The volcanoes of an oceanic arc from origin to destruction: A case from the northern Luzon Arc

Journal of Asian Earth Sciences 74 (2013) 97–112

Contents lists available at SciVerse ScienceDirect

Journal of Asian Earth Sciences journal homepage: www.elsevier.com/locate/jseaes

The volcanoes of an oceanic arc from origin to destruction: A case from the northern Luzon Arc Yu-Ming Lai, Sheng-Rong Song ⇑ Department of Geosciences, National Taiwan University, Taipei, Taiwan, ROC

a r t i c l e

i n f o

Article history: Received 30 November 2011 Received in revised form 19 March 2013 Accepted 20 March 2013 Available online 10 April 2013 Keywords: Volcanic lithofacies Coastal Range of eastern Taiwan Luzon Arc Arc–continent collision Geochemistry

a b s t r a c t Volcanoes were created, grew, uplifted, became dormant or extinct, and were accreted as part of continents during continuous arc–continent collision. Volcanic rocks in Eastern Taiwan’s Coastal Range (CR) are part of the northern Luzon Arc, an oceanic island arc produced by the subduction of the South China Sea Plate beneath the Philippine Sea Plate. Igneous rocks are characterized by intrusive bodies, lava and pyroclastic flows, and volcaniclastic rocks with minor tephra deposits. Based on volcanic facies associations, Sr–Nd isotopic geochemistry, and the geography of the region, four volcanoes were identified in the CR: Yuemei, Chimei, Chengkuangao, and Tuluanshan. Near-vent facies associations show different degrees of erosion in the volcanic edifices for Chimei, Chengkuangao, and Tuluanshan. Yuemei lacks near-vent rocks, implying that Yuemei’s main volcanic body may have been subducted at the Ryukyu Trench with the northward motion of the Philippine Sea Plate. These data suggest a hypothesis for the evolution of volcanism and geomorphology during arc growth and ensuing arc–continent collision in the northern Luzon Arc, which suggests that these volcanoes were formed from the seafloor, emerging as islands during arc volcanism. They then became dormant or extinct during collision, and finally, were uplifted and accreted by additional collision. The oldest volcano, Yuemei, may have already been subducted into the Ryukyu Trench. Ó 2013 Published by Elsevier Ltd.

1. Introduction Volcanoes form when magma erupts to the surface, mostly near plate boundaries. Volcanic island arcs form at the continent–ocean boundaries by slab subduction. Modern arc volcanism and its evolution have been analyzed (mainly using geochemical data) to elucidate the magmatic evolution or volcanic petrogenesis for the following arcs: the Aegean Volcanic Arc (Zellmer et al., 2000), the Aleutian Island Arc (Jicha et al., 2005; Jicha, 2009), the Izu-Bonin–Mariana Arc (Woodhead, 1989; Taylor and Nesbitt, 1998), the Kamchatka–Kuril Arc (Avdeiko et al., 1991), the Kermadec Arc (Ewart et al., 1977; Gamble et al., 1993; Smith et al., 2009), the Lesser Antilles Arc (Brown et al., 1977; Westercamp, 1988; Macdonald et al., 2000; Germa et al., 2010), and the Tonga Arc (Haase et al., 2009; Hergt and Woodhead, 2007). Additional studies have focused on volcanic geomorphology (Deplus et al., 2001; Goto and Tsuchiya, 2004; Lafrance et al., 2000; Robin et al., 1993; Wilson et al., 1995), tectonic structures (Lallemand, 1996; Petterson et al., 1999; Barker, 2001; Isse et al., 2009; Acocella and Fniciello, 2010), arc stratigraphy and lithogeochemistry (Wharton et al., 1995; Scott ⇑ Corresponding author. Address: Department of Geosciences, National Taiwan University, P.O. Box 13-318, Taipei 106, Taiwan, ROC. Tel.: +886 2 33662938; fax: +886 2 23636059. E-mail address: [email protected] (S.-R. Song). 1367-9120/$ - see front matter Ó 2013 Published by Elsevier Ltd. http://dx.doi.org/10.1016/j.jseaes.2013.03.021

et al., 2002), basin evolution (Geist et al., 1987), and submarine hydrothermal systems (de Ronde et al., 2001; Glasby and Notsu, 2003; Embley et al., 2004). However, these studies were focused mainly on either the characteristics of a single volcanic island or the partial region of an arc chain. Few examples have outlined the entire history of these arc volcanoes, including their origins from subduction, growth from the deep sea to the subaerial surface, and uplift and destruction caused by collision. Even in cases of active arc–continent collision, previous studies have focused on single topics (e.g., evidence of their birth from a submarine eruption, the uplift rate after the collision, or the waning of volcanic bodies by weathering or extrusion (Lee et al., 2006; Brown, 2009; Roosmawati and Harris, 2009; Escalona and Mann, 2011). This study examined the Luzon Arc, of which sections represent the entire range of evolutionary stages, including active volcanic islands, less after of volcanism, uplift and erosion of volcanic bodies, and subduction as plate movement continues. The active Luzon Arc comprises several volcanic bodies, separated by bathymetric lows between Luzon and Taiwan. The northern extension of the Luzon Arc has been accreted in Eastern Taiwan’s Coastal Range (CR), and individual volcanic bodies are difficult to recognize on land because of erosion. Volcanic lithofacies analyses have been used to reconstruct tectonic evolution (Scott et al., 2002; Petterson and Treloar, 2004), the history of volcanism (Vazquez and Ort, 2006), and volcanic hazards. Volcanic facies

98

Y.-M. Lai, S.-R. Song / Journal of Asian Earth Sciences 74 (2013) 97–112

Fig. 1. A tectonic map of Taiwan and the northern Luzon Arc. Rectangles show the scope of eastern Taiwan’s CR (Fig. 2) and the volcanic islands in this arc (Fig. 6). (Modified from Ho, 1986).

associations change with the upsurge of an island arc from the deep sea to the subaerial surface (Song and Lo, 2002). These associations can also indicate the distance from the volcanic center (Cas and Wright, 1987; Bryan et al., 2000). Song and Lo (2002) used this tool to reconstruct the volcanic bodies in the central section of the CR. However, more than one relict volcano in this area exists. This study describes the lithofacies and geochemistry of volcanic rocks in Eastern Taiwan’s CR and reconstructs its volcanoes. The Luzon Arc is an excellent example of the evolution of volcanoes in an oceanic arc system.

2. Geological setting Taiwan is located in an active mountain belt created by the oblique collision between the northern Luzon Arc and the Asian continent (Fig. 1) (Chai, 1972; Biq, 1973; Karig, 1973; Bowin et al., 1978). The northern Luzon Arc was produced when the South China Sea Plate subducted beneath the Philippine Sea Plate. After the initial collision, the plate moved northwest, deforming volcanic bodies and exposing volcanic rocks (Teng, 1996; Lundberg et al., 1997; Huang et al., 1997, 2000). In the southern region of the

arc, volcanoes of the Batan and Babuyun Islands are still active, but several volcanic islands (e.g., Lutao and Lanyu) have ceased eruption. Volcanic bodies were deformed on land after the collision, but are well preserved as volcanic islands in Southern Taiwan. The Neogene volcanic rocks in Eastern Taiwan’s CR extend for approximately 140 km between the cities of Hualien and Taitung (Fig. 2). Eruption of these rocks began in a submarine environment because of eastward subduction approximately 17–35 Ma ago (Taylor and Hayes, 1983), with volcanic edifices rising from deep to shallow water, and even to the subaerial surface (Song and Lo, 1987, 1988, 2002). Volcanism ceased, and the volcanoes deformed during arc–continent collision, and accreted onto the Asian continental margin to form the main body of Eastern Taiwan’s CR. The CR’s volcanic sequence, called the Chimei Igneous Complex and Tuluanshan Formation (Ho, 1986; Song and Lo, 1990), is composed of basaltic to andesitic lavas, pyroclastic breccias, and tuffs with tuffaceous sediments. Overlaying these sequences, the Kangkou Limestone and the Fanshuliao and Paliwan Formations represent deposition of sedimentary rocks after volcanic activity (Chang, 1968; Teng, 1979; Teng and Lo, 1985; Chen and Wang, 1988). Outcrops expose different sequences caused by varying degrees of erosion. Previous studies have produced abundant data on the

Y.-M. Lai, S.-R. Song / Journal of Asian Earth Sciences 74 (2013) 97–112

99

Fig. 2. (a) Geological map of the CR (after Teng et al., 1988), showing the pictures of volcanic sequences’ outcrops in lowercase letters. The volcanic centers are marked by stars and different colors correspond to the four volcanoes: Yuemei, Chimei, Chengkuangao and Tuluanshan. Two rectangles show the ranges of Fig. 3a and b; (b) the volcanic facies associations and the eNd values for all four volcanoes (Chen et al., 1990 and this study). The red, brown, and cyan colors show the near-vent, medial and distal volcanic facies associations, respectively; (c) the lithologic columns of nine continuous volcanic sequences. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)

geochemistry (Richard et al., 1986; Chen et al., 1990; Defant et al., 1990; McDermott et al., 1993) and radiometric and fission track age dates of these volcanic rocks (Juang and Bellon, 1984; Richard et al., 1986; Yang et al., 1988; Lo et al., 1994; Song and Lo, 2002). Age dating results showed that volcanism occurred during a period ranging from 29.7 to 5.1 Ma.

3. Analytical methods 3.1. Volcanic lithofacies analyses Volcanic lithofacies analyses are used to reconstruct the paleoenvironment (White and Busby-Spera, 1987; Busby-Spera, 1988; Song and Lo, 2002; Petterson and Treloar, 2004; Palinkas et al., 2008). Song and Lo (2002) used facies associations to speculate on the position of the volcanic center, and to model the evolution of the volcanic islands from the middle of Eastern Taiwan’s CR. This method is also applied to all of the CR in this study. A field survey of this area suggests that the volcanic rocks are classified into 10 principal lithofacies, and that the volcanic deposits are categorized into three distinct facies associations based on their distance from

the volcanic center (i.e., the eruptive environment) during the islands’ development. The lithological columns of nine continuous volcanic sequences are shown in Fig. 2c.

