DATA REPOSITORY DR009071 Duggen et al. SAMPLES AND ANALYTICAL METHODS Lavas were collected from a ca. 10 km by 100 km volcanic field consisting of numerous north-south trending Miocene and volcanic centres and lava flows. For geochemical analyses 0.1-1 cm diameter whole-rock chips were treated ultrasonically with de-ionised water. The dried chips were hand-picked using a binocular and then pulverised in an agate mill. Major and an array of trace elements as indicated in Table 1 were determined from fused tablets using a Philips X unique PW 1480 X-ray fluorescence spectrometer (XRF) at the IFM-GEOMAR in Kiel. International reference standards JB-, JB-3 (basalts), JA-, JA-3 (andesites), JR-, JR-3 (rhyolites), JG-, GM (granites) and JF-1 (feldspar) were analysed with the samples in order to evaluate the precision and accuracy of the measurements. H O and CO were measured photometrically with a Rosemont Infrared Photometer CSA 5003. Additional trace element concentrations were analysed by means of inductively coupled plasma-mass spectrometry (ICP-MS) at the Institute of Geosciences, University of Bremen, using a ThermoFinnigan Element. Sample powders were pressure digested in a MLS Ethos microwave with a mixture of pure HF and HNO 3 at 10 C. About 50 mg of sample was processed and the analyte solution was spiked with 1 ng/ml indium as internal standard; the final dilution was 1:5000 corresponding to 0. mg/ml of total dissolved solid. In order to avoid mass interferences, the REE and Hf were measured at high resolution (10,000), the transition metals at medium (4,000) and all other elements at low (300) resolution. Based on repeated analyses of standard reference materials the external precision is better than 5% for most elements, and is better than 7% for duplicate digestions of 1
samples. The accuracy of USGS standards BHVO- and BCR-, analysed along with the samples, is better than 10% except for Cs, Cr and Cu (up to 15%) with respect to the USGS reference values. The ICP-MS data is reported in Table 1. Sr-Nd isotope analyses of lavas were performed at Royal Holloway University of London (RHUL) using the clean laboratory facilities and the VG354 mass spectrometer (TIMS) of the Department of Geology. Powders were dissolved in polytetraflouroethylene (PTFE) Savillex beakers with a concentrated mixture of destilled HNO 3 and HF on a hotplate at ca. 130 ºC. For Sr-isotope analysis the powders were leached prior to digestion in the Savillex beakers with 6 M HCl on the hotplate for about 1 hour. After dissolution and conversion to nitrate, Sr was extracted and purified with two passes through small pipette-tip size columns loaded with Eichrom Sr-Spec resin. Light rare earth elements were separated from matrix elements on small columns filled with ~50 mg of TRU-Spec resin. Nd was then separated from the other rare earth elements by two passes on anion exchange columns. Sr was loaded on single Re filaments using a TaF 5 sandwich-loading technique and run multi-dynamically on the TIMS. Nd was loaded on single Refilaments with silica gel and dilute H 3 PO 4 and run multi-dynamically as NdO +. Details about the analytical procedures are reported in the literature (Thirlwall, 1991a, b). Long-term means of standards are 0.71050 ±14 ( s.d.) for 87 Sr/ 86 Sr (SRM 987 standard, n=0) and 0.511414 ±7 (Aldrich standard, n=86) for 143 Nd/ 144 Nd. The Sr- Nd isotope data of the Middle Atlas lavas along with internal errors ( s.e.) are reported in Table. Pb-isotope analyses were performed in clean laboratories at the Leibniz Institute of Marine Sciences, IFM-GEOMAR, in Kiel, using a MAT6 RPQ + TIMS. Prior to digestion handpicked 0.5-1 mm matrix chips were leached with hot ultrapure
