# Tholeiitic to calc-alkaline and alkaline volcanisms in an extensional arc setting of a Tethyan ophiolite: insights from small-scale compositional and temporal transitions from the Dali sector (Armenia)

Monique Seyler, Ghazar Galoyan, César Witt, Taniel Danelian

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Monique Seyler, Ghazar Galoyan, César Witt, Taniel Danelian. Tholeiitic to calc-alkaline and alkaline volcanisms in an extensional arc setting of a Tethyan ophiolite: insights from small-scale compositional and temporal transitions from the Dali sector (Armenia). Journal of Asian Earth Sciences, 2023, 241, pp.105478. 10.1016/j.jseaes.2022.105478. hal-04264562

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1 Tholeiitic to calc-alkaline and alkaline volcanisms in an extensional arc setting of a

2 Tethyan ophiolite: insights from small-scale compositional and temporal transitions

3 from the Dali sector (Armenia)

4 Monique Seyler¹, Ghazar Galoyan², César Witt¹, Taniel Danelian³

5 1 : Univ. Lille, CNRS, Univ. Littoral Côte d'Opale, UMR 8187, LOG, Laboratoire

6 d'Océanologie et de Géosciences, F-59000 Lille, France

7 2: Institute of Geological Sciences of the National Academy of Sciences of the Republic of

8 Armenia, 24A, Marshal Baghramyan Avenue, Yerevan 0019, Republic of Armenia

9 3: Univ. Lille, CNRS, UMR 8198- Evo-Eco-Paleo, F-59000 Lille, France

10

11 Corresponding author: monique.seyler@univ-lille.fr

12

13 Keywords: Tethyan ophiolite, Armenia, island-arc magmatism, enriched tholeiites, calc-

14 alkaline and alkaline lavas

15

16 Abstract

17

18 New field and petrographic observations, combined with whole rock and mineral geochemical

19 analyses are applied on volcanic rocks present in the Dali sector, east of Lake Sevan

20 (Armenia). A small-scale sampling of the volcanic sequence allows us to identify, for the first

21 time in Armenian ophiolites, two groups of lavas (groups B and C1) stratigraphically and
22 geochemically intermediate between previously recognized arc tholeiite (group A) and OIB-
23 like (group C2) basalts. Their age is constrained by two distinct intercalated radiolarite
24 sequences, which were dated as Tithonian – Valanginian. Group B lavas are low-K tholeiitic
25 basalts and basaltic andesites derived from an enriched mantle source (La/N/Yb_N 1.8–6.1;
26 Sm_N/Yb_N 1.3–2.4; Nb/Yb 2.0–6.7). The composition of their clinopyroxenes ranges from Ti-
27 poor augite to Ti-rich diopside augite in correlation with higher La/Yb and Nb/Yb ratios in
28 bulk rocks. Group C1 lavas are basaltic andesites containing Ti and Na-rich amphiboles
29 (kaersutites, hastingsites) as major mineral phases. Three analyzed diopside-amphibole-
30 porphyritic samples are alkaline trachybasalts (La/N/Yb_N 20–21; Nb/Yb 16–18). Both the
31 group B and C1 lavas exhibit variable, although moderate, enrichments in Th/Yb for given
32 Nb/Yb ratios and Nb negative anomalies in normalized multi-elements patterns (Nb/La 0.53–
33 1.02), which are not correlated with the degree of enrichment of their mantle sources. Our
34 results suggest that transitional and OIB-like volcanic lavas were generated by low- (group B)
35 and very low- (groups C1–C2) melting of a heterogeneous mantle source in an oceanic arc–
36 back-arc system in extension, possibly in relation with slab break-off.
37

37

38 1- Introduction

39

40 In the Lesser Caucasus, the Sevan-Hakari (Akera) ophiolite, along with the Amasia,
41 and Stepanavan ophiolitic units are organized along a ca. 400 km WNW-ESE oriented belt
42 that runs from Northern Armenia to Artsakh (Karabagh); they are part of a much larger
43 suture zone that continues westwards to Northern Turkey (Adamia et al., 1977, 1981, 2011;
44 Galoyan, 2008; Rolland et al., 2020; Sosson et al., 2016). These ophiolitic units represent
45 the suture zone that resulted from the closure of the Tethys oceanic realm between
Eurasia and the South-Armenian block (SAB), a micro-continent that was detached from Gondwana during the Late Paleozoic – Early Mesozoic time (Barrier and Vrielynck, 2008; Kazmin et al., 1987; Knipper and Khain, 1980). Together with the Vedi ophiolite (Aslanyan and Satian, 1977; Knipper and Khain, 1980; Sokolov, 1977), a folded klippe unit located at the south-east of Yerevan, They represent key oceanic remnant areas of the Alpine-Himalayan mountain belt. Since the Early Mesozoic to the final Paleocene collisional stage, the oceanic Tethyan realm was featured by a system of island arcs, intra-arc rifts and back-arc basins (e.g., Adamia et al., 2011). Knowledge of the age and type of the various preserved magmatic units is thus fundamental for identifying the tectonic setting of the different units and for reconstructing the complex geodynamic evolution of the Tethyan ophiolites in the region.

Remnants of the Mesozoic Tethyan oceanic crust, preserved in the Armenian ophiolites, comprise Upper Triassic – Jurassic mafic–ultramafic cumulates (Bogdanovski et al., 1992; Galoyan et al., 2009; Zakariadze et al., 1990) and lava flows associated with Middle Jurassic (Bajocian) to Mid Cretaceous (Cenomanian) radiolarites (Asatryan, 2009; Asatryan et al., 2010, 2011, 2012; Danelian et al., 2007, 2008, 2010, 2012, 2014, 2016, 2017; Galoyan et al., 2007; Knipper, 1980; Vishnevskaya, 1995; Zakariadze et al., 1983). It is since the 1980s (Zakariadze et al., 1983, 1988) that two geochemically distinct lava sequences have been recognized in the Sevan-Akera ophiolites, and later in the Stepanavan and Vedi ophiolites (Galoyan et al., 2007; Rolland et al., 2009b): a tholeiitic lava sequence of MORB-like affinity modified by subduction components and an alkaline lava sequence of OIB-like affinity. For Galoyan et al. (2007, 2009), Hässig et al. (2013a, 2013b), Rolland et al. (2009b, 2010, 2020) and Sosson et al. (2010) the bulk of the plutonic rocks and tholeiitic lavas were formed during the Early to Middle Jurassic through oceanic spreading in a back-arc basin, while alkaline rocks were emplaced on top of tholeiitic extrusives; nevertheless, it is worth
noting that the spatial relations between tholeiitic and alkaline lavas were not clearly established. Younger emplacement of the alkaline series appears to be supported by the $^{40}$Ar/$^{39}$Ar dating of a kaersutite amphibole from a single OIB-type alkaline lava present in the Vedi ophiolite that yielded a ca. 117 Ma (Aptian) age (Rolland et al., 2009b). These authors regarded the alkaline lavas as unrelated to subduction but remnants of an oceanic plateau or seamount generated by an intra-oceanic mantle plume that facilitated the obduction of the ophiolites some time during the Late Cenomanian–Turonian interval (Sosson et al., 2010).

In contrast, geochemical and paleontological data from Tethyan ophiolites in the Izmir–Ankara–Erzincan Suture Zone (IAESZ), which represents the western continuation of the Armenian ophiolites in NE Anatolia, show that Middle Jurassic–Cretaceous ophiolitic units were developed in an incipient intra-oceanic arc–forearc setting (e.g., Okay et al., 2022; Parlak et al., 2012, 2020), whereas blocks of Jurassic–Cretaceous arc-related plutonic and volcanic rocks coexist with blocks of Middle–Upper Triassic and Cretaceous alkaline seamounts in several IAESZ ophiolitic mélanges (Parlak et al., 2012; Robertson et al., 2013; Sarifakioglu et al., 2017). Cretaceous OIB-like lavas are locally associated with E- and P-MORB-type lavas in several Tethyan ophiolites, including Iran (Barbero et al., 2021; Ghazi and Hassanipak, 1999; Maghdour-Mashour et al., 2021; Monsef et al., 2019) and Turkey (Sarifakioglu et al., 2017; Tankut et al., 1998). They are generally interpreted as remnants of plume-related volcanism emplaced in a within-plate oceanic setting (e.g. Barbero et al., 2021; Galoyan, 2008; Ghazi and Hassanipak, 1999; Rolland et al., 2009). However, alkaline rocks compositionally similar to plume-derived OIB lavas are also found in modern oceanic and continental subduction zones (Aragon et al., 2013; Castillo et al., 2007; Gill, 1984; Lin et al., 1990; Sajona et al., 1994; Sorbadere et al., 2013a), where they are often referenced as Nb-enriched basalts (NEB; Hastie et al., 2011) and High-Nb basalts (HNB; Reagan and Gill, 1989). In Iran, Cretaceous alkaline volcanism has been shown to be in relation with late-stage
subduction processes, prior to and during obduction onto the continental margin (Maghdour-Mashour et al., 2021; Monsef et al., 2019). In the Armenian ophiolites, spatial and temporal relationships between subduction-related tholeiites and alkaline lavas are not well known, preventing thus discussion of petrogenetic/geodynamic relations.

This study focuses on the Dali sector (Fig. 1), a valley in the northeast of Lake Sevan, which is thought to be of utmost interest for the understanding of the geological evolution of Armenian ophiolites, as: (1) it exposes a relatively thick sequence of volcanic rocks in which preliminary observations report the presence of both tholeiitic and alkaline extrusives (Asatryan et al., 2012; Galoyan, 2008; Galoyan et al., 2009); (2) it includes at least two distinct levels of dated radiolarites that allow us to constrain the age of the associated lavas (Asatryan et al., 2012); (3) the above mentioned volcanic sequence overlies a dioritic-trondhjemitic complex. In this study the volcanic sequence was sampled very closely in order to characterize small-scale compositional variations in a restricted area of the Dali sector. We undertook petrographic and geochemical studies of whole rocks and *in situ* mineral major and trace element chemistry with the aim to (i) establish their magmatic affinities and origin(s), (ii) discuss their possible petrogenetic relations and (iii) suggest a revised model for the transition from tholeiitic to alkaline volcanism and for the origin of the latter volcanism recorded in Armenian ophiolites

114

## 2- Geological setting

116

Earlier studies, conducted at the time of the Soviet Union, set up the major structural and geodynamic outline of the Lesser Caucasus (e.g., Adamia et al., 1981; Abovyan, 1981; Knipper, 1975; Knipper et al., 1986; Knipper and Khain, 1980; Knipper and Sokolov, 1977;
Sokolov, 1977; Zakariadze et al., 1983, 1986, 1990). They established the first petrographic and geochemical data and radiometric ages, which conclude to the coexistence of crustal oceanic rocks of different magmatic affinities that were generated during the Late Triassic to Early Cretaceous both in subduction and within-plate tectonic settings (e.g., Bogdanovski et al., 1992; Ghazaryan, 1994; Knipper et al., 1997; Tsameryan et al., 1988; Zakariadze et al., 1983, 1988, 1990). Later studies provided new structural, petrological and radiometric age data on the Armenian ophiolitic rocks (Galoyan, 2008; Galoyan et al., 2007, 2009; Hässig et al., 2013a; Rolland et al., 2009b, 2010; Sosson et al., 2010) and new paleontological datings from radiolarites associated with the volcanic rocks (Asatryan, 2009; Asatryan et al., 2010, 2011, 2012; Danelian et al., 2007, 2008, 2010, 2012, 2014, 2016, 2017; Vishnevskaya, 1995). Results showed that the four ophiolitic units (Sevan-Hakari, Stepanavan, Amasia and Vedi) are coeval and exhibit similar geological, lithological, and geochemical characteristics, which all argue for their obduction as a single large ophiolite nappe over the SAB some time during the Late Cenomanian (?), Turonian-Coniacian interval (Danelian et al., 2014; Sosson et al., 2010). The ophiolitic outcrops display serpentinized ultramafic rocks locally including chromite pods, a plutonic component dominated by gabbroic rocks and a volcano-sedimentary cover. The sheeted dyke complex is reduced to a few dolerites crosscutting the gabbros and sometimes the upper units, as well as the volcano-sedimentary cover; it forms discontinuous outcrops overlying indifferently the serpentinites or gabbro-dioritic rocks. Contacts between the plutonic and volcanic rocks and within the volcano-sedimentary exposures are generally tectonic (thrust slices) and related to the compressive tectonic regime during the collision. However, undeformed (stratigraphic) contacts have been preserved locally. They expose rodingitic gabbros, ophicalcites and serpentinized peridotites affected by post-serpentinization hydrothermalism (occurrence of listwanite), which crop out below sedimentary breccias containing basalt, gabbro and peridotite clasts (Melikyan et al., 1967;
145 Zakariadze et al., 1983) and are locally covered by red radiolarites. These features are
146 interpreted as evidence for exhumation and long-time-span alteration at seafloor level of the
147 ultramafic and mafic plutonic rocks (Galoyan, 2008).

148 The plutonic rocks display a complete magmatic differentiation trend evolving from
149 ultramafics (wehrlites, websterites) through cumulate-banded olivine gabbros and norites,
150 anorthosites, amphibole- gabbros and gabbronorites to gabbroic diorites, diorites and quartz
diorites; locally plagiogranites intrude the gabbros and diorites through ductile extensional
152 shear zones (Galoyan et al., 2007, 2009). Seven radiometric ages exist on gabbros,
153 gabbronorites, and norites of the Sevan, Vedi and Amasia ophiolite units (Bogdanovski et al.,
154 1992; Galoyan et al., 2009; Hässig et al. 2013a; Rolland et al., 2010; Zakariadze et al. 1990);
155 the obtained ages correspond to the Toarcian–Bathonian/Early Callovian interval according to
156 the time scale of Gradstein et al. (2020). Zoblin and Zakariadze (1993) distinguished two
157 plutonic series, one showing tholeiitic composition and another with boninitic affinity
dominated by diorites; both series are thought to have been generated above an intra-oceanic
158 subduction zone within the Neotethys ocean. Later work confirms generation of the plutonics
159 from a depleted mantle source contaminated by a subduction component (Galoyan et al.,
160 2009; Hässig et al., 2013b; Rolland et al., 2009b).

162 The volcanic rocks are basaltic and basaltic andesitic pillow-lava flows, pillow-breccia
163 and massive flows associated with sedimentary rocks mainly composed of radiolarites. In the
164 Sevan-Hakari ophiolite, Tsameryan et al. (1988) and Zakariadze et al. (1983, 1986) described
165 an Upper Jurassic–Lower Cretaceous (Oxfordian–Barremian) unit made of alternations of
166 MORB-like, Ti-rich tholeiitic and alkaline lavas, and a Mid - Upper Cretaceous (Albian–
167 Cenomanian–early Coniacian?) upper unit composed of arc-related tholeiitic basalts and
168 basaltic andesites lying directly on the gabbros and diorites, and a tholeiitic–alkaline sequence
169 similar to the lower unit. However, the geodynamic setting of these different units has been a
170 matter of debate. For Zakariadze et al. (1983) they were all emplaced in an intra-continental
171 marginal basin or an oceanic basin that was situated close to the continental margin, while
172 Tsameryan et al. (1988) suggested three distinct settings: a marginal basin in which MORB-
173 type lava were formed during oceanic rigting setting and within-plate magmatism for the
174 alkaline and Ti-rich tholeiites, and an island arc setting for the Upper Cretaceous tholeiites
175 and boninites. Later, based on a close analysis of Zakariadze et al. (1983)'s geological cross-
176 sections, Galoyan et al. (2009) and Sosson et al. (2010) observed that alkaline and tholeiitic
177 lavas are not interlayered but tectonically separated by levels of serpentinite and they
178 interpreted them as tectonic nappe stacks.

179 New analyses of volcanic rocks within the Armenian ophiolites (Galoyan, 2008;
180 Galoyan et al., 2007, 2009; Ghazaryan, 2007; Hässig et al., 2013b; Rolland et al., 2009b,
181 2010) led to the recognition of two major compositional groups: (1) tholeiitic (MORB-type)
182 basalts and basaltic andesites variably contaminated by subduction components, including one
183 sample from the Dali sector; (2) alkaline pillow lavas, mainly basanites and trachybasalts,
184 with OIB-like compositions, which crop out in different locations throughout the Armenian-
185 Anatolian ophiolitic belt. Both types of lavas may be found to overly radiolarites that cover
186 hydrothermalized ultramafic-mafic plutonic rocks or to be intercalated with radiolarites. A
187 third magmatic group is represented by calc-alkaline basalts and basaltic andesites which lie
188 unconformably over Upper Cretaceous limestones; this has been observed only in the
189 Stepanavan ophiolite.

190 Radiolaria extracted from sedimentary rocks commonly associated with lava flows
191 and volcaniclastic material brought important constraints on the timing and environmental
192 setting of the different magmatic events. Radiolarian datings suggest episodic or continued
193 volcanic activity since the Middle Jurassic (Bajocian/Bathonian) to the Mid Cretaceous (e.g.,
194 Cenomanian; Danelian et al., 2012, 2014, 2016 and references therein). Whereas the crustal
rocks that were formed during the Late Triassic-Early Jurassic phases have marked island-arc affinity in coherence with radiometric datings and compositions of the plutonic rocks (Zakariadze et al., 1990; Zlobin and Zakariadze, 1985, 1993), the tectonic setting for the tholeiitic and alkaline extrusives that erupted during Middle Jurassic to Early Cretaceous is not consensual: the various authors either suggest a marginal basin, or a within-plate or island arc setting (Ghazaryan, 1994, 2007; Tsameryan et al., 1988, 1991; Zakariadze et al., 1983, 1986). In contrast, volcanic rocks that are closely associated with Valanginian to Aptian radiolarites in the Vedi and Stepanavan ophiolites belong to the alkaline series (Galoyan et al., 2007; Rolland et al., 2010), which is in good agreement with the $^{40}$Ar/$^{39}$Ar Aptian age (117.33 ± 0.9 Ma) obtained on amphiboles from a lava sample coming from the Vedi ophiolite (Rolland et al., 2009b), as well as other radiometric K-Ar datings (120 to 95 ± 20 Ma) of alkaline lavas from the same area (e.g., Baghdasaryan et al., 1988; Satian and Sarkisyan, 2006). Based on the available geochemical and isotopic compositions, tholeiitic lavas are thought to have been formed during oceanic spreading in a marginal or back-arc basin (Galoyan, 2008; Galoyan et al., 2009; Rolland et al., 2010; Sosson et al., 2010). Alkaline OIB-like volcanism was interpreted as intra-continental rifting (Satian et al., 2005) or as mantle plume-derived intra-oceanic magmatism (Galoyan et al., 2007, 2009; Hässig et al., 2013b; Rolland et al., 2010; Sosson et al., 2010), in both cases unrelated to a subduction setting.

The calc-alkaline series cropping out in the Stepanavan ophiolite are not dated; they are ascribed to the development of a Late Cretaceous intra-oceanic arc in the Tethys ocean (Galoyan et al., 2007). Indeed, geodynamic models (Hässig et al., 2013a; Rolland et al., 2010; Sosson et al., 2010) support the "presence" of a north-dipping intra-oceanic subduction zone, with a back-arc domain between the arc and the Eurasian margin, in addition to another
219 (main) north-dipping subduction zone beneath the active Eurasian margin, although
220 petrographic evidence for intra-oceanic volcanic arc is missing.

221

222 **3- Methods and analytical techniques**

223

224 The samples were first studied with optical and scanning electron microscopes;
225 mineral species were identified with an energy dispersive spectrometer (EDS). Fifteen Dali
226 volcanic rocks were selected for bulk analyses. Major and trace elements were acquired at
227 CRPG (Nancy, France) using inductively coupled plasma optical emission spectroscopy (ICP-
228 AES) for major elements and inductively coupled plasma mass spectrometry (ICP-MS) for
229 trace elements (see procedures in Carignan et al., 2001). The basaltic standard BR was
230 recurrently measured, and the estimated accuracy was ~1 % for major elements, 5 % for TiO2
231 and MnO, 10 % for P2O5, 15 % for U and between 5 and 10 % for other trace elements. Relict
232 igneous minerals in a selection of samples, including all the samples analyzed for whole rock,
233 were analyzed with a CAMECA SX100 electron microprobe with 4 wavelength-dispersive
234 spectrometers at the Ecole Nationale Supérieure de Chimie of Lille University. Operating
235 conditions were 15 keV for accelerating voltage and probe current of 20 nA, with a counting
236 time of 20 seconds for most major elements. Sodium was counted for 30 seconds. Beam size
237 was 2 µm. The oxide-ZAF correction procedure was applied for ten elements (Si, Ti, Al, Cr,
238 Fe, Mn, Mg, Ca, Na and K). Detection limits are within 0.01-0.03 wt.%. A subset of
239 clinopyroxenes and amphiboles were analyzed by secondary ion microprobe spectrometry
240 (SIMS) with a Cameca IMS5f at the University of Montpellier. Nine rare earth elements
241 ($^{139}$La, $^{140}$Ce, $^{143}$Nd, $^{147}$Sm, $^{151}$Eu, $^{160}$Gd, $^{159}$Tb, $^{163}$Dy, $^{165}$Ho, $^{167}$Er and $^{174}$Yb) were measured
242 in all sessions. Each spot was measured using 10 cycles with counting times of 40 seconds.
Concentrations were calibrated against the SRM NIST 610 glass using the values given by
Rocholl (1997). Repeated analyses show a precision of 5% (1 sigma).³⁰Si were used as an
internal standard to correct for differences between standard and samples, based on the EMP
analyses. The effects of most molecular interferences were eliminated following the energy
filtering technique described in Shimizu et al. (1978). Corrections and treatment of analytical
results follow the procedures described in Bottazzi et al. (1994), Fahey (1998), Plà Cid et al.
(2005) and Zinner and Crozaz (1986). Taking into account all the sources of uncertainty, the
overall accuracy is ~10% for each oxide/element ratio.