3.2. Variations of isotopic ratios Isotopic ratios in the magmas reflect their sources and are unchanged during fractionation. In addition, magmas from the same source may have the same isotopic value (Rollinson, 1993). Because of the northwest movement of the Philippine Sea Plate, the strontium and neodymium isotopic values for the arc’s magma became enriched because they were mixed with continental crust components (Depaolo and Wasserburg, 1977; White and Patchett, 1984; Davidson, 1985). This characteristic is also reflected in volcanic sequences from different volcanoes. For example, the isotopic values for the different volcanoes became more enriched in the various compositions between the lower to upper sequences. Comparing the isotopic variations of each volcanic sequence can be used as a tool for differentiating between the volcanoes. Seven volcanic sequences were chosen to continuously collect samples (Fig. 3a and b). The isotopic analyses of this study were performed

100

Y.-M. Lai, S.-R. Song / Journal of Asian Earth Sciences 74 (2013) 97–112

Fig. 2. (continued)

at the Institute of Geochemistry at Guangzhou using inductively coupled plasma mass spectrometry (ICP-MS, PE Elan 6000). The calibrated analytical uncertainty and detection limits for this machine have been reported by Li (1997).

4. Results and implications 4.1. Volcanic lithofacies Following the volcanic lithofacies analyses used by Song and Lo (2002), a detailed volcanic lithological facies for all of the CR is described below and divided into 10 categories (Table 1). The locations for the continuous sequences mentioned below are shown in Fig. 2b. Some lithofacies occur in narrow areas; thus, they could not be applied to the whole CR. These were recorded roughly, in addition to main lithofacies such as paleosols, hydrothermal alterations, and evidence of magma mingling.

4.1.1. Intrusives On Hsiukuluanchi River, near the village of Chimei, diabase intrusions are exposed midstream (Fig. 4a) (Yen, 1968). These are massive and dark greenish-gray rocks approximately 200 m thick that were altered by at least three stages of hydrothermal fluids (Fig. 4b) (Lan, 1982). They have been intruded by several andesitic dike swarms. The diabase, as determined by fission track dating (Yang et al., 1988), is older than 17 Ma, indicating that it is the oldest igneous rocks in the CR. Minerals include plagioclase, augite, hornblende, and orthopyroxene with ophitic textures. The thick diabase body may result from magma intrusions located deep

within a volcano (Song and Lo, 2002). This facies is found only in the central CR. 4.1.2. Lava flows Lava flows exposed in the CR are composed predominantly of andesitic rocks with subsidiary basalt. The flows are massive and well-jointed in appearance, ranging in thickness from 1 to 10 m. Phenocrysts of andesitic lava flows are composed of pyroxene and plagioclase, with plagioclase large enough to form porphyritic rocks in the central-southern and southern CR (Fig. 4c) (e.g., in the Sanhsienchi and Chilichi sequences). Basaltic lava flows containing olivine, plagioclase, and pyroxene as phenocrysts are found in the Shihtiping and Sanfuchuan sequences in the central CR. Some local paleosols produced by weathering of basaltic lava flows have also been found (Song and Lo, 2002). Thick lava flows occur at Hsiukuluanchi, Sanhsienchi, and Chilichi, but only the Hsiukuluanchi section was affected by hydrothermal alterations and dike intrusions. Thin lava flow layers are interbedded with volcanic breccias that are thicker close to the volcanic center and thinner away from the center (Song and Lo, 2002). 4.1.3. Dikes Two types of dikes have been found in the CR: parallel dike swarms in the diabase and individual dikes intruding breccias or lava flows. The first type is exposed in Hsiukuluanchi River, near the village of Chimei in the central CR. These dikes are dark gray to black and consist of augite, calcic plagioclase with minor olivine, and magnetite with different degrees of hydrothermal alterations (Fig. 4d) (Song and Lo, 2002). The composition of individual dikes varies from basaltic to andesitic with the same mineral content

Y.-M. Lai, S.-R. Song / Journal of Asian Earth Sciences 74 (2013) 97–112

101

Fig. 3. (a) eNd values decrease from bottom to top for the Chimei volcano (Fanshuliao, Shihmen-Shihtikung and Lohochi sections) but remain unchanged for Yuemei (Lingding section). The underlined numbers are their age dates; (b) epiclastic facies and different eNd values between the Mawukuchi sequences and volcanic blocks are evidence of the distal volcanic facies. eNd values in the Tuluanshan volcano changed unobviously from bottom to top (Chilichi section). The locations of these two areas and symbols are shown in Fig. 2.

as the dike swarms. In the central-southern area of the CR, the Sanhsienchi section, outcrops in basaltic and andesitic dikes approximately 10 m in thickness with well-developed plate joints are found (Fig. 4e and f) (Hsiao, 1993). The dikes have been widely subjected to hydrothermal alteration by post-volcanic activities, especially near the volcanic vent. Irregular veins of blue chalcedony, approximately 10 cm thick, occur near the Chilichi section of the southern CR (Huang, 1966). Dike swarms in the Hsiukuluanchi section show at least three stages of hydrothermal alterations (Lan, 1982). This evidence indicates that these dikes were formed near the center of a deep-seated volcano. 4.1.4. Pillow lava Pillow lava is produced by deep submarine volcanic eruptions (Sigvaldason, 1968; Moore et al., 1973; Furnes and Sturt, 1976; Dimroth et al., 1978). Scarce vesicles in the pillows suggest that they may be extruded from areas below the volatile fragmentation depth (VFD) (Fisher, 1984; Song and Lo, 1987). In the CR, pillow lavas are completely exposed only in the Lohochi section (Fig. 4g) (Song and Lo, 1987, 2002). These are basaltic, dark grayish, and oval with chilled glassy margins. This lithofacies rarely occurs in the central-southern or southern parts of the CR, and may result from short exposure and erosion caused by a collapse that occurred sequentially from the north to the south (Huang et al., 1995). 4.1.5. Pillow breccias and hyaloclastites Pillow breccias, similar to pillow lavas, are formed under the submarine. These breccias formed because of a volcano developing

near or above the VFD. These manifestations characteristically show massive and clast-supported monolithologic breccias with glassy rims (Fig. 4h). The principal minerals are plagioclase and pyroxene. Hyaloclastites are massive, black, fine-grained glassy tuffs, containing approximately 80–90% glassy fragments (Song and Lo, 2002). They are produced when rising magma contacts and reacts with seawater (Wohletz, 1983; Song and Lo, 1987). A continuous outcrop is found in the Lohochi section, but other rare examples are also found around the central (e.g., in the Sanfuchuan and Shihtikuanchi sections) (Song and Lo, 2002), the central-southern (e.g., the Tuweichi section), and the Yungshuichi sections in the southern CR. 4.1.6. Monolithologic breccias Monolithologic breccias may have been deposited directly from volcanic activity (Song and Lo, 2002). According to the ratio between the blocks and the matrix, this lithofacies can be divided into two types found in the CR. One type of monothologic breccia is clast-supported and uses poor- to well-sorted tuffs as its matrix, consisting of angular to subangular blocks (Fig. 4i). These blocks vary from black to gray, and range from 5 to 50 cm in diameter. Plagioclase and pyroxene predominate in the phenocrysts. Massive breccias with a little matrix, such as those found in the Shihmen and Mawakuchi sections, may have formed through autobrecciation during the movement of cooling lava flows (Fig. 4j) (Lai et al., 2008). Another type of monothologic breccia is matrix-supported with a poorly sorted matrix interbedded with polylithologic breccias,

102

Y.-M. Lai, S.-R. Song / Journal of Asian Earth Sciences 74 (2013) 97–112

Table 1 Summary of the 10 volcanic lithofacies in the Coastal Range of eastern Taiwan. Name

Rock type(s)

Thin section characteristics

Field characteristics

Interpretations of the processes

Intrusives

Diabase

Plagioclase, augite, hornblende, orthopyroxene and showed ophitic textures

Massive, dark greenish gray rocks with at least three stages of hydrothermal alteration

Lava flows

Basaltic to andesitic lava flows

Dikes

Basaltic to andesitic dikes

Plagioclase, augite, hornblende, orthopyroxene and some olivine in basaltic lava Plagioclase, augite, (olivine), magnetite

Massive, weak bedding, ranging in thickness from 1 m to 10 m with good joint development. 1. Several parallel dikes formed dike swarms 2. Single dike intruded in the breccias or lava flows

The thickness of the diabase intrusion as a result of magma intruding indicate that it might be near the eruption center The thicker the lava flows the closer the volcanic center

Pillow lavas

Basaltic pillow lavas

Pillow breccias and hyaloclastites

Basaltic pillow breccias and glassy clasts

Monolithologic breccias

Basaltic to andesitic breccias

Plaioclase microlites with pilotaxitic texture and an orientation parallel to the margins (Song and Lo, 2002) Plagioclase and pyroxene were the principal minerals

Pillow lavas were 0.5–1.5 m in diameter and covered or interbedded with pillow breccias and hyaloclastites Pillow breccias showed massive clast-supported monolithologic breccias with glassy rims, while the hyaloclastites were black, massive, had bad bedding and fine grains

Plaioclase with zoning, augite, orthopyroxene, hornblende. Minerals were broken into fragments

1. Clast-supported, angular to subangular blocks with poor to well sorted tuff as its matrix. Massive breccias formed by autobrecciation with very little groundmass

Polylithologic breccias

Basaltic to andesitic breccias

The same as monolithologic breccias

Ignimbrite

Pumice lapilli tuff, white volcanic bombs and tuff breccias with lithic lapilli

Phenocrysts within pumice clasts. The feldspar and quartz are cut by sharp and jagged fractures

Peperite

Ignimbrites mingled with mud of tuffaceous sandstone

Flow structure, and the contact boundary between the juveniles and sediments were identified

Tuffaceous sediments

Andesitic to basaltic lithic fragments

Glassy shards are dominant, with small amounts of crystals in the lithic fragments

ignimbrites, or tuffs (Fig. 4k). The blocks are commonly angular to subrounded, ranging from 5 to 20 cm in diameter, and have the same mineral assemblage as the clast-supported type. In several sections (e.g., the Hsiukuluanchi, Sanhsienchi, and Chilichi) this lithofacies appears as part of a characteristic vertical sequence, from single monolithologic breccias to interbedded monolithologic and polylithologic breccias, and then to monolithologic breccias interbedded with ignimbrites and tuffs. These lithofacies are located in the central, central-southern, and southern parts of the CR, respectively. This type of monolithologic breccia is found in the Lingding, Yuemeishan, Fanshuliaochi, Hsinfeng, Shihmen, Shihtikung, Hsiukuluanchi, Lohochi, Sanhsienchi, Mawukuchi, and Chilichi sections.

