Trachyte weathering in the urban built environment related to air quality

Heritage Science

Table 1 Major-element chemical composition expressed as oxide weight percent of representative samples of Euganean trachyte from the Renaissance city walls of Padua determined by LA-ICPMS, on both surface (i.e., weathering crust or patina) and host rock (inner part)

Sample	SiO₂	TiO₂	Al₂O₃	Fe₂O₃	MnO	MgO	CaO	Na₂O	K₂O	P₂O₅	SO₃
*Calcite-rich alteration*
SCR-01
Surface	8.57	0.02	1.14	0.58	0.04	1.49	85.85	0.17	0.12	0.69	0.38
Host rock	63.69	0.12	18.09	0.76	0.01	0.14	4.40	6.18	4.56	0.04	0.45
GAR-03
Surface	52.04	0.17	13.40	3.98	0.31	1.21	16.29	3.28	0.83	3.21	1.18
Host rock	67.17	0.09	18.08	0.91	0.00	0.20	1.51	5.75	5.70	0.12	0.10
CSN-03
Surface	55.10	0.40	11.59	3.51	0.09	1.51	15.60	3.00	0.97	1.42	2.93
Host rock	65.78	0.11	18.31	2.04	0.01	0.35	1.03	5.82	5.63	0.04	0.06
SCR-05
Surface	58.50	0.19	13.81	3.31	0.05	0.72	10.42	2.77	0.55	1.22	0.44
Host rock	67.89	0.30	15.96	1.97	0.02	0.59	1.69	5.26	5.21	0.17	0.12
*Iron-rich alteration*
SCR-07
Surface	40.97	0.39	14.27	21.19	0.15	1.22	5.22	1.96	0.57	7.47	0.82
Host rock	68.09	0.15	17.23	1.34	0.02	0.40	1.21	5.32	5.64	0.10	0.08
*Weak alteration*
FST-07
Surface	66.20	0.13	17.71	2.99	0.12	0.33	3.73	5.07	0.91	0.72	0.65
Host rock	69.08	0.06	16.46	0.84	0.01	0.12	2.01	5.20	4.33	0.07	0.11
*Gypsum-rich alteration*
FST-05
Surface	5.44	0.01	0.41	0.11	0.00	0.17	66.07	1.34	0.12	0.58	24.87
Host rock	70.62	0.23	14.93	1.29	0.01	0.32	1.05	4.01	6.32	0.03	0.19
Average composition of Euganean trachyte^a	66.02	0.66	16.77	3.26	0.06	0.66	1.42	5.04	5.35	0.21	0.01

The samples are divided by different types of alteration and sampling location as in Fig. 2 (SCR, Bastione Santa Croce; GAR, Torrione dell’Arena; CSN, Bastione Castelnuovo; FST, Torrione Venier)
^a Bulk-rock chemical composition determined by X-ray fluorescence and averaged among 86 fresh trachyte samples collected on the Euganean Hills in 40 different quarries and outcrops [32]