251

252 **4- Results**

253

254 **4.1- Field observations**

The sector of study is situated north-east of the Lake Sevan, about 4 km north-west of
the village Jil (Fig. 1). Here, the roughly N-S oriented Dali valley cuts across a plutonic body
that is unconformably overlain by volcanic rocks intercalated by two distinct radiolarite
sequences, each one a few meters thick. The sector has been described in detail in several
publications (Asatryan et al., 2012; Galoyan et al. 2009) and only some aspects relevant to
this study will be further addressed here.

The plutonic rocks vary largely in structure and texture, grain size and mineral
proportion. The massif is mainly composed of banded gabbrodioritic cumulates, diorites,
quartz-diorites and trondhjemites that contain scarce layers of quartz-bearing norites and
lenses of fine-grained diorites that are elongated parallel to the banding. The diorite also
displays an igneous foliation defined by flux-oriented amphibole and plagioclase crystals. On
266 the whole the banding and igneous foliation strike N10°E-N85°E. A sample of fine-grained
diorite (DA3) was taken for a geochemical analysis.
267

268 The rocks forming the western flank of the Dali valley may be divided into two
269 lithotectonic units (Fig. 2). Unit 1 corresponds to the western part of the plutonic massif,
270 intruded by a network of extensional veins, dikelets and other irregular forms of
271 plagiogranite, forming in places mingling structures; the plutonic massif is overlain by dark
green-grey, pillow and massive lava flows, herein referenced as group A lavas. The contacts
272 between the extrusives and the diorite are locally underlined by thin layers or lenses of
273 epidosite (epidote ± quartz). Upward to the west and toward the northeast, both the plutonic
274 complex and group A volcanics occur as subvertical panels of a few meters in thickness,
275 exposing sliding surfaces; these structures are repeated several times and are interpreted as
276 tectonic intercalations limited by fault planes. Group A lavas are cut by calc-alkaline, silicic
277 dikes oriented N60°-65°E, attributed to the continental arc that was emplaced above the
278 ophiolite.
279

280 Unit 2 is represented by a ~100 m thick volcano-sedimentary sequence. It is separated
281 from the plutonic massif by a 20 cm-thick greenish-gray sheared zone running along a
~N130°E direction. The volcano-sedimentary sequence is itself unconformably overlain to the
282 south by a thick pile of Upper Cretaceous (Campanian-Maastrichtian?) pelagic limestones
283 containing reddish-brown transgressive sandstones and conglomerates at their base, dipping
284 ~45° to the south. The contact between the ensemble of the gabbrodiorite/trondhjemite massif
285 and the overlying volcanics is masked by vegetal cover and soil, but on its both sides the
286 rocks are strongly deformed. Just below the contact, the structures of the plutonic rocks are
287 highly disturbed with formation of gabbrodioritic breccia cemented by quartz and albite,
288 whereas the base of the volcanic sequence is sheared and disrupted by calcite-filled fractures
289 parallel to the contact. Above the contact, the lava flows are broadly oriented ~N130°-
290
291 N145°E, dipping SW, locally affected by minor strike faults. The lavas from this unit differ
292 from the group A lavas by the absence of hydrothermal epidotization and the frequency of
293 carbonate-filled microfractures and vesicles. Two superimposed groups of extrusives have
294 been distinguished in the unit 2 (Fig. 2). The lavas which crop out in the upper part contain
295 titanium-rich amphibole or kaersutite and have been interpreted in the past as being part of the
296 alkaline magmatic series described by Galoyan et al. (2009) and Rolland et al. (2010). In this
297 study, these lavas are referenced as group C lavas, while the volcanics forming the base of
298 this unit are referenced as group B lavas. The contacts between group B and C lavas were
299 observed in two locations; one of them is marked by a slope break, where topographically
300 elevated group C pillow lavas (sample DA7) overly an olivine-phyric lava flood (sample
301 MS5) belonging to group B, itself overlying a brecciated diorite. A second contact was
302 observed between group C amphibole-phyric pillow lavas (samples DA6, DA8) and a group
303 B volcanic breccia (sample DA13). Two major intercalations of radiolarites are located (i)
304 near the top of the group B lavas, and (ii) on the top of a group C basalt. They are both well-
305 dated as Late Tithonian to Late Valanginian and constrain the age of submarine volcanic
306 activity (Asatryan et al. 2012). The lower sedimentary unit consists of a ca. 3 m thick
307 sequence of radiolarites that include metric and fairly rounded blocks of oolithic limestones.
308 They crop out just below a ~1.5 m thick basaltic andesitic flow (sample G09-10) showing
309 columnar jointed structure, forming a sharp topography, while the base of the flow (sample
310 DA12) is intermingled with claystones. The upper sequence of radiolarian cherts is located
311 about 75 meters above the lower sequence. These cherts are up to 6 m thick and colored dark
312 red/pink. The contacts with both the underlying and overlying volcanic rocks are not clearly
313 visible in the field, but both rocks are alkaline basalts.

314 In order to have a representative sampling of the lavas of interest, our approach
315 involved sampling along a strike of all (fresh enough) lavas of Groups B and C cropping from
316 the base of the lithotectonic unit 2 up to the Valanginian radiolarite level (19 samples; Fig. 2).
317 Consequently, the entire sequence of group B lavas has been sampled, as well as the transition
318 from group B to group C lavas. Then, three group A lavas were sampled from the
319 lithotectonic unit 1, beneath the group B lavas.

320 Other two minor outcrops were also investigated. One of them is located on the
321 eastern flank of the valley, at the southern edge of the studied sector. Lavas assigned to
322 groups A and B are absent here, and group C magmatic breccias and pillow lavas (sample
323 MS11) rest on a thin sedimentary interval of siliceous claystones and chert lying
324 unconformably over plutonic rocks (Galoyan et al. 2009). At this location, the volcanic and
325 sedimentary rocks are not deformed although the diorite massif is slightly cataclastic. The
326 other outcrop is located at the northern edge of the studied sector, where, on both sides of the
327 valley, the plutonic massif is in contact on its northern side with group A lavas (samples
328 MS12, MS13, MS14). The contact is not clearly visible being covered by a few centimeters of
329 altered sediments, but the rocks show no deformation.

330

331 **4.2- Petrography**

332

333 The Dali volcanic rocks occur in various eruptive styles, mostly pillow lavas and
334 pillow breccia, rarely sheet flows or sills, and few magmatic breccias. Samples are variably
335 weathered and hydrothermally altered under static conditions leading to the replacement of
336 the igneous mineral phases and groundmass by low-temperature minerals, but primary
337 igneous textures are in general preserved. In most cases, altered primary igneous minerals can
338 still be identified by combining their morphological characteristics and the nature of the
339 alteration products. However, many outcrops are too extensively weathered and
340 hydrothermally altered to identify all the mineral species initially present in the primary

341 assemblages. The three major volcanic groups that were identified on the field (A, B and C,

342 from bottom to top) differ by their magmatic texture, relic igneous mineralogy and alteration

343 style.

344

345 4.2.1 Group A lavas

346

347 Group A lavas (Fig. 3a–c) are dark greenish gray colored basalts and basaltic

348 andesites. Samples are fine-grained, aphyric or sparsely phyric with sub-millimetric (0.5–

349 1mm) microphenocrysts of clinopyroxene, plagioclase and euhedral titanomagnetite.

350 Groundmass textures (<0.1-0.3 mm) are subophitic or intersertal, occasionally flow-oriented,

351 and consist of euhedral to subhedral clinopyroxene crystals, plagioclase, dendritic

352 titanomagnetite and apatite. Clinopyroxene are overgrown or even fully replaced by

353 amphibole. Subsequently, the mineral assemblages were affected by greenschist facies

354 alteration: pyroxenes and opaque minerals were partially replaced by chlorite and titanite,

355 plagioclases were fully albitized, and fibrous actinolite crystallized after hornblende.

356 Greenschist facies metamorphism is commonly overprinted by hydrothermal epidotization

357 and silicification, leading locally to the formation of granular patches and thin veins of

358 epidosites (epidote ± quartz) also filling vesicles; the latter are particularly abundant (0.3–2.5

359 mm; up to 15 vol.%) in sample MS13. No olivine or orthopyroxene was observed. Sulfide

360 grains (pyrite) are occasionally present. Group A lavas include the "ophiolitic lava" AR-03-17

361 previously analyzed by Galoyan et al. (2009).

362
363 4.2.2 Group B lavas

364

365 Group B volcanic rocks are distinguished from group A lavas by lacking late-stage
366 amphibolitization (hornblende) and epidotization. Pervasive alteration is typical of low-
367 temperature, sea-water alteration (albite, chlorite, titanite, and minor quartz and epidote,
368 rarely fibrous actinolite after clinopyroxene). Vesicles and amygdules (0.2–5 mm) filled with
369 calcite or chlorite, as well as thin calcite-filled cracks and joints are common. Several
370 petrographic types can be distinguished. (1) Most samples (DA5, DA10, DA11, AR-16-03 to
371 AR-16-06, AR-16-15) are dark gray basalts and basaltic andesites with aphyric to sparsely
372 microporphyritic textures (Fig. 3d,e). Where present, microphenocrysts (0.5–1 mm) consist of
373 clinopyroxene, fully albitized plagioclase commonly associated in clusters, and occasional,
374 euhedral–subhedral, grains of titanomagnetite. Groundmass textures vary from
375 hyalocrystalline to fine-grained (≤0.5 mm) intersertal and consist of plagioclase,
376 clinopyroxene, and accessory skeletal titanomagnetite and fluoroapatite. An interstitial phase
377 is altered to aggregates of chlorite ± carbonates. (2) Sample DA13 is a monomictic breccia
378 hosting angular basaltic andesite fragments cemented by sparry calcite. Mafic clasts display a
379 porphyritic texture and contain large (0–5 mm) calcite-filled amygdules and smaller chlorite-
380 filled vesicles. Phenocrysts consist of partially resorbed, up to 1.5 mm long, tabular laths of
381 plagioclase, and of 0.2–0.5 mm sized relicts of clinopyroxene crystals that have dismembered
382 and partially dissolved (Fig. 3f). Groundmass is fine-grained (0.2–0.3 mm), made of
383 clinopyroxene, plagioclase and skeletal titanomagnetite. (3) The two samples collected from
384 the lava flow above (G09-10) and partially embedded (DA12) in the lower level radiolarites
385 have similar texture and mineralogy. Texture is porphyritic, consisting of tabular (1–3 mm)
386 phenocrysts and microphenocrysts (0.5–1 mm) of plagioclase (Fig. 3g) often associated in
387 clusters; they include titanomagnetite grains, and are commonly rimmed by very fine-grained
aggregates of albite and chlorite. A second type of pheno- and microphenocrysts occur as scarce, completely opacified, losangic minerals identified as amphibole ghosts (Fig. 3h). The groundmass is intensively altered; fresher parts exhibit intersertal texture dominated by albitized plagioclase laths (~0.6 mm in length) enclosing smaller sized (<30–500 µm), subhedral crystals of clinopyroxene. Accessory minerals are acicular prisms of ilmenite, euhedral titanomagnetite, and needles of oxyfluoroapatite; they occur in the groundmass and as inclusions in plagioclase and pyroxene. In addition, grains of potassic feldspar crystals have been detected with the EDS. (4) Three samples (G08-10, MS5, AR-16-02) are porphyritic basalts characterized by fully altered phenocrysts that have been identified as olivine pseudomorphs on the basis of their shapes, alteration minerals (greenish-brownish clay minerals, iron-bearing calcite, quartz) and inclusions of Cr-spinel (Fig. 3i). The shape of the olivine pseudomorphs varies from elongated with euhedral tips and embayed flanks to anhedral and deeply resorbed grains. Their size (0.5–2 mm) and abundance are very variable, from ~1 to 8 vol.%. Groundmass consists of quenched plagioclase laths (0.2–0.6 mm long) and less abundant subhedral-anhedral microcrysts of clinopyroxene of ~0.5 mm in size; locally acicular crystals of clinopyroxene and plagioclase occur in bundles. Euhedral crystals of Cr-spinel and titanomagnetite, as well as fluoroapatite are also scattered through the rocks, although spinels are preferentially located close to resorbed olivine ghosts; all accessory mineral phases are occasionally enclosed in the silicates.

### 4.2.3 Group C lavas

Volcanic rocks containing titanium-enriched igneous amphibole have been classified in group C lavas. Two petrographic types have been distinguished: (i) in group C1 lavas
412 amphibole occurs as a major phase; these are clinopyroxene-amphibole-porphyritic
413 trachybasalts (samples DA6 to DA8) and kaersutite-bearing basaltic andesites (samples AR-
414 16-07 and AR-16-08), (ii) in group C2 lavas amphibole only occurs in groundmass; these are
415 clinopyroxene ± olivine-porphyritic basalts (samples MS6, G10-10, MS11). In all group C
416 lavas alteration is widespread, dominated by Fe-Mg carbonates replacing pyroxenes and
417 amphiboles, titanite replacing opaque minerals and largely albitized plagioclase. A few grains
418 of pyrite and Fe-Ni sulfides are also present. Other secondary minerals are chlorites and clay
419 minerals, and minor quartz and epidote. Vesicles (~0.8-3 mm) filled with calcite ± albite are
420 common.

421 Group C1 trachybasaltic samples vary in color from green to reddish brown. Samples
422 DA6 and DA8 represent, respectively, the border and the interior of a pillow lava flow. They
423 are porphyritic - glomerocrystic (~15 vol.% in sample DA7; Fig. 3j), with phenocrysts and
424 microphenocrysts of clinopyroxene and amphibole (Fig. 3k) and rare microphenocrysts of
425 plagioclase (<1 vol.%). Clinopyroxene commonly occurs as homogeneous, untwinned,
426 colorless crystals or as twinned and zoned crystals. Their cores are frequently resorbed and
427 overgrown by a thin corona of light brown clinopyroxene (Fig. 3l) or dark brown amphibole.
428 Amphibole phenocrysts and microphenocrysts vary in shape from stubby to elongated,
429 twinned crystals, partially replaced by a mixture of calcite and titanite, likely crystallized after
430 breakdown products of the amphibole (i.e., pyroxene + opaque minerals). Plagioclase
431 microphenocrysts exhibit albitized cores and sodi-potassic rims. Fine-grained (~0.1-0.5 mm)
432 groundmass assemblage is dominated by plagioclase laths, and less abundant and slightly
433 zoned microlites of pale brown clinopyroxene and dark brown amphibole. Skeletal
434 titanomagnetite (~5 vol.%) and needles of fluoroapatite are scattered throughout the rock, also
435 enclosed in the silicate phases. Interstices are filled by a felty mineral assemblage including
436 tiny (1-50 µm) microlites of albite, anorthoclase feldspar and dark brown amphibole.
437 Samples AR-16-07 and AR-16-08 are made of plagioclase, clinopyroxene and red-brown
438 amphibole (kaersutite), occurring in ~0.6-0.7 mm sized tabular crystals, in nearly equal
439 amounts in AR-16-08, or dominated by amphibole commonly surrounding clinopyroxene,
440 leaving resorbed clinopyroxene cores in AR-16-07. Minor phases include equant to cruciform
441 or dendritic titanomagnetite, blade-shaped ilmenite and fluoroapatite. An interstitial phase is
442 locally abundant, dominated by a network of fine laths of (quenched) feldspar (albite,
443 anorthoclase) and chlorite.

444 Group C2 sample G10-10 contains ~2-5 vol.% phenocrysts of clinopyroxene. They
445 occur as stubby crystals, isolated or associated in glomerules, with colorless, homogeneous
446 cores, generally overgrown by a contrasting, pale brown corona. In sample MS11
447 clinopyroxene phenocrysts and microphenocrysts (<5 vol.%) are characterized by complex
448 zoning (Fig. 3m); they coexist with phenocrysts of olivine, now completely replaced by
449 calcite, chalcedony and brown clay minerals, also enclosing coarse grains of Cr-spinel of 50-
450 150 µm in diameter. Olivine pseudomorphs (Fig. 3n) vary in shape from euhedral or
451 subhedral, with resorbed or corroded outlines; they are locally grouped into a synneusis
452 texture. Sample MS6 is ankaramitic with ~35 vol.% of corroded phenocrysts of olivine
453 pseudomorphs hosting Cr-spinel grains and clinopyroxene (~0.5-5 mm). In the three group
454 C2 basalts, groundmass (~50-300 µm; Fig. 3o) consists of microlites clinopyroxene and
455 plagioclase, minor dark to red-brown amphibole, sodic-potassic feldspar, skeletal opaque
456 minerals (titanomagnetite, ilmenite and hematite), fluoroapatite and a few grains of pyrite and
457 Fe-Ni sulfides. Plagioclase microlites are zoned with more calcic cores and albitic rims. In
458 olivine-bearing samples Cr-spinel and titanomagnetite are disseminated within the
459 groundmass, but Cr-spinel grains are preferentially located near the margins of the olivine
460 pseudomorphs and in other places the titanomagnetite has nucleated on the Cr-spinel grains.
461 Interstitial material, likely representing devitrified glass, forms felty assemblage of albite
462 (interstitial patches of polygonal albite grains and rare grains of quartz in sample MS11),
463 chlorite, iron oxides, apatite needles and clay minerals.

464

465 **4.3- Whole rock geochemistry**

466

467 **4.3.1 Alteration effect**

468

469 All the analyzed samples display variable degrees of alteration/weathering, with loss
470 of ignition (LOI =1.3-10.8 wt.%) only partly correlated with the apparent degree of alteration.
471 Group A samples are affected by strong epidotization and silica addition; as such, they have
472 the lowest LOI and H₂O contents (<2 wt.%) and virtually no CO₂ (e.g., MS12, MS13, MS14,
473 Table 1). In addition, samples MS12 and MS14 have anomalously low Na₂O contents (<1
474 wt.%) associated with high CaO contents (19-21 wt.%) and virtually no K₂O, whereas sample
475 MS13 is strongly enriched in silica due to quartz-filled vesicles. High CO₂ contents (2.1-8.2
476 wt.%) in group C rocks reflect the abundance of carbonates replacing mafic minerals and
477 scattered in the groundmass. Such high carbonate contents possibly result from late and/or
478 post-magmatic interaction with CO₂-rich fluids. In the other lavas moderate-high amounts of
479 CO₂ are mostly due to calcite that fills amygdules, veins and microfractures that could not be
480 avoided during sampling and crushing. Overall H₂O contents (up to 5.1 wt.%) are on the
481 average values for oceanic volcanic rocks affected by sea-floor alteration. As a consequence,
482 for most samples and more particularly for group A samples, major element variations
483 (Supplementary figure A.1a) cannot clearly reflect magmatic affinities and processes and the
484 same effects are expected for the large-ion lithophile elements (LILE, such as Rb, Ba, Sr, U,
Pb) that are easily mobilized during hydrothermal and sea-floor alteration (Polat and Hofmann, 2003). Instead, TiO₂, the transition elements, the heavy rare-earth elements (HREE), the high field strength elements (HFSE, such as Y, Zr, Hf, Nb, Ta) and Th are known to be relatively immobile under metamorphic conditions and alteration at low to moderate water/rock ratios (e.g., Pearce and Peate, 1995; Wood et al., 1979); similarly, the light rare-earth elements (LREE) are only modified under high water/rock ratio and in strongly altered rocks (Humphris, 1984). These incompatible elements better distinguish the different Dali magmatic groups (Supplementary figure A.1b) and are thus preferentially used for classification and discussion.