2. Matrix-supported with the matrix composed of poorly sorted tuff, sometimes interbedded with polylithologic breccias, ignimbrites or tuff Matrix- to clast-supported, subangular to rounded blocks with 30–60% vesicular. Different rock types with poorly sorted tuff as the matrix Abundant rounded to subangular white volcanic bombs, pumice, lithic fragments with poorly sorted matrix of crystal vitric tuff. White volcanic bombs formed plastic structures with peperite inside some outcrops. Welded and impacted structures appeared in some sections 1. Blocky peperites showed a jigsaw-fit texture, brittle regime 2. Fluidal peperites showed fluidal or globular morphology, ductile regime Three types in the field: thin beds interbedded within breccias, fineto coarse-grained tuffs and blockash-flow tuffs

Dike swarms and a great degree of hydrothermal alterations reference near-vent volcanic lithofacies Pillow lavas are treated as the product of deeper submarine volcanic eruptions, below the volatile fragmentation depth They form when the sea mountain grew near the volatile fragmentation depth, and the glassy fragments were due to the rising magma coming into contact with sea water Aubobrecciated breccias formed during the movements of cooling lava flows. Thick and predominantly monolithologic breccias are expected to be nearvent volcanic lithofacies

Various kinds of volcanic rock might erode from more than one source

Ignimbrites are defined as pyroclastic flows with highly pumiceous and vesiculated glass. Deformed structures show that the pyroclastic flows still retained their high temperature during deposition. Ignimbrites with peperites are the result of hot pyrocalstic flow mingling with water Peperites in the white volcanic bombs might refer to the mingling between the hot ignimbrites and unconsolidated tuffaceous sediments Tuffs fallout was deposited with the lithics and glass and then eroded to form tuffaceous sand- to mudstone

4.1.7. Polylithologic breccias Polylithologic breccias are widely exposed in Eastern Taiwan’s CR. They often form massive, matrix- to clast-supported breccias with various types of blocks containing a mixture of gray, black, green, and red (Fig. 4l). The subangular and subrounded blocks range from 5 to 100 cm in diameter, with vesicles comprising approximately 30–60% by volume. They are found at the Lingding, Yuemeishan, Shihmen, Shihtikung, Hsiukuluanchi, Sanhsienchi, Mawukuchi, and Chilichi sections. Most of these breccias are thick but poorly bedded, or are partially interbedded with monolithologic breccias, ignimbrites, or tuffs. Epiclastic blocks, such as peperites, limestones, and ignimbrites, are also found in these breccias in the Lingding and Shihtikung sections (Fig. 4m).

Y.-M. Lai, S.-R. Song / Journal of Asian Earth Sciences 74 (2013) 97–112

103

Fig. 4. Volcanic lithofacies in eastern Taiwan’s CR. The sites of these photos are marked in Fig. 2a. (a) A diabase intrusion; (b) an hydrothermal alteration; (c) an andesitic lava flow; (d) a dike swarm; (e) a basaltic dike; (f) an andesitic dike; (g) a pillow lava; (h) pillow breccias; (i) clast-supported monolithologic breccias; (j) autobrecciation breccias; (k) matrix-supported monolithologic breccias; (l) polylithologic breccias; (m) epiclastic breccias; (n) ignimbrites; (o) blocky peperites; (p) fluidal peperites; (q) tuffaceous sediments; (r) herringbone cross bedding.

According to the lithologic variety of breccias and epiclastic detritus, the polylithologic breccias blocks were eroded from older deposits of volcanic edifices. Reddish blocks, which resulted from thermal oxidation in subaerial environments, are contained at the top of this sequence (Cas and Wright, 1987; Song and Lo, 2002). 4.1.8. Ignimbrite Ignimbrites are pyroclastic flows with highly pumiceous and vesiculated glassy materials (Sparks et al., 1973; Fisher and Schmincke, 1984). Ignimbrites in the CR contain rounded to subangular white volcanic bombs, pumice, and lithic fragments with a poorly sorted matrix of crystal vitric and lapilli tuffs (Fig. 4n). These lithofacies are often exposed in the volcaniclasts, but are occasionally interbedded with mono- to polylithologic breccias. White volcanic bombs are andesitic to dacitic, and consist of plastic, welded, and impacted structures in the outcrops. These deformed structures show that the pyroclastic flows were still high in temperature during transportation and deposition (Branney and

Kokelaar, 1992; Freundt, 1999; Busby et al., 2006). This evidence suggests that these pyroclastic flows erupted and were deposited in a subaerial environment. In some sections, peperite formed inside the white volcanic bombs because of the hot flow mingling with water or wet unconsolidated sediments (Jerram and Stollhofen, 2002; Busby et al., 2006; Lai et al., 2008). White volcanic bombs and pumice contain abundant vesicles with various shapes because of subaerial explosions. Lithic fragments in the ignimbrites are blackish, greenish, and reddish, and subangular to angular. Ignimbrites containing peperites were found in the Lingding, Fanshuliaochi, Shihtikung, Shihtiping, Mawukuchi, and Chilichi sections. In the Hsiukuluanchi sections, white volcanic bombs contain no peperites. 4.1.9. Peperites Peperite is a special type of volcaniclastic rock formed by the mingling of juvenile magma with unconsolidated sediments (Jerram and Stollhofen, 2002). In the CR, peperites were observed in-

104

Y.-M. Lai, S.-R. Song / Journal of Asian Earth Sciences 74 (2013) 97–112

Fig. 4. (continued)

side the white volcanic bombs alongside ignimbrites. They are categorized into two types: blocky peperites and fluidal peperites. The blocky clasts commonly display a brittle regime and form a jigsawfit texture, whereas the fluidal clasts are fragmented in a ductile regime and have fluidal or globular morphology (Skilling et al., 2002; Galerne et al., 2006; Brown and Bell, 2007). The blocky peperites are dominant in most cases (Fig. 4o), except in the Mawukuchi and Chilichi sections (Fig. 4p) (Lai et al., 2008). The juvenile material varies from andesitic to dacitic bombs, and mingles with mud or tuffaceous sandstone. Peperites are found only in the white volcanic bombs formed by ignimbrites, and were likely produced when hot ignimbritic flows met with unconsolidated tuffaceous sediments in a subaerial environment (Lai et al., 2008).

4.1.10. Tuffaceous sediments Massive and matrix-supported tuffaceous sediments with mono- to polylithologic lithic, glassy, and lapilli fragments are exposed in the CR (Fig. 4q) in 5–100 cm thick layers between breccia layers (which are between 1 m and over 10 m thick).

Tuffaceous detritus eroded from volcanic eldfices to form tuffaceous sand- to mudstone. The most complete tuffaceous sequence is located at the Shihtiping section in the central CR. Herringbone cross-bedding in this section suggests a tidal environment (Fig. 4r) (Reineck and Singh, 1973; Song and Lo, 2002). Sedimentary structures include parallel laminations with double-grading or cross-bedding in some sections (Song and Lo, 2002).

4.2. Volcanic facies associations Volcanic lithofacies may have a complementary relationship with their eruptive processes. Although 10 volcanic lithofacies were revealed in Section 4.1, a single volcanic lithofacies may be produced by different processes and environments. Several volcanic lithofacies make up one volcanic facies association representing a particular environment (Bryan et al., 2000; Busby et al., 2006). Song and Lo (2002) categorized the lithofacies in the central CR into five facies associations. Three of these associations were based on the distance from a volcanic center (Fig. 5).

Y.-M. Lai, S.-R. Song / Journal of Asian Earth Sciences 74 (2013) 97–112

105

Fig. 4. (continued)

4.2.1. Near-vent volcanic facies association This facies association displays lithofacies produced close to the volcanic center. These include magmas intruded or erupted to form extensive intrusives, dikes, thick lava flows, and thin beds of monolithologic breccias. Alterations and mineralizations near the volcanic vent indicate intense hydrothermal fluids. This facies association is predominantly distributed in the Chimei, Chengkuangao, and Tuluanshan areas of the CR.

Fig. 5. Distribution of volcanic lithofacies, forming near-vent, medial and distal volcanic facies associations from the volcanic center to the margins of a volcano.

