Imprints of Late Mesozoic tectono-magmatic events on Palawan Continental Block in northern Palawan, Philippines

Accepted Manuscript Imprints of Late Mesozoic tectono-magmatic events on Palawan Continental Block in northern Palawan, Philippines Jenielyn T. Padrones, Kenichiro Tani, Yukiyasu Tsutsumi, Akira Imai PII: DOI: Reference:

S1367-9120(17)30027-5 http://dx.doi.org/10.1016/j.jseaes.2017.01.027 JAES 2945

To appear in:

Journal of Asian Earth Sciences

Received Date: Revised Date: Accepted Date:

25 January 2016 21 January 2017 21 January 2017

Please cite this article as: Padrones, J.T., Tani, K., Tsutsumi, Y., Imai, A., Imprints of Late Mesozoic tectonomagmatic events on Palawan Continental Block in northern Palawan, Philippines, Journal of Asian Earth Sciences (2017), doi: http://dx.doi.org/10.1016/j.jseaes.2017.01.027

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Imprints of Late Mesozoic tectono-magmatic events on Palawan Continental Block in northern Palawan, Philippines Jenielyn T. Padrones1*, Kenichiro Tani2, Yukiyasu Tsutsumi2, Akira Imai3,

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2

Graduate School of Engineering and Resource Sciences, Akita University, Japan

Department of Geology and Paleontology, National Museum of Nature and Science, Japan 3

Graduate School of International Resource Sciences, Akita University, Japan

Abstract A recent investigation in Palawan Island led to the recognition of the Daroctan Granite, a pluton that intruded the Mesozoic mélange in the northernmost part. The occurrence and age of the magmatism is presented in this study as well as the maximum age of deposition for some Late Mesozoic lithostratigraphic units. Geochronological studies on zircon and monazite was carried out to unravel the Late Mesozoic tectonic evolution of this area. Monazite U-Th-total Pb dating was used to determine the age of the Daroctan Granite, which yielded a Late Cretaceous age similar to some of the Mesozoic granites surrounding the South China Sea. Zircon U-Pb and monazite U-Th-total Pb dating were also used to determine the maximum age of deposition of the sedimentary units belonging to the Guinlo Formation and Tumarbong Semi-schist. The results show a Jurassic to Early Cretaceous age range with a Late Cretaceous maximum age of deposition for the meta-sedimentary units. This sliver of the Palawan Continental Block, which is composed of accreted units, might have been located at the margin of the continent-ocean collision during the Mesozoic wherein detrital minerals with mostly Late Cretaceous ages were deposited. It was later intruded by the Daroctan Granite and eventually broke off from the southeastern Eurasian margin. These findings provide additional constraints on the tectonic evolution of the Palawan Continental

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Block.

Keywords: LA-ICPMS; geochronology; U-Th-total Pb; zircon; monazite; Yanshanian magmatism

*Correspondence should be addressed to: [email protected]; Present address: Institute of Renewable Natural Resources, College of Forestry and Natural Resources, University of the Philippines, Los Baños, Laguna 4031, Philippines

1. Introduction

Recent studies on the Palawan Continental Block (PCB) have provided new insights on its tectonic evolution. In northern Palawan, the works of Encarnacion and Mukasa (1997), Suzuki et al. (2000), Walia et al. (2012), Yokoyama et al. (2012), and Suggate et al. (2014) highlighted the geochemical character, ages, and possible provenance of the different lithologic units. Zircon ages were reported for some of the granitic rocks (i.e., Central Palawan Granite and Kapoas Granitoid). In addition, maximum depositional ages for some of the meta-sedimentary rocks (i.e., Babuyan River Turbidite, Caramay Schist) were obtained. Monazite ages were also reported for the Kapoas Granitoid, the Mesozoic King Ranch Formation and the Liminangcong Formation in the northern islands (Encarnacion and Mukasa, 1997; Walia et al., 2012; Yokoyama et al., 2012; Suggate et al., 2014). It was suggested that the detrital grains were derived either from South China (Suzuki et al., 2000; Suggate et al., 2014), South East China (Walia et al., 2012), or the Korean Peninsula and East China (Yokoyama et al., 2012).

Mesozoic igneous rocks are prevalent in the South China Sea region including the areas in the Pearl River Mouth Basin, Xisha Block, Zhongsha Block, Nansha Block, and the 2

Schwaner Mountains in Borneo (Yan et al., 2014 and references therein). However, only Cenozoic intrusive units (i.e., Late Eocene Central Palawan Granite and the Middle Miocene Kapoas Granitoid) were recognized in Palawan Island. The reported ages for the Central Palawan Granite are 37 ± 2 Ma (Mitchell et al., 1986), 36.0 ± 1.8 Ma (Metal Mining Agency of Japan - Japan International Cooperation Agency [MMAJ-JICA], 1987), and 42 ±0.5 (Suggate et al., 2014). For the Kapoas Granitoid, Encarnacion and Mukasa (1997) reported an age of 15 +3/-4 Ma, based on Thermal Ionization Mass Spectrometry (TIMS) analysis of zircon concentrates. Suggate et al. (2014), based on a single grain dating, provided a more precise age of 13.5 ± 0.2 Ma. The age of the Bay Peak intrusive body to the south of Mt. Kapoas is 13.8 ± 0.3 Ma (Suggate et al., 2014). The Daroctan Granite, another intrusive unit located in El Nido, in the northern portion of Palawan mainland, was assigned a Cretaceous age by MMAJ-JICA (1987) based on stratigraphic correlation. The Daroctan Granite was not included in recent works and was only mapped as part of the Mesozoic mélange.

In northern Palawan, most of the clastic sediments were dated as Late Cretaceous (Walia et al., 2012; Suggate et al., 2014). However, it should be noted that samples were not taken from the sedimentary units north of Roxas.

In this study, we report the maximum age of the meta-sedimentary units of the Tumarbong Semi-schist north of Roxas and present data on the occurrence and age of the Daroctan Granite. A tuffaceous sedimentary sequence is also recognized in northern Palawan. The age of this sequence is reported here for the first time. These findings provide additional constraints on the tectonic evolution of the PCB.

2. Geology of the PCB and northern Palawan The PCB, also known as the North Palawan Block (Holloway, 1982) or Palawan Continental Terrane (Walia et al., 2012), is a tectonic unit in the Philippine archipelago that is 3

of continental affinity. It is a fragment which broke off from the southeastern Eurasian margin and was translated south with the opening of the South China Sea during the Late Eocene (Hsu et al., 2004). The PCB is composed of the islands of Palawan, Mindoro, Romblon Island Group, the Buruanga Peninsula in Northwest Panay, and the western part of Mindanao Island (Figure 1) (Gabo et al., 2009; Yumul et al., 2009; Canto et al., 2012; Concepcion et al., 2012; Walia et al., 2012; Aurelio et al., 2013; 2014). Its offshore extent includes the Reed Bank and the Dangerous Grounds (Hinz and Schlüter, 1985; Franke et al., 2011). The PCB exhibits characteristics of accretionary wedges/terranes related to the subduction of oceanic crust along the southeastern Eurasian margin during the Mesozoic. The northern part of Mindoro Island represents amalgamated blocks of fragmented subducting oceanic crusts (Canto et al., 2012). The pre-Triassic Halcon Metamorphic rocks are considered to be the metamorphosed sedimentary rocks that contain clasts of ophiolitic, gneissic and granodioritic origin (Knittel et al., 2010; Knittel, 2011; Canto et al., 2012). The lithologies in Panay and Palawan islands showing accretionary nature are interpreted to be offscraped sedimentary deposits of Middle Permian to Cretaceous ages (Zamoras and Matsuoka, 2001; 2004; Gabo et al., 2009).

Palawan Island is composed of tectonic blocks representing different slivers of the PCB. The northern part is divided into two blocks, namely the Mesozoic mélange correlated with the lithostratigraphic sequence exposed in southern Mindoro and Buruanga Peninsula of the Panay Island (Hashimoto and Sato, 1973; Faure and Ishida, 1990; Zamoras and Matsuoka, 2001; Gabo et al., 2009) and the Cretaceous sedimentary to meta-sedimentary sequences to the south (Faure and Ishida, 1990 and references therein; Walia et al., 2012). Both of these units were intruded by Cenozoic granitoids including the Central Palawan Granite and the Kapoas Granitoid. In southern Palawan, the lithologies are dominantly Cenozoic in age consisting of an Eocene turbiditic sequence overthrusted by the Cretaceous Palawan 4

Ophiolite. This was later overlain by Upper Neogene shallow marine clastic sequences (Aurelio et al., 2013 and references therein). The Mt. Beaufort Ultramafics of the Palawan Ophiolite is shown in the geologic map (Figure 2). The remainder of the ophiolite sequence is not shown in the figure.