494

495 4.3.2 General features and classification

496

Fig. 4 shows that the Dali volcanic rocks exhibit a wide compositional variability; the most incompatible trace element (Th, Nb, La, Sm) abundances increase gradually from group A through group B to group C lavas, whereas the abundances of Yb and Y (Table 1) tend to decrease from group A to group C. The chemical distinction between the three petrographic groups is also well evidenced on the diagram Ti/Zr vs. Nb/Y (Fig. 5) used as a proxy for the total alkali vs. silica (TAS) classification for altered volcanic rocks (Floyd and Winchester, 1975; Pearce, 1996, 2014). On this diagram the Dali lavas have basaltic compositions ranging from subalkaline to alkaline, with Nb/Y ratios increasing from 0.04–0.06 (group A) through 0.25–0.64 (group B) to 1.29–1.56 (group C). Group B lavas also have relatively high contents of TiO₂ (1.0–1.8 wt.%) and P₂O₅ (0.12–0.46 wt.%), intermediate between those in group A (0.06–0.15 wt.%) and group C (0.34–0.81 wt.%). Data for Upper Jurassic – Lower Cretaceous volcanic rocks from the Armenian ophiolite units (Galoyan et al., 2007, 2009; Hässig et al., 2010).
509 2013a, 2013b; Rolland et al., 2009, 2010) are also plotted for comparison; these results show
510 that Dali groups A and C correspond, respectively, to the tholeiitic ("ophiolitic") and alkaline
511 series of the above authors. The geochemically intermediate group B lavas exposed in Dali is
512 clearly identified for the first time in the Armenian ophiolites.

513

514 4.3.3 Group A volcanic rocks

515

516 Sample MS9 is a basalt with SiO₂ 49.2 wt.% and MgO 6.7 wt.% (volatile-free), Mg# 517 64.8 [= molar 100 Mg/(Mg + Fe²⁺), assuming a Fe³⁺/Fe²⁺ ratio of 0.15] and relatively low Cr 518 (198 ppm) and Ni (67 ppm) contents. This sample also has low TiO₂ content (0.83 wt.%). The 519 other samples have more evolved compositions characterized by lower MgO (2.6–4.3 wt.%) 520 and Mg# (33-44), higher TiO₂ (1.1–1.4 wt.%) contents and very low Ni and Cr contents (≤17 521 ppm). The five samples are low-K tholeiites. Chondrite (C)-normalized REE concentrations 522 (Fig. 6A) define subparallel, nearly flat patterns [(La/Yb)C 0.71–0.99; YbC 10.7–20.0] with no 523 or weak anomalies for Eu (Eu/Eu* 0.82–1.17). The abundances of Nb (0.63–1.57 ppm), Zr 524 (46–86 ppm) and Th (0.14–0.38 ppm) are low. On N-MORB normalized multi-element 525 diagrams (Fig. 7A) the samples exhibit negative anomalies in Nb [(Nb/La)MORB 0.36–0.47] 526 and enrichments in U and Pb relative to the REE of similar incompatibility [(U/La)MORB 1.3– 527 3.7); (Pb/Ce)MORB 4–24)]. Due to their enrichment in Th, they plot above the MORB–OIB 528 mantle array, toward the field of oceanic arc magmas on Pearce (2008, 2014)'s diagram (Fig. 529 8).

530

531 4.3.4 Group B volcanic rocks
532

533 Four samples (DA5, DA12, G09-10, DA13) are basalts and basaltic andesites (SiO₂
534 52.2-54.0 wt.%; MgO 6.9-8.3 wt.%; Mg# 64-69) moderately depleted in Cr (85-168 ppm)
535 and Ni (33-68 ppm). Sample DA10 (SiO₂ 53.4 wt.%) has lower MgO (5.1 wt.%) and Mg#
536 (~52), and Cr and Ni contents below detection limit. Accumulation of olivine pseudomorphs
537 associated with Cr-spinel in sample G08-10 is reflected by the abundances of Cr (684 ppm)
538 and Ni (209 ppm) and the low SiO₂ content (46.6 wt%). However, the Mg# (~44) and MgO
539 content (4.8 wt.%) of this sample are surprisingly low with respect to the Cr and Ni contents
540 (Supplementary figure A.1); this feature is discussed in section 7.1.2. On the whole, the
541 compositions of the group B lavas show some chemical characteristics of enriched MORB (E-
542 MORB), as shown by relatively high contents of TiO₂ (1.0-1.8 wt.%), P₂O₅ (0.12-0.46 wt.%)
543 and Nb (5.3-13.8 ppm), and by high Nb/Y ratios (0.2-0.6); they are low-K tholeiites in K₂O-
544 SiO₂ diagram of Peccerillo and Taylor (1976). The chondrite-normalized REE patterns (Fig.
545 6B) show that all the samples are enriched in the LREEs and several styles of REE
546 fractionation can be observed. The HREEs are slightly to moderately more fractionated than
547 N-MORB, with (Gd/Yb)C 1.25-1.41 in samples DA5, DA10 and DA13; samples G08-10,
548 G09-10 and DA12 display marked HREE fractionations [(Gd/Yb)C 1.64-1.69]. Sample DA5
549 has the lowest enrichment in the LREEs [LaC 28; (La/Yb)C 1.80], while samples DA10,
550 DA13, G08-10 show moderate enrichments in the LREEs relative to the HREEs and MREEs;
551 [(La/Yb)C 2.27-3.35; (La/Sm)C 1.49-1.78]. Samples DA12 and G09-10 are the most
552 enriched in the LREE [LaC ~65-75; (La/Yb)C 6.1; (La/Sm)C 2.51-2.62]; they also display
553 distinctive Eu anomalies (Eu/Eu* 1.12-1.14) consistent with the abundance of the plagioclase
554 phenocrysts observed in thin sections. Compared to N-MORB (Fig. 7B), group B samples are
555 slightly depleted in HREE (YbMORB 0.59-0.93). Three samples (DA10, DA12, G09-10)
556 exhibit negative anomalies in Nb, with (Nb/La)MORB = 0.57, 0.75 and 0.79, respectively; these
ratios are less pronounced than for typical arc magmas (<0.5; Gill, 1991). The other samples have insignificant or no anomalies in Nb [(Nb/La)MORB = 0.82–1.10]. In the Th/Yb vs. Nb/Yb diagram (Fig. 8) group B lavas plot on and slightly above the mantle array. The basaltic andesite DA10 is the most enriched in Th relative to Nb and plots very close to the area where fields for oceanic and continental arc lavas overlap, in agreement with its lower Nb/La ratio.

562

563 4.3.5 Group C volcanic rocks

564

Their alkaline nature is evidenced by high Nb/Y (1.3–1.6) ratios (Fig. 5). Group C1 trachybasalts have 48.3–51.9 wt.% SiO₂ and 3.4–6.2 wt.% MgO contents and Mg# 44–59. They have high contents of TiO₂ (1.8–1.9 wt.%), Na₂O (5.3–7.0 wt.%) and P₂O₅ (0.7–0.8 wt.%). Chondrite-normalized patterns (Fig. 6C) show enrichments in the LREEs relative to the HREEs [(La/Yb)C 20–21] with YbC 9.1–10.4 within the range of OIBs (e.g. compilation of Willbold and Stracke, 2006). The REE patterns display a slightly sigmoid shape, as shown by weak HREE fractionation [(Er/Yb)C ~1.2], relatively strong enrichments in the MREE/HREE [(Sm/Yb)C ~5.5] and less pronounced enrichments in the LREE/MREE [(La/Sm)C ~3.7]. On Primitive Mantle (PM)-normalized multi-element diagram (Fig. 7C) they exhibit negative anomalies in Nb [Nb 24–30 ppm; (Nb/La)PM 0.51–0.59)] similar to that observed in the group B sample DA10 [(Nb/La)PM 0.51]. They also have relatively high Th/Nb ratios (0.26–0.28), also similar to that of sample DA10 (0.25), and thus they plot above the mantle array on the Th/Yb – Nb/Yb diagram (Fig. 8). Group C2 samples (G10-10, MS11) are basaltic rocks with SiO₂ 42.5–44.5 wt.%, MgO 7.8–6.1 wt.%, Mg# 46–60, TiO₂ 2.2–3.2 wt.% and P₂O₅ 0.34–0.45 wt.%. The bulk composition of MS11 appears to be controlled by the abundances of olivine, Cr-spinel and clinopyroxene as shown by high Cr (1068 ppm) and
581 Ni (418 ppm) contents, as well as high CaO (23 wt.%) concentration and high CaO/Al₂O₃ ratio (2.1) (Supplementary figure A.1). Group C2 basalts have similar HREE contents than
582 Group C1 trachybasalts, but their enrichments in M- and LREE/HREE [(La/Yb)C 10–12] are
583 almost half lower than those observed in the Group C1 trachybasalts and also in most OIB
584 (Fig. 6D). The two basalts also differ from the trachybasalts in having positive Nb anomalies
585 on the PM-normalized diagram [(Nb/La)PM 1.1–1.2; Fig. 7D) for nearly similar Nb
586 concentrations (27–38 ppm); these concentrations are nevertheless low compared with those
587 of typical OIBs (57.7 ± 17.6 ppm, Willbold and Stracke, 2006). Indeed, PM-normalized
588 multi-elements of the two basaltic samples, especially that of the sample MS11, are more
589 depleted than the OIBs in all incompatible trace elements; REE dilution by accumulation of
590 olivine and Cr-spinel may be a possible explanation. Th/Nb ratios (0.10) are within the range
591 of OIBs (Willbold and Stracke, 2006) and plot on the mantle array in the Th/Yb – Nb/Yb
592 diagram (Fig. 8).
593 diagram (Fig. 8).
594

594

595 **4.4. Mineral chemistry**

596

597 4.4.1 Clinopyroxene

598

599 4.4.1.1 Major and trace element compositions

600

601 Representative major element analyses of clinopyroxenes of Dali volcanic rocks are
602 presented in Table 2. Clinopyroxene compositions are plotted in the Mg-Ca-Fe classification
diagram of Morimoto et al. (1988) (Supplementary figure A.2) and in the Al₂O₃ and TiO₂ vs. Mg# binary diagrams (Fig. 9), where decreasing Mg# [= 100*Mg/(Mg + Fe*)] reflects crystallization under decreasing temperature (Philpotts, 1993) and thus the degree of differentiation of the parental magmas.

The clinopyroxenes from group A samples are Ca-rich augites. Collectively, they define a trend of decreasing wollastonite and enstatite contents with increasing ferrosilite. Clinopyroxene Mg# are well restricted in the basaltic sample MS9 (Mg# 81–85), but vary from ~80 down to ~70 from grain to grain and from core to rim in the basaltic andesites. With decreasing Mg#, Cr₂O₃ contents first decrease rapidly from ~0.62 wt.% to 0.18 wt.% in the most magnesian sample MS9, then decrease regularly down to below detection limit in more evolved compositions. Al₂O₃ contents show an overall moderate decrease from 4.10 ± 0.65 wt.% to 1.91 ± 0.27 wt.% (Fig. 9A). TiO₂ contents are very low (<1 wt.%) and increase slightly with decreasing Mg#, from 0.66 ± 0.05 wt.% to 0.78 ± 0.12 (Fig. 9B). The compositions were also plotted in the Ti vs. (Ca + Na) and (Ti + Cr) vs. Ca diagrams of Leterrier et al. (1982), where they fall in the subalkaline, orogenic fields (Supplementary figure A.3). The compositional characteristics of group A clinopyroxenes are compatible with fractional crystallization of plagioclase + augite + minor Fe-Ti oxides, as observed in arc tholeiitic lavas.

The clinopyroxenes from group C lavas plot in the diopside field and show wide compositional variations both in individual samples and within the group. However, in all samples, the variations follow similar compositional trends of increasing Al₂O₃ (Fig. 9A), TiO₂ (Fig. 9B) and Na₂O (not shown) contents with decreasing Mg#, which are typical of alkaline lavas (LeBas, 1962; Liotard et al., 1990; Nisbet and Pearce, 1977). In addition, wollastonite contents tend to increase with increasing ferrosilite contents. In the basalt G10-10 and trachybasalts DA6, DA7, and DA8, most clinopyroxene phenocrysts and
628 glomerocrysts are stubby crystals with homogeneous, Mg-rich (Mg# ~80-85) cores and
629 highly variable Cr₂O₃ contents (0.11-0.90 wt.%); Al₂O₃ contents vary from 2.7 to 5.3 wt.% in
630 the basalt and from 3.7 to 6.1 wt.% in the trachybasalts; TiO₂ contents range from 0.93 to
631 1.92 wt.% in the basalt and from 0.85 to 1.57 wt.% in the trachybasalts. In the basalt G10-10
632 a few phenocryst cores have higher Mg# (88-89), lower TiO₂ (0.61 ± 0.02 wt.%) and
633 moderate Al₂O₃ (2.36 ± 0.13 wt.%) contents; these phenocrysts are optically indistinguishable
634 from other phenocrysts. In the trachybasalts core compositions of the prismatic, normally
635 zoned clinopyroxene phenocrysts are the same as in unzoned phenocrysts, whereas mantle
636 compositions vary within the same range as the groundmass clinopyroxenes, from ~4.8 to 8.0
637 wt.% Al₂O₃ and from ~1.5 to 3.0 wt.% TiO₂ in the ~68-78 Mg# interval. All the phenocrysts
638 are overgrown by a light-brown diopside corona (locally replaced by brown amphibole) that
639 marks an abrupt decrease in MgO (Mg# 68-72) and increases in Al₂O₃ (6.3-13.0 wt.%) and
640 TiO₂ (2.18-3.29 wt.%). The basalt MS11 differs in containing rare clinopyroxene phenocrysts
641 and microphenocrysts showing complex, oscillatory zoning, with compositions in the ranges
642 of Mg# 78-85; Cr₂O₃ 1.05-0.07 wt.%; Al₂O₃ 2.7-7.5 wt.%; TiO₂ 0.96-2.32 wt.%. It is
643 noteworthy that the outer rims may be Fe-richer as well as Fe-poorer. Compositions of the
644 groundmass clinopyroxenes are highly variable, and overlap those of the phenocrysts. On the
645 whole, abundances of Al₂O₃ (from~2.3 to 7.8 wt.%) and TiO₂ (from 0.61 to 2.76 wt.%)
646 increase as Mg# decrease from 87 to 74, also roughly correlated with decreasing grain size. In
647 addition, a few Fe-rich microlites (Mg# 60-69) are highly enriched in Al₂O₃ (up to 12.7
648 wt.%) and TiO₂ (up to 5.1 wt.%). The more evolved diopside compositions are found in the
649 kaersutite-bearing samples AR-16-07 and AR-16-08; they are characterized by high Al₂O₃
650 (9.9 ± 0.9 wt.%) and TiO₂ (4.57 ± 0.48 wt.%) contents for Mg# in the 63-68 range. The
651 sample AR-16-07 contains two, very coarse, diopside xenocrysts with very high MgO
652 contents (Mg# 86 and 87) and low Al₂O₃ (3.11 wt.%) and TiO₂ (0.45 and 0.78 wt.%)

653 contents, set in a groundmass containing Mg-poorer clinopyroxenes (Mg# 78–82; Table 2).

654 The clinopyroxenes from group B lavas cover a large spectrum of compositions that
655 partly includes group A and group C compositions. They plot in three broad subgroups: (i)

656 Ca-rich augite in samples DA5, DA10 and DA13, (ii) diopside evolving to augite with
657 increasing ferrosilite in sample G08-10, (iii) Ca-rich augite evolving to diopside with
658 increasing ferrosilite in samples DA12 and G09-10 (Supplementary figure A.2). Like group A
659 augites, group B augites exhibit decreasing Al₂O₃ contents with decreasing Mg# (Fig. 9C) and
660 low TiO₂ contents (Fig. 9D), but differ by higher Al₂O₃ contents for the most magnesian

661 compositions. For Mg# 80 ± 1.5, Al₂O₃ and TiO₂ contents are well restricted (3.9 ± 0.7 wt.%
662 and 1.05 ± 0.31 wt.%, respectively) in the aphyric sample DA5. Sample DA10 augites show
663 wider ranges of compositions, with Mg# decreasing from 83 to 68, while the abundances of

664 Al₂O₃ decrease from 5.4 to 1.9 wt.% and TiO₂ vary between 1.35 and 0.62 wt.%; the cores of
665 the rare microphenocrysts have the highest Mg#, Al₂O₃ and TiO₂ contents, all decreasing
666 towards the rims. Phenocryst relicts in sample DA13 show oscillatory zoning patterns in

667 resorbed cores, principally marked by variations in MgO and FeO (Mg# ~70–81) at low and
668 nearly constant Al₂O₃ (2.2 ± 0.5 wt.%) and TiO₂ (0.64 ± 0.15 wt.%) contents. They are
669 overgrown by thin rims of similar compositions than the microlites. The latter are

670 significantly enriched in MgO (Mg# 77–86) and Al₂O₃ (4.8 ± 1.1 wt.%). Both the phenocrysts
671 and microlites have very low TiO₂ contents (0.71 ± 0.16 wt.%). In the Ti vs. (Ca+ Na)

672 diagram, the augitic subgroup plot within the subalkaline field and is transitional between
673 orogenic and anorogenic fields in the (Ti+Cr) vs. Ca diagram (Supplementary figure A.3).

674 Clinopyroxene microcrysts in sample G08-10 appear to have crystallized or equilibrated in a
675 fractionating magma. In the Mg# interval 72–75, a subset of clinopyroxenes have moderate
676 Al₂O₃ (5.4 ± 1.2 wt.%) and TiO₂ contents (2.2 ± 0.2 wt.%). As Mg# increase to reach 65–67,
Al₂O₃ contents remain constant (5.4 ± 1.0 wt.%) while TiO₂ slightly increase to 2.6 ± 0.2 wt.%. At lower Mg# (~57–64), Al₂O₃ and TiO₂ contents decrease to 3.0 ± 0.8 wt.% and 1.8 ± 0.3 wt.%, respectively. In addition, the wollastonite component continuously decreases with decreasing Mg# (Supplementary figure A.2), a feature reported in clinopyroxenes from mildly alkaline rocks of Japan (Aoki, 1964). There is no difference in terms of grain size or shape between the Mg-rich and the Mg-poor crystals; all are groundmass microlites. All the analyzed compositions plot within the alkaline field in the Ti vs. (Ca + Na) diagram (Supplementary figure A.3). The compositions of the groundmass clinopyroxenes in samples DA12 and G09-10 display wide variations without any relation with the size and shape of the crystals. As Mg# decrease from ~81 to ~73, Al₂O₃ and TiO₂ increase from ~1.7 wt.% to ~6.3 wt.%, and from 0.96 wt.% to 2.88 wt.%, respectively. These compositional trends are parallel to those of the group C alkaline rocks, slightly offset to lower Al₂O₃ and TiO₂. In the Ti vs. (Ca+ Na) diagram (Supplementary figure A.3), the DA12 and G09-10 clinopyroxenes straddle the boundary between the subalkaline and alkaline fields, in agreement with increasing wollastonite and with both decreasing ferrosilite and Mg#. This trend is the opposite of that observed in sample G08-10. However, the compositions are more magnesian in DA12 and G09-10, and they might represent an earlier stage of differentiation of a magma having similar geochemical features. It is interesting to note that the crystals having the lower CaO, MgO, Al₂O₃ and TiO₂ contents in samples DA12 and G09-10 plot in the same subalkaline field in the Ti vs. (Ca + Na) diagram (Supplementary figure A.3) as the DA5 and DA10 augites.

REE concentrations were measured in clinopyroxenes of six samples; results are listed in Table 3 and chondrite-normalized values are plotted on Fig. 10. Three crystals in MS12 (group A) and four microphenocrysts in DA10 (group B) show REE patterns typical of tholeiitic rocks, with flat HREE sections and depletions in LREE/HREE. The latter are more
702 pronounced in MS12 [(La/Yb)<sub>c</sub> 0.10–0.11] than in DA10 [(La/Yb)<sub>c</sub> 0.38–0.41]. REE
703 compositions appear to be more variable from grain to grain in DA10, with the more
704 magnesian crystals having the lowest REE contents. In both samples, Eu anomalies are
705 negligible (Eu/Eu* 0.80–0.98), indicating that plagioclase was not a major crystallizing phase
706 prior to the clinopyroxene. In DA13, a single analysis performed in the resorbed core of a
707 phenocryst/xenocryst yields a chondrite-normalized pattern similar to DA10 [(La/Yb<sub>c</sub> 0.45].
708 Diopsides in group C samples were analyzed in DA7 (two phenocryst cores), MS11 (three
709 microphenocryst cores) and in G10-10 (two phenocryst cores). The three diopside sets have
710 nearly similar, hump-shaped chondrite-normalized patterns, characterized by HREE sections
711 with negative slopes [(Gd/Yb)<sub>c</sub> 2.7–3.6) and slight depletion in LREE [(La/Sm)<sub>c</sub> 0.38–0.72].
712 Hypothetical melts in equilibrium with the measured clinopyroxenes are calculated using
713 partition coefficients relevant for island arc basaltic (Zajacz and Halter, 2007, for MS12 and
714 DA13), tholeiitic (Fujimaki et al., 1984 for DA10) and alkaline (D'Orazio et al., 1998, for
715 group C samples) compositions. For all samples but DA13, the clinopyroxene REE contents
716 are in equilibrium with their host rocks. The phenocryst core analyzed in DA13 yields REE
717 contents in equilibrium with a melt that is more enriched in all REEs and in LREE/HREE
718 than the host rock, whatever the chosen partition coefficients.

