Fig 1.
a. Iron staples of the top walls (southern nave looking on the angle of the southern transept). b. Iron staples inside the monolithic columns of the nave (view of the staple in red). c. Iron staples in the tribunes of the choir (staples n° 121 to 124).
Fig 2.
Map of the tribunes of the choir, showing the location of the staples (red lines) and the sampling (red stars).
Fig 3.
View of the checked cornice of the choir with its series of staples drawn by Viollet-le-Duc (left) [19 tome 2, p. 400] and today, with the chains implemented by Lassus (right).
Fig 4.
Map of the upper walls in the nave, showing the location of the staples and the sampling (Red = staples observed, Yellow, staples not measured (below provisional roof beams), blue = staples that fell with the fire, Green = staples sampled, Grey = staples formerly removed).
Red stars: sampling locations.
Fig 5.
Map of the upper walls in the choir, showing the location of the staples and the sampling (Red = staples observed, Yellow, staples not measured (below provisional roof beams), blue = staples that fell with the fire, Green = staples sampled, Grey = staples formerly removed).
Red stars: sampling locations.
Table 1.
List of studied artefacts and samples.
Fig 6.
Broken staple in the tribunes (TRIB01S).
The red line indicates the sampling. The sample was then cut longitudinally for analysis.
Fig 7.
Sampling on the studied staples.
Table 2.
Analytical LA-ICP-MS parameters.
Fig 8.
Dimensions of the staples of the tribunes.
Fig 9.
Dimensions of the staples of the upper walls.
Fig 10.
Metallographic features after Nital etching.
a. Micrograph of NS8-L showing the welding of ferrous alloys of different qualities (from bottom to top, ferrite with small SI, ferrite with big SI, carburized ferrite-pearlite). b. Slag inclusion and porosity (NS106-T1). C. Ghost structure and different ferrite grain size (NS8-L), d. Slightly carburized zone with Widmanstätten ferrite and small SI (NS106T1) e. Carburized zone with Pearlite and Widmanstätten ferrite (TRIB01S).
Fig 11.
Oberhoffer etching on sample NN9-T showing mesoscopic and microscopic variation in P content (the lighter zones are richer in P).
Fig 12.
Micrograph of sample VN2-T showing several welding lines and different microstructures (Nital etching).
Table 3.
Results of metallographic analyses.
Fig 13.
Comparison of radiocarbon dating of the staples of the tribunes and the upper walls.
Table 4.
Results of radiocarbon dating on the staples of Notre-Dame de Paris.
Fig 14.
SI composition regarding their location in sample NS7-T.
Composition clusters (blue, green, red) were determined by HCA on Xij data. The clusters were then plotted on binary graphs highlighting differences in Al2O3/SiO2 and K2O/CaO ratios between the clusters.
Table 5.
Different clusters highlighted by welding lines and major elements analyses and variation in P2O5 and MnO content (given in average weighted content per cluster).
Fig 15.
HCA on the SI trace element composition (Xij) of all samples.
The two main branches with the highest dissimilarity are highlighted in blue and red. For samples represented in different branches, the number of SI in each branch is indicated in brackets. Clusters were determined by the elbow method.
Fig 16.
t-SNE on the SI trace element composition (Xij) of all samples.
Table 6.
Summary of provenance results.
“?” means unsure compatibility as very few SI are involved in the group or staples belong to different subgroups (a&b).
Fig 17.
Network graph indicating the relationships between the staples.
Orange: 95% probability beg. of the 13th c., Cyan: 95% probability middle of the 12th c. Yellow: 95% probability middle of 12th, beg. of 13th c., Green: location. When two staples are linked, they show at least one constitutive part with the same provenance (see Table 6). Thick lines indicate certain common provenance. Thin lines indicate unsure common provenance (noted “?” in Table 6). Each staple is also linked to its location.