6 M HCl or M HCl (samples ATL010400-6B and 9), rinsed with water and then digested with a mixture of ultrapure HF and HNO 3. Pb was separated and purified by two passes on the AG1-X8 anion resin, loaded on Re filaments with silica gel and run in static multicollection on the TIMS. The long-term reproducibility as determined from repeated measurements of NBS 981 (N=1) is 06 Pb/ 04 Pb = 16.898 ±0.007, 07 Pb/ 04 Pb = 15.436 ±0.009, 08 Pb/ 04 Pb = 36.53 ±0.07 and are corrected to the NBS 981 values given in (Todt et al., 1996). Total chemistry blanks were <100 pg for Pb and thus considered negligible. REFERENCES Thirlwall, M.F., 1991a, High-precision multicollector isotopic analysis of low levels of Nd as oxide: Chemical Geology (Isotope Science Section), v. 94, p. 13-., 1991b, Long-term reproducibility of multicollector Sr and Nd isotope ratio analyses: Chemical Geology (Isotope Science Section), v. 94, p. 85-104. Todt, W., Cliff, R.A., Hanser, A., and Hofmann, A.W., 1996, Evaluation of a 0 Pb- 05 Pb double spike for high precision lead isotope analyses, in Basu, A., and Hart, S., eds., Earth Processes: Reading the Isotopic Code, Volume 95: Washington D.C., Geophys. Monogr. Ser., AGU, p. 49-437. 3
Table DR1: Major and trace element data of Middle Atlas lavas and igneous rock standards Sample no. ATL010400-6B duplatl010400-6batl010400-9atl010400-5aatl010400-10eatl010400-8 (a?)atl010400-7 Location Ain Kahla area Ain Kahla areaain Kahla areaain Kahla area Bekrit village Ain Kahla area Ain Kahla area Rock type basanite basanite basanite picrite? basanite basanite basanite lava flow lava flow lava flow cobble cobble boulder lava flow Major elements in weight % measured by XRF SiO 38.3 38.4 38.4 38.4 38.6 39.4 41.4 MgO 13.5 13.5 13.5 14. 1.9 11.1 11.9 Al O 3 11.0 11.0 11.0 11.0 11.6 1.6 13.3 MnO 0.1 0.1 0.3 0.1 0.1 0. 0.0 Na O 4.48 4.48 3. 1.43 3.1 3.94 3.31 CaO 15.5 15.4 15.9 17.8 15.8 15.6 14.0 TiO.73.73.80.80.88.84.95 P O 5 1.90 1.9.13 1.96 1.78 1.67 1.39 K O 1.4 1.3 1.45 0.30 1.71 1.36 0.38 FeO total 11.1 11. 11.4 11.7 11.0 10.9 10.8 CO 0.00 0.05 0.07 0.14 0.04 0.09 0.35 H O 1.44 1.44 1.76 3.34 0.8 0.7 3.08 Sum 101.4 101.5 101.8 103.3 100.5 100.3 103.0 Trace elements in parts per million (ppm) determined by XRF (*) and ICP-MS (#) Li * 7.01 8.99 7.18 Sc * 1.8 5.9 8.0 V # 60 63 77 59 85 90 300 Cr # 586 604 436 4 5 41 357 Co # 60.0 59.0 57.0 63.0 55.0 53.0 55.0 Ni # 96 309 364 95 06 148 09 Cu * 8.0 64.9 48.4 Zn # 93.0 88.0 89.0 9.0 79.0 86.0 8.0 Ga # 14.0 14.0 16.0 13.0 13.0 14.0 13.0 Rb # 40.0 39.0 43.0 15.0 45.0 39.0 17.0 Sr # 1595 160 363 081 164 1477 1477 Y # 4. 38.5 6.3 Zr # 363 370 38 363 308 349 97 Nb * 140 13 138 Cs * 1.13 0.65 0.87 Ba # 987 943 144 953 1085 98 891 La * 117 35 105 Ce * 16 397 196 Pr *.4 37.6 0.0 Nd * 81.5 18 73.