In northern Palawan, the Mesozoic mélange corresponds to the Malampaya Sound Group of Hashimoto and Sato (1973). This consists of conglomerate, sandstone, and altered tuff (the Middle Permian Bacuit Formation), partly recrystallized limestone (the Middle to Late Permian Minilog Limestone; renamed by Wolfart et al., 1986), bedded chert sequences intercalated with clayey layers (the Middle Triassic to Late Jurassic Liminangcong Formation; redefined by Zamoras and Matsuoka, 2001), and limestone interbedded with sandstone and shale (the Late Triassic to Late Jurassic Coron Limestone) olistoliths set in a sandy black pelite equivalent to the Guinlo Formation (Faure and Ishida, 1990) (see Figure 2). The Cretaceous sedimentary to meta-sedimentary sequences are composed of graphite, mica schists, and quartzite (Caramay Schists), quartz semi-schists, psammitic schists, and quartzite (the Tumarbong Semi-schist; named by the United Nations Development Programme (UNDP), 1985) and sandstone, shale, and mudstone sequences (Babuyan River Turbidite; named by UNDP, 1985) (Figure 2). This Cretaceous succession was affected by very low- to low-grade regional metamorphism (Suzuki et al., 2000) potentially caused by the thrusting of the Palawan Ophiolite onto the Caramay Schists (Faure et al., 1989). The emplacement of the Palawan Ophiolite was constrained to have occurred pre-Eocene to Early Miocene time based on the age of the underlying sedimentary sequence in South Palawan. The age of the overlying clastic sequence constrains the upper limit of the emplacement (Aurelio et al., 2014). The reported Late Eocene age (using

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Ar–40Ar isotopic dating of amphibolites) of

ophiolite obduction by Encarnacion et al. (1995) is within this range.

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Among these different lithostratigraphic units in northern Palawan, the Guinlo Formation, Tumarbong Semi-schist and the Daroctan Granite will be discussed in detail.

2.1 Guinlo Formation The Guinlo Formation (Hashimoto and Sato, 1973; Zamoras and Matsuoka, 2001) is equivalent to the King Ranch Formation (Yokoyama et al., 2012) although various workers describe the lithologies differently. The minor clastic components were mapped separately as the Liminangcong Formation by Zamoras and Matsuoka (2001). Yokoyama et al. (2012) mapped the King Ranch Formation on the basis of the tuffaceous character of the clastic sediments. In this study, we adopted the use of the King Ranch Formation (Yokoyama et al., 2012) in referring to a sequence of tuffaceous shale and sandstone intercalated with tuff and minor thinly-bedded chert. Similar massive, white and coarse-grained sandstones outcrop in the Roxas area, near Umalad River (Santos et al., 1998) although this unit was assigned to the Babuyan River Turbidite by MMAJ-JICA (1987). The Guinlo Formation is assigned a Middle Jurassic to Early Cretaceous age based on the radiolarian fossil assemblage (Zamoras and Matsuoka, 2001). This is compatible with detrital monazites from the Jurassic to Early Cretaceous sandstones in Busuanga Island that yielded ages ranging from 150 to 270 Ma (Yokoyama et al., 2012) recording the Permian to Late Jurassic metamorphic events prior to the sedimentation of the Guinlo Formation. An outcrop composed of interbedded gray tuffaceous sandstone, shale, and white tuffaceous sandstone was examined in the Roxas area (Figure 3a). As mentioned above, it was previously mapped as part of the Babuyan River Turbidite but more aptly resembles the description of the Guinlo Formation, i.e. massive white coarsed-grained sandstones (Reyes et al., 1992; Yokoyama et al., 2012). It should be noted that it was only Yokoyama et al. (2012) who remarked on the tuffaceous character of the sandstones. The representative samples Roxas 1a and 1c are composed of quartz, plagioclase, K-feldspar with zircon as an accessory 6

mineral (Figures 3b,c). Quartz shows undulose extinction denoting the effects of the regional metamorphism that affected this part of Palawan Island.

2.2 Tumarbong Semi-schist The Tumarbong Semi-schist is equivalent to the Concepcion Pebbly Phyllite of Suzuki et al. (2001) and Concepcion Phyllite of Peña (2008). It is composed of phyllite, pelitic semi-schist, slate and quartzite between phyllite layers (Peña, 2008). Reyes et al. (1992) reported that this unit is composed of phyllitic mudstones, siltstones, sandstones, and meta-sediments. Based on stratigraphic correlation, this unit is interpreted to be part of the Upper Cretaceous to Eocene succession representing a low-grade metamorphosed sedimentary unit (Suzuki et al., 2000). Detrital zircons yielded age peaks of Early Cretaceous (115.2 ± 1.6 Ma and 142 ± 1.8 Ma) and the youngest grain, dated at 88 ± 2 Ma, provides the maximum age of deposition (Walia et al., 2012). This unit overlies the Caramay Schist and underlies the Babuyan River Turbidite. Both units also yielded a Late Cretaceous maximum age of deposition (Walia et al., 2012; Suggate et al., 2014). River sediment samples were collected at the outcrop exposures in the Roxas area which is traversed by the tributaries of Minara, Balantion, Arutayan, and Taradungan rivers (Figure 4b). Representative rocks along Taradungan and Balantion rivers are phyllites showing weak to moderately intense foliation. The phyllites are quartz-rich and contain mica and accessory minerals such as monazite that are less than 25 μm across. The samples from Taradungan River contain monazites that appear to follow the foliation exhibited by other minerals. This indicates that these monazites are possibly detrital grains that were also affected by the regional metamorphism, which affected the PCB sediments.

2.3 Daroctan Granite

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The Daroctan Granite is composed of two intrusive bodies cropping out at Barotuan and Tenegueban in El Nido (Figure 2). It was recognized as a Cretaceous unit by MMAJJICA (1987). Ringis et al. (1993) reported the intrusive rocks at Kapoas as the Middle Miocene “Tiniguiban Granodiorite” (it was earlier reported as Early Miocene based on K-Ar age), the type locality of which may have been from the Tenegueban area. Several other maps of northern Palawan do not show the occurrence of the Daroctan Granite, which is mostly mapped as part of the Mesozoic mélange (Encarnacion and Mukasa, 1997; Suggate et al., 2014) or the Jurassic olistrostrome (Suzuki et al., 2000). Both granite bodies intruded the Permian Bacuit Formation. The Barotuan granite is a boomerang-shaped intrusive body located to the northeast of the El Nido town center (Figure 2). It is composed of medium-grained massive biotite granite. Abundant biotite is observed in the hand specimens. The outcrops are mostly massive and highly jointed with conjugate joints trending NE and NW. The representative sample contains consertal intergrowth mainly of quartz, plagioclase, K-feldspar and biotite. Quartz is mostly subhedral to anhedral. Plagioclase and K-feldspar crystals are mostly subhedral and are moderately to completely replaced by sericite. Chlorite occurs as alteration products at the rims of biotite or sometimes completely replacing biotite grains. Zircon and monazite occur as inclusions in quartz while ilmenite occurs as inclusions in biotite. Calcite stringer veinlets cut through some sections of the sample. The Tenegueban intrusive body is located at the northernmost part of Palawan mainland. It is composed of medium-grained biotite granite with quartz xenocrysts, granodiorite enclaves, and meta-sedimentary xenoliths (Figure 3d). Quartz veins cutting through the granodiorites are observed in some areas. The mineralogical composition of the granite and the enclaves are similar. Both contain quartz, seriate plagioclase and K-feldspar, and biotite. However, the enclaves contain a greater amount of opaque minerals (e.g. ilmenite,

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cassiterite) compared to the host granite.

3. Sample descriptions Nine (9) samples were selected for monazite and zircon separation. These were collected from the Daroctan granite (EN 7), granodiorite enclave (EN 10) within the Daroctan Granite, tuffaceous sandstones (Roxas 1a and Roxas 1c) and stream sediments from areas overlain by the Tumarbong Semi-schist (RX2, RX 3, RX 7 and RX 10) and the Daroctan Granite (Taberna) (Table 1). The rock samples from the Daroctan Granite are composed of biotite granite (EN 7) and its biotite granodiorite enclave (EN 10) consisting chiefly of Kfeldspar, plagioclase, quartz, and biotite (Figures 3e,f). Monazite and zircon occur as inclusions in quartz and feldspars. The tuffaceous sandstones, on the other hand, only contain detrital zircon grains. Thus these samples were used only for zircon geochronology.