719

720 4.4.1.2 Fe/Mg relations between clinopyroxenes and whole rocks

721

722 The Fe/Mg equilibrium between the clinopyroxene and the whole-rock composition
723 can be evaluated by comparing the ratio (Fe/Mg)<sub>Cpx</sub>/(Fe/Mg)<sub>WR</sub> with experimentally
724 determined clinopyroxene/liquid partition coefficients (Fe/Mg)<sub>K<sub>D Cpx/Liq</sub></sub>. It is expected that in
725 aphyric or sparsely microphyric rocks, the whole rock Fe/Mg ratio reflects the mean Fe/Mg
value measured in the clinopyroxenes. Using the $Fe/MgK_D_{Cpx/Liq}$ of 0.23–0.30 determined by Pichavant and Macdonald (2007) for hydrous basaltic compositions, calculations show that clinopyroxenes in samples MS9, DA10, DA12 and G09-10 are within or close to equilibrium with their host rocks. In contrast, the low $(Fe/Mg)_{Cpx}/(Fe/Mg)_{WR}$ values (0.14–0.21) calculated for the samples MS12, MS13, MS14 (group A) suggest that these lavas lost variable amounts of MgO during hydrothermal alteration (epidotization). Application to the porphyritic rocks (Fig. 11) shows that groundmass clinopyroxenes in samples DA6, DA7, DA8 and G10-10 reflect distinctly more evolved compositions than the clinopyroxene phenocrysts, with a clear separation between Mg-rich and Mg-poor compositions; this abrupt variation is in good agreement with the optically contrasting rims observed in thin sections. The clinopyroxene phenocrysts in sample DA7 appear nevertheless to be in equilibrium with the whole rock composition, while the microlites crystallized from a more differentiated magma. The clinopyroxene phenocrysts present in samples DA6 and DA8 have similar major element compositions than DA7 clinopyroxenes, but are not in equilibrium with the whole rock; a possible explanation could be the higher proportion of clinopyroxene phenocrysts in sample DA7 observed in thin sections, also suggested by a bulk Cr concentration about two times higher than the one in samples DA6 and DA8 (Table 1). Similarly, clinopyroxene phenocrysts in sample G10-10 are more magnesian than expected from the whole rock composition. In these four samples (DA6–DA8 and G10-10) Mg-rich compositions (Mg# 80–85) are indicative of early crystallization in magmas having experienced low extents of fractional crystallization (corresponding to melt Mg# ≤59). But the most magnesian phenocrysts in G10-10 (Mg# 88–89) reflect derivation from a more primitive melt composition having Mg# ~67; however, their low $Al^{VI}/Al^{IV}$ ratios suggest crystallization at shallow crustal depth (Wass, 1979). In sample MS11, the compositions of the phenocrysts overlap with the microlites, defining a large range of Fe/Mg values; this suggests
751 crystallization of the more magnesian crystals from a magma having the composition of the
752 host rock, while progressive fractional crystallization generated clinopyroxenes with lower
753 Mg# (Trua et al., 2014). These features combined with oscillatory and reverse zoning
754 observed in the phenocrysts suggest multiple replenishment and magma mixing in the magma
755 chamber. Fe/Mg compositions in ragged clinopyroxene phenocrysts of sample DA13 clearly
756 indicate crystallization from a magma significantly more evolved than the host rock, and
757 probably represent xenocrysts.

758 A xenocrystic origin is also probable for the olivine phenocrysts (now fully altered)
759 and associated Cr-spinel crystals in sample G08-10. It is well established that Cr-spinel is an
760 early crystallizing phase in mafic magmas, indicating that the phenocryst assemblage was in
761 equilibrium with a primitive or near primitive magma. In contrast, the G08-10 groundmass
762 must have solidified from an evolved magma, as shown by the low Mg# (66.2 ± 4.6) of the
763 clinopyroxene microlites (the most evolved compositions of all the studied samples). The
764 samples MS5 and AR-16-02 (not analyzed for bulk compositions) show similar features, also
765 having olivine pseudomorphs and Cr-spinel crystals set in groundmass containing
766 clinopyroxene microlites significantly enriched in iron (Table 2). Furthermore, the number of
767 these primitive crystals is highly variable throughout the rocks; for example, a single thin
768 section of AR-16-02 contains a unique, coarse (~100 µm) Cr-spinel and two small Cr-spinels
769 isolated in the groundmass, a feature consistent with an origin as xenocrysts.

770

771 4.4.2 Amphibole

772

773 Amphibole compositions are listed in Table 4. Amphiboles in group A samples occur
774 in two species: 1) silica-poor, high-Al amphiboles that overgrew the clinopyroxenes plot at
the limit between tschermakite and magnesio-hornblende and 2) needles of actinolite
replacing the high-Al amphibole and clinopyroxene during low-temperature alteration (Fig.
12A). The high-Al amphiboles have very low TiO₂ contents (Fig. 12B), characteristic of
subduction-related settings (Bénard and Ionov, 2012; Ridolfi and Renzulli, 2012). On the
other hand, high Al content suggests crystallization at relatively high temperature (>700°C)
from late-magmatic fluids or high-temperature hydrothermal fluids or a mixture of both
(Coogan et al., 2001). In group B lavas igneous amphiboles are missing or totally altered
(e.g., DA12, G09-10). All the amphiboles in group C lavas are silica-poor (Si ≤6), in
agreement with a magmatic origin. In the trachybasalts, amphibole phenocrysts and
microphenocrysts range from magnesio-hastingsite to pargasite; the compositional range is as
follow (Fig. 12C): Mg# 75-85; Si 5.5-6.5; Ti = 0.40-0.47 (TiO₂ 3.4-4.4 wt.%); (Na+K)ₐ 0.7-
0.9. Based on their K₂O contents (K₂O 0.9-1.2 wt.%; K 0.17-0.26) they have alkaline affinity
(Fig. 12D; Ridolfi and Renzulli, 2012); but magnesio-hastingsites of similar compositions are
also found in calc-alkaline volcanics (Romick et al., 1992). The phenocryst rims and
microlites are kaersutites (Ti >0.5); this increase in Ti contents is correlated with higher K₂O
contents (1.1-1.4 wt.%) and lower Fe³⁺ and Al VI, which may reflect plagioclase fractionation
in the parental magma. In the most differentiated rock (e.g., AR-16-07) kaersutite (Mg# 38-
59; Ti 0.55-0.59) becomes the dominant mafic phase. Plotted with the coexisting
clinopyroxenes in the Mg-Ca-Fe diagram (Supplementary figure A.2), the amphibole in the
trachybasalts DA6 to DA8 appears to be better equilibrated with the clinopyroxene microlites
(and phenocryst mantles) although their sizes are similar to those of the clinopyroxene
phenocrysts. In contrast, AR-16-08 amphiboles have slightly lower Mg# than expected for
equilibrium with the associated clinopyroxenes, while AR-16-07 amphiboles are clearly out
of equilibrium with the associated clinopyroxenes. These conclusions agree with the textures,
which indicate that in these two samples magmatic amphibole crystallized after
800 clinopyroxenes having the lower Mg#. Two amphibole phenocrysts were analyzed for the
801 REEs in sample DA7; both crystals exhibit hump-shaped chondrite-normalized REE patterns
802 with a peak in Nd [(La/Nd)<sub>C</sub> 0.5-0.6; (La/Sm)<sub>C</sub> 0.6-0.8] and negative HREE slopes [(Gd/Yb)<sub>C</sub>
803 3.5-4.1) at Yb<sub>C</sub> ~13 (Fig. 11). These patterns are nearly parallel to those of the associated
diopside, but differ by a slight negative Eu anomaly (Eu/Eu* ~0.8), indicating that the
804 amphibole crystallization occurred with the more evolved diopside crystals coexisting with
805 the plagioclase. Within basalts, the amphiboles only occur as groundmass microlites. These
806 are hastingsites in G10-10, with lower Mg# (33-52), Al<sup>IV</sup> (~2.0) and Ti (0.37-0.44; TiO<sub>2</sub> 3.1-
807 3.8 wt.%) contents than those of the trachybasalt phenocrysts, but slightly higher K contents
808 (0.23-0.29; K<sub>2</sub>O 1.1-1.4 wt.%). In the other two basalts the microlite compositions range
809 from magnesio-kaersutites in MS6 (Mg# ~69; Ti 0.68-0.72; TiO<sub>2</sub> 6.1-6.5 wt.%) to ferroan-
810 kaersutites in MS11 (Mg# ~50; Ti 0.60-0.68; TiO<sub>2</sub> 5.2-5.9 wt.%).
811

812

813 4.4.3 Feldspar

814

815 Plagioclases in group A rocks are commonly replaced by albite and/or epidote; some
816 crystal cores contain calcite, suggesting Ca-rich cores; former zoning is also suggested by
817 alteration patterns. Rare fresh spots in MS13 vary in composition from An₃₁ to An₅₁. In
818 groups B and C, fresh plagioclases are more abundant, but still too few to be representative.
819 Scarce plagioclase microphenocrysts in DA5 (group B) are albitized and/or chloritized, still
820 showing relicts of zoning; microlite compositions are in the An₁₈-An₆₄ (avg. An₄₇; n=13),
821 while DA10 microlites that escaped albitization range between An₂₀ and An₃₇ (avg. An₃₀;
822 n=5). Plagioclase phenocrysts in DA13 are extensively altered, nevertheless some crystals
823 show more calcic cores ~An₅₈ and albitic rims; fresh microlites display a wide range of
composition, from An$_{13}$ to An$_{54}$ (avg. An$_{38}$; n=11) and two analyzed tiny crystals are enriched in K (Or$_{15}$Ab$_{77}$An$_{8}$). In samples DA12 and G09-10, plagioclase phenocrysts are relatively abundant, but they are highly altered; rare relicts show normal zonation, with ~An$_{51}$ in cores, An$_{30-33}$ in mantles and albitic (± chlorite) rims. All the plagioclase microlites are albitized; several tiny grains of alkali feldspar (Or$_{13-19}$Ab$_{77-80}$An$_{4-7}$) were detected with the EDS. The olivine-phyric samples contain plagioclase microlites ranging in composition from An$_{12}$ to An$_{55}$ (avg. An$_{32}$; n=6) in G08-10 and from An$_{37}$ to An$_{71}$ (avg. An$_{58}$; n=7) in MS5. In group C lavas, plagioclase occurs only in the groundmass, and only exceptionally as very scarce microphenocrysts in DA6 and DA8. The latter crystals are almost fully albitized, except of a fresh spot of labradorite An$_{72}$, but former compositional zoning is still recognizable despite alteration. Groundmass microlites in the trachybasalts are also albitized, with rare relicts of andesine An$_{34-53}$, and orthoclase Ab$_{53}$Or$_{40}$An$_{7}$. In both AR-16-07 and AR-16-08, plagioclase compositions vary from An$_{49}$ to An$_{59}$. Orthoclase crystals Ab$_{30-48}$Or$_{46-68}$An$_{2-3}$ are also present. In the basalt G10-10, plagioclase microlites are normally zoned in the range of An$_{17-65}$ (avg. An$_{49}$; n=11) and rimmed by albite. In the olivine-phyric basalt MS11 microlites define a large range of compositions from An$_{27}$ to An$_{52}$ (avg. An$_{42}$; n=11), with orthoclase contents up to 9%. Plagioclase in MS6 is all albitized, in the An$_{12-26}$ range.

841

842 4.4.4 Spinel

843

Spinels occur in two species: Cr-Al spinel and titanomagnetite. Cr-Al spinels were found in three group B samples (G08-10, MS5, AR-16-02) and two group C2 samples (MS11, MS6). Grains are enclosed in olivine pseudomorphs or are located close to their resorbed margins; in addition, discrete, smaller grains are disseminated in the groundmass. All the
grains are subrounded to euhedral. Representative analyses are given in Table 5 and compositions are plotted on Fig. 13. There is no difference of composition between the enclosed and disseminated grains. The spinels from the three group B samples have similar compositions, with Cr# [= 100 Cr/(Cr+Al)] 40–55 (avg. 47; n=15), Mg# [= 100 Cr/(Mg+Fe²⁺)] 52–64 (av. 57), Fe³⁺# [=100 Fe³⁺/(Fe³⁺+Al+Cr)] 3–12 (avg. 9) and 0.7–1.5 wt.% TiO₂ (avg. 1.2 wt.%). The spinels in the sample MS11 have higher Cr# (58–68; avg. 65; n=9), Mg# (49–56; avg. 57), Fe³⁺# (13–17; avg. 15) and TiO₂ contents (1.6–2.6 wt.%; avg. 2.2 wt.%). Despite some scattering, possibly caused by subsolidus Mg-Fe²⁺ exchange with the surrounding rock during hydrothermal alteration, these compositions are within the range of spinels hosted in olivines that were in equilibrium with primitive basaltic melts (Clynne and Borg, 1997; Smith and Leeman, 2004); in particular, they are too poor in Al₂O₃ to have crystallized at high pressures (i.e. > 0.5 GPa) in ultramafic cumulates or in the mantle (Fig. 13A; Barnes and Roeder, 2001; Clynne and Borg, 1997; Mata and Munhà, 2004). The compositions follow Cr-Al trends of increasing Cr# and Fe²⁺# (i.e., decreasing Mg#) associated with limited increases in Fe³⁺# (Fig. 13B), which characterize most of the spinels that crystallize in primitive alkaline basalts and ocean floor basalts (Barnes and Roeder, 2001; Clynne and Borg, 1997; Luhr and Carmichael, 1985; Smith and Leeman, 2004). In contrast, spinels in the sample MS6 are anomalously enriched in TiO₂ (6.4–11.1 wt.%; avg. 8.3 wt.%; n=4) and Fe³⁺ (Fe³⁺# 34–38; avg. 36), with low Mg# (35–44; av. 40) and Cr# (35–41; avg. 38; n=4) and tend to follow Fe-Ti trends, toward Ti-rich chromium magnetite (Fig. 13B,C). Such compositions suggest post-entrapment modifications of these spinels likely resulting from reactions with an evolved melt highly enriched in Ti (cf. Barnes and Roeder, 2001). The abundances of TiO₂ vs. Al₂O₃ are controlled by source fertility (e.g., Clynne and Borg, 1997); on Fig. 13C group B spinels and MS11 spinels have distinct magmatic affinities, reflecting the distinct enrichments in TiO₂ of the host rocks (Kamenetsky et al., 2001). Group B spinels
873 are similar in composition to that observed in spinels from enriched MORB or mildly alkaline lavas (Batiza and Vanko, 1984; Kamenetsky et al., 2001), whereas MS11 spinels are akin to 874 OIB-like spinels (Allan et al., 1988; Kamenetsky et al., 2001). Group B spinels also fall in the 875 field of spinels from subduction-related OIB and associated calc-alkaline primitive basalts 876 (Fig. 13C; Conrey et al., 1997). 877

878 The titanomagnetites typically occur with dendritic and cruciform quenched 879 morphologies, disseminated in groundmass. In some group B rocks (G09-10, DA12, MS5, 880 G08) they also form euhedral microphenocrysts that are poorer in Fe³⁺# than the spinel 881 groundmass. Mol.% ulvöspinel in groundmass titanomagnetite varies widely, even at the 882 sample scale; however, most of the variation is likely due to their small size and skeletal 883 habit, and for these reasons, their compositions are not well constrained. 884

885

## 5. Discussion

886

887 5.1 Constraints from mineral chemistry

888

889 The compositions of the relict igneous minerals confirm the subdivision of the Dali 890 volcanic rocks in three major magmatic groups with a transition from island arc affinity 891 (group A) to subalkaline transitional rocks (group B) and alkaline lavas (group C). Major and 892 trace elements of the investigated clinopyroxenes also reflect the occurrences among the 893 group B samples of subalkaline lavas, with affinities that are transitional between orogenic 894 and within-plate (DA5, DA10, DA13), and more alkaline magmatism (G08-10, DA12, G09- 895 10). Therefore, mineral chemistry can be used in the first instance to classify the other Dali
896 volcanic rocks which were not analyzed for their bulk composition. Based on this assumption,
897 field relationships of lavas exposed in the lithotectonic unit 2 show that the two types of
898 group B lavas are interlayered and overlain indifferently by group C1 or C2 lavas.

899 Additionally, the inconsistency between clinopyroxene and whole rock Mg# in the
900 (nearly) aphyric group A samples suggests that some amount of MgO was lost during the
901 alteration. In contrast, in group B and C porphyric lavas, accumulation of diopside ± olivine
902 (+ Cr-spinel) along with the chemistry of clinopyroxenes indicate that whole rock Mg# result
903 from variable proportions of Mg-rich minerals and a more evolved groundmass composition.
904 Such mixing may have had significant effects on the whole rock major element composition
905 and on the abundance and ratio of incompatible trace elements in differentiated rocks (e.g.
906 Neumann et al., 1999). However, and with the exception of phenocrysts in sample DA13,
907 whole rock REE contents and REE contents in hypothetical melts in equilibrium with the
908 analyzed clinopyroxenes (and amphiboles) are similarly fractionated, at least in the studied
909 samples (Fig. 10). We thus assume that despite limitations, mainly due to the small number of
910 investigated crystals, phenocryst and groundmass rock components derive from magmas that
911 are genetically related; the incompatible element ratios should not be significantly affected by
912 magmatic processes and can be used to characterize the magmatic and tectonic affinities.

913

914 5.2 Magma affinities and source compositions

915

916 Incompatible trace elements, such as the HFSEs (Nb, Zr, Y), the MREEs and HREEs
917 (Sm–Lu) are generally thought to be conservative with respect to the mantle source
918 composition, i.e. not affected by slab dehydration fluids (e.g. Pearce and Peate, 1995). In
919 contrast, the LREEs and Th are mobilized during partial melting of subducted sediments,
leading to higher La/Yb, La/Nb and Th/Nb ratios in suprasubduction zone lavas, as well as in continental crust (Dilek and Furnes, 2014; Pearce, 2014). On the other hand, Th, Nb, Zr, Y and Yb are incompatible in olivine, pyroxene and plagioclase, the main fractionating phases of anhydrous basaltic magmas at low pressure; their ratios are thus not significantly affected by low to moderate amounts of fractional crystallization and can be used to assess the nature of the magmas and the mantle source characteristics (Abdel-Rahman and Nassar, 2004; Pearce and Peate, 1995). In hydrous magmas, fractional crystallization of amphibole tends to deplete the residual melts in MREE relative to LREE and HREE and in HFSE relative to REE because HFSE and MREE are more compatible in amphibole (e.g., Foley et al., 2002; Nandedkar et al., 2016). However, experimental studies and modelling show that the amphibole signature appears only in silica-rich residual melts (SiO₂ > 58 wt.%) when amphibole-melt partition coefficients for the REEs and HFSEs drastically increase with the melt silica content (e.g., Dessimoz et al., 2012 and therein references). Thus, the geochemistry of the mafic volcanic rocks of this study should not be significantly affected by amphibole fractionation.

### 5.2.1 Group A lavas

Sample MS9 displays the least evolved composition (MgO = 5 wt.%; bulk Mg# 65; clinopyroxene Mg# 80–85). Its chondrite-normalized MREE–HREE pattern is parallel to that of N-MORB [(Sm/Yb)C = 1.09] but with more depleted bulk REE concentrations (YbMORB = 0.56) and a marked depletion in the LREEs [(La/Sm)C = 0.67; Figs. 6, 14A]. It also has a very low Nb/Y ratio (0.04) and a very high Zr/Nb ratio (71.2), in spite of the fact that their Zr/Y (2.7) and Zr/Hf (35) ratios are similar to those of N-MORB lavas (~3 and ~36, respectively,
Sun and McDonough, 1989; Fig. 14B). This sample also displays a strong depletion in Nb relative to the LREEs (Nb/La = 0.34; Figs. 7, 14C) and it is enriched in Th relative to Nb and the HREEs (Figs. 7, 8, 14D). All these features are indicative of magma derivation by partial melting of a mantle source that is more depleted than that sampled by N-MORB and metasomatized by a subduction-fluid component. The other group A samples are globally more enriched in all incompatible trace elements, but with similarly shaped trace element patterns when normalized to chondrite and N-MORB (Figs. 6, 7); they can thus be interpreted as having more evolved compositions after fractional crystallization. This conclusion agrees with the lower Mg# content of their clinopyroxenes (Fig. 9A). Additionally, the REE pattern of sample MS12 clinopyroxenes (Fig. 11) is also consistent with derivation of the parent magma from a MORB mantle source equilibrated in the spinel stability field. Concomitant decreases of Mg# and Al₂O₃ in group A augites (Fig. 10A) are characteristic of a tholeiitic trend controlled by clinopyroxene and plagioclase fractionation, while nearly constant TiO₂ contents (Fig. 10B) suggest crystallization of Fe–Ti oxides. From these features, we deduce that the group A lavas are tholeiitic basalts and basaltic andesites generated over an intra-oceanic subduction zone.