4.2.2. Medial volcanic facies association This facies association represents lithofacies that were formed between the volcanic center and more distal areas. It is widely distributed around the whole CR and is composed predominantly of interbedded monolithologic and polylithologic breccias, respectively. Monolithologic breccias are resulted mostly from direct volcanic eruptions and resedimentation of older eruptive deposits. Polylithologic and epiclastic breccias located further from the volcanic center are thicker. In the CR, this facies association spreads from near-vent facies associations (i.e., Chimei and Chengkuangao)

106

Y.-M. Lai, S.-R. Song / Journal of Asian Earth Sciences 74 (2013) 97–112

Table 2 Sr–Nd isotope composition of the volcanic sequences in the Coastal Range.

a

No.

Section

Lithofacies

87

Sr/86Sr

M96001-2 M95002-2 TCR-07 M95036 M97102 M97105 M97107 M97004-3 M98009

Lingding Lingding Fanshuliao Shihmen and Shihtikung Mawukuchi Mawukuchi Chilichi Chilichi

White volcanic bombs Black volcanic breccias White volcanic bombs White volcanic bombs Black volcanic breccias Epiclastic breccias Black volcanic breccias White volcanic bombs Black volcanic breccias

0.704505 0.703554 0.704961 0.705045 0.703915 0.704999 0.703402 0.703764 0.703613

±2r

143

Nd/144Nd

14 20 18 20 10 10 10 14 10

0.513122 0.513123 0.512857 0.512811 0.512996 0.512773 0.513099 0.513034 0.513088

±2r

eNda

8 6 8 8 12 12 12 6 12

+9.5 +9.5 +4.3 +3.4 +7.0 +2.6 +9.0 +7.7 +8.8

eNd = [(143Nd/144Nd)measured/(143Nd/144Nd)CHUR  1]  104, CHUR (Chondritic uniform reservoir) = 0.512638 (Goldstein et al., 1984).

toward the north and south. The decreasing amounts of volcanic debris, in addition to the increase in lava flows, were used to trace the volcanic center in the central CR (Song and Lo, 2002).

4.2.3. Distal volcanic facies association The distal facies association indicate the boundary of the volcano. It is predominantly composed of epiclastic deposits with subsidary pyroclastic ones. Epiclastic deposits were eroded from near-vent or medial facies rocks and consist of polylithologic breccias and tuffaceous sediments, whereas pyroclastic deposits formed directly from eruptive events. Polylithologic breccias are composed of andesitic blocks of varying colors with peperitic and limestone fragments. In the northern CR, epiclastic polylithologic breccias are the dominant lithofacies type and are mainly distributed along the coast, defining the distal volcano region. In the central part, pillow lavas, pillow breccias, hyaloclasts, and thick tuffaceous rocks with parallel bedding are exposed far from the volcanic center (Song and Lo, 2002). Polylithologic breccias also occur in the Tungho area, which may represent a distal area between the central-southern and southern CR.

4.3. Variations in eNd values Previous studies have indicated that the geochemical characteristics of volcanic rocks in the CR show increases in K2O content, LILEs, and 87Sr/86Sr values over time (Richard et al., 1986; Chen et al., 1990; Defant et al., 1990; McDermott et al., 1993). Neodymium isotopic analyses in the CR were first published by Chen et al. (1990). However, the samples in that study were selected randomly; therefore, they could not be compared in different volcanic edifices. For this study, we selected volcanic rocks in five sequences for Nd-isotopic analyses, and the eNd variation results are shown in Fig. 3. These rocks were selected from the Lingding section in the north, the Fanshuliao, Shihmen, and Shihtikung sections in the center, the Mawukuchi section, which falls between the central-southern and southern areas, and the Chilichi section in the southern CR. The isotoptic compositions are shown in Table 2. The eNd values in Lingding’s volcanic rocks are approximately +9.5 in the lower and upper parts of the sequence. In the Fanshuliao section, the eNd value is approximately +9.6 at the bottom and +4.3 at the top. For the Shihmen and Shihtikung sections, the eNd value decreased from the lower (approximately +7.0) to the upper part (approximately +3.4) (Fig. 3a). In the Mawukuchi section, blocks of white volcanic bomb had an eNd value of approximately +2.6, but the samples caught in the black breccias showed an eNd value of approximately +9.0. In the Chilichi section, the eNd value is approximately +8.8 at the bottom and +7.7 at the top (Fig. 3b).

5. Discussion 5.1. Reconstruction of volcanic bodies in the Coastal Range 5.1.1. The volcanic bodies in the Coastal Range To estimate the number and average size of volcanoes in the CR, the boundaries of offshore volcanic islands must be considered. Lutao, Lanyu, and other volcanic islands in the northern Luzon Arc are colliding with the Asian continental margin, which will extend part of the CR in the near future (Yu et al., 1997). The northern Luzon Arc consists of several volcanic islands with a fore-arc or intraarc basin between them (Huang et al., 1992; Reed et al., 1992; Lundberg et al., 1997). The basins shrink as the collision occurs, but most of the volcanic edifices remain relatively unchanged. The volcanic area that can be calculated from these islands could be treated as a reasonable range for the volcanic bodies in this arc. DEM images of the offshore region between Taiwan and Luzon Island were used in this study (Fig. 6a). Bathymetric data were provided by the National Center for Ocean Research (NCOR) and published by Liu et al. (1998). According to the bathymetric map, most of the volcanic islands show a flat slope below 1000 m depths (Fig. 6b). Thus, the areas encircled at a 1000 m depth were defined as the territory of the volcanic islands. The volume range from all of the volcanic islands between Taiwan and Luzon Island were calculated using the ArcGIS 9.2 software (Fig. 6c). Each volcanic volume and their diameters are shown in Table 3 and Fig. 6c. The average diameter of islands in the northern Luzon Arc is approximately 25–30 km. Three forearc basins, Shuilien, Loho, and Taiyuan, and two intra-arc basins, Chingpu and Chengkung, are between the volcanoes in the CR (Huang et al., 1995). The distance for the whole range is approximately 140 km. Considering the approximate total basin space, four to five volcanic bodies may exist in the CR. 5.1.2. Locations of the volcanic centers Based on the facies associations, the distribution of volcanic bodies can be determined. Furthermore, the volcanic center can be identified by the near-vent volcanic facies association (Fig. 2b). In the northern CR, no near-vent volcanic facies associations are found in the Yuemei volcano area. All of the volcanic lithofacies here are mono- to polylithologic breccias, tuffs, and tuffaceous sandstones, all of which belong to the medial and distal facies associations. In the central CR, near-vent volcanic facies association, such as thick lava flows, dike swarms, and hydrothermal alterations, can be found near Hsiukuluanchi River, midstream near the village of Chimei. The medial and distal facies associations occur both to the north and to the south of this area (Song and Lo, 2002). This volcanic body was named the Chimei volcano based on the location of its volcanic center. A detailed discussion on the subject was published by Song and Lo (2002).

107

Y.-M. Lai, S.-R. Song / Journal of Asian Earth Sciences 74 (2013) 97–112

Fig. 6. Bathymetric data for the northern Luzon Arc from Taiwan to Luzon Island is shown in (a), with a contour interval of 200 m (published by Liu et al. (1998)). Seven cross sections cutting through Lutao Island, Lanyu Island, two no name islands, two volcanic islands from the Batan Islands: Sabtang and Itbayat, and the Babuyan Island, are shown in (b), labelled sections A–A0 to G–G0 . In (c), the territory of a volcanic island is defined by the 1000 m line encircling the area, which is also measured in km2.

Table 3 Methods used to reconstruct the number of volcanoes in the Coastal Range. Volcanic islands

Lutao island

Lanyu island

No name

No name

Batan island

Babuyan island

1000 m bathymetry areas (km2) Areas = pd2 2d = x (km)

318.77 20.15

497.17 25.17

591.99 27.46

163.79 14.44

2893.33 60.71 (contain two)

750.26 30.92

The average diameter of the volcanoes: 25–30 km. Total distance of the Coastal Range: 140 km. Possible numbers of volcanoes: 4–5.

In the central-southern CR, the near-vent volcanic facies association is exposed upstream of Sanhsienchi River and Mount Chengkuangao. Thick lava flows with basaltic and andesitic dikes are

found in this area, and an increase in the monolithologic and polylithologic breccias is found away from the mountain to the north and south. Unlike the Chimei volcano, the distal facies associations