4. Analytical methods 4.1 Monazite U-Th-total Pb geochronology Heavy mineral separation from two (2) granite and granodiorite enclave samples (EN 7, EN 10) and five (5) stream sediment samples (RX 2, RX 3, RX 7, RX 10 and Taberna) was carried out using diiodomethane heavy liquid. For the granite and granodiorite enclaves, about 150 µm grain sizes of crushed samples were used. Magnetic mineral separation was carried out prior to the separation by heavy liquid. Polished thin sections of mounted heavy minerals were made and carbon coated. Examination of the heavy mineral content, particularly to confirm the presence of monazite in the samples, was carried out using a JEOL JSM-6610 Scanning Electron Microscope (SEM) equipped with energy dispersive X-ray spectrometer (EDS) at the National Museum of Nature and Science in Japan. The U-Th-total Pb method dating of monazite was conducted using a JEOL JXA 8230 Superprobe Electron

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Probe Microanalyzer (EPMA) also at the National Museum of Nature and Science in Japan. The analytical conditions and age calibrations were based on the procedure described by Santosh et al. (2003) and Yokoyama et al. (2012). Errors of age are given at the 1-sigma confidence level. Weighted mean was calculated using the Isoplot v. 3.7 program (Ludwig, 2008).

4.2 Zircon U-Pb geochronology Zircon grains were handpicked from the prepared heavy mineral separates under a binocular stereo microscope. Two samples (Roxas 1a and Roxas 1c) were obtained from crushed tuffaceous sediments (about 150 µm size) and 2 samples (RX 2 and RX 7) from panned stream sediments. The zircon grains were mounted, together with zircon standards such as TEOMORA2 (417 Ma; Black et al., 2004), FC1 (1099.9 Ma; Paces and Miller, 1993), OD3 (33 Ma; Iwano et al., 2013) and SRM NIST 610 (glass standard), in an epoxy disc. Samples were polished down to the center of the zircon grains and coated with carbon. Cathodoluminescene (CL) and backscattered electron images were taken to characterize the internal features (i.e. growth zones) of the zircon grains and to check the presence of fractures and inclusions to select the laser spot locations. This was also carried out using a JEOL JSM6610 SEM at the National Museum of Nature and Science in Japan. The U-Pb-Th isotope dating was carried out using an Electro Scientific Industries NWR213 laser ablation system and an Agilent Technologies 7700x Quadrupole ICP-MS at the National Museum of Nature and Science in Japan. Experimental conditions, measurement procedures, and data reduction followed those of Tsutsumi et al. (2012). The errors quoted are at 1-sigma confidence level. Corrections for common Pb on U/Pb values and ages were carried out using

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Pb-correction

(age 1, see Table 3) assuming the Th/U system in the analyzed area has remained closed. The 207

Pb-correction (age 2) assumed that the Th/U did not remain in a closed system (Williams,

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1998). Weighted mean was also calculated and Tera-Wasserburg concordia plots were produced using the Isoplot v. 3.7 program (Ludwig, 2008).

5. Results 5.1 Heavy mineral analysis Modal analysis of heavy minerals was carried out on four (4) stream sediment samples from Arutayan (RX 10), Balantion (RX 3), Minara (RX 2), and Taradungan (RX 7) rivers. Mineral assemblages were observed in the stream sediments of El Nido (Taberna River) and granitoid samples EN 7 and EN 10. Figure 4 shows the modal composition of heavy minerals in the stream sediment samples. Monazite and zircon comprise most of the heavy minerals (>25 %) while rutile and ilmenite are the minor components, except for the sample from Minara (RX 2). The stream sediments at the Arutayan River (RX 10) have less heavy mineral components (i.e. zircon, monazite, rutile, and ilmenite). However, the stream sediments at the Taradungan River (RX 7) have a more diverse heavy mineral composition (i.e. zircon, monazite, rutile, ilmenite, epidote, spinel, allanite, and xenotime). Thorite is observed in the stream sediments at Balantion River (RX 3) while spinels occur in the stream sediments both at the Minara (RX 2) and Balantion (RX 3) rivers. Stream sediments from the Minara River (RX 2) indicate gold mineralization. Native gold grains associated with some quartz are observed in the samples, which might be sourced from the quartz veins cutting through the phyllites commonly found in most of the outcrops of the Tumarbong Semi-schist. Heavy minerals from the Taberna River, a tributary mapped within the Daroctan Granite, contain zircon, monazite, rutile, ilmenite, and cassiterite. The presence of cassiterite indicates Sn mineralization associated with the Daroctan Granite. The heavy mineral composition of the granite and granodiorite enclave samples was also analyzed. The granite sample (EN 7) contains zircon, monazite, rutile, ilmenite, epidote, and thorite while the

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granodiorite enclave (EN 10) has zircon, monazite, epidote, and galena. In the Busuanga Island, which is composed of the Liminangcong and Guinlo Formations, Yokoyama et al. (2012) reported the occurrence of garnet, titanite, apatite, and tourmaline. The heavy minerals in the Tumarbong Semi-schist reported by Suggate et al. (2014) include tourmaline and garnet while the Caramay Schists contain garnet, apatite, sillimanite, and kyanite. These minerals were not observed in the study area; thus the source of sediments might be different. Some of these minerals are metamorphic in origin, which suggests that the Tumarbong Semi-schist does not have sediment input from terranes that have been affected by intense metamorphism. Detrital heavy minerals in the study area are mostly from granitic assemblages, with minor metamorphic or probably ultramafic rock origin (i.e. spinel, secondary monazite). Minerals found from the Tumarbong Semi-schist are also present in the Daroctan Granite, indicating a more likely granitic rather than volcanic rock origin.

5.2 Monazite ages Monazite grains from the four tributaries representing the Tumarbong Semi-schist vary in shape. These range from spherical, tabular to prismatic, though most are anhedral to subhedral (RX 2, RX 3, RX 7, and RX 10). The monazite grains are notably nodular in shape as reported by Santos (1991). The grains are gray to black and ellipsoidal to spheroidal similar to those reported in the Marvast region, Iran (Alipour-Asll et al., 2012) and southwestern Taiwan (Soong, 1978). The back-scattered images show that these monazite grains appear to be poikilotopic grains containing quartz inclusions (Figure 5a). This texture is interpreted to be authigenic, wherein the monazite grains were partially dissolved creating secondary porosity, which was later filled with quartz (Alipour-Asll et al., 2012). However, the intensely altered grains did not yield good age results (single grain age differences range

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from 100 to 300 Ma). Some monazite grains are euhedral and do not contain mineral inclusions. These monazite grains are similar in occurrence to the secondary monazite reported by Yokoyama et al. (2012) suggesting formation of monazite after the deposition as a product of metamorphism. These are the grains that yielded good ages. Among the stream sediment samples, RX 7 contains greater amounts of less altered monazite grains. On the other hand, the authigenic poikilotopic texture was not observed in the samples from the Daroctan Granite, clearly suggesting that the monazite grains are primary. The monazite grains are mostly anhedral to euhedral (Figure 5e). There are also monazite grains which occur as inclusions in ilmenite as noted in the granite sample EN7 (Figure 5f). Monazite samples from the Taberna River show similarities with the monazite grains from the granitoids. The stream sediment samples from the Taberna River (Taberna), representing the tributary that traverses through the Daroctan Granite, show Late Cretaceous (65.5 Ma to 98.6 Ma; with a peak age at 87.3 ± 4.9 Ma), Jurassic (~174 Ma) and Paleoproterozoic (~1805 Ma) age peaks (Figure 6a). The monazite inclusions in ilmenite of the Daroctan Granite (Taberna) yielded Late Cretaceous ages (65.6 Ma to 108 Ma; with a peak age at 85.7 ± 8.2 Ma), which most likely represent the age of the Daroctan magmatism (Figure 6a inset). On the other hand, monazites separated from the granodiorite enclave (EN 10) also yielded a Late Cretaceous age (63.7 Ma to 111 Ma; with a peak age at 87.3 ± 4.9 Ma) suggesting a co-magmatic origin (Figure 6b). The probability plots of the stream sediment samples from the Tumarbong Semischist (RX 2, RX 3, RX 7, and RX 10) show an age range from 85.5 Ma to 1897 Ma (Table 2). The age range observed for the stream sediment samples from the Arutayan (RX 10), Minara (RX 2), and Taradungan (RX 7) rivers occur at 487 Ma to 754 Ma (Ordovician to Neoproterozoic), 90 Ma to 213 Ma (Late Cretaceous to Late Triassic), and 67 Ma to 266 Ma

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(Late Cretaceous to Permian) (Figures 6c, e and f). Other age clusters are at Middle to Early Devonian (RX 2), Early Devonian to Silurian (RX 7) and Paleoproterozoic (RX 2, RX 7 and RX 10). The stream sediment samples from the Balantion River (RX 3) contain an Early Cretaceous to Triassic age cluster (105 Ma to 242 Ma; peak at 176 ± 25 Ma). Minor age clusters occur at Early Devonian (407 Ma to 421 Ma) and Mesoproterozoic to Paleoproterozoic (1194 Ma to 1829 Ma) time.