Evidence for an intra-oceanic arc setting is also shown by the Dali intrusives which are mainly composed of gabbroic diorites (plagioclase andesine, magnesio-hornblende, Fe-Ti oxides) and hornblende-bearing quartz-diorites indicating derivation from hydrous magmas. We have analyzed a sample of the diorite, namely sample DA3 in Table 1. This sample is characterized by strong depletion in Nb (Nb/La = 0.23; Nb/Y = 0.02) and enrichment in Th (Th/Nb = 0.40; Fig. 8). Therefore, the Dali plutonic sequence is a remnant of the crust of an intra-oceanic arc. The stratigraphic and petrogenetic relations between the Dali plutonic section and group A lavas have not been clearly established, but both intrusive and extrusive rocks are thought to be Jurassic in age (Galoyan et al., 2009); zircon U/Pb dating of a
trondhjemite yielded an age of ca. 172 Ma (GG, unpublished). On Fig. 8 the tholeiitic rocks from the Armenian ophiolites plot in two groups, both derived from a N-MORB-type mantle source. One group plots within the mantle array, the second, which includes the Dali rocks, plots above the mantle array, being weakly affected by subduction-related fluids. These tholeiitic rocks also plot within MORB-IAT fields in tectono-magmatic discrimination diagrams (not shown). The tholeiitic rocks have been collectively interpreted as oceanic crust formed in a marginal or back-arc basin spreading center (Galoyan et al., 2009; Rolland et al., 2010; Sosson et al., 2010). However, N-MORB-type basalts can also be generated during subduction initiation, followed by MORB-type basalts weakly affected by subduction-fluids (forearc basalts or FAB) and true IAT formed in a forearc setting (Stern et al., 2012; Stern and Gerya, 2018; Wattam and Stern, 2011).

### 5.2.2 Group B and C lavas

Group B and C samples are enriched in the more incompatible elements relative to those of group A (Figs. 4, 6, 7). Together with other Lower Cretaceous alkaline rocks from the Armenian ophiolites, they plot in a field that extends parallel to the MORB–OIB mantle array on the Th/Yb vs. Nb/Yb diagram (Fig. 8). Continuity between slightly and more enriched compositions is also observed on most other diagrams involving incompatible element abundances and ratios. The Th/Yb vs. Nb/Yb diagram highlights two features: (i) a dispersion of the Nb/Yb ratios that can be interpreted as a mixing line between E-MORB (group B) and OIB-like (group C) compositions; (ii) slight-moderate enrichments in Th/Yb (for given Nb/Yb) observed in some samples, both in Dali groups B and C, also including two alkaline lavas studied by Galoyan et al. (2009) and Rolland et al. (2009, 2010); they are
indicative of a subduction component in their mantle sources or crustal contamination or
crustal recycling in the deep mantle (Pearce, 2008). A subset of group B and C lavas (as well
as the two Th-rich alkaline lavas cited above) also display negative Nb anomalies in
normalized multi-element diagrams, a feature commonly associated with magmas emplaced
above subduction zones.

998

5.2.2.1 The crustal signature

1000

Displacement of alkaline, OIB-like compositions toward higher Th/Yb (Fig. 8) is a
very uncommon feature (Pearce, 2008). It was observed in a few alkali basalts from ocean
islands and explained by small amounts of recycled pelagic sediments or continental material
in their mantle sources, which had for effects to increase their Th/Nb but also La/Nb ratios
(Pearce, 2008; Weaver et al., 1986; White and Duncan, 1995; Willbold and Stracke, 2010).
Such increases are, however, much less pronounced than in group C1 lavas. In addition,
group C1 samples contain amphibole phenocrysts, which indicates crystallization from a
hydrous parental magma, a feature not consistent with an intra-oceanic plume-like mantle
source. Compared to group C2 lavas, which have no Th and Nb anomalies, the amphibole-
phyric trachybasalts are enriched in LREE (La), U, Sr and Pb (Fig. 3); in particular, the Nb/U
ratios of the C1 samples are ca. 2.6 times lower than those of the C2 samples (~16 and ~41,
respectively) and clearly outside the range of OIB compositions (43.8 ± 6.7, Willblod and
Stracke, 2006). Therefore, group C1 lavas can be defined as transitional between calc-alkaline
and alkaline OIB-like lavas, suggesting emplacement in a subduction-related setting or partial
melting of metasomatized lithospheric mantle.
Like group C lavas, some group B samples display a signature of subduction affinity, whereas other samples lack this signature. Surprisingly, samples DA12 and G09-10, with the most typical within-plate compositions and close to alkaline compositions in terms of Nb/Yb and TiO₂/Yb (<4 and >0.8, respectively, according to Pearce, 2014), as well as in terms of La/Yb (~9), Sm/Yb (>2) and Y/Zr (0.11), have high La/Nb ratios (~1.4). Conversely, sample G08-10, which also has within-plate-like composition in terms of Nb/Yb and TiO₂/Yb, displays no Nb anomaly (La/Nb ~0.99). As a whole, regarding the B and C sample set, La/Nb ratios vary between 0.81 and 1.89 and Th/Nb ratios vary between 0.10 and 0.28; and these ratios are only weakly correlated with the Nb abundances and other incompatible element ratios indicative of source fertility and/or degrees of partial melting, such as La/Yb, La/Sm (Figs. 14A-C) or whole rock MgO or Mg# (not shown), but broadly correlated with each other (Fig. 14D). This suggests that fractional crystallization and crustal contamination processes could not have played a major role, except perhaps for sample DA10. This sample is the most enriched in REE and shows the more pronounced subduction signature; it has the lowest MgO and Mg# (5.1 wt.%, Mg# 52), with Ni and Cr contents below detection limit both in the whole rock and individual clinopyroxene crystals (for Cr), indicating extensive fractionation of olivine (+ Cr-spinel) and clinopyroxene. However, the silica content of this sample is similar to that of the other group B samples.

Where present, the subduction influence is not as strong as in typical island-arc basalts and basaltic andesites (cf. Gill, 1981; Pearce, 2008, 2014). The most pronounced negative Nb anomalies observed in Dali lavas are moderate (Nb/La >0.5) and not associated with negative Ti anomalies (Fig. 7), as commonly observed in arc lavas. Similarly, enrichments in LILLE are very limited if any; K₂O contents vary between 0.17 and 0.61 wt.% in group B (identified as low-K tholeiites) and between 0.41 and 0.63 wt.% in group C; Ba contents are below 200 ppm in group B lavas with Ba/La ratios varying between 3 and 14 (>15 for common island-
arc basalts) and Ba/Nb ratios varying between 5.5 and 11.8, up to ~27 for sample DA10 (>30 for common island-arc basalts), whereas group C lavas plot on the MORB–OIB mantle array on the Ba/Nb vs. Nb/Zr diagram (Fig. 14E). With respect to usual OIB compositions, group C1 lavas have very high Th/Nb values (Fig. 14F).

In summary, the compositions of the Dali group B and C lavas show close similarities with within-plate basalts; nevertheless, they also bear evidence for mantle sources enriched in H₂O and incompatible elements indicative of sediment-derived fluid/melt component (Dilek and Furnes, 2014; Plank and Langmuir, 1998); moreover, there is no correlation between mantle source enrichment (alkalinity) and subduction signature. Therefore, at least three components are involved in their genesis: a depleted MORB mantle (DMM), an enriched OIB-like source, and a hydrous component.

1052

5.2.2.2 The enriched mantle

1054

The origin of E-MORB requires very small degrees of melting of an enriched mantle source or, alternatively, may be interpreted as a mixture between MORB magmas and more enriched melts. In group B samples, the Nb/Yb ratios (a proxy for alkalinity, Pearce, 2014) are positively correlated with the Sm/Yb ratios, which vary from near-typical MORB values (~1.2 for sample DA5) up to 2.2 (Fig. 15A), which is twice as high as chondritic values; this ratio is often considered as a marker for residual garnet in the source (e.g., Çoban, 2007; Thirlwall et al., 1994). To constrain the possible involvement of garnet during melting, we modelled the variations of the Sm/Nd vs. Sm/Yb ratios assuming that the M- and HREEs were not significantly modified by the subduction component. The results show (Fig. 15B) that the compositional variability of the studied rocks cannot be explained by simple binary
mixing between group B and group C compositions. With the exception of sample DA5,
group B lavas cannot be reproduced by partial melting of depleted (DMM) or enriched (PM)
peridotite in the spinel stability field, but they could be a mixture of melts generated by ~1-
12% melting of an enriched mantle containing a small amount of garnet (~2%). The
composition of sample DA5 matches with ~7% melting of an enriched mantle in the spinel
stability field (not shown). Finally, group C samples do not fit any melting models involving
either enriched peridotite or pyroxenite sources, whatever the chosen mineral modes. On Fig.
15B we have reported the melt trajectory calculated by Waters et al. (2011) for partial melting
of a heterogeneous mantle containing small amounts (≤5%) of garnet-pyroxenite inclusions;
their model simulates mixing of accumulated peridotite melts and pyroxenite melts during
melt extraction and transport in the melting region (see Waters et al., 2011 for more details).
The calculated trajectory (curve D) is not so different from the hypothetical mixing curve
(dotted line). Both curves reproduce reasonably well the observed compositions taking into
consideration the lack of primitive basaltic compositions in our sample set and the importance
of their alteration. Partial melting of a heterogeneous mantle containing veins or blobs of
garnet-bearing mafic rocks enclosed in spinel peridotite might thus be a plausible explanation
for the diversity of the Dali rock composition and preservation of a weak garnet signature in
most group B lavas. Such compositions imply small degrees of melting of the heterogeneous
mantle and/or high proportions of mafic veins/blobs, and group B lavas require higher
degrees of melting of the spinel peridotite than group C lavas.

The low volume of erupted lavas and their hydrous nature are inconsistent with a
plume-derived origin. Instead, decompression melting of upwelling, heterogeneous
asthenospheric mantle above a subduction zone is a more suitable explanation for both the
evidence of hydration and the geochemically revealed subduction influence, as well as the
low-volume of variably enriched basaltic compositions. It is now well established that the
1090 uppermost asthenospheric (MORB) mantle likely contains small-scale heterogeneities, generally considered as garnet-pyroxenites, even in regions not influenced by hotspots (e.g., Lambart et al., 2013; Hirschmann and Stolper, 1996; Pertermann and Hirschmann, 2003; Salters and Dick, 2002; Stracke et al., 1999; Warren et al., 2009). Pyroxenites inferred to be enclosed in the mantle may show a large spectrum of modal and chemical compositions reflecting different origins (Lambart et al., 2013; Stracke and Bourdon, 2009 and therein references). As an alternative, chemical and lithological heterogeneities may result from metasomatic processes in relation with previous subduction event(s) that crystallized ± amphibole ± garnet-clinopyroxene rich mineral assemblages in residual or lithospheric mantle (Ionov and Hofmann, 1995). Melting experiments of pyroxenite-bearing peridotite have shown that pyroxenite and peridotite have similar solidus temperatures under hydrous and oxidizing conditions, compatible with subduction-zone thermal structure, and are able to generate a wide range of compositions from nepheline-normative to quartz-normative during a melting event (Sorbadere et al., 2013b).

1104

1105 5.3 Geodynamic implications

1106

1107 The chemical compositions of the Dali volcanic rocks indicate a transition through time from a depleted mantle wedge (group A) to variably enriched mantle sources (groups B and C). Furthermore, the weak subduction signature observed in groups B and C lavas may indicate a lava emplacement at a greater distance from the arc. In modern arc-back-arc systems, co-existence of volcanic rocks of various magmatic nature, including low volumes of OIB-like lavas and alkaline rocks transitional between calc-alkaline and OIB, has been considered as an indicator of slab-window-generated magmatism following slab break-off
1114 during trench retreat or ridge subduction (e.g., Benoît et al., 2002; Castillo et al., 2007; Hastie et al., 2011; Sajona et al., 1994). By comparison, the small volumes of alkaline and OIB-like magmatic rocks present in some Tethyan ophiolites of Iran and Turkey have been interpreted as the result of late-stage magmatism in response to slab tearing, occurring prior to or during obduction onto a continental block or continental margin (Çelik, 2007; Maghdour-Mashhour et al., 2021; Monsef et al., 2019; Parlak et al., 2006). We suggest a similar scenario for the origin of the Dali group B and C volcanic rocks. The shift from Jurassic intra-oceanic island-arc magmatism to Late Jurassic-Early Cretaceous subalkaline-alkaline, orogenic-anorogenic volcanism, should reflect a major change in the geodynamic regime. The two levels of radiolarite sequences intercalated within the group B and C lavas are dated as Late Tithonian to Valanginian (Asatryan et al., 2012) and they thus constrain, at least partially, the studied Dali volcanic rocks. Moreover, they are the oldest magmatic products with an alkaline affinity recognized so far within the Armenian ophiolites. Elsewhere in Armenia an Aptian age was obtained by Rolland et al. (2009) on a kaersutite from a single alkaline lava in the Vedi area. This volcanism occurred ca. 20 Ma before the ophiolite obduction onto the SAB and closure of the oceanic basin (Hässig et al., 2016a, 2016b; Rolland et al., 2020).

1130

## 6. Conclusions

1132

1. The Dali sector exposes island-arc tholeiites overlying a plutonic complex ascribed to the middle crust of a Jurassic intra-oceanic arc. The contact between the two formations is underlined by epidote-quartz veins, while the volcanic rocks are highly epidotized.

2. To the south-west of Dali sector, a ~100 m thick volcano-sedimentary sequence overthrusts both the arc volcanic and intrusive rocks. The basal part corresponds to low-K
1138 tholeiites derived from enriched mantle source(s), whereas the upper part is represented by
1139 alkaline basalts and trachybasalts. To the south-east, the enriched tholeiites are missing, and
1140 alkaline lavas lie conformably over the plutonic massif. REE modelling suggests that they
1141 were generated by moderate (enriched tholeiites) and very low (alkaline) degrees of melting
1142 of an upper mantle that was lithologically heterogeneous.

1143 3. Both the enriched tholeiites and alkaline lavas show randomly slight to moderate
1144 enrichments in Th and LREE (La) relative to Nb; these enrichments are not correlated with
1145 the degree of alkalinity of the rocks. Moreover, some alkaline lavas contain amphibole
1146 phenocrysts indicating crystallization from hydrous mafic magmas. These characteristics are
1147 ascribed to emplacement in a subduction-related setting.

1148 4. The pelagic sediments (radiolarites) intercalated between the volcanic flows have
1149 been previously dated by Asatryan et al. (2012); they suggest that the enriched lavas erupted
1150 during the Late Tithonian–Valanginian are the oldest alkaline magmatic products recognized
1151 so far within the Armenian ophiolites.

1152 5. The diversity of whole rock magmatic affinities, ranging from MORB-type to OIB-
1153 like, and from orogenic to anorogenic, are also supported by the compositions of the igneous
1154 minerals. By comparison with similar magmatic associations described in the literature, we
1155 suggest an extensional intra-oceanic arc–back-arc geodynamic setting for the Dali
1156 magmatism.

1157

1158 Acknowledgements

1159
1160 We are grateful to the two anonymous reviewers and to Associate Editor Ibrahim Uysal for
1161 their constructive suggestions that greatly improved the initial manuscript. We thank the
1162 Institute of Geological Sciences, NAS, Yerevan, for logistical support and more especially
1163 our driver Marat Yeritsyan, who accompanied us though all our fieldtrips. M.S. thanks Philip
1164 Recourt (Lille) for his assistance with the SEM and Séverine Bellayer (Lille) and Bernard
1165 Boyer (Montpellier) for their assistance with the electron and ion microprobes. We also thank
1166 George Ceuleneer and Azam Soltanmohammadi for useful discussions in many workshops.
1167 Fieldwork and geochemical analyses were funded by the DARIUS programme (PI Danelian)
1168 and the Lille Institute on Environmental Sciences (IRePSE); additional financial support was
1169 provided by the Laboratoire d'Océanologie et de Géosciences, CNRS– University of Lille.
1170 The 2015 visit of Gh. Galoyan to the University of Lille was funded by the *Groupement de
1171 Recherche International (GDRI)* South Caucasus.

1172

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1633 38. doi:10.1016/0168-1176(86)87039-2.

1634 Zlobin, S.K., Zakariadze, G.S., 1985. Geochemical features of island-arc complexes and their
1635 paleo-analogs. Geochemistry 11, 1567–577 (in Russian).

1636 Zlobin, S.K., Zakariadze, G.S., 1993. Composition and the geodynamic conditions of
1637 formation of plutonic series of the ophiolites Sevan-Akera zone, Lesser Caucasus. Petrology
1638 4, 413–430 (in Russian)

1639

1640 **Figure Captions**

1641

1642 Fig. 1 Geological map of the Lesser Caucasus (after Sosson et al., 2010, modified), showing
1643 the geographic distribution of outcrops with ophiolitic units, along the Amasia-Stepanavan-
1644 Sevan-Akera zone and the Vedi ophiolite klippe. The studied Dali sector is indicated north-
1645 east of Lake Sevan.

1646

1647 Fig. 2 Panoramic view of outcrops situated at the western flank of the Dali valley and
1648 location of studied samples. The red line represents a shear fault separating the lithotectonic
1649 units 1 and 2. The yellow line highlights the contact between the plutonic rocks (diorite -
1650 trondhjemite; black cross) and the group A volcanic rocks (orange crosses). The lithotectonic
1651 unit 2 is a volcano-sedimentary sequence, broadly oriented N160°E. Green crosses: group B
1652 samples. Blue samples: group C samples. Late Tithonian radiolarites are associated with
1653 samples G09-10 and DA12 (same lava flow). Valanginian radiolarites are situated just below
1654 sample G10-10. Campanian-Maastrichtian limestones, with basal sandstones, are
1655 transgressive on the ophiolitic lavas.

1656

1657 Fig. 3 Photomicrographs and backscattered electron images (BSE) showing a range of
1658 textures from the Dali lavas. Group A samples: panels (a-c). Group B samples: panels (d-i).
1659 Group C samples: panels (j-o). (a) Sample MS9 (XPL). Microlites of plagioclase (Pg) and
1660 augite partially replaced by amphibole (Cpxam). Secondary epidote (Ep) and quartz filled the
1661 interstices. (b) Sample MS12 (BSE). Augitic clinopyroxene (Cpx) crystals partially
1662 overgrown by honblende (Am1). Arrow indicates actinolite fibers (Am2) formed after the
1663 hornblende. Other abbreviations: albite (Ab) and titanite (Tt). (c) Sample MS13 (PPL). Flow
1664 texture dominated by microlites of plagioclase. Other minerals are augites (Cpx) and
1665 titanomagnetite (Tmt), and secondary quartz enclosing epidote grains (Qu+Ep). (d) Sample
1666 DA5 (PPL). Rare microphenocryst of plagioclase altered to albite and clay minerals set in
1667 hyalomicrolitic groundmass made of plagioclase, augite and titanomagnetite. (e) Sample
1668 DA10 (XPL). Microphenocryst of augitic clinopyroxene (Cpx) within a matrix of plagioclase, clinopyroxene (Cpx) and titanomagnetite. Interstices (Int) are filled with a felty assemblage of phyllosilicates and carbonates. (f) Sample DA13 (BSE). Augitic clinopyroxene phenocryst showing assymmetric resorption and a relic core. (g) Sample G09-10 (XPL). Plagioclase phenocryst set in a microlitic assemblage of plagioclase (Pg), clinopyroxene (Cpx) and titanomagnetite (Tm). (h) Sample DA12 (PPL). Phenocrysts of plagioclase (Pg) and of an opacified mineral interpreted as former amphibole (Am?). (i) Sample G08-10 (PPL). Olivine phenocryst pseudomorph including a coarse grain of Cr-spinel (Cr-Sp). Groundmass is poorly crystallized with abundant quenched interstitial crystals (Int). (j) Sample DA7 (XPL).
1669
1670
1671
1672
1673
1674
1675
1676
1677 Glomerule of clinopyroxenes (diopside). (k) Sample DA7 (PPL). Cluster of brown amphibole (Am, magnesio-hastingsite) phenocryst and microphenocrysts set in a microlitic assemblage of plagioclase (Pg), diopside (Cpx), amphibole and opaque minerals. Patches of calcite (Cc) are common. (l) Sample DA7 (XPL). Microphenocryst of diopside showing subrounded, homogeneous core mantled by a Fe-Ti-rich rim. (m) Sample MS11 (BSE). Clinopyroxene (diopside) phenocryst and microphenocryst showing complex zoning set in a matrix dominated by microcrysts of diopside. (n) Sample MS11 (PPL). Cluster of olivine pseudomorphs. Arrows indicate Cr-spinel grains (Cr-Sp). (o) Sample G10-10 (XPL). Well crystallized assemblage of diopside (Cpx), plagioclase (Pg), amphibole (Am) and titanomagnetite (Tmt).
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687

1688 Fig. 4 Plots of selected incompatible trace element abundances (ppm) in Dali volcanic rocks.
1689 Other tholeiitic (Thol.Arm.) and alkaline (Alk.Arm.) volcanic rocks (SiO₂ ≤ 58 wt% volatile-free) from the Armenian ophiolites are also plotted for comparison (data from Galoyan et al., 2009; Rolland et al., 2009, 2010; Hässig et al., 2013; unpublished data).
1690
1691
1692

1693 Fig. 5 Plots of Armenian ophiolitic volcanic rocks on the diagram Zr/Ti vs. Nb/Y (Floyd and
1694 Winchester, 1975; Pearce, 2014). Same symbols as Fig. 4.