108

Y.-M. Lai, S.-R. Song / Journal of Asian Earth Sciences 74 (2013) 97–112

are not clear enough to determine the boundaries of this volcano, Chengkuangao. In the southern CR, outcrops of volcanic rocks are not well-defined or continuous. However, some andesitic lava flows can be found in the Chilichi upstream near the Tuluanshan area. The blue chalcedony veins are caused by lower-grade hydrothermal alterations (Huang, 1966), indicating that this area is close to the volcanic center. According to the territory of the volcanic islands, this area is far from the Chengkuangao volcano. Distal volcanic facies associations are found in the Taiyuan area, and thick polylithologic breccias and epiclastic volcaniclasts signify the boundary with the Chengkuangao volcano to the north. This volcanic body is named Tuluanshan. Based on the volcanic facies associations, at least three volcanic centers can be identified (Fig. 2b), the Chimei, Chengkuangao, and Tuluanshan volcanoes, which lie in the central, central-southern, and southern CR, respectively. However, a cryptic volcanic edifice, the Yuemei volcano to the north, can be determined based on geochemistry (discussed later in the paper). 5.1.3. Implications of isotopic data In previous studies, strontium and neodymium isotopic data for arc magmas have been shown to be contaminated by crustal or subducted materials (Depaolo and Wasserburg, 1977; White and Patchett, 1984; Davidson, 1985). Volcanic rocks in the northern Luzon Arc initially formed with the eNd value characteristic of depleted mantle, but assimilated an increasing number of melted components of subducted crustal materials because they were moved closer to the Eurasian Plate margin by the Philippine Sea Plate, resulting in contamination. Volcanic sequences from different volcanoes may show eNd variations, which can be used as tools to identify each volcano. In the northern CR, young volcanic rocks (6.2 ± 0.6 Ma; Song and Lo, 2002) with an eNd value of approximately +9.5 (Fig. 3a) are located in the Lingding section. This shows that the magma source was still uncontaminated by subducted sediments or other crustal materials. In the central CR, the eNd value in the lower parts (pillow lavas) of the Lohochi section is depleted (approximately +9.5), but changes to +7.1 in the upper section (Song and Lo, 1987). In the Shihmen and Shihtikung sections, the eNd value changes from +7.0 (approximately 5.5 ± 1.5 Ma; Song and Lo, 2002) to +3.4; in the Fanshuliao section, the value changes from +9.6 (Chen et al., 1990) to +4.3 because of contamination. The different eNd values show that these volcanic rocks were produced from different magma sources, forming the Yuemei and Chimei volcanoes, respectively. Between the central-southern and southern CR, the eNd values show high fluctuations. In the Mawukuchi section of the southern CR, epiclastic breccias with an eNd value of approximately +2.6 are found in a sequence of black breccias with an eNd value of approximately +9.0 (Table 3). Another breccia outcrop approximately 500 m from this section has an eNd value from +7.2 to +6.3 (Lai et al., 2008). These results indicate that this area may be the boundary between two volcanoes. Furthermore, the isotopic data in the Chilichi section of the Tuluanshan volcano show uncontaminated signals with an eNd value of approximately +8.8 in the lower parts (black volcanic breccias) and +7.7 in the upper parts (white volcanic bombs) (Table 3). This differs from the Chengkuangao volcano, which has an eNd value of approximately +2.2 at 5.6 Ma (Chen et al., 1990; Lo et al., 1994). The isotopic data implications can also be an auxiliary tool used to identify the Tuluanshan volcano. 5.1.4. The lost volcanic center in the northern CR Volcanic rocks preserved from the Yuemei volcano are characterized by volcanic breccias and tuffs without near-vent facies association rocks. Although the volcanic center cannot be identi-

fied, Yuemei was a distinct volcano based on isotopic data, with an eNd value higher than 9.5 at 6.2 Ma that distinguishes it from the Chimei volcano, which has an eNd value lower than 7.0 at 15– 16 Ma. Yuemei is also different from other parts of the CR regarding the isotopic data and volcanic structure. This evidence indicates that the main volcanic body has been eroded, covered, and/ or subducted, and was not found in this area. According to GPS data (Yu et al., 1997), the northern CR is still moving northward relative to Eurasia, showing that the arc–continent collision and northward subduction are ongoing. Seismic tomography shows that the arc material in the northern Luzon Arc has been subducted northward underneath the Eurasian Plate along the Ryukyu trench (Wang and Chiang, 1998; Chou et al., 2006). Huang et al. (2000) suggested that an arc collapse/subduction is occurring in the northern Luzon Arc, and Font et al. (2001) showed a detailed bathymetric map indicating that the Hoping basin rose because of material subduction from the Luzon Arc. Combining the field examples, lithofacies analyses, GPS data, and seismic tomography, the northern Luzon Arc is continuously moving and subducting underneath the Eurasian Plate post-collision. The main Yuemei volcanic edifice in the northern CR may have already been subducted, and remnants of volcanic terrains in the medial to distal volcanic facies associations remain on land. 5.2. Volcano evolution in the northern Luzon Arc 5.2.1. Implications of the lithofacies of four CR volcanoes According to the lithofacies analyses in the CR, four volcanic bodies have been identified with different preserved lithofacies. In the northern CR, Yuemei’s center has already been partly destroyed and subducted, with only medial to distal lithofacies exposed onland. In the central CR, Chimei’s volcanic body has been well preserved and can be identified clearly. The facies associations from the near-vent, medial, and distal regions are exposed clearly and continuously. Deep-seated diabase and dike swarms have been widely exposed with intruding rocks of the near-vent associations, suggesting that this volcano has been deeply eroded. The marine volcanic lithofacies that arose from the deep sea to the shallows (e.g., pillow lavas, pillow breccias, and hyaloclastites) also outcrop, providing futher evidence of deep erosion of this volcano’s edifice (Fig. 7a). In the central-southern CR, sequences from the Chengkuangao volcano also outcrop continuously. The facies associations define the near-vent to distal environments; however, they show thick, less exposed piles of deep-seated rocks, and few near-vent lithofacies. In addition, shallower underwater lithofacies, such as pillow breccias with subsidiary pillow lavas, can also be found. This evidence suggests that the Chengkuangao volcano has suffered less erosion than Chimei. In the southern CR, volcanic landforms for the Tuluanshan volcano are well preserved, and volcanic lithofacies outcrop less widely (Fig. 7a). Near-vent facies association can be identified near the top of a volcano, but pillow breccias are rare and present in only some outcrops. This suggests that this volcano is young and was only recently accreted into the CR. In summary, the exposed lithofacies of these four volcanoes show that the degree of erosion increases in the CR from the south to the north. This observation is supported by the ages of volcanic cessation, from 3.5 Ma in the south to 5.0 Ma for the central CR, to older than 6.2 Ma in the northern CR (Song and Lo, 2002) (Fig. 7b). 5.2.2. The relationships between the volcanoes and sedimentary basins in the CR To recognize the geotectonic changes between the Luzon volcanic arc and Taiwan while the arc–continent collision is ongoing, researchers have studied the relationships between the volcanoes and sedimentary basins during the collision (Huang et al., 1992;

Y.-M. Lai, S.-R. Song / Journal of Asian Earth Sciences 74 (2013) 97–112

109

Fig. 7. (a) Different degrees of erosion inside the volcano edifices of the Chimei, Chengkuangao and Tuluanshan volcanoes; (b and c) the volcanoes’ evolution model in four stages. Volcanic islands are still active in the first stage, while they moved and ceased in the second stage. They uplifted, accreted and suffered different degrees of erosion to form a part of Taiwan in the third stage. Finally, in the last stage a volcano is subducted beneath the Eurasian Plate. Section A–A0 shows the volcanoes’ detailed evolution from birth to extinction in (c). The final eruption ages were from Yang et al. (1992) and Song and Lo (2002).

Fuh and Liu, 1998). Huang et al. (1995) used stratigraphic and sedimentological analyses to reconstruct three forearc basins, the Shuilien, Loho, and Taiyuan basins, two volcanic islands, the Chimei and Chengkuangao volcanoes, and two intra-arc basins, the Chingpu and Chengkuang basins, in the CR. Huang et al. (2000) combined the ocean bottom seismograph (OBS) data results over this region, the P-wave velocity of forearc sediments and the Tuluanshan Formation in the CR (Tsai et al., 1974; Wang and Chiang, 1998). These results suggest that the arc bodies might be partially subducted with the Philippine Sea Plate beneath the Eurasian Plate.

Our study also found that the CR is a part of the extension of the northern Luzon Arc and is composed of several volcanic bodies. According to the volcanic facies associations, the near-vent facies associations (related to the centers of volcanoes) can be identified in three volcanoes: Chimei, Chengkuangao, and Tuluanshan. Although previous studies have not recognized the Tuluanshan volcano in the CR, this study expounds the distal facies associations between the Chengkuangao and Tuluanshan volcanoes, the variations of isotopic data, the volcanic territories, and the near-vent facies associations near the Tuluanshan area. This evidence suggests

110

Y.-M. Lai, S.-R. Song / Journal of Asian Earth Sciences 74 (2013) 97–112

that the Tuluanshan volcano can be distinguished from the Chengkuangao volcano. Regarding the relationships among forearc basins and the distributions of the volcanos, three pairs can be recognized: the Shuilien basin versus the Chimei volcano, the Loho basin versus the Chengkuangao volcano, and the Taiyuan basin versus the Tuluanshan volcano. These forearc basins and volcanic islands were rotated and uplifted during the collision (Fuh and Liu, 1998). Thereafter, the arc collapse occurred in the volcanic islands (the Chimei and Chengkuangao volcanoes), and strike-slip faults developed and induced the formation of the intra-arc basins (the Chingpu and Chengkung basin) (Huang et al., 1995). Finally, sedimentary basins and volcanic islands accreted and formed the CR of Taiwan. The most northern volcanic body in the CR, the Yuemei volcano, had been interpreted as subducting with the Philippine Sea Plate using seismology and regional structural geology (Huang et al., 2000). However, these studies lack sufficient evidence to prove whether the northern part of these volcanic rocks belong to the Chimei volcano. This study provides strong evidence to distinguish the difference between the Chimei and Yuemei volcanoes by using the isotopic data and the volcanic territory variations.

5.2.3. Evolution of volcanoes in the northern Luzon Arc The volcanoes in Eastern Taiwan’s CR were formed using the same processes as the volcanic islands found offshore, between Taiwan and Luzon Island. These volcanoes were produced by the subduction of the South China Sea Plate beneath the Philippine Sea Plate. Volcanic rocks erupted and formed seamounts that grew from the deep sea to become subaerial volcanoes, ending with a collision and subsequent accretion into the CR. This study identified four volcanic bodies in the accreted arc on land, which shows varying levels of erosion from deep-seated centers to the outer skin of volcanoes. These variations suggest that the four volcanoes were uplifted in different periods. Erosion increased from the south to the north, with Yuemei being at least partially subducted beneath the Eurasian Plate. In summary, the evidence for the volcanic territories of four volcanoes in the northern Luzon Arc was identified by the distribution of volcanic facies associations and isotopic rock ratios. A model for the evolution of volcanoes in an oceanic island arc setting, from their creation to extinction, can be established (Fig. 7b and c). In the first stage, magmas were produced by subduction and erupted to form seamounts rising from the deep sea to the subaerial surface. In the northern Luzon Arc, active volcanoes such as Batan and Babuyun represent this stage (Richard et al., 1986; Defant et al., 1989, 1990; Yang et al., 1996). In the second stage, the volcanoes moved with the Philippine Sea Plate but ceased their eruptions as arc–continent collision commenced. The volcanic islands located offshore of Eastern Taiwan, Lutao and Lanyu, are at this stage. The volcanic extinction dates progressively younger from the north to the south (Yang et al., 1996). The last recorded eruption near Lanyu’s ocean floor was in 1858 A.D. (Chen and Shen, 2005), and may be the boundary between active and extinct volcanoes. In the third stage, the volcanic islands were uplifted and accreted to the CR by an oblique arc–continent collision and suffered varying degrees of erosion and crustal exposure during different periods on land. That the Chimei, Chengkuangao and Tuluanshan volcanoes show the near-vent facies association with distinctive internal lithofacies is powerful evidence of the gradual uplift and erosional processes in this stage. Finally, in the last stage, a volcano is being subducted beneath the Eurasian Plate at the northernmost end of the Luzon Arc along with the western Philippine Sea Plate. The cryptic volcanic center of Yuemei may have been subducted underneath the Eurasian Plate, documenting this stage (Fig. 7b and c).