5.3 Zircon ages Zircon grains from samples Roxas 1a and Roxas 1c are mostly euhedral, rounded to prismatic and display oscillatory zoning in CL images (Figure 7). Some grains show inherited cores in the CL image; however, only the outer rims were analyzed. The zircon grains in stream sediment samples RX 2 and RX 7 vary considerably in shape and internal structures. The grains are subhedral to euhedral and exhibit tabular, prismatic, and rounded shapes. The internal structure shows sector zoning in addition to oscillatory zoning. The

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U/206Pb ages from the tuffaceous sediments of the Guinlo Formation range

from 86.5 to 1857 Ma for sample Roxas 1a and from 92 to 1623 Ma for sample Roxas 1c (Figure 8a,b). In the age from Late Cretaceous to Late Triassic; 87 Ma to 224 Ma for Roxas 1a and 92 Ma to 230 Ma for Roxas 1c (Figure 8a,b insets) significant peaks are seen in the probability density plot at ca. 110-120 Ma, 180 Ma, and 220 Ma. In addition, Roxas 1a contains few Mesoproterozoic and Paleoproterozoic grains with poorly defined peaks at 1.60 Ga and at 1.80 Ga, whereas Roxas 1c contains a few Mesoproterozoic and a few Paleoproterozoic grains. The Tera-Wasserburg concordia plots for Roxas 1a and Roxas 1c show that most grains have concordant ages (Figure 9). The zircons of stream sediment samples RX 2 and RX 7 have

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U/206Pb ages ranging from 76 to 2106 Ma and from 93 to

2434 Ma, respectively (Figures 8c,d). Most ages for both samples correspond to Late

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Cretaceous to Late Triassic (76 Ma to 227 Ma) and Late Cretaceous to Permian (93 Ma to 273 Ma), respectively. Significant age peaks occur at ca. 105 Ma, 140 Ma, and 165 Ma in RX 2 (Figure 8c inset). Single grains are of Silurian (429 Ma), Neoproterozoic (617 Ma to 801 Ma), and Mesoproterozoic to Paleoproterozoic (1576 Ma to 2106 Ma) age. Sample RX 7 has age clusters at ca. 110 Ma, 180 Ma, and 230 Ma (Figure 8d inset). A few grains have Neoproterozoic (771 Ma to 848 Ma) and Paleoproterozoic (1925 Ma to 2434 Ma) ages. The Tera-Wasserburg concordia plots for RX 2 and RX 7 show most grains plot on the concordia (Figure 9). The Th/U ratio is used to identify the growth process reflecting the condition of the crystallization. The Th/U ratio for magmatic zircons is >0.1 while the ratio for metamorphic zircons is generally < 0.1 (Williams and Claesson, 1987; Kirkland et al., 2015). This is partly due to the lower Th content (compared to magmatic zircon) because Th is also taken up by high Th minerals such as monazite and allanite in crystallizing metamorphic zircons (Rubatto, 2002; Kirkland et al., 2015). On the other hand, U is not partitioned into high Th minerals during the metamorphic process, but it is partitioned into zircon during metamorphism. The Th/U ratios of most of the analyzed zircons in this study range from 0.13 to 2.67 (Table 3, Figure 8e), indicating a magmatic origin, while Th/U ratios of four (4) grain samples from Roxas 1a and Roxas 1c are < 0.1 suggesting a potential metamorphic derivation.

6. Discussion 6.1 Late Jurassic to Early Cretaceous sediments In this study, the tuffaceous sandstones of Guinlo Formation (Roxas 1a and 1c) yielded a Late Cretaceous maximum age of deposition. The youngest ages are 86.5 + 5.9/-5.7 Ma for Roxas 1a and 92.3 ±4.1 Ma for Roxas 1c. These are relatively younger compared with the youngest age from the same unit in Busuanga Island (125 Ma) as reported by 15

Yokoyama et al. (2012). Despite the difference in the maximum age of deposition, this unit may have been one of the slices of the Guinlo Formation that occurred as part of a mélange embedded in the Late Cretaceous meta-sedimentary rocks. Other Guinlo Formation blocks are located northeast of the Bay Peak intrusion and overlie the Liminangcong Formation, similar to the distribution of the same unit in the Busuanga Island (Zamoras and Matsuoka, 2001). The zircon and monazite ages from rivers draining the exposure of the Tumarbong Semi-schist in northern Palawan suggest Cambrian (RX 10), Early Cretaceous (RX 3), and Late Cretaceous (RX 2, RX 7) maximum ages of deposition. Previous studies (Walia et al., 2012; Suggate et al., 2014) reported a Late Cretaceous maximum age of deposition for the meta-sedimentary units in northern Palawan. The results of this study show that some of the samples from the Tumarbong Semi-schist, which was mapped as the intermediate unit in the Upper Cretaceous to Eocene succession, have a maximum age of deposition similar to the previously reported ages. Stream sediment samples from Balantion River (RX 3) and Arutayan River (RX 10) show youngest grains dated at 104 Ma (Early Cretaceous) and 487 Ma (Cambrian) (Table 2). These ages more likely represent sediments derived from the Guinlo Formation and not the Tumarbong Semi-schist. Blocks within the area which were previously mapped as Tumarbong Semi-schist may represent the Guinlo Formation. The maximum age of deposition of the magmatic minerals (i.e. zircon and monazite) point to similar Late Cretaceous ages for the meta-sedimentary units. In terms of detrital zircon and monazites, which represent magmatic (and minor metamorphic) events in the source area, there appears to be an Early to Late Cretaceous source rock, which comprises the basement in northern Palawan. Figure 10 shows a comparison of monazite and zircon-derived ages of the different meta-sedimentary units in PCB including those reported from Mindoro and Panay islands by Yokoyama et al. (2012). The ages from Mindoro and Panay exhibit a

16

similar age range as the Guinlo Formation, particularly the ages of monazite. The peaks of the zircon ages of the Guinlo Formation are close to those of the Tumarbong Semi-schist. Although the youngest ages were used to constrain the maximum age of deposition, peak ages indicate related magmatic episodes during the Yanshanian magmatism in southeastern Eurasian margin, particularly the Late Yanshanian episode. There were four major episodes of Cretaceous magmatism: 136 – 146 Ma, 122 – 129 Ma, 101 – 109 Ma, and 87 – 97 Ma (Li, 2000). Most of the peaks from the zircon-derived ages coincide with the first three episodes.

6.2 Implication of the Late Cretaceous magmatism The age of the Cretaceous granitic intrusions in northern Palawan is determined in this study using monazite U-Th-total Pb dating. The Daroctan Granite is a Late Cretaceous (87 Ma) pluton, probably part of the late episode of the Yanshanian magmatism in eastern China. This unit could be related to the different Mesozoic granites surrounding the South China Sea basin (Figure 1) particularly the areas with similar Cretaceous age ranges such as the Pearl River Mouth Basin, Dalat zone in southern Vietnam, and Schwaner Mountains in West Kalimantan, Borneo (Yan et al., 2014 and references therein). Samples of stream sediments from the Taberna River yielded Early Jurassic and Paleoproterozoic ages, which are common inherited ages of zircons from the Central Palawan Granite and Kapoas Granitoid (Suggate et al., 2014). These can also be found in detrital zircons and monazites in the different sedimentary sequences of the PCB (Walia et al., 2012; Yokoyama et al., 2012; Suggate et al., 2014). Encarnacion and Mukasa (1997) mentioned that the geochemical signatures of the Kapoas Granitoid point to an arc-like and collisional granite despite the fact that it was formed in a post-rifting, non-collisional tectonic setting unrelated to any subduction zone. These signatures were most likely inherited from source rocks that formed in the Mesozoic Andean-type margin. The Daroctan Granite could be derived from a similar

17

source rock since it was likely formed in a similar setting during the Late Cretaceous. The tectonic event that triggered the Kapoas Granitoid’s magmatism is still debatable i.e. melting might have been induced by subduction rollback (Suggate et al., 2014) or as a result of crustal thinning due to the extension during the Neogene (Hall, 2013). Ages of inherited zircons i.e. Late Cretaceous, Middle Jurassic, and Paleoproterozoic were also observed in the Kapoas Granitoid and the Central Palawan Granite, suggesting contributions from older crustal rocks similar to the Daroctan Granite.

