

0.06

0.06

0.06

4.56

0.90

0.36

0.30

0.52

0.47

2.28

1.24

0.73

 K2O

0.05

0.07

0.07

1.71

1.75

0.96

1.08

1.37

0.98

1.46

4.13

1.76

 P2O5

0.01

0.02

0.02

0.07

0.04

0.18

0.09

0.05

0.04

0.03

0.04

0.04

 LOI

27.77

6.59

26.77

7.82

2.90

27.54

8.82

13.08

8.20

1.90

14.43

14.30

TOTAL

100.98

94.96

94.97

97.73

98.62

100.04

98.27

98.22

97.40

98.44

98.50

97.37

Trace elements (p.p.m.)

 Li

<2

<2

<2

19

9

5

6

3

4

7

4

4

 Ba

>2000

51

33

506

395

70

98

48

47

33

24

65

 V

17

34

18

59

93

18

52

10

12

15

10

9

 Cu

3

2

5

28

23

9

18

11

10

10

8

8

 Zn

5

6

2

46

17

6

12

4

5

10

4

4

 Pb

5

<2

<2

19

7

3

4

2

<2

<2

<2

<2

 As

<5

<5

<5

11

12

10

5

<5

<5

<5

<5

<5

  1. Presence and concentration of oxides and trace elements are congruent with those from the Cretaceous Gondwanic hydrothermal cycle, thus supporting synchronicity between SGP hydrothermal and dinosaur ovideposition activities. Five hydrothermal cycles are known to be in association with the orogeny of the Sierras Pampeanas15,16. The Gondwanic extensional cycle is related to the early opening of the Atlantic rift, when Mn (Fe-F-Ba) and F (Fe-Mn)-rich veins were formed in association with granitoids16. Furthermore, this extensional cycle caused the migration of hydrothermal solutions of low and moderate temperatures, low salinity and enriched with As, Cu, Mo, Pb, V, Zn, Sr, Li, W and Sb16,40. Our geochemical results compare favorably with the Gondwanic cycle but not those that are pre or postdated the Cretaceous, thus indicating a Cretaceous hydrothermal age for the Los Llanos Formation and also a coeval timing between hydrothermal and egg laying activities. SAN 1–9 identifies the various samples. Sub-sites represent grouping of clutches within SGP.
  2. *Rock sample from the upper Permian levels.
  3. †Rock sample from the lower Cretaceous levels.
  4. ‡Rock sample from the upper Cretaceous levels. The lower limit for detection of the major oxides is 0.01 wt%. Limit detection for Li there is between 2 and 10,000 p.p.m.; for Ba is between 2 and 2,000 p.p.m.; for V between 1 and 10,000 p.p.m.; for Cu between 1 and 10,000 p.p.m.; for Zn between 1 and 10,000 p.p.m.; for Pb between 2 and 10,000 p.p.m.; and for As between 5 and 10,000 p.p.m.
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