1695

1696 Fig. 6 Chondrite-normalized rare earth element patterns for the Dali volcanic rocks.

1697 Normalizing values and average compositions for N-MORB and E-MORB are from Sun and
1698 McDonough (1989). The primitive island arc tholeiite (IAT) and average compositions of
1699 OIB are after Ewart et al. (1998) and Willbold and Stracke (2006), respectively.

1700

1701 Fig. 7 Multi-element patterns for the Dali volcanic rocks normalized to N-MORB (panels A
1702 and B) and to the primitive mantle (PM; panels C and D). Normalizing values are from Sun
1703 and McDonough (1989). Dashed red line represents OIB composition the less enriched in
1704 incompatible trace elements (Willbold and Stracke, 2006). Same symbols as Fig. 6.

1705

1706 Fig. 8 Plots of Th/Yb vs. Nb/Yb for Armenian ophiolitic (SiO₂ ≤ 58 wt% volatile-free)
1707 volcanic rocks and for a Dali diorite sample (DA3, Table 1). Fields are from Pearce (2014).
1708 Same symbols as Fig. 4.

1709

1710 Fig. 9 Variations of clinopyroxene compositions from Dali volcanic rocks. Panels A and B:
1711 Al₂O₃ vs. Mg# and TiO₂ vs. Mg# for group A and group C rocks. Panels C and D: Al₂O₃ vs.
1712 Mg# and TiO₂ vs. Mg# for group B rocks. Gdm= groundmass microlites (including
1713 microphenocrysts in group A, DA5 and DA10 samples). Pc = phenocryst cores. mPhc =
1714 microphenocryst cores (and phenocryst mantles for samples DA6 and DA8). On panels C and
1715 D, fields correspond to group A (green) and group C (blue) clinopyroxene compositions. Mg#
1716 is defined as 100.Mg/(Mg+Fe*) with Fe* = Fe total as FeO.

1717

1718 Fig. 10 Chondrite-normalized REE patterns of clinopyroxenes from Dali volcanic rocks (thin
1719 black lines) and of two amphiboles from sample DA7 (thin orange lines). Melts in
1720 equilibrium with the average compositions of the clinopyroxenes and amphiboles (dashed
1721 lines) are calculated using partition coefficients (K<sub>D</sub> phenocryst/matrix)) of Fujimak et al.
1722 (1984) for clinopyroxene in tholeiitic basalt for the samples MS12, DA10, DA13, of Zajacz
1723 and Halter (2007) for clinopyroxene in alkaline basalt for DA7, MS11, G10-10. Partition
1724 coefficient between amphibole and alkaline basalt is from Tiepolo et al. (2000). Mg# of
1725 analyzed crystals are indicated. Thick lines are bulk rock compositions.

1726

1727 Fig. 11 Plot of Fe*/Mg in clinopyroxene vs. Fe²⁺/Mg in whole rock for the porphyritic
1728 volcanic rocks. The K<sub>D</sub> Fe/Mg exchange coefficient between clinopyroxene and basaltic melt
1729 is from Pichavant and Macdonald (2007). Sample G08-10 contains no pyroxene phenocrysts
1730 but abundant olivine pseudomorphs enclosing Cr-spinel grains, which cannot be in
1731 equilibrium with the Fe-rich clinopyroxene microlites.

1732

1733 Fig. 12 Compositions of amphiboles from Dali volcanic rocks. Panel A: Mg# vs. Si; the
1734 nomenclature is after Leake et al. (1997). Panel B: Ti vs. Al<sup>IV</sup>; the dotted lines represent (1)
1735 the mean compositional trend and (2) the lower boundary field of natural calcic amphiboles
1736 from calc-alkaline and alkaline volcanic rocks. Panel C: (Na+K)<sub>A</sub> vs. Al<sup>IV</sup>. Panel D: K vs.
1737 AlIV. In panels B–D fields for calcic amphiboles in equilibrium with calc-alkaline and alkaline magmatic suites are from Ridolfi and Renzulli (2012). Atoms par formula unit (apfu) are calculated on the basis of 13 cations excluding Ca, Na, K.

1740

1741 Fig. 13 Compositions of spinels from Dali group B (samples G08-10, MS5, AR16-02) and group C2 (samples MS6, MS11) volcanic rocks. Panel A: Cr–Al diagram of Mata and Munhà (2004); UM = Cr-spinel field for ultramafic rocks; M = Cr-spinel field for mafic rocks. The line Cr+Al = 16 corresponds to the Cr–Al trend defined by the majority of magmatic Cr-spinels. The arrow indicates the transition from Cr-spinel to titanomagnetite. Panel B: Cr–Al and Fe–Ti trends after Barnes and Roeder (2001). Panel C: TiO₂ vs. Al₂O₃ diagram. Fields for intra-oceanic arc basalts, MORB, Large Igneous Province (LIP) and OIB are from Kamenetsky et al. (2001). Field for calc-alkaline – OIB basalts (CAB-OIB) from the Cascades continental arc is drawn using Conrey et al. (1997)'s data. Titanomagnetite (Ti-mt) compositions plotted on the diagrams are those occurring as euhedral crystals in groundmass.

1751

1752 Fig. 14 Plots of incompatible element ratios for the studied Dali volcanic rocks. These diagrams show that there are no correlation between mantle source enrichment (Nb, La/Sm, Nb/Zr) and subduction signature (La/Nb, Th/Nb, Ba/Nb). Average subducted sediment value (GLOSS = Global Subducted Sediment) is after Plank and Langmuir (1998). Th/Nb ratios separate samples with arc-like signature (Th/Nb > ~0.12, Pearce, 2014) from samples having chondritic Th/Nb ratios. Same symbols as Fig. 4.

1758
1759 Fig. 15 Plots of Nb/Yb vs. Sm/Yb (A) and Sm/Yb vs. Sm/Nd (B) for the studied Dali volcanic rocks. Panel B: accumulated non-modal fractional melting melts for spinel lherzolite (DMM; curve A), garnet-bearing primitive mantle with 2% garnet (curve B) and 5% garnet (curve C). Batch melting garnet-pyroxenite (80% cpx + 20% garnet; curve D). Crosses on the melting trajectories (curves A–C) indicate melting 0.1%, 1–5% in 1% increments, then 10% and 15%. Crosses on curve D indicate 0.1%, 1–5% in 1% increments, 10–40% in 5% increments, then 50%. Curve E is a mixed melt trajectory calculated by mixing garnet-pyroxenite and peridotite melts within the melting region (cf Waters et al., 2011). Parameters are those used by Waters et al., 2011: depleted MORB Mantle (DMM) after Workman and Hart, 2005, primitive mantle (PM) after Sun and McDonough, 1989, proxy for garnet-pyroxenite after Donnelly et al., 2004. Melting modes and partition coefficients for mantle melting after Donnelly et al., 2004. Modes and bulk coefficients after Waters et al., 2011. In (A) and (B) dotted line is a hypothetical mixing curve. Symbols as Fig. 4.

1772

1773 Table Captions

1774

1775 Table 1. Major and trace element compositions of Dali volcanic rocks.

1776

1777 Table 2. Major element compositions in wt.% of clinopyroxenes of Dali volcanic rocks classified by textural types.

1779
1780 Table 3. Rare Earth Element concentrations in ppm for clinopyroxenes and amphiboles of a

1781 selection of Dali volcanic rocks

1782

1783 Table 4. Major element compositions in wt.% of amphiboles of Dali volcanic rocks.

1784

1785 Table 5. Major element compositions in wt.% of spinels of Dali volcanic rocks.
<figure><img src="image_2.png" /></figure>

## South Armenian Block

## Eurasian Margin: Zombekte-Karabagh Island Area and Greater Cenozoic Crevasses

Cretaceous and Cenozoic intrusions

Albanian to Maastrichtian sediments

Crustaceans to Maastrichtian sediments

Upper Jurassic - Lower Cretaceous intrusions

Cretaceous in Middle Miocene

Deposition to Late Jurassic

Sedimentary and alkaline volcanics

Deposition to Palaeozoic terrains formations

Depositional palaeoterraneum: sedimentation

Hercynian orogeny

Volcanic and magmatic features

Jurassic sediments of Greater Cenozoic Crevasses

47°N
<figure><img src="image_3.png" /></figure>

Lithotectonic Unit 2

AR-16

G15-99

MS13

DA13

MS13

DA13

MS13

DA13

MS13

DA13

MS13

DA13

MS13

DA13

Lithotectonic Unit 4

AR-16

G15-99

MS13

DA13

MS13

DA13

MS13

DA13

MS13

DA13

MS13

DA13

MS13

DA13
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<table><caption>Table 1. Major and trace element compositions of Dali volcanic rocks</caption><thead><tr><th>Sample #</th><th>AR-03-17*</th><th>MS9</th><th>MS12</th><th>MS13</th><th>MS14</th><th>DA5</th><th>DA10</th><th>DA13</th><th>DA12</th><th>G09-10</th><th>G08-10</th><th>DA6</th><th>DA7</th><th>DA8</th><th>G10-10</th><th>MS11</th><th>DA3</th></tr><tr><th>Group</th><th>A</th><th>A</th><th>A</th><th>A</th><th>A</th><th>B</th><th>B</th><th>B</th><th>B</th><th>B</th><th>B</th><th>C1</th><th>C1</th><th>C1</th><th>C2</th><th>C2</th><th>DIORITE</th></tr></thead><tbody><tr><td colspan="18">Results in wt.%</td></tr><tr><td>SiO<sub>2</sub></td><td>54.27</td><td>47.45</td><td>45.72</td><td>63.70</td><td>44.04</td><td>49.41</td><td>51.39</td><td>47.35</td><td>49.88</td><td>50.96</td><td>43.44</td><td>46.47</td><td>44.99</td><td>48.09</td><td>41.20</td><td>37.58</td><td>50.71</td></tr><tr><td>TiO<sub>2</sub></td><td>1.33</td><td>0.80</td><td>1.09</td><td>1.11</td><td>1.27</td><td>1.18</td><td>1.50</td><td>0.93</td><td>1.65</td><td>1.66</td><td>1.55</td><td>1.72</td><td>1.74</td><td>1.71</td><td>2.96</td><td>1.94</td><td>16.70</td></tr><tr><td>Al<sub>2</sub>O<sub>3</sub></td><td>15.16</td><td>15.90</td><td>15.78</td><td>12.58</td><td>17.14</td><td>14.49</td><td>16.03</td><td>13.12</td><td>16.61</td><td>16.75</td><td>14.22</td><td>17.12</td><td>15.62</td><td>16.04</td><td>13.87</td><td>9.53</td><td>9.41</td></tr><tr><td>Fe<sub>2</sub>O<sub>3</sub></td><td>12.36</td><td>8.07</td><td>12.63</td><td>10.44</td><td>12.42</td><td>8.16</td><td>10.37</td><td>8.20</td><td>8.39</td><td>8.27</td><td>13.09</td><td>9.99</td><td>9.19</td><td>9.27</td><td>14.98</td><td>10.47</td><td>0.17</td></tr><tr><td>MnO</td><td>0.19</td><td>0.17</td><td>0.22</td><td>0.13</td><td>0.21</td><td>0.15</td><td>0.17</td><td>0.16</td><td>0.16</td><td>0.15</td><td>0.16</td><td>0.15</td><td>0.16</td><td>0.12</td><td>0.24</td><td>0.19</td><td>7.84</td></tr><tr><td>MgO</td><td>3.74</td><td>6.45</td><td>4.19</td><td>2.76</td><td>2.57</td><td>7.83</td><td>4.91</td><td>6.70</td><td>6.59</td><td>6.49</td><td>4.51</td><td>3.39</td><td>5.75</td><td>3.17</td><td>5.62</td><td>6.93</td><td>10.12</td></tr><tr><td>CaO</td><td>4.38</td><td>16.18</td><td>18.33</td><td>2.90</td><td>20.78</td><td>9.84</td><td>6.03</td><td>10.39</td><td>3.54</td><td>3.95</td><td>12.77</td><td>7.61</td><td>10.46</td><td>7.56</td><td>11.12</td><td>20.36</td><td>2.67</td></tr><tr><td>Na<sub>2</sub>O</td><td>6.63</td><td>2.11</td><td>0.89</td><td>6.07</td><td>0.06</td><td>3.81</td><td>6.13</td><td>4.04</td><td>6.08</td><td>6.08</td><td>3.82</td><td>5.95</td><td>4.92</td><td>6.47</td><td>3.14</td><td>1.39</td><td>0.54</td></tr><tr><td>K<sub>2</sub>O</td><td>&lt; D.L.</td><td>0.02</td><td>0.02</td><td>0.03</td><td>&lt; D.L.</td><td>0.15</td><td>0.25</td><td>0.33</td><td>0.35</td><td>0.37</td><td>0.54</td><td>0.51</td><td>0.47</td><td>0.37</td><td>0.36</td><td>0.53</td><td>0.31</td></tr><tr><td>P<sub>2</sub>O<sub>5</sub></td><td>0.15</td><td>0.06</td><td>0.11</td><td>0.10</td><td>0.12</td><td>0.15</td><td>0.30</td><td>0.11</td><td>0.36</td><td>0.43</td><td>0.24</td><td>0.75</td><td>0.63</td><td>0.66</td><td>0.42</td><td>0.30</td><td>&lt; D.L.</td></tr><tr><td>LOI</td><td>1.78</td><td>3.23</td><td>1.76</td><td>1.34</td><td>1.63</td><td>4.77</td><td>3.43</td><td>7.93</td><td>5.26</td><td>4.81</td><td>6.57</td><td>6.40</td><td>7.01</td><td>6.90</td><td>7.06</td><td>10.76</td><td>1.82</td></tr><tr><td>Total</td><td>99.99</td><td>100.44</td><td>100.72</td><td>101.17</td><td>100.24</td><td>99.95</td><td>100.52</td><td>99.26</td><td>98.85</td><td>99.95</td><td>100.90</td><td>100.06</td><td>100.95</td><td>100.36</td><td>100.97</td><td>99.97</td><td>100.28</td></tr><tr><td>CO<sub>2</sub> total</td><td>n.a.</td><td>0.05</td><td>0.06</td><td>0.01</td><td>0.10</td><td>1.62</td><td>0.07</td><td>5.50</td><td>0.67</td><td>0.45</td><td>3.74</td><td>3.02</td><td>2.11</td><td>3.72</td><td>4.25</td><td>8.20</td><td>0.03</td></tr><tr><td>H<sub>2</sub>O total</td><td>n.a.</td><td>3.73</td><td>2.11</td><td>1.75</td><td>1.85</td><td>3.74</td><td>3.83</td><td>4.09</td><td>5.07</td><td>4.88</td><td>3.58</td><td>3.98</td><td>5.11</td><td>3.60</td><td>3.87</td><td>3.16</td><td>2.41</td></tr><tr><td colspan="18">Recalculated volatile-free with Fe<sup>3+</sup>/Fe<sup>2+</sup> = 0.15</td></tr><tr><td>SiO<sub>2</sub></td><td>55.87</td><td>49.17</td><td>46.72</td><td>64.40</td><td>45.16</td><td>52.30</td><td>53.42</td><td>52.25</td><td>53.72</td><td>53.98</td><td>46.61</td><td>50.08</td><td>48.30</td><td>51.90</td><td>44.49</td><td>42.56</td><td>51.45</td></tr><tr><td>TiO<sub>2</sub></td><td>1.37</td><td>0.83</td><td>1.11</td><td>1.12</td><td>1.31</td><td>1.25</td><td>1.56</td><td>1.02</td><td>1.78</td><td>1.76</td><td>1.66</td><td>1.86</td><td>1.87</td><td>1.84</td><td>3.20</td><td>2.20</td><td>16.94</td></tr><tr><td>Al<sub>2</sub>O<sub>3</sub></td><td>15.61</td><td>16.47</td><td>16.12</td><td>12.72</td><td>17.57</td><td>15.34</td><td>16.67</td><td>14.48</td><td>17.88</td><td>17.75</td><td>15.26</td><td>18.45</td><td>16.77</td><td>17.31</td><td>14.98</td><td>10.79</td><td>9.55</td></tr><tr><td>Fe<sub>2</sub>O<sub>3</sub></td><td>1.65</td><td>1.09</td><td>1.68</td><td>1.37</td><td>1.66</td><td>1.12</td><td>1.40</td><td>1.18</td><td>1.17</td><td>1.14</td><td>1.83</td><td>1.40</td><td>1.28</td><td>1.30</td><td>2.10</td><td>1.54</td><td>1.17</td></tr><tr><td>FeO</td><td>9.96</td><td>6.55</td><td>10.10</td><td>8.26</td><td>9.97</td><td>6.77</td><td>8.44</td><td>7.08</td><td>7.07</td><td>6.86</td><td>10.99</td><td>8.43</td><td>7.72</td><td>7.83</td><td>12.67</td><td>9.29</td><td>7.05</td></tr><tr><td>MnO</td><td>0.20</td><td>0.18</td><td>0.22</td><td>0.14</td><td>0.22</td><td>0.16</td><td>0.18</td><td>0.18</td><td>0.17</td><td>0.16</td><td>0.18</td><td>0.16</td><td>0.18</td><td>0.13</td><td>0.26</td><td>0.21</td><td>0.00</td></tr><tr><td>MgO</td><td>3.85</td><td>6.69</td><td>4.28</td><td>2.79</td><td>2.64</td><td>8.29</td><td>5.11</td><td>7.40</td><td>7.09</td><td>6.88</td><td>4.84</td><td>3.65</td><td>6.18</td><td>3.42</td><td>6.07</td><td>7.84</td><td>10.27</td></tr><tr><td>CaO</td><td>4.51</td><td>16.76</td><td>18.73</td><td>2.93</td><td>21.30</td><td>10.41</td><td>6.27</td><td>11.46</td><td>3.81</td><td>4.18</td><td>13.70</td><td>8.20</td><td>11.23</td><td>8.16</td><td>12.01</td><td>23.06</td><td>2.71</td></tr><tr><td>Na<sub>2</sub>O</td><td>6.83</td><td>2.19</td><td>0.91</td><td>6.14</td><td>0.06</td><td>4.04</td><td>6.37</td><td>4.46</td><td>6.54</td><td>6.44</td><td>4.10</td><td>6.41</td><td>5.29</td><td>6.98</td><td>3.39</td><td>1.57</td><td>0.55</td></tr><tr><td>K<sub>2</sub>O</td><td>0.00</td><td>0.02</td><td>0.02</td><td>0.03</td><td>0.00</td><td>0.16</td><td>0.26</td><td>0.36</td><td>0.37</td><td>0.40</td><td>0.58</td><td>0.55</td><td>0.50</td><td>0.40</td><td>0.38</td><td>0.60</td><td>0.31</td></tr><tr><td>P<sub>2</sub>O<sub>5</sub></td><td>0.15</td><td>0.06</td><td>0.11</td><td>0.10</td><td>0.12</td><td>0.16</td><td>0.31</td><td>0.12</td><td>0.39</td><td>0.46</td><td>0.26</td><td>0.81</td><td>0.68</td><td>0.71</td><td>0.45</td><td>0.34</td><td>0.00</td></tr><tr><td colspan="18">Trace elements in ppm</td></tr><tr><td>Ba</td><td>19.01</td><td>8.076</td><td>14.45</td><td>25.06</td><td>6.222</td><td>45.97</td><td>194.05</td><td>71.52</td><td>187.2</td><td>176.5</td><td>78.71</td><td>234.4</td><td>207.3</td><td>141.4</td><td>255.3</td><td>319.5</td><td>75.69</td></tr><tr><td>Ce</td><td>10.93</td><td>5.656</td><td>10.46</td><td>9.102</td><td>10.64</td><td>15.29</td><td>31.515</td><td>14.64</td><td>33.84</td><td>39.3</td><td>20.2</td><td>104.8</td><td>96.33</td><td>98.14</td><td>64.06</td><td>48.12</td><td>2.676</td></tr><tr><td>Co</td><td>24.33</td><td>30.86</td><td>23.27</td><td>24.55</td><td>13.7</td><td>46.59</td><td>31.975</td><td>36.6</td><td>29.55</td><td>29.78</td><td>61.92</td><td>29.98</td><td>32.5</td><td>30.95</td><td>44.07</td><td>66.94</td><td>&lt; D.L.</td></tr><tr><td>Cr</td><td>&lt; D.L.</td><td>197.7</td><td>16.86</td><td>&lt; D.L.</td><td>9.817</td><td>167.6</td><td>&lt; D.L.</td><td>85.39</td><td>100.1</td><td>99.97</td><td>683.6</td><td>46.34</td><td>111.3</td><td>65.15</td><td>7.882</td><td>1068</td><td>31.16</td></tr><tr><td>Dy</td><td>4.99</td><td>2.739</td><td>4.078</td><td>4.33</td><td>4.547</td><td>4.28</td><td>4.921</td><td>3.499</td><td>3.333</td><td>3.735</td><td>3.657</td><td>4.158</td><td>3.921</td><td>3.898</td><td>4.944</td><td>3.608</td><td>1.951</td></tr><tr><td>Er</td><td>3.11</td><td>1.717</td><td>2.57</td><td>2.726</td><td>2.856</td><td>2.547</td><td>2.8435</td><td>2.019</td><td>1.796</td><td>2.013</td><td>1.936</td><td>1.932</td><td>1.772</td><td>1.747</td><td>2.345</td><td>1.608</td><td>1.308</td></tr><tr><td>Eu</td><td>1.15</td><td>0.522</td><td>1.133</td><td>0.873</td><td>0.965</td><td>1.171</td><td>1.6185</td><td>0.889</td><td>1.372</td><td>1.514</td><td>1.232</td><td>2.278</td><td>2.212</td><td>2.165</td><td>2.182</td><td>1.695</td><td>0.393</td></tr><tr><td>Gd</td><td>4.18</td><td>2.171</td><td>3.278</td><td>3.461</td><td>3.529</td><td>3.806</td><td>4.942</td><td>3.013</td><td>3.49</td><td>3.996</td><td>3.747</td><td>6.09</td><td>5.619</td><td>5.495</td><td>6.032</td><td>4.424</td><td>1.491</td></tr><tr><td>Hf</td><td>2.38</td><td>1.287</td><td>1.865</td><td>2.153</td><td>2.193</td><td>1.93</td><td>3.2785</td><td>1.927</td><td>3.383</td><td>3.978</td><td>2.428</td><td>4.183</td><td>3.971</td><td>4.026</td><td>4.703</td><td>3.236</td><td>0.486</td></tr><tr><td>Ho</td><td>1.06</td><td>0.639</td><td>0.939</td><td>0.99</td><td>1.029</td><td>0.892</td><td>0.991</td><td>0.769</td><td>0.689</td><td>0.722</td><td>0.717</td><td>0.72</td><td>0.715</td><td>0.707</td><td>0.895</td><td>0.673</td><td>0.46</td></tr><tr><td>La</td><td>3.91</td><td>1.857</td><td>3.758</td><td>2.865</td><td>3.79</td><td>6.563</td><td>13.665</td><td>6.086</td><td>15.45</td><td>17.7</td><td>8.827</td><td>49.15</td><td>45.22</td><td>46.07</td><td>30.42</td><td>23.38</td><td>0.91</td></tr><tr><td>Lu</td><td>0.51</td><td>0.267</td><td>0.392</td><td>0.419</td><td>0.446</td><td>0.372</td><td>0.435</td><td>0.266</td><td>0.257</td><td>0.303</td><td>0.266</td><td>0.244</td><td>0.22</td><td>0.22</td><td>0.291</td><td>0.185</td><td>0.218</td></tr><tr><td>Nb</td><td>1.44</td><td>0.628</td><td>1.524</td><td>1.242</td><td>1.572</td><td>5.022</td><td>7.2235</td><td>6.228</td><td>10.79</td><td>13.11</td><td>8.921</td><td>30.29</td><td>24.13</td><td>25.69</td><td>37.58</td><td>27.02</td><td>0.207</td></tr><tr><td>Nd</td><td>9.35</td><td>5.014</td><td>8.114</td><td>&lt; D.L.</td><td>8.678</td><td>10.03</td><td>18.705</td><td>8.954</td><td>16.75</td><td>19.3</td><td>12.67</td><td>45.96</td><td>42.44</td><td>42.97</td><td>31.75</td><td>23.5</td><td>2.688</td></tr><tr><td>Ni</td><td>5.14</td><td>67.39</td><td>19.19</td><td>&lt; D.L.</td><td>13.19</td><td>54.84</td><td>&lt; D.L.</td><td>33.15</td><td>66.21</td><td>67.99</td><td>209.2</td><td>50.92</td><td>63.66</td><td>55.06</td><td>48.09</td><td>417.9</td><td>24.95</td></tr><tr><td>Pb</td><td>4.45</td><td>1.2274</td><td>1.7832</td><td>4.1791</td><td>10.1658</td><td>&lt; D.L.</td><td>1.0448</td><td>&lt; D.L.</td><td>5.8814</td><td>3.3281</td><td>1.1214</td><td>3.7479</td><td>7.798</td><td>13.1656</td><td>2.8275</td><td>2.7818</td><td>0.8002</td></tr><tr><td>Pr</td><td>1.81</td><td>0.944</td><td>1.625</td><td>1.546</td><td>1.683</td><td>2.089</td><td>4.1865</td><td>1.966</td><td>4.138</td><td>4.83</td><td>2.849</td><td>12.14</td><td>11.26</td><td>11.42</td><td>7.849</td><td>5.822</td><td>0.473</td></tr><tr><td>Sc</td><td>n.a.</td><td>40.26</td><td>32.37</td><td>29.15</td><td>28.51</td><td>46.71</td><td>30.59</td><td>39.73</td><td>17.83</td><td>n.a.</td><td>n.a.</td><td>20.34</td><td>25.3</td><td>21.63</td><td>n.a.</td><td>34.19</td><td>47.22</td></tr><tr><td>Sm</td><td>3.26</td><td>1.722</td><td>2.662</td><td>2.836</td><td>2.898</td><td>3.036</td><td>4.7915</td><td>2.555</td><td>3.839</td><td>4.212</td><td>3.389</td><td>7.963</td><td>7.638</td><td>7.56</td><td>6.681</td><td>4.98</td><td>1.065</td></tr><tr><td>Sr</td><td>49.82</td><td>126.9</td><td>266.6</td><td>40.06</td><td>249.7</td><td>175.8</td><td>709</td><td>207.2</td><td>644.5</td><td>705.9</td><td>255.8</td><td>760.5</td><td>571.6</td><td>557.4</td><td>533.3</td><td>452.8</td><td>221.6</td></tr><tr><td>Ta</td><td>0.12</td><td>0.065</td><td>0.14</td><td>0.113</td><td>0.145</td><td>0.388</td><td>0.531</td><td>0.643</td><td>0.934</td><td>1.124</td><td>0.717</td><td>2.014</td><td>1.731</td><td>1.85</td><td>2.879</td><td>2.142</td><td>0.016</td></tr><tr><td>Tb</td><td>0.75</td><td>0.394</td><td>0.597</td><td>0.624</td><td>0.647</td><td>0.654</td><td>0.806</td><td>0.523</td><td>0.541</td><td>0.629</td><td>0.604</td><td>0.807</td><td>0.747</td><td>0.725</td><td>0.896</td><td>0.634</td><td>0.272</td></tr><tr><td>Th</td><td>0.37</td><td>0.143</td><td>0.37</td><td>0.346</td><td>0.384</td><td>0.506</td><td>1.7875</td><td>1.014</td><td>1.652</td><td>1.977</td><td>0.888</td><td>7.965</td><td>6.839</td><td>7.199</td><td>3.896</td><td>2.698</td><td>0.082</td></tr><tr><td>Trm</td><td>0.47</td><td>0.253</td><td>0.383</td><td>0.401</td><td>0.42</td><td>0.374</td><td>0.42</td><td>0.286</td><td>0.261</td><td>0.29</td><td>0.28</td><td>0.261</td><td>0.23</td><td>0.227</td><td>0.323</td><td>0.207</td><td>0.201</td></tr><tr><td>U</td><td>0.27</td><td>0.044</td><td>0.128</td><td>0.178</td><td>0.125</td><td>0.356</td><td>0.5335</td><td>1.223</td><td>0.57</td><td>0.72</td><td>0.291</td><td>1.74</td><td>1.476</td><td>1.587</td><td>0.921</td><td>0.667</td><td>0.069</td></tr><tr><td>V</td><td>321.8</td><td>215.7</td><td>302.6</td><td>275.7</td><td>303.1</td><td>238.6</td><td>287.55</td><td>198.1</td><td>131.1</td><td>134.3</td><td>205.7</td><td>267.8</td><td>245.5</td><td>246.1</td><td>312.8</td><td>233</td><td>256.2</td></tr><tr><td>Y</td><td>29.88</td><td>16.34</td><td>24.71</td><td>25.27</td><td>26.88</td><td>25.24</td><td>28.97</td><td>20.82</td><td>18.15</td><td>20.64</td><td>20.4</td><td>21.56</td><td>18.65</td><td>18.78</td><td>24.62</td><td>17.36</td><td>12.49</td></tr><tr><td>Yb</td><td>3.22</td><td>1.718</td><td>2.575</td><td>2.757</td><td>2.851</td><td>2.472</td><td>2.828</td><td>1.819</td><td>1.723</td><td>1.972</td><td>1.789</td><td>1.67</td><td>1.462</td><td>1.477</td><td>2.052</td><td>1.301</td><td>1.402</td></tr><tr><td>Zr</td><td>85.6</td><td>44.73</td><td>64.98</td><td>71.68</td><td>77.3</td><td>73.57</td><td>144.75</td><td>60.18</td><td>170.8</td><td>215.9</td><td>92.82</td><td>206.4</td><td>172.2</td><td>178.4</td><td>196.2</td><td>121</td><td>11.64</td></tr></tbody></table>