Several geodynamic models have been proposed to interpret four stages of oblique arc–continent collision that occurred in Taiwan (Chen and Juang, 1986; Huang et al., 1995, 2000; Lallemand et al., 1997; Liu et al., 1996, 1998; Shyu and Chen, 1991): the intra-oceanic subduction, initial arc–continent collision, advanced arc–continent collision, and arc collapse/subduction. Our four stages may be respectively correlated to their four geodynamic stages. However, determining whether this model in the northern Luzon Arc can be applied to the whole oceanic arc–continent collision requires further investigation.

6. Conclusions Detailed field surveys were completed in volcanic and volcaniclastic rocks along the entire Eastern Taiwan’s CR. Ten volcanic lithofacies and six facies associations were identified and categorized. Based on the volcanic territory, volcanic facies associations, and geochemical data, four volcanoes in Eastern Taiwan’s CR were identified, and the evolution of an oceanic island arc, from birth to extinction, was reconstructed. The three volcanic centers identified through the near-vent facies associations were named Chimei, Chengkuangao, and Tuluanshan, each of which has suffered from different degrees of erosion. The fourth volcanic center that is no longer exposed, the distinct volcano Yuemei in the northern most part of the CR, can also be identified based on isotopic data. It shows a distinctive eNd value, and the age of its volcanic rocks differs from those of the three other volcanoes. With the northward subduction of the Philippine Sea Plate, Yuemei’s volcanic center has probably already been subducted, at least in part underneath the Eurasian Plate. Based on volcanic landforms, facies associations, and geochemistry, a model for the evolution of volcanoes in the northern Luzon Arc can be proposed. Volcanic islands are created by melting above subducted oceanic slabs, and grow from the deep sea to the subaerial environment. Volcanoes were moved, ceased eruption, were uplifted, and essentially destroyed under different conditions during the ongoing oblique arc–continent collision. Different degrees of erosion expose particular lithofacies produced by the volcanoes. Finally, a volcano was destroyed and sank underneath the surface because of the northward-shifting subducting slab. Acknowledgments We are grateful to Profs. C.H. Chen, T.F. Yang, and S. Tsao for their constructive comments. We also thank Dr. Neil Lungberg and Prof. C.Y. Huang, who gave great comments to greatly improve this manuscript. This research was supported by the National Science Council of Taiwan under the Grants NSC 96-2745-M-002-001 and NSC 97-2745-M-002-014. References Acocella, V., Fniciello, F., 2010. Kinematic setting and structural control of arc volcanism. Earth and Planetary Science Letters 289, 43–53. Avdeiko, G.P., Volynets, O.N., Antonov, A.Yu., Tsvetkov, A.A., 1991. Kurile island–arc volcanism: structural and petrological aspects. Tectonophysics 199, 271–287. Barker, P., 2001. Scotia Sea regional tectonic evolution: implications for mantle flow and palaeocirculation. Earth-Science Reviews 55, 1–39. Biq, C.C., 1973. Kinematic Pattern of Taiwan as an Example of Actual Continent-arc Collision. Report of the Seminar on Seismology, US-ROC Cooperative Science Program, vol. 25, pp. 149–166. Bowin, C., Lu, R.S., Lee, C.S., Schouten, H., 1978. Plate convergence and accretion in Taiwan–Luzon region. American Association Petroleum Geologists Bulletin 62, 1645–1672. Branney, M.J., Kokelaar, P., 1992. A reappraisal of ignimbrite emplacement: progressive aggradation and changes from particulate to non-particulate flow during emplacement of high-grade ignimbrite. Bulletin of Volcanology 54, 504– 520.

Y.-M. Lai, S.-R. Song / Journal of Asian Earth Sciences 74 (2013) 97–112 Brown, M., 2009. Metamorphic patterns in orogenic systems and the geological record. In: Cawood, P.A., Kröner, A. (Eds.), Accretionary Orogens in Space and Time. Geological Society, London, Special Publications, vol. 318, pp. 37–74. Brown, D.J., Bell, B., 2007. How do you grade peperites? Journal of Volcanology and Geothermal Research 159, 409–420. Brown, G.M., Holland, J.G., Sigurdsson, H., Tomblin, J.F., Arculus, R.J., 1977. Geochemistry of the Lesser Antilles volcanic island arc. Geochimica et Cosmochimica Acta 41, 785–801. Bryan, S.E., Ewart, A., Stephens, C.J., Parianos, J., Downes, P.J., 2000. The Whitsunday Volcanic Province, Central Queensland, Australia: lithological and stratigraphic investigations of a silicic-dominated large igneous province. Journal of Volcanology and Geothermal Research 99, 55–78. Busby, C., Adams, B.F., Mattinson, J., Deoreo, S., 2006. View of an intact oceanic arc, from surficial to mesozonal levels: Cretaceous Alisitos arc, Baja California. Journal of Volcanology and Geothermal Research 149, 1–46. Busby-Spera, C.J., 1988. Speculative tectonic model for the Early Mesozoic arc of the southwest Cordilleran United States. Geology 16, 1121–1125. Cas, R.A.F., Wright, J.V., 1987. Volcanic Successions: Modern and Ancient. Allen and Unwin, London, 528 pp. Chai, B.H.T., 1972. Structure and tectonic evolution of Taiwan. American Journal of Science 272, 389–422. Chang, L.S., 1968. A biostratigraphic study of the Tertiary in the Coastal Range, eastern Taiwan, based on smaller foraminifera. (II. Northern Part). Proceedings of the Geological Society of China 11, 19–33. Chen, M.P., Juang, W.S., 1986. Seafloor physiography off southeastern Taiwan. Acta Oceanographica Taiwanica 16, 1–7. Chen, C.-H., Shen, J.J.-S., 2005. A refined historical record of volcanic eruptions around Taiwan: tectonic implications in the arc–continent Collision Area. Terrestrial, Atmospheric, and Oceanic Sciences 16 (2), 331–343. Chen, W.S., Wang, Y., 1988. Development of deep-sea fan systems in Coastal Range basin, eastern Taiwan. Acta Geologica Taiwanica 26, 37–56. Chen, C.-H., Shieh, Y.-N., Lee, T., Chen, C.-H., Mertzman, S.A., 1990. Nd–Sr–O isotopic evidence for source contamination and an unusual mantle component under Luzon Arc. Geochimica et Cosmochimica Acta 54, 2473–2483. Chou, H.-C., Kuo, B.-Y., Hung, S.-H., Chiao, L.-Y., Zhao, D., Wu, Y.-M., 2006. The Taiwan–Ryukyu subduction–collision complex: folding of a viscoelastic slab and the double seismic zone. Journal of Geophysical Research 111, 1–14. Davidson, J.P., 1985. Mechanisms of contamination in Lesser Antilles island arc magmas from radiogenic and oxygen isotope relationships. Earth and Planetary Science Letters 72, 163–174. de Ronde, C.E.J., Baker, E.T., Masoth, G.J., Lupton, J.E., Wright, I.C., Feely, R.A., Greene, R.R., 2001. Intra-ocean subduction-related hydrothermal venting, Kermadec volcanic arc, New Zealand. Earth and Planetary Science Letters 193, 359–369. Defant, M.J., Jacques, D., Maury, R.C., de Boer, J.Z., 1989. Geochemistry of the Luzon arc Philippines. Geological Society of America Bulletin 101, 663–672. Defant, M.J., Maury, R.C., Joron, J.-L., Feigenson, M.D., Leterrier, J., Bellon, H., Jacques, D., Richard, M., 1990. The geochemistry and tectonic setting of the northern section of the Luzon arc (the Philippines and Taiwan). Tectonics 183, 187–205. Depaolo, D.J., Wasserburg, G.J., 1977. The sources of island arcs as indicated by Nd and Sr isotopic studies. Geophysical Research Letters 4, 465–468. Deplus, C., Le Friant, A., Boudon, G., Komorowski, J.-C., Villemant, B., Harford, C., Segoufin, J., Cheminee, J.-L., 2001. Submarine evidence for large-scale debris avalanches in the Lesser Antilles Arc. Earth and Planetary Science Letters 192, 145–157. Dimroth, E., Cousineau, P., Leduc, M., Sanchagrin, Y., 1978. Structure and organization of Archean subaqueous basalt flows, Rouyn-Noranda area, Quebec, Canada. Canadian Journal of Earth Sciences 15, 902–918. Embley, R.W., Baker, E.T., Chadwick, W.W., Lupton, J.E., Resing, J.A., Massoth, G.J., Nakamura, K., 2004. Explorations of Mariana Arc volcanoes reveal new hydrothermal systems. EOS, Transactions, American Geophysical Union 85 (4), 37–40. Escalona, A., Mann, P., 2011. Tectonics, basin subsidence mechanisms, and paleogeography of the Caribbean–South American plate boundary zone. Marine and Petroleum Geology 28 (1), 8–39. Ewart, A., Brothers, R.N., Mateen, A., 1977. An outline of the geology and geochemistry, and the possible petrogenetic evolution of the volcanic rocks of the Tonga-Kermadec–New Zealand island arc. Journal of Volcanology and Geothermal Research 2, 205–250. Fisher, R.V., 1984. Submarine volcaniclastic rocks. In: Kokelaar, B.P., Howells, M.F. (Eds.), Marginal Basin Geology-Volcanic and Associated Sedimentary and Tectonic Process in Modern and Ancient Marginal Basin. Special Publication of the Geology Society of London, vol. 16, pp. 5–27. Fisher, R.V., Schmincke, H.-U., 1984. Pyroclastic Rocks. Springer-Verlag, New York, 472 pp. Font, Y., Liu, C.-S., Schnurle, P., Lallemand, S., 2001. Constraints on backstop geometry of the southwest Ryukyu subduction based on reflection seismic data. Tectonophysics 333, 135–158. Freundt, A., 1999. Formation of high-grade ignimbrites: Part II. A pyroclastic suspension current model with implications also for low-grade ignimbrites. Bulletin Volcanologique 60, 545–567. Fuh, S.-C., Liu, C.-S., 1998. Evolution of the southern longitudinal trough in the incipient Taiwan arc–continent collision zone and its tectonic implication. Journal of the Geological Society of China 41 (4), 497–516.