6.3 Tectonic evolution of the northern Palawan block of the PCB The evolution of the different lithologic units in northern Palawan, based on the age of magmatic minerals, is summarized in Figure 11. During the Jurassic period, the PCB was located at the southeastern Eurasian margin. The subduction of Mesozoic oceanic crust (Izanagi Plate of Zamoras and Matsuoka, 2004 and Canto et al., 2012 or the proto-Philippine Sea Plate of Pubellier et al., 2004) beneath this margin was still active. During that time, accretion of the oceanic sediments (i.e. Liminangcong Formation) occurred at the margin of the continent-ocean boundary. The Permian blocks (i.e. Bacuit Formation and Minilog Limestone) were also accreted to the Liminangcong Formation. The accretion of Permian blocks occurred from Middle Jurassic to Early Cretaceous (Zamoras and Matsuoka, 2004) (Figure 11a). At present, these units are located in Busuanga Island and the northernmost part of Palawan Island. The source rocks of the Guinlo Formation are Late Jurassic to Early Cretaceous volcanic rocks. The tuffaceous character of the sandstones of the Guinlo Formation suggests derivation from a volcanic eruption or erosion of volcanics. As noted by Yokoyama et al. (2012), the Jurassic to Early Cretaceous range could imply continuous volcanism during that period. This was contemporaneous with the Yanshanian magmatism in eastern China associated with bimodal volcanism (Li, 2000; Zhou et al., 2006). The source

18

rocks of the Tumarbong Semi-schist were likely Late Cretaceous granitic rocks. Mindoro Island, which contains blocks of accreted Cretaceous oceanic crust representing offscraped oceanic floor of the subducting slab (Canto et al., 2012), was presumed to be located just above the subduction zone during the Cretaceous. It was later incorporated as part of the PCB when Luconia–Dangerous Grounds became sutured along the southeastern Eurasian margin (Hall, 2012) (Figure 11b). The tectonic history of this area is still debatable. The tectonic reconstruction of Zahirovic et al. (2014) suggests that the Izanagi Plate was still active until 70 Ma. In the work of Hall (2012), subduction in the southeastern Eurasian margin already terminated at about 90–80 Ma due to the arrival and suturing of the Luconia–Dangerous Grounds block at the present Asian margin. Zhou and Li (2000) believed that subduction persisted until 97 Ma as manifested by the change in the subduction angle since Early Cretaceous causing the migration of the magmatic zone oceanward. Despite the cessation of the subduction, magmatism in the southeastern Eurasian margin continued until 90 – 87 Ma (Zhou and Li, 2000; Li, 2000). However, Li (2000) argued that the Cretaceous magmas in Southeast China could be products of partial melting induced by lithospheric extension. Crustal thinning during Late Mesozoic time could be attributed to the partial melting of the continental crust. Since the Daroctan Granite intruded the chert-clastic sequence of the Liminangcong - Guinlo Formations, which were presumed to be located near the continent- ocean boundary, it might have been a product of partial melting of continental crust during the Late Cretaceous (Figure 11c). The PCB later broke off from the southeastern Eurasian margin during Eocene and was translated to its present position due to the opening of the South China Sea (Figure 11c). The PCB collided first with the Sabah and Cagayan arc in the southeast, and eventually collided with the Philippine Mobile Belt in Central Luzon during the Middle Miocene and ended before 8 Ma (Walia et al., 2013; Hall et al., 2013) (Figure 11d). The Central Palawan Granite

19

magmatism occurred prior to the opening of the South China Sea whereas the Kapoas Granitoid magmatism occurred during Middle Miocene. However, the petrogenesis of these units and the Daroctan Granite remain unknown.

7. Conclusions The tectono-magmatic events prior to the translation of the PCB to its present position are reconstructed in this study. Dating of monazite and zircons extracted from the metasedimentary units in northern Palawan, comprising the Tumarbong Semi-schist and the Guinlo Formation, yielded Jurassic to Early Cretaceous ages. The sources of detrital materials of these sedimentary sequences were probably the granitic and volcanic rocks related to the Yanshanian magmatism event. A granitic pluton, the Daroctan Granite, which is probably a product of Yanshanian magmatism, is recognized in the northernmost part of Palawan Island. It intruded the clastic sequences during the Late Cretaceous.

8. Acknowledgements The authors acknowledge the financial support given by the Akita University Leading Program for Rare Metal Resources. We thank Ms. Masako Shigeoka of the National Museum of Nature and Science for her assistance during the chemical analyses and Dr. Jillian Aira Gabo-Ratio for her help during the fieldwork. We are also grateful for the sample provided by Mr. Rolando Reyes of the Philippine Nuclear Research Institute. We also thank Dr. Ulrich Knittel and Dr. Graciano P. Yumul, Jr. for their helpful reviews that greatly improved this manuscript. We are indebted to Dr. Carla B. Dimalanta for her help in improving this manuscript.

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FIGURECAPTIONS

Figure 1. Tectonic map of the Philippine archipelago showing the two (2) major blocks, the 27

PCB, and the PMB. The Mesozoic granites (adopted from Yan et al., 2014) surrounding South China are shown. Basemap was generated using SubMap 4.1 (http://submap.gm.univmontp2.fr/), which was based on the subduction parameters of Heuret & Lallemand (2005). Abbreviations: MKB = Mekong Basin; PCB = Palawan Continental Block; PMB = Philippine Mobile Belt; PRMB = Pearl River Mouth Basin; RIG =Romblon Island Group; SCSB = South China Sea basin.

Figure 2. Geologic map and stratigraphic column of northern Palawan (modified from MMAJ-JICA, 1987).

Figure 3. Outcrop photo of a) Guinlo Formation (star symbols show sampling locations) and corresponding photomicrographs of b) Roxas 1a and c) Roxas 1c. d) Daroctan Granite outcrop (inset shows a sample photo of enclave EN10) and representative photomicrographs of e) Daroctan granite (EN 7), f) magmatic enclave (EN 10). Open nichol, scale: 500 µm.

Figure 4. Heavy minerals composition of the stream sediments from Tumarbong Semi-schist and location of sampling areas.

Figure 5. Back-scattered images showing different types of monazites in the study area. a) Skeletal monazite grain from Taradungan River with quartz inclusions, b) monazite grain from Minara River, c) monazite with quartz intergrowth from Arutayan River, d) monazite with quartz intergrowth from the magmatic enclave of the Daroctan Granite, e) monazite grain from Taberna River and f) monazite inclusions in the ilmenite from Taberna River.

Figure 6. Probability density curves and histogram plots for the monazite samples from a) Taberna River; inset shows Late Cretaceous ages from the monazite inclusions in ilmenite from Taberna River. b) Daroctan Granite’s magmatic enclave (EN 10) sample shows Late 28

Cretaceous monazite age. Monazite samples from Tumarbong Semi-schist tributaries, c) Arutayan River show Ordovician to Neoproterozoic ages while d) Balantion River show Early Cretaceous to Triassic age clusters. The samples from e) Minara and f) Taradungan Rivers both show Late Cretaceous ages which extends to Late Triassic and Permian.

Figure 7. Representative cathodoluminescence images of the analyzed zircon grains. Analysis spots are marked with red circles and labeled according to spot number in Table 3 and the corresponding age. Error on the ages is 1-sigma.

Figure 8. a,b) Probability density curves for the zircon samples from Guinlo Formation showing Late Cretaceous to Late Triassic age clusters and from c,d) Tumarbong Semi-schist tributaries showing Late Cretaceous to Late Triassic (RX 2) and Late Cretaceous to Permian (RX 7) ages. Insets show significant peaks from 0 to 500 Ma. e) The Th/U ratios of all the analyzed zircons show dominantly magmatic origin.

Figure 9. Tera-Wasserburg U-Pb concordia diagrams showing a cluster of ages which are mostly < 200Ma.