<footnote>* from Galoyan et al. (2009)
< D.L. means below detection limit
n.a. means not analyzed</footnote>
<table><caption>Table 3. Rare Earth Element concentrations in ppm for clinopyroxenes and amphiboles of a selection of Dali volcanic rocks*</caption><thead><tr><th>Group</th><th>Sample</th><th>Mineral</th><th>Grain #</th><th>La</th><th>Ce</th><th>Nd</th><th>Sm</th><th>Eu</th><th>Gd</th><th>Tb</th><th>Dy</th><th>Ho</th><th>Er</th><th>Yb</th></tr></thead><tbody><tr><td>A</td><td>MS12</td><td>cpx</td><td>sims1</td><td>0.3878</td><td>2.252</td><td>4.330</td><td>2.181</td><td>0.863</td><td>3.850</td><td>0.682</td><td>4.858</td><td>1.0267</td><td>3.048</td><td>2.680</td></tr><tr><td>A</td><td>MS12</td><td>cpx</td><td>sims2</td><td>0.3753</td><td>1.728</td><td>3.565</td><td>1.959</td><td>0.660</td><td>3.267</td><td>0.599</td><td>4.316</td><td>0.8929</td><td>2.493</td><td>2.173</td></tr><tr><td>A</td><td>MS12</td><td>cpx</td><td>sims3</td><td>0.4208</td><td>1.901</td><td>3.740</td><td>2.211</td><td>0.764</td><td>3.923</td><td>0.662</td><td>4.712</td><td>0.9600</td><td>2.824</td><td>2.567</td></tr><tr><td>B</td><td>DA10</td><td>cpx</td><td>sims1</td><td>0.7155</td><td>2.860</td><td>3.931</td><td>1.626</td><td>0.590</td><td>2.080</td><td>n.a.</td><td>2.128</td><td>n.a.</td><td>1.199</td><td>1.221</td></tr><tr><td>B</td><td>DA10</td><td>cpx</td><td>sims2</td><td>0.7744</td><td>2.952</td><td>3.901</td><td>1.773</td><td>0.581</td><td>2.263</td><td>n.a.</td><td>2.217</td><td>n.a.</td><td>1.333</td><td>1.339</td></tr><tr><td>B</td><td>DA10</td><td>cpx</td><td>sims3</td><td>1.0482</td><td>4.080</td><td>5.901</td><td>2.449</td><td>0.614</td><td>3.162</td><td>n.a.</td><td>3.229</td><td>n.a.</td><td>2.010</td><td>1.873</td></tr><tr><td>B</td><td>DA10</td><td>cpx</td><td>sims4</td><td>1.1891</td><td>4.138</td><td>6.144</td><td>2.541</td><td>0.596</td><td>3.394</td><td>n.a.</td><td>3.337</td><td>n.a.</td><td>2.081</td><td>1.980</td></tr><tr><td>B</td><td>DA13</td><td>cpx</td><td>sims1</td><td>1.5762</td><td>5.279</td><td>6.311</td><td>2.217</td><td>0.819</td><td>3.177</td><td>0.578</td><td>3.865</td><td>0.8603</td><td>2.435</td><td>2.357</td></tr><tr><td>C1</td><td>DA7</td><td>cpx</td><td>sims1</td><td>2.9197</td><td>10.790</td><td>10.660</td><td>3.232</td><td>1.008</td><td>3.017</td><td>0.433</td><td>1.973</td><td>0.3787</td><td>0.921</td><td>0.678</td></tr><tr><td>C1</td><td>DA7</td><td>cpx</td><td>sims2</td><td>3.5704</td><td>13.204</td><td>13.802</td><td>4.010</td><td>1.194</td><td>3.591</td><td>0.501</td><td>2.428</td><td>0.4243</td><td>0.991</td><td>0.812</td></tr><tr><td>C1</td><td>DA7</td><td>amphibole</td><td>sims3</td><td>6.3484</td><td>21.570</td><td>19.610</td><td>5.005</td><td>1.408</td><td>5.255</td><td>0.675</td><td>3.196</td><td>0.5839</td><td>1.411</td><td>1.031</td></tr><tr><td>C1</td><td>DA7</td><td>amphibole</td><td>sims4</td><td>9.6232</td><td>30.907</td><td>22.877</td><td>6.216</td><td>1.574</td><td>6.689</td><td>0.874</td><td>4.292</td><td>0.7643</td><td>1.797</td><td>1.598</td></tr><tr><td>C2</td><td>G10-10</td><td>cpx</td><td>sims1</td><td>0.8818</td><td>3.076</td><td>3.404</td><td>1.179</td><td>0.393</td><td>1.283</td><td>0.182</td><td>1.000</td><td>0.1968</td><td>0.473</td><td>0.384</td></tr><tr><td>C2</td><td>G10-10</td><td>cpx</td><td>sims2</td><td>1.1734</td><td>4.391</td><td>5.243</td><td>1.907</td><td>0.692</td><td>2.169</td><td>0.303</td><td>1.765</td><td>0.3224</td><td>0.734</td><td>0.551</td></tr><tr><td>C2</td><td>MS11</td><td>cpx</td><td>sims1</td><td>1.9839</td><td>7.046</td><td>7.275</td><td>2.254</td><td>0.823</td><td>2.649</td><td>0.413</td><td>2.076</td><td>0.3977</td><td>0.962</td><td>0.783</td></tr><tr><td>C2</td><td>MS11</td><td>cpx</td><td>sims2</td><td>4.1137</td><td>12.618</td><td>12.323</td><td>3.576</td><td>1.147</td><td>4.102</td><td>0.580</td><td>3.034</td><td>0.5555</td><td>1.332</td><td>1.077</td></tr><tr><td>C2</td><td>MS11</td><td>cpx</td><td>sims3</td><td>2.7843</td><td>9.335</td><td>8.925</td><td>2.683</td><td>0.801</td><td>3.119</td><td>0.443</td><td>2.287</td><td>0.4288</td><td>1.108</td><td>0.783</td></tr></tbody></table>