Ta * 8.55 13.1 8.14 Tl * 0.1 0.11 0.10 Pb * 4.55 6.7 4.36 Th * 14.6 40.9 1.1 U * 3.88 9.31 3.30 Dy/Yb 3.08.93.75 Zr/Hf 55.1 47. 47.8
Table 1 continued. Table 1 continued. Sample no. ATL300300-1 ATL010400-6A ATL310300-4 ATL310300- ATL010400-8c ATL300300-d Sample no. Location Jebel Habri Ain Kahla area Ben Said Talialite, south Ain Kahla area Jebel Hebri Location Rock type basanite basanite basanite, essent. clas basanite with mantle basanite basanite Rock type scoria agglutinate con lava flow from scoria cone xenolith from lava flow boulder huge bomb (50 cm) b Major elements in weight % measured by XRF SiO 41.5 41.6 4.0 4. 4.5 4.8 SiO MgO 11. 10.1 11.3 14.5 8.7 1.6 MgO AL O 3 1.6 1.3 1.5 11.6 1.7 1.5 AL O 3 MnO 0.0 0.3 0.0 0.19 0. 0.19 MnO Na O 3.18 5.13 3.13 3.1 6.10 3.47 Na O CaO 1.9 1.0 1.6 11.1 11.5 11.3 CaO TiO 3.1 3.33.98.77.86.6 TiO P O 5 1.17 1.3 1.18 1.05 1.4 1.08 P O 5 K O 1.83 1.80 1.56 1.67 1.54 1.59 K O FeO total 11.9 1.3 1.1 11.4 11.8 11.4 FeO total CO 0.04 0.0 0.06 0.0 0.05 0.0 CO H O 1.90 0.4 1.45 0.0 0.69 0.53 H O Sum 101.6 100.4 101.1 99.8 100.0 100.1 Sum Major elements in we Trace elements in parts per million (ppm) determined by XRF (*) and ICP-MS (#) Trace elements in par Li * 6.4 6.83 8.89 8.6 Li * Sc * 0.3 19.1 4.8 3.6 Sc * V # 60 58 44 34 8 4 V # Cr # 308 353 86 604 5 453 Cr # Co # 56.0 55.0 56.0 57.0 54.0 56.0 Co # Ni # 173 167 03 37 19 69 Ni # Cu * 30.1 33.5 37.8 39.5 Cu * Zn # 115.0 134.0 114.0 107.0 141.0 107.0 Zn # Ga # 16.0 16.0 17.0 13.0 18.0 17.0 Ga # Rb # 48.0 65.0 44.0 5.0 44.0 48.0 Rb # Sr # 119 146 1164 1149 1519 116 Sr # Y # 3. 1.9 6.6 5.9 Y # Zr # 31 445 78 36 407 40 Zr # Nb * 93.6 8.9 109 98.6 Nb * Cs * 0.61 0.57 0.84 0.7 Cs * Ba # 744 805 669 694 979 714 Ba # La * 79.6 69.4 86.9 81.7 La * Ce * 147 133 160 155 Ce * Pr * 15.7 14.4 17. 16.4 Pr * Nd * 6. 54.4 63.1 61.7 Nd *
Ta * 5.81 4.86 6.63 5.5 Ta * Tl * 0.11 0.14 0.17 0.13 Tl * Pb * 3.33.98 3.99 3.44 Pb * Th * 9.75 7.99 10.6 9.5 Th * U *.84 3.0 4.10 3.19 U * Dy/Yb 3.33.93 3.09 3.17 Dy/Yb Zr/Hf 48.9 49.8 40.0 Zr/Hf
Table 1 continued. ATL300300-e ATL010400-11 ATL300300-3a ATL010400-3 ATL310300-1 ATL010400-1 Sample no. ATL010400- Jebel Hebri Bekrit area Gouffre S of J. Hebri 1km W of J. Hebri Talialite, northoutgui NE of El HaiebLocation Azrou, N entrance basanite basanite basanite basanite with mantle alkali basalt alkali basalt Rock type alkali basalt bomb or dike fragmen lava flow lava flow xenoliths from lava flow lava flow lava flow lava flow weight % measured by XRF Major elements in weight % measured 43.4 43.6 43.6 44.6 45.7 48.1 SiO 48.9 11.9 11.6 1.7 1.4 10.8 9.6 MgO 9. 1.9 13.0 1.3 1.4 13.6 14.0 AL O 3 14.0 0.18 0.18 0.19 0.18 0.17 0.17 MnO 0.16 3.5 3.00 3.0 3.07.79.85 Na O.9 11.4 11.6 10.9 10.7 10.8 10.1 CaO 9.9.67.78.83.69.53.31 TiO.9 1.01 0.85 0.80 0.74 0.69 0.6 P O 5 0.59 1.41 1.6 1.31 1.4 1.46 1.19 K O 1.05 11.5 11.4 11.8 11.5 11.1 10.6 FeO total 10.6 0.0 0.01 0.03 0.00 0.0 0.0 CO 0.00 0.57 0.47 0.35 0.6 0.44 0.3 H O 0.0 100. 