Figure 10. Tectono-magmatic events related to the formation of Palawan Island and the maximum ages of sedimentary units in the northern portion. (Legend: blue tick lines denote zircon-derived ages while gray tick lines denote monazite-derived ages, gray lines correspond to age ranges derived from both zircon and monazite dating. Symbols: * equivalent to the Babuyan River Turbidite, ** equivalent to the Concepcion Phyllites of Walia et al. (2012). Abbreviations: Mio = Miocene, Oli = Oligocene, Eo = Eocene, K = Cretaceous, Jr = Jurassic, Tr = Triassic, P = Permian; Fm = Formation, SCS = South China Sea, PCB = Palawan Continental Block, PMB = Philippine Mobile Belt). 29

Figure 11. Schematic diagram showing the evolution of northern Palawan based on magmatic mineral-derived ages. Tectonic reconstruction map was adopted from Hall (2012). (Abbreviations: CPG = Central Palawan Granite, GF = Guinlo Formation, KG = KapoasGranitoid, LF = Liminangcong Formation, Pb = Permian block, PMB = Philippine Mobile Belt).

TABLE CAPTIONS

Table 1. Sample list and sampling locations. Table 2. EPMA U-Th-total Pb data of monazites from northern Palawan. Table 3. LA-ICP MS zircon U-Pb data of samples from northern Palawan

30

31

32

33

34

35

36

37

38

39

40

41

Table 1. Sample list and sampling locations.

Sample name EN 7 EN 10 Roxas 1a Roxas 1c RX 2 RX 3 RX 7 RX 10 Taberna

Sample location (WGS84) 11°21'48.01"N, 119°30'30.43"E 11°21'51.58"N, 119°30'34.69" E 10°19'18.50"N, 119°20'10.80"E 10°21'29.50"N, 119° 21'26.63"E 10°23'50.60"N, 119°18'56.83"E 10°23'43.97"N, 119°31'33.51"E 10°23'43.01"N, 119°21'51.85"E along Taberna River

Rock type

Geologic Unit

granite

Daroctan Granite

granodiorite enclave

Daroctan Granite

tuffaceous sandstone tuffaceous sandstone

Guinlo Formation Guinlo Formation

stream sediments

Tumarbong Semi-schist

stream sediments

Tumarbong Semi-schist

stream sediments

Tumarbong Semi-schist

stream sediments

Tumarbong Semi-schist

stream sediments

Daroctan Granite

42

Table 2. EPMA U-Th-total Pb data of monazites from northern Palawan. UO2

ThO2

PbO

Age

error of Age

wt (%)

wt (%)

wt (%)

(Ma)

(1σ)

20

0.15

6.83

0.02

65.5

12.7

RX7b-125

44

0.18

11.21

0.04

76.1

7.9

47

0.13

8.01

0.03

79.7

11.0

17

0.41

7.43

0.03

80.7

40

0.05

5.65

0.02

86.3

15

0.21

7.19

0.03

42

0.42

7.80

0.03

18

0.14

10.42

27

0.09

6.82

44

0.28

24

0.20

29 13

UO2

ThO2

PbO

Age

error of Age

wt (%)

wt (%)

wt (%)

(Ma)

(1σ)

0.06

6.44

0.03

114.4

14.0

RX7b-3

0.03

3.34

0.02

114.6

27.0

RX7b-86

0.22

6.73

0.04

114.9

12.5

10.6

RX7b-503

0.39

10.30

0.06

115.3

8.1

16.0

RX7b-491

0.16

3.32

0.02

115.5

24.3

86.3

11.8

RX7b-63

0.33

3.13

0.02

116.5

22.3

86.9

10.2

RX7b-537

0.27

9.86

0.05

118.8

8.7

0.04

87.4

8.6

RX7b-136

0.15

6.34

0.03

119.9

13.6

0.03

88.0

13.1

RX7b-440

0.22

10.05

0.05

120.1

8.7

9.79

0.04

89.2

8.7

RX7b-124

0.71

12.89

0.08

120.4

6.1

9.91

0.04

90.0

8.8

RX7b-588

0.38

10.16

0.06

121.2

8.2

0.13

9.91

0.04

90.3

9.0

RX7b-427

0.25

9.27

0.05

121.5

9.3

0.15

10.59

0.04

92.6

8.4

RX7b-198

0.44

10.91

0.06

121.7

7.6

19

0.21

13.15

0.06

95.3

6.7

RX7b-13

0.13

10.85

0.06

121.9

8.3

46

0.14

8.36

0.04

98.6

10.6

RX7b-425

0.14

10.25

0.05

121.9

8.7

45

0.00

4.44

0.03

174.6

20.9

RX7b-105

0.16

4.19

0.02

122.4

19.7

17

0.51

6.30

0.65

1806.0

12.7

RX7b-96

0.55

10.94

0.07

122.4

7.3

No.

Taberna

No.

Taradungan (cont.)

Taberna inclusions

RX7b-530

0.24

10.40

0.06

122.4

8.3

39

0.05

6.64

0.02

65.6

13.7

RX7b-384

0.43

7.32

0.04

122.9

10.7

12

0.09

6.70

0.02

77.8

13.3

RX7b-610

0.29

10.32

0.06

122.9

8.3

36

0.53

5.38

0.02

81.2

13.2

RX7b-564

0.24

4.00

0.02

123.5

19.5

25

0.08

6.12

0.02

81.7

14.6

RX7b-437

0.15

4.81

0.03

126.3

17.6

23

0.06

5.91

0.02

86.4

15.3

RX7b-356

0.15

10.28

0.06

126.4

8.6

38

0.09

5.86

0.02

87.6

15.1

RX7b-365

0.11

4.44

0.03

126.6

19.4

22

0.07

5.69

0.02

87.9

15.7

RX7b-477

0.04

4.01

0.02

128.9

22.5

26

0.49

9.25

0.04

89.0

8.6

RX7b-393

0.15

5.28

0.03

129.3

16.2

13

0.06

6.17

0.03

98.0

14.7

RX7b-18

0.07

3.43

0.02

130.9

25.5

43

0.11

6.45

0.03

99.7

13.7

RX7b-326

0.41

2.23

0.02

131.6

26.3

42

0.16

6.90

0.03

100.9

12.6

RX7b-120'

0.31

13.75

0.08

132.2

6.3

45

0.10

6.62

0.03

107.8

13.4

RX7b-319

0.29

8.31

0.05

133.9

10.1

RX7b-83

0.25

3.74

0.03

136.8

20.5

Arutayan RX10b25 RX1036 RX1026 RX10b26 RX1019 RX10b35 RX1018 RX1016 RX10b-

0.48

4.87

0.05

487

47.5

RX7b-401

0.11

5.04

0.03

137.4

17.3

0.07

5.09

0.03

509

7.4

RX7b-80

0.11

8.14

0.05

137.9

10.9

1.08

6.23

0.07

623

108.3

RX7b-502

0.08

6.34

0.04

138.3

14.1

0.30

6.43

0.04

643

29.8

RX7b-386

0.14

5.97

0.04

139.0

14.5

0.06

6.47

0.12

647

5.6

RX7b-209

0.42

13.32

0.09

141.5

6.3

0.12

6.85

0.03

685

11.8

RX7b-642

0.21

4.39

0.03

142.3

18.4

0.11

7.54

0.14

754

11.4

RX7b-324

0.28

9.02

0.06

144.9

9.4

0.52

16.39

0.09

1639

51.8

RX7b-404

0.82

5.18

0.05

149.1

11.9

0.58

20.32

0.20

2032

58.5

RX7b-513

0.17

5.39

0.04

150.8

15.6

43

28 Balantion

RX7b-593

1.28

5.40

0.06

156.1

9.8

RX3-16 RX3b29 RX3b21 RX3b35 RX3b26 RX3b17 RX3b15 RX3b50 RX3-17

0.05

2.82

0.01

104.6

31.1

RX7b-510

0.09

6.40

0.04

156.4

13.9

0.12

7.48

0.04

127.2

11.8

RX7b-480

0.24

5.89

0.04

157.0

13.9

0.16

8.80

0.05

133.5

10.0

RX7b-346

0.43

4.33

0.04

159.0

16.3

0.20

9.91

0.06

140.1

8.8

RX7b-327

0.12

12.96

0.09

159.1

7.0

0.31

5.84

0.04

143.9

13.6

RX7b-479

0.13

8.35

0.06

159.5

10.6

0.69

6.27

0.06

155.6

10.9

RX7b-492

0.38

11.48

0.09

160.0

7.3

0.09

7.36

0.05

160.2

12.2

RX7b-472

0.37

4.53

0.04

160.2

16.2

0.31

7.10

0.06

172.5

11.5

RX7b-117

0.09

4.24

0.03

160.6

20.5

0.45

3.89

0.04

185.8

17.4

RX7b-187

0.63

2.58

0.03

161.7

20.1

RX3-20 RX3b55 RX3b44 RX3-14 RX3b16 RX3-15 RX3b34' RX3b-5'