111

Furnes, H., Sturt, B.A., 1976. Beach/shallow marine hyaloclastite deposits and their geological significance: an example from Gran Canaria. The Journal of Geology 84, 439–453. Galerne, C., Caroff, M., Rolet, J., Gall, B.L., 2006. Magma-sediment mingling in an Ordovician rift basin: The Plouezec–Plourivo half-graben, American Massif, France. Journal of Volcanology and Geothermal Research 155, 164–178. Gamble, J.A., Smith, I.E.M., McCulloch, M.T., Graham, I.J., Kokelaar, B.P., 1993. The geochemistry and petrogenesis of basalts from the Taupo Volcanic Zone and Kermadec Island Arc, S. W. Pacific. Journal of Volcanology and Geothermal Research 54, 265–290. Geist, E.L., Childs, J.R., Scholl, D.W., 1987. The evolution and petroleum geology of Amlia and Amukta intra-arc basins, Aleutian Ridge. Marine and Petroleum Geology 4, 334–352. Germa, A., Quidelleur, X., Labanieh, S., Lahitte, P., Chauvel, C., 2010. The eruptive history of Morne Jacob volcano (Martinique Island, French West Indies): geochronology, geomorphology and geochemistry of the earliest volcanism in the recent Lesser Antilles arc. Journal of Volcanology and Geothermal Research 198 (3–4), 297–310. Glasby, G.P., Notsu, K., 2003. Submarine hydrothermal mineralization in the Okinawa Trough, SW of Japan: an overview. Ore Geology Reviews 23, 299–339. Goldstein, S.L., O’Nions, R.K., Hamilton, P.J., 1984. A Sm–Nd isotopic study of atmospheric dusts and particulates from major river systems. Earth and Planetary Science Letters 70, 221–236. Goto, Y., Tsuchiya, N., 2004. Morphology and growth style of a Miocene submarine dacite lava dome at Atsumi, northeast Japan. Journal of Volcanology and Geothermal Research 134, 255–275. Haase, K.M., Koschinsky, A., Petersen, S., Devey, C.W., German, C., Lackschewitz, K.S., Melchert, B., Seifert, R., Borowski, C., Giere, O., Paulick, H., 2009. Diking, young volcanism and diffuse hydrothermal activity on the southern Mid-Atlantic Ridge: the Lilliput field at 9°330 S. Marine Geology 266, 52–64. Hergt, J.M., Woodhead, J.D., 2007. A critical evaluation of recent models for LauTonga arc-backarc basin magmatic evolution. Chemical Geology 245, 9–44. Ho, C.S., 1986. A synthesis of geologic evolution of Taiwan. Tectonophysics 125, 1– 16. Hsiao, T.H., 1993. Study on the Volcanic Rocks in the Sanhsienchi Area Near Chengkung, Eastern Coastal Range of Taiwan. Ms. Dissertation, National Taiwan University (in Chinese). Huang, C.K., 1966. Nephrite and blue chalcedony from Taiwan. Proceedings of the Geological Society of China 9, 11–19. Huang, C.-Y., Shyu, C.-T., Lin, S.-B., Lee, T.-Q., Sheu, D., 1992. Marine geology in the arc–continent collision zone off southeastern Taiwan: implications for late Neogene evolution of the Coastal Range. Marine Geology 107 (3), 183–212. Huang, C.Y., Yuan, P.B., Song, S.R., Lin, C.W., Wang, C., Chen, M.T., Shyu, C.T., Karp, B., 1995. Tectonics of short-lived intra-arc basins in the arc–continent collision terrane of the Coastal Range, eastern Taiwan. Tectonics 14, 19–38. Huang, C.-Y., Wu, W.-Y., Chang, C.-P., Tsao, S., Yuan, P.B., Lin, C.-W., Xia, K.-Y., 1997. Tectonic evolution of accretionary prism in the arc–continent collision terrane of Taiwan. Tectonics 281, 31–51. Huang, C.Y., Yuan, P.B., Lin, C.W., Wang, T.K., Chang, C.P., 2000. Geodynamic processes of Taiwan arc–continent collision and comparison with analogs in Timor, Papua New Guinea, Urals, and Corsica. Tectonophysics 325, 1–21. Isse, T., Shiobara, H., Tamura, Y., Suetsugu, D., Yoshizawa, K., Sugioka, H., Ito, A., Kanazawa, T., Shinohara, M., Mochizuki, K., Araki, E., Nakahigashi, K., Kawakatsu, H., Shito, A., Fukao, Y., Ishizuka, O., Gill, J.B., 2009. Seismic structure of the upper mantle beneath the Philippine Sea from seafloor and land observation: Implications for mantle convection and magma genesis in the Izu-Bonin-Mariana subduction zone. Earth and Planetary Science Letters 278, 107–119. Jerram, D.A., Stollhofen, H., 2002. Lava-sediment interaction in desert settings: are all peperite-like textures the result of magma–water interaction? Journal of Volcanology and Geothermal Research 114, 231–249. Jicha, B.R., 2009. Holocene volcanic activity at Koniuji Island, Aleutians. Journal of Volcanology and Geothermal Research 185 (3), 214–222. Jicha, B.R., Singer, B.S., Beard, B.L., Johnson, C.M., 2005. Contrasting timescales of crystallization and magma storage beneath the Aleutian Island arc. Earth and Planetary Science Letters 236, 195–210. Juang, W.S., Bellon, H., 1984. The potassium–argon dating of andesites from Taiwan. Proceedings of the Geological Society of China 27, 86–100. Karig, D.E., 1973. Plate convergence between the Philippines and the Ryuku Island. Marine Geology 14, 153–168. Lafrance, B., Mueller, W.U., Daigneault, R., Dupras, N., 2000. Evolution of a submerged composite arc volcano: volcanology and geochemistry of the Normétal volcanic complex, Abitibi greenstone belt, Québec. Canada Precambrian Research 101, 277–311. Lai, Y.-M., Song, S.-R., Iizuka, Y., 2008. Magma mingling in the Tungho area, Coastal Range of eastern Taiwan. Journal of Volcanology and Geothermal Research 178, 608–623. Lallemand, S.E., 1996. Impact of tectonic erosion by subduction processes on intensity of arc volcanism. The Island Arc 5 (1), 16–24. Lallemand, S.E., Liu, C.S., ACT Cruise Scientific Team, 1997. Swath bathymetry reveal active arc–continent collision near Taiwan. EOS, Transactions American Geophysical Union 78 (17), 173–175. Lan, C.Y., 1982. Mineralogy, Petrology and Hydrothermal Alteration of Chimei Igneous Complex, Hualien, Taiwan. MRSO Report 193, 60 pp.