100.1 100.0 99.9 100.1 100.0 Sum 99.8 arts per million (ppm) determined by XRF (*) and ICP-MS (#) Trace elements in parts per million (ppm 8.37 8.53 7.98 1.00 7.96 Li * 1.00.8 3.5 3.3 4.9 19.5 Sc * 3.0 5 4 35 9 5 08 V # 05 393 380 51 555 400 337 Cr # 347 55.0 53.0 55.0 54.0 50.0 46.0 Co # 46.0 0 15 310 78 08 173 Ni # 161 37.9 43.9 43.6 4.6 33.1 Cu * 37.0 113.0 109.0 11.0 111.0 109.0 106.0 Zn # 105.0 17.0 19.0 17.0 17.0 15.0 16.0 Ga # 18.0 45.0 47.0 35.0 33.0 41.0 35.0 Rb # 7.0 196 1033 1058 937 918 788 Sr # 740 3.9 5.1.4 4.7 18.0 Y #.4 34 34 41 1 14 19 Zr # 180 78.8 104 86.5 73.7 59.9 Nb * 57.5 0.71 0.53 0.43 0.75 0.38 Cs * 0.43 700 603 553 464 530 396 Ba # 358 65. 70.6 66.8 55.3 40. La * 47.1 131 139 19 109 79.8 Ce * 91.9 14.4 15.6 14.5 1.4 8.9 Pr * 10.7 57.1 58. 55.3 50.0 35.5 Nd * 43.4
4.90 6.44 5.44 4.19 3.75 Ta * 3.31 0.1 0.13 0.17 0.17 0.14 Tl * 0.14 3.37 3.3 3.15 3.78.94 Pb *.90 8.6 7.5 7.30 6.17 4.71 Th * 4.68.08 3.4.73 1.71 1.89 U * 1.51 3.05 3..93 3.16.88 Dy/Yb.81 40.6 40.9 37.3 40.5 49. Zr/Hf 37.3
Table 1 continued. ATL300300-a TZ130400-1 BIR RGM MAG AGV Sample no. BCR- BCR- Jebel Hebri Oued Amlil quarry Location basalt from xenolithbasanite/hawaiite Standard Standard Standard Standard Rock type Standard Standard block in scoria cone lava flow d by XRF 50.0 45.5 9.1 10.6 14.1 13.4 0.15 0.0.86 3.65 9.1 10.1.31.35 0.50 1.03 0.97 1.53 10.6 11.5 0.04 0.01 1.16 0.17 100.9 100.1 pm) determined by XRF (*) and ICP-MS (#) Trace elements in parts per million (ppm) determined 10.44 3.09 61.4 81.8 11.1 Li * 10.1 9.0.7 41. 4.47 17.3 13.0 Sc * 36.3 3. 199 00 V # 335 38 Cr # 45.0 5.0 Co # 155 33 Ni # 40.6 107 9.70 6.5 48.3 Cu * 16.4 15.0 103.0 10.0 Zn # 0.0 18.0 Ga # 4.0 47.0 Rb # 616 1107 Sr # 8.8 Y # 173 44 Zr # 104 0.5 8.5 14.9 13.6 Nb * 1.7 11.8 0.71 0.01 10.79 9.38 1.8 Cs * 1.34 1.3 364 7 Ba # 86. 0.63 4.1 45.0 4.4 La * 9.7 7.4 150 1.99 50.9 95.6 79. Ce * 61.8 59.9 16.1 0.38 5.53 10.9 8.97 Pr * 7.59 7.07 58.8.54 0.6 41.4 33.6 Nd * 31.9 9.3
5.6 0.06 0.98 1.19 0.90 Ta * 0.91 0.87 0.16 0.14 1.10 0.9 0.39 Tl * 0.48 0.43 4.07.9 4.5 8.8 14. Pb * 10.9 11.5 9.7 0.03 17.3 13.9 7.8 Th * 7.0 6.90.7 0.01 6.36 3.10.14 U * 1.98 1.90.8 Dy/Yb 44.3 Zr/Hf
BCR- Standard BCR- Standard d by XRF (*) and ICP-MS (#) 9.5 9.91 33.7 35.5 15.9 17.0 11.8 1.5 1. 1.9 6.4 6.9 56.5 60.0 6.68 7.5 9.1 30.8
0.80 0.91 0.40 0.4 10.3 10.9 6.55 7.00 1.8 1.9
Table DR: Radiogenic isotope data of Middle Atlas lavas Sample no. Rock type 87 Sr/ 86 Sr s.e. 143 Nd/ 144 Nd s.e. 06 Pb/ 04 Pb s.e. 07 Pb/ 04 Pb s.e. 08 Pb/ 04 Pb s.e. ATL010400-1 alkali basalt 0.703484 10 0.51805 10 19.35 0.001 15.60 0.001 39.115 0.003 ATL010400-11 basanite 0.7035 10 0.51851 9 19.516 0.004 15.615 0.003 39.300 0.008 ATL010400- alkali basalt 0.703451 10 0.5180 8 19.408 0.00 15.619 0.001 39.14 0.004 ATL010400-3 basanite 0.70336 10 0.5184 8 19.660 0.00 15.615 0.00 39.36 0.004 ATL010400-6B basanite 0.703179 9 0.51853 9 19.964 0.0015 15.619 0.001 39.588 0.003 ATL010400-9 basanite 0.703108 8 0.51870 8 19.957 0.001 15.617 0.001 39.861 0.004 ATL300300-1 basanite 0.703169 10 0.51855 8 19.813 0.001 15.603 0.001 39.41 0.003 ATL300300-d basanite 0.703154 9 0.51870 9 19.714 0.004 15.603 0.004 39.349 0.009 ATL300300-3a basanite 0.70350 9 0.51839 8 19.770 0.00 15.603 0.00 39.380 0.005 ATL310300-1 alkali basalt 0.703487 10 0.51787 9 19.53 0.00 15.597 0.001 39.73 0.003 ATL310300- basanite 0.703176 1 0.51868 10 ATL310300-4 basanite 0.703195 10 0.51845 10 19.70 0.001 15.605 0.001 39.348 0.00 TZ130400-1 basanite/hawaiit 0.703144 10 0.51874 1 19.539 0.003 15.594 0.003 39.47 0.007