0.13

4.87

0.04

198.0

17.5

RX7b-566

0.24

4.78

0.04

162.5

16.8

0.29

4.47

0.05

224.5

17.2

RX7b-556

0.36

4.61

0.04

163.5

16.1

0.57

5.27

0.07

227.0

13.0

RX7b-545

0.37

5.24

0.04

164.4

14.5

0.41

5.57

0.07

232.9

13.5

RX7b-466

0.48

4.19

0.04

164.5

16.2

0.69

6.29

0.08

236.3

10.9

RX7b-82

0.23

4.88

0.04

164.5

16.5

0.13

5.89

0.06

242.0

14.7

RX7b-467

0.14

6.82

0.05

167.3

12.8

0.34

10.80

0.20

407.0

7.8

RX7b-536

0.15

5.59

0.04

168.4

15.3

0.08

6.28

0.12

420.9

14.2

RX7b-607

0.54

11.31

0.09

169.7

7.1

RX3-16

0.06

6.77

0.36

1194

13.9

RX7b-519

0.72

8.12

0.07

170.1

8.9

RX3-10

0.05

6.14

0.36

1311

15.4

RX7b-379

0.35

9.81

0.08

170.4

8.5

RX3-9

0.04

5.88

0.39

1502

16.5

RX7b-571

0.18

6.58

0.05

171.0

13.0

RX3-12

0.18

6.66

0.57

1771

14.1

RX7b-366'

0.11

5.67

0.04

171.4

15.5

RX3-13

0.90

6.06

0.75

1829

11.1

RX7b-345

0.72

8.35

0.08

171.6

8.7

RX7b-354

0.05

3.83

0.03

173.3

23.2

RX2-20

0.08

12.38

0.05

90.1

7.4

RX7b-481

1.74

7.70

0.10

175.4

7.0

RX2-54

0.08

7.90

0.03

97.9

11.4

RX7b-394

0.52

5.51

0.05

175.9

12.9

RX2-48

0.16

7.06

0.03

103.2

12.3

RX7b-207

0.26

4.95

0.04

178.1

16.0

RX2b-2

0.07

5.83

0.03

106.6

15.4

RX7b-347

0.80

4.24

0.05

178.6

13.6

RX2-13 RX2b24 RX2b18 RX2-34

0.46

11.78

0.06

107.0

7.0

RX7b-7

0.67

6.81

0.07

179.8

10.4

0.44

17.01

0.09

110.1

5.1

RX7b-459

0.13

6.60

0.05

180.9

13.2

0.11

14.33

0.07

112.9

6.3

RX7b-448

0.73

12.62

0.11

181.7

6.2

0.23

10.66

0.06

119.5

8.2

RX7b-89

0.35

4.69

0.05

184.4

16.0

RX2-21 RX2b16 RX2-28

0.46

8.77

0.05

120.6

9.1

RX7b-527

0.15

5.49

0.05

184.4

15.6

0.35

10.39

0.06

131.1

8.1

RX7b-639

0.85

4.15

0.05

187.8

13.5

0.19

5.21

0.03

135.5

15.9

RX7b-323

0.39

4.06

0.04

191.2

17.5

RX2-24 RX2b15 RX2-25

0.19

15.80

0.09

136.1

5.7

RX7b-224

0.07

3.32

0.03

192.9

26.1

0.31

5.38

0.04

136.3

14.6

RX7b-611

0.16

6.57

0.06

195.4

13.1

0.04

5.47

0.03

144.3

16.7

RX7b-409

0.33

5.25

0.05

196.7

14.7

RX2-50 RX2b25' RX2-19

0.16

5.46

0.04

145.4

15.6

RX7b-555

0.22

6.95

0.06

197.7

12.2

0.50

7.29

0.05

145.9

10.5

RX7b-421

0.12

4.87

0.04

199.7

17.7

0.07

5.52

0.04

152.2

16.2

RX7b-494

0.23

8.42

0.08

202.0

10.2

Minara

44

RX2b21 RX2-56 RX2b17 RX2b12' RX2b31 RX2-14 RX2b23' RX2-44 RX2b10' RX2-33

0.45

7.22

0.06

160.7

10.7

RX7b-484

0.68

6.67

0.08

202.5

10.5

0.25

7.73

0.06

168.3

10.9

RX7b-27'

0.87

6.80

0.08

203.6

9.7

0.82

8.56

0.08

174.8

8.3

RX7b-578

0.71

6.14

0.07

206.3

11.0

0.04

2.95

0.02

188.9

30.2

RX7b-46

0.82

5.48

0.07

206.5

11.4

0.10

6.61

0.06

194.0

13.4

RX7b-449

0.32

6.13

0.06

207.1

13.0

0.70

6.26

0.07

207.8

10.9

RX7b-186

0.11

8.04

0.07

209.7

11.1

0.55

5.23

0.06

213.1

13.3

RX7b-148

0.40

7.19

0.08

214.3

11.0

0.28

6.60

0.12

380.3

12.4

RX7b-183

0.10

6.32

0.06

215.3

14.0

0.08

6.77

0.12

400.0

13.2

RX7b-160

0.34

5.98

0.06

217.7

13.1

0.37

6.27

0.13

412.2

12.4

RX7b-623

0.07

8.40

0.08

218.0

10.8

RX2-23

0.15

8.34

0.70

1805

11.8

RX7b-418

0.78

5.67

0.08

219.2

11.3

RX2-11

0.44

4.84

0.51

1808

15.9

RX7b-512

0.18

9.00

0.09

220.5

9.7

RX2-29

0.25

9.02

0.79

1815

10.6

RX7b-634

0.11

10.01

0.10

222.0

9.0

RX7b-637

2.14

11.02

0.17

222.6

5.2

Taradungan RX7b0.04 338 RX7b0.06 336 RX7b0.06 447 RX7b0.04 68 RX7b0.04 499 RX7b0.04 596 RX7b0.08 441 RX7b0.20 156 RX7b0.10 495 RX7b0.07 533 RX7b0.04 614 RX7b0.04 595 RX7b0.08 627 RX7b0.27 131 RX7b0.06 620 RX7b0.08 115 RX7b0.07 478 RX7b0.25 19 RX7b0.99 558 RX7b0.30 341 RX7b0.07 624 RX7b0.09 95

6.19

0.02

66.9

14.7

RX7b-600

0.87

8.69

0.11

228.1

8.1

4.93

0.02

72.1

18.2

RX7b-66

0.51

5.75

0.07

228.5

12.6

6.21

0.02

74.0

14.6

RX7b-340

0.51

4.68

0.06

229.9

14.7

6.82

0.02

75.1

13.4

RX7b-188

0.21

8.19

0.09

230.3

10.5

5.67

0.02

75.9

16.0

RX7b-544

0.56

3.62

0.05

238.5

17.1

6.07

0.02

76.6

15.0

RX7b-122

2.01

8.61

0.15

239.1

6.2

7.21

0.02

77.1

12.5

RX7b-169

0.26

2.51

0.03

242.4

27.7

4.80

0.02

79.0

17.1

RX7b-90

0.64

6.47

0.09

244.8

10.9

4.44

0.02

80.6

19.6

RX7b-375

0.17

5.62

0.06

246.1

15.1

5.79

0.02

83.0

15.5

RX7b-638

0.45

10.93

0.13

249.4

7.5

6.42

0.02

83.4

14.2

RX7b-507'

0.86

9.36

0.13

260.1

7.7

6.21

0.02

83.9

14.7

RX7b-65'

0.15

8.69

0.10

266.2

10.1

5.87

0.02

85.3

15.2

RX7b-228'

0.11

6.25

0.11

402.1

14.1

8.09

0.03

87.9

10.4

RX7b-488'

0.57

6.05

0.14

429.4

11.8

4.88

0.02

92.0

18.3

RX7b-426 '

0.37

10.58

0.22

433.3

7.9

10.31

0.04

92.8

8.8

RX7b-67'

0.39

6.86

0.15

435.6

11.4

5.17

0.02

92.9

17.3

RX7b-192

1.91

7.31

1.15

1825

7.4

3.52

0.02

93.0

21.6

RX7b-371'

0.15

9.93

0.84

1828

10.1

7.80

0.04

93.4

8.5

RX7b-103

0.41

6.13

0.62

1849

13.6

7.06

0.03

93.5

11.6

RX7b-344

1.07

6.93

0.89

1857

9.7

9.32

0.04

94.3

9.8

RX7b-353

1.16

5.49

0.80

1863

10.7

10.43

0.04

94.4

8.7

RX7b-552'