112

Y.-M. Lai, S.-R. Song / Journal of Asian Earth Sciences 74 (2013) 97–112

Lee, Y.H., Chen, C.C., Liu, T.K., Ho, H.C., Lu, H.Y., Lo, W., 2006. Mountain building mechanisms in the Southern Central Range of the Taiwan Orogenic Belt-from accretionary wedge deformation to arc–continental collision. Earth and Planetary Science Letters 252, 413–422. Li, X.H., 1997. Geochemistry of the Longsheng Ophiolite from the sourthern margin of Yangtze Craton, SE China. Geochemical Journal 31, 323–337. Liu, C.S., Liu, S.Y., Song, G.S., Shyu, C.T., Yu, H.S., Chiao, L.Y., Wang, C.S., Karp, B., 1996. Digital bathymetry data offshore Taiwan. 1996 Annual Meeting, Geological Society of China. Prog-Abstr., pp. 420–425. Liu, C.S., Liu, S.Y., Lallemend, S.E., Lundberg, N., Reed, D.L., 1998. Digital elevation model offshore Taiwan and its tectonic implications. Terrestrial, Atmospheric, and Oceanic Sciences 9 (4), 705–738. Lo, C.H., Onstott, T.C., Chen, C.H., Lee, T., 1994. An assessment of 40Ar/39Ar dating for the whole-rock volcanic samples from the Luzon Arc near Taiwan. Chemical Geology 114, 157–178. Lundberg, N., Reed, D.L., Liu, C.-S., Lieske Jr., J., 1997. Forearc-basin closure and arc accretion in the submarine suture zone south of Taiwan. Tectonophysics 274, 5–23. Macdonald, R., Hawkesworth, C.J., Heath, E., 2000. The Lesser Antilles volcanic chain: a study in arc magmatism. Earth-Science Reviews 49, 1–76. McDermott, F., Defant, M.J., Hawkesworth, C.J., Maury, R.C., Joron, J.L., 1993. Isotope and trace element evidence for three component mixing in the genesis of the North Luzon arc lavas (Philippines). Contributions to Mineralogy and Petrology 113, 9–23. Moore, J.G., Phillips, R.L., Grigg, R.W., Peterson, D.W., Swanson, D.A., 1973. Flow of lava into the sea, 1969–1971, Kilauea Volcano, Hawaii. Geological Society of America Bulletin 84, 537–546. Palinkas, L.A., Bermanec, V., Borojevic Sostaric, S., Kolar Jurkovsek, T., Palinkas, S.S., Molnar, F., Kniewald, G., 2008. Volcanic facies analysis of a subaqueous basalt lava-flow complex at Hruskovec, NW Croatia – evidence of advanced rifting in the Tethyan domain. Journal of Volcanology and Geothermal Research 178, 644–656. Petterson, M.G., Treloar, P.J., 2004. Volcanostratigraphy of arc volcanic sequences in the Kohistan arc, North Pakistan: volcanism within island arc, back-arc-basin, and intra-continental tectonic settings. Journal of Volcanology and Geothermal Research 130, 147–178. Petterson, M.G., Babbs, T., Neal, C.R., Mahoney, J.J., Saunders, A.D., Duncan, R.A., Tolia, D., Magu, R., Qopoto, C., Mahoa, H., Natogga, D., 1999. Geological-tectonic framework of Solomon Islands, Southwest Pacific; crustal accretion and growth within an intra-oceanic setting. Tectonophysics 301, 35–60. Reed, D.L., Lundberg, N., Liu, C.-S., Kuo, B.-Y., 1992. Structural relations along the margins of the offshore Taiwan accretionary wedge: implications for accretion and crustal kinematics. Acta Geologica Taiwanica 30, 105–122. Reineck, H.-E., Singh, I.B., 1973. Depositional Sedimentary Environments. SpringerVerlag, 439 pp. Richard, M., Bellon, H., Maury, R.C., Barrier, E., Juang, W.S., 1986. Miocene to recent calc-alkaline volcanism in eastern Taiwan: K–Ar ages and petrography. Tectonophysics 125, 87–102. Robin, C., Eissen, J.-P., Monzier, M., 1993. Giant tuff cone and 12-km-wide associated caldera at Ambrym Volcano (Vanuatu, New Hebrides Arc). Journal of Volcanology and Geothermal Research 55, 225–238. Rollinson, H.R., 1993. Using Geochemical Data: Evaluation, Presentation. Interpretation. Longman UK Limited, Essex, England, 352 pp. Roosmawati, N., Harris, R.A., 2009. Surface uplift history of the incipient Banda arc– continent collision: geology and synorogenic foraminifera of Rote and Savu Islands, Indonesia. Tectonophysics 479, 95–110. Scott, C.R., Mueller, W.U., Pilote, P., 2002. Physical volcanology, stratigraphy, and lithogeochemistry of an Archean volcanic arc: evolution from plume-related volcanism to arc rifting of SE Abitibi Greenstone Belt, Val d’Or, Canada. Precambrian Research 115, 223–260. Shyu, C.-T., Chen, S.-C., 1991. A topographic and magnetic analysis off southeastern Taiwan. Acta Oceanographica Taiwanica 27, 1–20. Sigvaldason, G.E., 1968. Structure and products of subaquatic volcanoes in Iceland. Contributions to Mineralogy and Petrology 18, 1–16. Skilling, I.P., White, J.D.L., McPhie, J., 2002. Peperite: a review of magma-sediment mingling. Journal of Volcanology and Geothermal Research 114, 1–17. Smith, I.E.M., Price, R.C., Stewart, R.B., Worthington, T.J., 2009. An assessment of the mantle and slab components in the magmas of an oceanic arc volcano: Raoul Volcano, Kermadec arc. Journal of Volcanology and Geothermal Research 184, 437–450. Song, S.R., Lo, H.J., 1987. Volcanic rocks of the Coastal Range of Taiwan as the products of submarine eruption-the evidences from Loho area. Acta Geologica Taiwanica 25, 97–110.

Song, S.-R., Lo, H.-J., 1988. Volcanic geology of Fengpin-Takangkou area, coastal range of Taiwan. Acta Geologica Taiwanica 26, 223–235. Song, S.-R., Lo, H.-J., 1990. Stratigraphy of volcanics and related rocks in the Coastal Range, eastern Taiwan. Special Publication of Central Geological Survey 4, 261– 270 (in Chinese with English Abstract). Song, S.-R., Lo, H.-J., 2002. Lithofacies of volcanic rocks in the central Coastal Range, eastern Taiwan: implications for island arc evolution. Journal of Southeast Asian Earth Sciences 21, 23–38. Sparks, R.S.J., Self, S., Walker, G.P.L., 1973. Products of ignimbrite eruptions. Geology 1, 115–118. Taylor, B., Hayes, D.E., 1983. Origin and history of the South China Sea basin. In: Hayes, D.E. (Ed.), The Tectonic and Geologic Evolution of Southeast Asian Seas and Islands. Part 2. Geophysical Monograph, American Geophysical Union, vol. 27, pp. 89–104. Taylor, R.N., Nesbitt, R.W., 1998. Isotopic characteristics of subduction fluids in an intra-oceanic setting, Izu-Bonin Arc, Japan. Earth and Planetary Science Letters 164, 79–98. Teng, L.S., 1979. Petrographical study of the Neogene sandstones of the Coastal Range, eastern Taiwan. (I. Northern Part). Acta Geologica Taiwanica 20, 129– 156. Teng, L.S., 1988. Toward a comprehensive stratigraphic system of the Coastal Range, eastern Taiwan. Acta Geologica Taiwanica 26, 19–36. Teng, L.S., 1996. Extensional collapse of the northern Taiwan mountain belt. Geology 24, 949–952. Teng, L.S., Lo, H.J., 1985. Sedimentary sequences in the island arc setting of the Coastal Range, eastern Taiwan. Acta Geologica Taiwanica 23, 77–98. Tsai, Y.B., Hsiung, Y.M., Liaw, H.B., Lueng, H.P., Tao, T.H., Yeh, Y.H., Yeh, Y.T., 1974. A seismic refraction study of eastern Taiwan. Petroleum Geology Taiwan 11, 165– 182. Vazquez, J.A., Ort, M.H., 2006. Facies variation of eruption units produced by the passage of single pyroclastic surge currents, Hopi Buttes volcanic field, USA. Journal of Volcanology and Geothermal Research 154, 222–236. Wang, T.-K., Chiang, C.-H., 1998. Imaging of arc–arc collision in the Ryukyu forearc region offshore Hualien from TAICRUST OBS line 16. Terrestrial, Atmospheric, and Oceanic Sciences 9 (3), 329–344. Westercamp, D., 1988. Magma generation in the Lesser Antilles: geological constraints. Tectonophysics 149 (1–2), 145–163. Wharton, M.R., Hathway, B., Colley, H., 1995. Volcanism associated with extension in an Oligocene–Miocene arc, southwestern Viti Levu, Fiji. In: Smellie, J.L. (Ed.), Volcanism Associated with Extension at Consuming Plate Margins. Special Publication of the Geological Society of London 81 pp. 95–114. White, J.D.L., Busby-Spera, C.J., 1987. Deep marine arc apron deposits and syndepositional magmatism in the Alisitos Group at Punta Cono, Baja California, Mexico. Sedimentology 34 (5), 911–927. White, W.M., Patchett, P.J., 1984. Hf–Nd–Sr isotopes and incompatible element abundances in island arcs: implication for magma origins and crust mantle evolution. Earth and Planetary Science Letters 6, 167–185. Wilson, C.J.N., Houghton, B.F., McWilliams, M.O., Lanphere, M.A., Weaver, S.D., Briggs, R.M., 1995. Volcanic and structural evolution of Taupo Volcanic Zone, New Zealand: a review. Journal of Volcanology and Geothermal Research 68, 1– 28. Wohletz, K.H., 1983. Mechanisms of hydrovolcanic pyroclast formation: size, scanning electron microscopy, and experimental studies. Journal of Volcanology and Geothermal Research 17, 31–63. Woodhead, J.D., 1989. Geochemistry of the Mariana Arc (western Pacific): source composition and processes. Chemical Geology 76, 1–24. Yang, T.F., Liu, T.K., Chen, C.H., 1988. Thermal event records of the Chimei igneous complex: constraint on the ages of magma activities and the structural implication based on fission track dating. Acta Geologica Taiwanica 26, 237– 246. Yang, T.F., Chen, C.-H., Lee, T., 1992. Fission-track dating of Lutao volcanics: implications of partial annealing and eruption history. Journal of the Geological Society of China 35, 19–34. Yang, T.F., Lee, T., Chen, C.-H., Cheng, S.-N., Knittel, U., Punongbayan, R.S., Easdas, A.R., 1996. A double island arc between Taiwan and Luzon: consequence of ridge subduction. Tectonics 258, 85–101. Yen, T.P., 1968. Volcanic geology of the Coastal Range, eastern Taiwan. Proceedings of the Geological Society of China 11, 74–88. Yu, S.B., Chen, H.Y., Kuo, L.C., 1997. Velocity field of GPS stations in the Taiwan area. Tectonophysics 273, 41–59. Zellmer, G., Turner, S., Hawkesworth, C., 2000. Timescales of destructive plate margin magmatism: new insights from Santorini, Aegean volcanic arc. Earth and Planetary Science Letters 174, 265–281.