<footnote>*Major element compositions are given in Table 2</footnote>

<footnote>n.a. means not analyzed</footnote>
<table><caption>Table 4. Major element compositions in wt.% of amphiboles of Dali volcanic rocks</caption><thead><tr><th>Group</th><th>Sample</th><th>Texture</th><th>N</th><th>SIMS</th><th>SiO<sub>2</sub></th><th>±</th><th>TiO<sub>2</sub></th><th>±</th><th>Al<sub>2</sub>O<sub>3</sub></th><th>±</th><th>Cr<sub>2</sub>O<sub>3</sub></th><th>±</th><th>FeO</th><th>±</th><th>MnO</th><th>±</th><th>MgO</th><th>±</th><th>CaO</th><th>±</th><th>Na<sub>2</sub>O</th><th>±</th><th>K<sub>2</sub>O</th><th>±</th><th>Total</th><th>Mg#</th><th>±</th></tr></thead><tbody><tr><td>A</td><td>MS9</td><td>avg on cpx</td><td>3</td><td></td><td>43.44</td><td>0.30</td><td>0.31</td><td>0.07</td><td>10.37</td><td>0.14</td><td>0.01</td><td>0.00</td><td>18.16</td><td>0.79</td><td>0.32</td><td>0.07</td><td>10.71</td><td>0.65</td><td>11.83</td><td>0.03</td><td>1.54</td><td>0.02</td><td>0.44</td><td>0.14</td><td>97.13</td><td>51.24</td><td>2.61</td></tr><tr><td>A</td><td>MS9</td><td>avg on cpx</td><td>4</td><td></td><td>44.79</td><td>2.64</td><td>0.35</td><td>0.14</td><td>9.24</td><td>2.13</td><td>0.01</td><td>0.01</td><td>17.26</td><td>1.93</td><td>0.29</td><td>0.14</td><td>11.18</td><td>1.35</td><td>12.22</td><td>0.45</td><td>1.46</td><td>0.45</td><td>0.43</td><td>0.05</td><td>97.24</td><td>53.52</td><td>5.74</td></tr><tr><td>A</td><td>MS9</td><td>avg on cpx</td><td>4</td><td></td><td>48.51</td><td>1.63</td><td>0.21</td><td>0.03</td><td>6.52</td><td>1.06</td><td>0.01</td><td>0.00</td><td>15.73</td><td>1.95</td><td>0.25</td><td>0.12</td><td>12.39</td><td>1.29</td><td>12.54</td><td>0.18</td><td>1.16</td><td>0.13</td><td>0.42</td><td>0.15</td><td>97.73</td><td>58.37</td><td>5.50</td></tr><tr><td>A</td><td>MS12</td><td>avg on cpx</td><td>8</td><td></td><td>47.13</td><td>1.41</td><td>0.28</td><td>0.27</td><td>6.02</td><td>0.86</td><td>0.03</td><td>0.01</td><td>21.76</td><td>0.72</td><td>0.54</td><td>0.11</td><td>8.58</td><td>0.59</td><td>11.89</td><td>0.20</td><td>0.63</td><td>0.14</td><td>0.28</td><td>0.07</td><td>97.14</td><td>41.27</td><td>2.34</td></tr><tr><td>A</td><td>MS13</td><td>needle</td><td>2</td><td></td><td>52.99</td><td>0.26</td><td>0.08</td><td>0.02</td><td>2.60</td><td>0.62</td><td>0.02</td><td>0.01</td><td>18.75</td><td>0.42</td><td>0.63</td><td>0.06</td><td>9.70</td><td>0.31</td><td>12.26</td><td>0.06</td><td>0.24</td><td>0.11</td><td>0.06</td><td>0.01</td><td>97.34</td><td>47.98</td><td>0.22</td></tr><tr><td>A</td><td>MS14</td><td>needle</td><td>2</td><td></td><td>52.99</td><td>0.26</td><td>0.08</td><td>0.02</td><td>2.60</td><td>0.62</td><td>0.01</td><td>0.00</td><td>18.75</td><td>0.42</td><td>0.63</td><td>0.06</td><td>9.70</td><td>0.31</td><td>12.32</td><td>0.15</td><td>0.18</td><td>0.02</td><td>0.06</td><td>0.00</td><td>97.33</td><td>47.98</td><td>0.22</td></tr><tr><td>A</td><td>AR-16-12</td><td>avg on cpx</td><td>2</td><td></td><td>44.05</td><td>7.89</td><td>0.01</td><td>0.01</td><td>6.86</td><td>4.23</td><td>0.01</td><td>0.00</td><td>22.02</td><td>3.32</td><td>0.53</td><td>0.14</td><td>12.00</td><td>1.03</td><td>12.08</td><td>0.73</td><td>0.37</td><td>0.10</td><td>0.07</td><td>0.01</td><td>98.01</td><td>49.37</td><td>1.63</td></tr><tr><td>C</td><td>DA6</td><td>Ph C</td><td>6</td><td></td><td>39.88</td><td>0.59</td><td>3.93</td><td>0.22</td><td>13.55</td><td>0.14</td><td>0.02</td><td>0.04</td><td>9.82</td><td>0.76</td><td>0.03</td><td>0.05</td><td>14.35</td><td>0.28</td><td>12.09</td><td>0.31</td><td>2.35</td><td>0.14</td><td>1.23</td><td>0.17</td><td>97.24</td><td>72.27</td><td>1.90</td></tr><tr><td>C</td><td>DA8</td><td>Ph C</td><td>4</td><td></td><td>39.27</td><td>0.05</td><td>3.95</td><td>0.24</td><td>13.52</td><td>0.14</td><td>0.00</td><td>0.00</td><td>9.47</td><td>0.22</td><td>0.00</td><td>0.00</td><td>14.79</td><td>0.22</td><td>12.25</td><td>0.16</td><td>2.28</td><td>0.08</td><td>1.16</td><td>0.07</td><td>96.68</td><td>73.57</td><td>0.49</td></tr><tr><td>C</td><td>DA8</td><td>Ph C</td><td>5</td><td></td><td>39.98</td><td>0.36</td><td>3.79</td><td>0.06</td><td>13.58</td><td>0.23</td><td>0.06</td><td>0.04</td><td>8.98</td><td>0.04</td><td>0.10</td><td>0.02</td><td>14.67</td><td>0.05</td><td>12.38</td><td>0.13</td><td>2.30</td><td>0.16</td><td>1.15</td><td>0.08</td><td>96.99</td><td>74.44</td><td>0.11</td></tr><tr><td>C</td><td>DA7</td><td>Ph C</td><td>10</td><td></td><td>39.57</td><td>0.24</td><td>3.84</td><td>0.12</td><td>13.85</td><td>0.29</td><td>0.09</td><td>0.11</td><td>9.21</td><td>0.43</td><td>0.10</td><td>0.07</td><td>14.44</td><td>0.22</td><td>12.26</td><td>0.18</td><td>2.28</td><td>0.12</td><td>1.07</td><td>0.11</td><td>96.70</td><td>73.65</td><td>0.96</td></tr><tr><td>C</td><td>DA7</td><td>Ph C</td><td>1</td><td>sims3</td><td>39.45</td><td></td><td>3.84</td><td></td><td>13.98</td><td></td><td>0.26</td><td></td><td>9.02</td><td></td><td>0.20</td><td></td><td>14.37</td><td></td><td>12.32</td><td></td><td>2.09</td><td></td><td>0.95</td><td></td><td>96.49</td><td>73.95</td><td></td></tr><tr><td>C</td><td>DA7</td><td>Ph C</td><td>1</td><td>sims4</td><td>39.43</td><td></td><td>3.71</td><td></td><td>13.30</td><td></td><td>0.01</td><td></td><td>10.22</td><td></td><td>0.13</td><td></td><td>14.49</td><td></td><td>12.33</td><td></td><td>2.09</td><td></td><td>0.94</td><td></td><td>96.65</td><td>71.66</td><td></td></tr><tr><td>C</td><td>DA7</td><td>mPh</td><td>3</td><td></td><td>39.85</td><td>0.06</td><td>5.17</td><td>0.05</td><td>12.75</td><td>0.42</td><td>0.00</td><td>0.00</td><td>9.79</td><td>0.32</td><td>0.15</td><td>0.06</td><td>13.99</td><td>0.05</td><td>11.78</td><td>0.20</td><td>2.74</td><td>0.25</td><td>1.22</td><td>0.12</td><td>97.44</td><td>71.82</td><td>0.60</td></tr><tr><td>C</td><td>G10-10</td><td>Gdm</td><td>3</td><td></td><td>38.41</td><td>0.56</td><td>3.17</td><td>0.04</td><td>11.48</td><td>0.19</td><td>0.00</td><td>0.00</td><td>22.52</td><td>1.08</td><td>0.39</td><td>0.04</td><td>6.38</td><td>0.68</td><td>10.89</td><td>0.26</td><td>2.63</td><td>0.25</td><td>1.39</td><td>0.03</td><td>97.25</td><td>33.54</td><td>3.46</td></tr><tr><td>C</td><td>MS6</td><td>Gdm</td><td>3</td><td></td><td>38.72</td><td>0.08</td><td>6.33</td><td>0.20</td><td>13.79</td><td>0.18</td><td>0.03</td><td>0.03</td><td>11.44</td><td>0.07</td><td>0.03</td><td>0.04</td><td>12.40</td><td>0.07</td><td>11.43</td><td>0.12</td><td>2.41</td><td>0.19</td><td>0.93</td><td>0.07</td><td>97.50</td><td>65.91</td><td>0.25</td></tr><tr><td>C</td><td>MS11</td><td>Gdm</td><td>2</td><td></td><td>37.29</td><td>0.19</td><td>5.50</td><td>0.34</td><td>14.19</td><td>0.14</td><td>0.01</td><td>0.01</td><td>16.36</td><td>0.27</td><td>0.24</td><td>0.03</td><td>8.61</td><td>0.16</td><td>11.28</td><td>0.07</td><td>2.63</td><td>0.15</td><td>0.87</td><td>0.09</td><td>96.97</td><td>48.40</td><td>0.85</td></tr><tr><td>C</td><td>AR-16-07</td><td>Gdm</td><td>2</td><td></td><td>39.27</td><td>0.41</td><td>4.99</td><td>0.23</td><td>11.61</td><td>1.02</td><td>0.00</td><td>0.00</td><td>15.76</td><td>1.06</td><td>0.34</td><td>0.04</td><td>11.16</td><td>1.03</td><td>11.40</td><td>0.17</td><td>2.55</td><td>0.20</td><td>0.88</td><td>0.00</td><td>97.95</td><td>55.75</td><td>3.93</td></tr><tr><td>C</td><td>AR-16-08</td><td>Gdm</td><td>3</td><td></td><td>37.67</td><td>0.29</td><td>5.25</td><td>0.20</td><td>13.37</td><td>0.54</td><td>0.00</td><td>0.00</td><td>15.79</td><td>0.77</td><td>0.28</td><td>0.18</td><td>9.99</td><td>0.61</td><td>12.36</td><td>0.25</td><td>2.34</td><td>0.10</td><td>0.96</td><td>0.10</td><td>98.00</td><td>53.00</td><td>2.51</td></tr></tbody></table>

Textures: phenocryst (Ph); microphenocryst (mPh); groundmass crystal (Gdm); core (C); overgrowth (ovg)

N: number of analyses

SIMS: refers to crystals analyzed for the REES (Table 3)
<table><caption>Table 5. Major element compositions in wt.% of spinels of Dali volcanic rocks</caption><thead><tr><th>Group</th><th>Sample</th><th>Mineral</th><th>Texture</th><th>SiO<sub>2</sub></th><th>TiO<sub>2</sub></th><th>Al<sub>2</sub>O<sub>3</sub></th><th>Cr<sub>2</sub>O<sub>3</sub></th><th>Fe<sub>2</sub>O<sub>3</sub></th><th>FeO</th><th>MnO</th><th>MgO</th><th>Total</th><th>Cr#</th><th>Mg#</th><th>Fe<sup>3+</sup>#</th><th>Fe<sup>2+</sup>#</th><th>Usp%</th></tr></thead><tbody><tr><td>B</td><td>G08-10</td><td>Cr-spinel</td><td>Incl.</td><td>0.34</td><td>0.98</td><td>21.89</td><td>38.96</td><td>5.80</td><td>20.35</td><td>0.61</td><td>10.13</td><td>99.07</td><td>54.41</td><td>47.02</td><td>7.15</td><td>52.98</td><td>-</td></tr><tr><td>B</td><td>G08-10</td><td>Cr-spinel</td><td>Incl.</td><td>1.01</td><td>1.22</td><td>26.15</td><td>30.78</td><td>9.65</td><td>14.61</td><td>1.18</td><td>14.65</td><td>99.25</td><td>44.12</td><td>64.14</td><td>11.64</td><td>35.86</td><td>-</td></tr><tr><td>B</td><td>G08-10</td><td>Cr-spinel</td><td>Incl.</td><td>1.60</td><td>1.50</td><td>26.55</td><td>31.40</td><td>5.02</td><td>19.65</td><td>1.03</td><td>12.15</td><td>98.91</td><td>44.23</td><td>52.43</td><td>6.31</td><td>47.57</td><td>-</td></tr><tr><td>B</td><td>G08-10</td><td>Cr-spinel</td><td>mPh</td><td>0.30</td><td>0.93</td><td>23.66</td><td>36.60</td><td>7.91</td><td>16.94</td><td>1.64</td><td>11.96</td><td>99.95</td><td>50.92</td><td>55.73</td><td>9.48</td><td>44.27</td><td>-</td></tr><tr><td>B</td><td>G08-10</td><td>Cr-spinel</td><td>mPh</td><td>0.32</td><td>1.23</td><td>25.98</td><td>33.32</td><td>7.90</td><td>18.00</td><td>0.82</td><td>12.21</td><td>99.77</td><td>46.25</td><td>54.73</td><td>9.45</td><td>45.27</td><td>-</td></tr><tr><td>B</td><td>G08-10</td><td>Cr-spinel</td><td>mPh</td><td>0.32</td><td>1.27</td><td>24.33</td><td>34.13</td><td>9.48</td><td>16.81</td><td>0.89</td><td>12.84</td><td>100.08</td><td>48.48</td><td>57.67</td><td>11.36</td><td>42.33</td><td>-</td></tr><tr><td>B</td><td>G08-10</td><td>Cr-spinel</td><td>Incl.</td><td>0.18</td><td>1.58</td><td>28.65</td><td>29.06</td><td>9.86</td><td>16.64</td><td>0.76</td><td>13.59</td><td>100.30</td><td>40.49</td><td>59.28</td><td>11.56</td><td>40.72</td><td>-</td></tr><tr><td>B</td><td>G08-10</td><td>Ti-magn.</td><td>mPh</td><td>1.93</td><td>2.49</td><td>4.68</td><td>0.41</td><td>54.89</td><td>34.83</td><td>0.48</td><td>1.11</td><td>100.83</td><td>5.50</td><td>5.37</td><td>87.61</td><td>94.63</td><td>8.82</td></tr><tr><td>B</td><td>G08-10</td><td>Ti-magn.</td><td>mPh</td><td>3.21</td><td>2.46</td><td>8.86</td><td>0.35</td><td>47.06</td><td>36.28</td><td>0.55</td><td>1.60</td><td>100.37</td><td>2.59</td><td>7.28</td><td>76.76</td><td>92.72</td><td>11.07</td></tr><tr><td>B</td><td>G08-10</td><td>Ti-magn.</td><td>mPh</td><td>2.55</td><td>2.93</td><td>6.51</td><td>0.18</td><td>51.19</td><td>33.98</td><td>0.50</td><td>2.58</td><td>100.43</td><td>1.78</td><td>11.94</td><td>83.13</td><td>88.06</td><td>10.69</td></tr><tr><td>B</td><td>G08-10</td><td>Ti-magn.</td><td>mPh</td><td>0.11</td><td>2.43</td><td>3.40</td><td>0.32</td><td>60.42</td><td>32.90</td><td>0.43</td><td>0.59</td><td>100.61</td><td>5.98</td><td>3.09</td><td>91.44</td><td>96.91</td><td>7.77</td></tr><tr><td>B</td><td>MS5</td><td>Cr-spinel</td><td>Incl.</td><td>0.16</td><td>1.24</td><td>26.00</td><td>32.56</td><td>8.47</td><td>16.96</td><td>0.22</td><td>12.80</td><td>98.57</td><td>45.66</td><td>57.36</td><td>10.16</td><td>42.64</td><td>-</td></tr><tr><td>B</td><td>MS5</td><td>Cr-spinel</td><td>Incl.</td><td>0.18</td><td>1.14</td><td>27.44</td><td>31.15</td><td>8.63</td><td>17.58</td><td>0.28</td><td>12.60</td><td>99.09</td><td>43.22</td><td>56.10</td><td>10.23</td><td>43.90</td><td>-</td></tr><tr><td>B</td><td>MS5</td><td>Cr-spinel</td><td>Incl.</td><td>0.16</td><td>1.11</td><td>28.54</td><td>29.90</td><td>8.42</td><td>18.13</td><td>0.22</td><td>12.30</td><td>98.94</td><td>41.27</td><td>54.75</td><td>9.96</td><td>45.25</td><td>-</td></tr><tr><td>B</td><td>MS5</td><td>Cr-spinel</td><td>Incl.</td><td>0.33</td><td>1.11</td><td>24.57</td><td>36.39</td><td>7.44</td><td>17.10</td><td>0.00</td><td>13.16</td><td>100.19</td><td>49.83</td><td>57.84</td><td>8.85</td><td>42.16</td><td>-</td></tr><tr><td>B</td><td>MS5</td><td>Cr-spinel</td><td>Incl.</td><td>0.17</td><td>0.77</td><td>21.99</td><td>38.54</td><td>9.12</td><td>16.60</td><td>0.23</td><td>12.68</td><td>100.27</td><td>54.04</td><td>57.66</td><td>10.85</td><td>42.34</td><td>-</td></tr><tr><td>B</td><td>MS5</td><td>Ti-magn.</td><td>mPh</td><td>3.52</td><td>7.73</td><td>3.01</td><td>0.16</td><td>43.13</td><td>39.09</td><td>0.00</td><td>2.72</td><td>99.35</td><td>3.45</td><td>11.02</td><td>89.84</td><td>88.98</td><td>26.19</td></tr><tr><td>B</td><td>AR-16-02</td><td>Cr-spinel</td><td>Xen.</td><td>0.34</td><td>0.71</td><td>28.26</td><td>33.37</td><td>7.21</td><td>16.36</td><td>0.45</td><td>13.58</td><td>100.29</td><td>44.19</td><td>59.68</td><td>8.33</td><td>40.32</td><td>-</td></tr><tr><td>B</td><td>AR-16-02</td><td>Cr-spinel</td><td>Xen.</td><td>0.06</td><td>0.77</td><td>28.44</td><td>33.81</td><td>6.10</td><td>15.86</td><td>0.27</td><td>13.56</td><td>98.87</td><td>44.36</td><td>60.38</td><td>7.08</td><td>39.62</td><td>-</td></tr><tr><td>B</td><td>AR-16-02</td><td>Cr-spinel</td><td>Xen.</td><td>0.13</td><td>0.82</td><td>28.00</td><td>33.71</td><td>6.43</td><td>16.17</td><td>0.25</td><td>13.42</td><td>98.93</td><td>44.68</td><td>59.68</td><td>7.50</td><td>40.32</td><td>-</td></tr><tr><td>B</td><td>AR-16-02</td><td>Ti-magn.</td><td>mPh</td><td>0.90</td><td>3.68</td><td>1.37</td><td>0.07</td><td>59.26</td><td>35.39</td><td>0.24</td><td>0.45</td><td>101.36</td><td>3.48</td><td>2.24</td><td>96.40</td><td>97.76</td><td>11.12</td></tr><tr><td>C</td><td>MS6</td><td>Cr-spinel</td><td>Incl.</td><td>0.06</td><td>6.44</td><td>18.87</td><td>15.68</td><td>24.04</td><td>24.14</td><td>0.09</td><td>10.67</td><td>99.99</td><td>35.79</td><td>44.07</td><td>34.31</td><td>55.93</td><td>-</td></tr><tr><td>C</td><td>MS6</td><td>Cr-spinel</td><td>Incl.</td><td>0.33</td><td>11.13</td><td>13.77</td><td>14.28</td><td>20.72</td><td>29.59</td><td>0.07</td><td>9.50</td><td>99.40</td><td>41.03</td><td>36.40</td><td>36.17</td><td>63.60</td><td>-</td></tr><tr><td>C</td><td>MS6</td><td>Cr-spinel</td><td>mPh</td><td>0.36</td><td>9.46</td><td>15.12</td><td>15.69</td><td>20.71</td><td>28.96</td><td>0.00</td><td>9.15</td><td>99.44</td><td>41.04</td><td>36.02</td><td>34.02</td><td>63.98</td><td>-</td></tr><tr><td>C</td><td>MS6</td><td>Cr-spinel</td><td>mPh</td><td>0.21</td><td>6.08</td><td>18.63</td><td>14.94</td><td>25.26</td><td>24.19</td><td>0.28</td><td>10.39</td><td>99.98</td><td>34.98</td><td>43.37</td><td>36.02</td><td>56.63</td><td>-</td></tr><tr><td>C</td><td>MS6</td><td>Ti-magn.</td><td>mPh</td><td>0.03</td><td>5.00</td><td>2.50</td><td>0.92</td><td>58.38</td><td>37.14</td><td>0.00</td><td>0.22</td><td>104.19</td><td>19.80</td><td>1.03</td><td>92.27</td><td>98.97</td><td>15.51</td></tr><tr><td>C</td><td>MS11</td><td>Cr-spinel</td><td>Incl.</td><td>0.12</td><td>1.96</td><td>14.95</td><td>37.91</td><td>12.79</td><td>17.09</td><td>0.23</td><td>11.53</td><td>96.77</td><td>62.97</td><td>54.60</td><td>16.83</td><td>45.40</td><td>-</td></tr><tr><td>C</td><td>MS11</td><td>Cr-spinel</td><td>mPh</td><td>0.09</td><td>1.63</td><td>18.04</td><td>37.30</td><td>10.37</td><td>19.21</td><td>0.06</td><td>10.56</td><td>97.32</td><td>58.10</td><td>49.49</td><td>13.33</td><td>50.51</td><td>-</td></tr><tr><td>C</td><td>MS11</td><td>Cr-spinel</td><td>Incl.</td><td>0.11</td><td>2.25</td><td>13.58</td><td>41.49</td><td>10.99</td><td>17.53</td><td>0.34</td><td>11.43</td><td>97.95</td><td>67.21</td><td>53.76</td><td>14.49</td><td>46.24</td><td>-</td></tr><tr><td>C</td><td>MS11</td><td>Cr-spinel</td><td>Incl.</td><td>0.06</td><td>2.27</td><td>13.46</td><td>42.41</td><td>11.02</td><td>17.26</td><td>0.30</td><td>11.82</td><td>98.67</td><td>67.88</td><td>54.97</td><td>14.37</td><td>45.03</td><td>-</td></tr><tr><td>C</td><td>MS11</td><td>Cr-spinel</td><td>mPh</td><td>0.12</td><td>2.62</td><td>13.67</td><td>42.17</td><td>10.74</td><td>17.66</td><td>0.26</td><td>11.95</td><td>99.37</td><td>67.41</td><td>54.68</td><td>14.05</td><td>45.32</td><td>-</td></tr><tr><td>C</td><td>MS11</td><td>Cr-spinel</td><td>Incl.</td><td>0.07</td><td>2.23</td><td>14.32</td><td>42.05</td><td>11.93</td><td>18.08</td><td>0.23</td><td>11.89</td><td>100.80</td><td>66.32</td><td>53.97</td><td>15.19</td><td>46.03</td><td>-</td></tr><tr><td>C</td><td>MS11</td><td>Cr-spinel</td><td>Incl.</td><td>0.21</td><td>2.10</td><td>14.44</td><td>40.84</td><td>11.97</td><td>17.55</td><td>0.31</td><td>11.94</td><td>99.36</td><td>65.48</td><td>54.80</td><td>15.45</td><td>45.20</td><td>-</td></tr><tr><td>C</td><td>MS11</td><td>Cr-spinel</td><td>Incl.</td><td>0.12</td><td>2.08</td><td>14.83</td><td>39.95</td><td>12.27</td><td>17.19</td><td>0.27</td><td>12.02</td><td>98.73</td><td>64.38</td><td>55.50</td><td>15.84</td><td>44.50</td><td>-</td></tr><tr><td>C</td><td>MS11</td><td>Cr-spinel</td><td>Incl.</td><td>0.15</td><td>2.52</td><td>14.23</td><td>41.26</td><td>10.80</td><td>17.56</td><td>0.24</td><td>12.04</td><td>98.81</td><td>66.04</td><td>55.01</td><td>14.13</td><td>44.99</td><td>-</td></tr><tr><td>C</td><td>MS11</td><td>Ti-magn.</td><td>mPh</td><td>0.17</td><td>6.07</td><td>2.90</td><td>0.59</td><td>54.24</td><td>37.05</td><td>0.75</td><td>0.14</td><td>101.91</td><td>12.06</td><td>0.68</td><td>91.30</td><td>99.32</td><td>19.26</td></tr><tr><td>C</td><td>MS11</td><td>Ti-magn.</td><td>mPh</td><td>0.44</td><td>6.78</td><td>1.16</td><td>0.39</td><td>54.04</td><td>36.75</td><td>0.00</td><td>1.02</td><td>100.57</td><td>18.53</td><td>4.70</td><td>96.04</td><td>95.30</td><td>19.92</td></tr></tbody></table>

Inclusion in olivine pseudomorph (Incl.); microphenocryst (mPh); xenocryst (Xen. in sample AR-16-02 that contains only 3 Cr-spinel grains).

Cr# = 100.Cr/(Cr+Al); Mg# = 100.Mg/(Mg+Fe²⁺); Fe³⁺# = 100.Fe³⁺/(Fe³⁺+Al+Cr); Fe²⁺# = 100.Fe²⁺/(Fe²⁺+Fe³⁺); Usp% = %ulvospinel.

Fe³⁺ is calculated according to Barnes and Roedder (2001).