0.18

5.95

0.54

1864

15.6

45

RX7b483 RX7b508 RX7b54 RX7b490 RX7b446 RX7b403 RX7b397 RX7b400 RX7b586 RX7b621 RX7b190 RX7b643 RX7b335 RX7b497 RX7b78 RX7b177 RX7b515 RX7b193 RX7b180 RX7b415 RX7b458 RX7b434 RX7b372 RX7b511 RX7b470 RX7b36 RX7b69 RX7b85 RX7b539 RX7b154 RX7b489 RX7b635 RX7b406

0.12

10.85

0.04

94.6

8.3

RX7b-118

1.21

5.91

0.86

1883

10.1

0.09

9.22

0.04

95.2

9.8

RX7b-41'

1.08

6.07

0.84

1897

10.5

0.03

4.62

0.02

95.5

19.7

RX7b-521'

0.57

5.17

0.62

1938

14.4

0.04

6.16

0.03

96.8

14.8

RX7b-509'

0.42

3.83

0.46

1944

19.1

0.26

9.15

0.04

97.1

9.3

EN10

0.06

7.95

0.03

97.5

11.4

EN10-4

0.09

8.38

0.02

63.7

10.7

0.34

4.34

0.02

98.1

17.1

EN10-14

0.08

7.13

0.02

69.2

12.6

0.11

3.76

0.02

99.2

22.6

EN10-20

0.12

8.08

0.03

74.7

11.0

0.03

3.75

0.02

99.2

24.3

EN10-12

0.08

6.81

0.02

78.3

13.2

0.06

6.12

0.03

99.7

14.8

EN10-22

0.07

6.76

0.02

79.4

13.3

0.10

9.76

0.04

101.4

9.2

EN10-29

0.09

7.07

0.02

79.9

12.7

0.08

4.23

0.02

101.6

20.7

EN10-30

0.05

5.36

0.02

81.3

16.8

0.03

5.94

0.03

102.8

15.4

EN10-15

0.05

5.94

0.02

82.0

15.3

0.20

4.54

0.02

103.3

17.9

EN10-19

0.12

8.49

0.03

82.7

10.5

0.06

7.22

0.03

103.4

12.5

EN10-7

0.13

9.12

0.03

83.6

9.8

0.17

13.57

0.06

103.4

6.6

EN10-10

0.07

6.38

0.02

84.7

14.1

0.02

4.36

0.02

103.7

21.1

EN10-8

0.10

7.87

0.03

86.1

11.4

0.11

10.82

0.05

103.8

8.3

EN10-23

0.09

6.96

0.03

86.8

12.9

0.11

6.64

0.03

104.4

13.3

EN10-28

0.20

9.09

0.04

89.1

9.6

2.21

4.49

0.05

104.6

8.0

EN10-2

0.16

10.53

0.04

90.0

8.4

0.13

6.92

0.03

105.3

12.7

EN10-21

0.08

7.97

0.03

90.0

11.3

0.15

10.99

0.05

106.6

8.1

EN10-13

0.13

8.85

0.04

90.2

10.0

0.11

6.84

0.03

107.1

12.9

EN10-9

0.20

11.75

0.05

90.3

7.5

0.06

7.45

0.03

107.6

12.2

EN10-3

0.17

9.77

0.04

93.1

9.0

0.17

13.47

0.06

109.3

6.6

EN10-16

0.14

9.64

0.04

93.7

9.2

0.05

3.96

0.02

109.4

22.5

EN10-18

0.18

11.53

0.05

94.1

7.7

0.05

4.16

0.02

109.5

21.6

EN10-25

0.19

8.84

0.04

96.1

9.9

0.02

4.42

0.02

109.7

20.7

EN10-26

0.09

7.58

0.03

98.3

11.8

0.11

7.44

0.04

111.0

11.9

EN10-27

0.06

6.02

0.03

99.0

15.0

0.23

10.63

0.05

111.0

8.2

EN10-11

0.07

6.99

0.03

99.1

12.9

0.06

5.67

0.03

111.8

15.9

EN10-17

0.13

8.68

0.04

99.2

10.2

0.18

11.21

0.06

112.3

7.9

EN10-24

0.06

6.25

0.03

104.4

14.4

0.26

16.11

0.08

113.2

5.5

EN10-6

0.11

8.63

0.04

104.5

10.4

46

RX7b0.05 5.76 0.03 113.8 15.7 EN10-1 91 RX7b0.27 11.34 0.06 114.2 7.6 EN10-5 168 Data in italic were excluded in the calculation for weighted mean ages.

0.05

5.38

0.03

107.8

16.8

0.09

6.81

0.03

111.8

13.1

47

Table 3. LA-ICP MS zircon U-Pb data of samples from northern Palawan. Spot Analysis

Roxas1a 4 5 6 8 10 15 16 18 19 20 24 25 26 27 28 29 30 34 35 36 37 38 39 40 45 46 48 49 50 51 56 57 58 59 60 61 62 67 68 69 70 71 72 73 Roxas1c 78 79 80 81 82 83 84 89 90 91

238

U/206Pb* age

U

Th (ppm)

(%)

(ppm)

(ppm)

Ratio

Ratio

±

Ratio

±

(Ma)

1σ err

(Ma)

1σ err

0.96 1.21 0.00 0.00 0.00 0.00 0.05 3.43 0.00 0.00 0.74 0.14 0.00 0.00 0.06 0.00 0.13 4.08 0.00 0.00 0.00 0.00 0.00 0.00 0.42 0.24 0.30 0.00 0.00 0.36 0.00 0.00 0.15 2.22 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

368 121 1458 630 943 366 474 107 302 180 82 1044 915 1389 490 113 208 107 358 349 528 87 204 407 410 496 327 543 351 133 1516 231 594 154 434 189 332 468 199 944 586 114 127 520

207 107 239 135 290 443 80 113 157 130 79 307 367 673 78 51 44 97 271 439 78 83 104 105 259 91 81 365 726 200 55 206 282 127 100 147 78 245 127 1238 5 52 168 581

0.58 0.91 0.17 0.22 0.32 1.24 0.17 1.09 0.53 0.74 0.99 0.30 0.41 0.50 0.16 0.46 0.22 0.93 0.78 1.29 0.15 0.98 0.52 0.27 0.65 0.19 0.25 0.69 2.12 1.55 0.04 0.91 0.49 0.85 0.24 0.80 0.24 0.54 0.65 1.34 0.01 0.47 1.36 1.15

56.13 61.34 29.17 3.55 3.06 60.93 3.11 59.64 34.75 18.22 57.68 28.87 28.53 35.57 4.10 56.05 3.46 60.67 64.63 55.24 3.60 54.22 48.89 3.18 38.29 2.97 34.65 36.34 50.52 73.93 35.36 43.28 29.37 59.37 28.34 49.74 35.49 57.08 37.56 28.39 36.59 36.84 55.67 58.03

0.99 1.79 0.35 0.04 0.03 1.53 0.04 2.60 0.56 0.33 2.47 0.42 0.40 0.52 0.05 2.24 0.06 2.30 1.33 1.36 0.05 1.93 1.15 0.04 0.76 0.05 0.76 0.66 0.98 2.90 0.48 0.94 0.46 1.88 0.43 1.30 0.69 1.08 1.00 0.39 0.61 0.99 1.91 1.20

0.0428 0.0441 0.0508 0.1120 0.1128 0.0549 0.1138 0.0270 0.0548 0.0575 0.0375 0.0497 0.0512 0.0506 0.1107 0.0510 0.1185 0.0564 0.0474 0.0459 0.1123 0.0348 0.0434 0.1129 0.0413 0.1222 0.0452 0.0535 0.0441 0.0486 0.0494 0.0481 0.0496 0.0280 0.0489 0.0484 0.0487 0.0433 0.0541 0.0482 0.0513 0.0525 0.0449 0.0556

0.0064 0.0134 0.0011 0.0012 0.0008 0.0037 0.0015 0.0200 0.0027 0.0026 0.0149 0.0019 0.0014 0.0013 0.0013 0.0054 0.0017 0.0171 0.0031 0.0025 0.0013 0.0060 0.0031 0.0013 0.0048 0.0018 0.0036 0.0022 0.0033 0.0167 0.0013 0.0035 0.0031 0.0127 0.0020 0.0039 0.0027 0.0025 0.0035 0.0015 0.0022 0.0053 0.0050 0.0028

113.8 104.2 217.3 1600 1825 104.9 1798 107.2 182.9 344.5 110.8 219.5 222.1 178.7 1408 114.0 1639 105.4 99.0 115.7 1581 117.8 130.5 1762 166.2 1871 183.4 175.0 126.4 86.6 179.8 147.3 215.9 107.7 223.6 128.3 179.1 111.9 169.4 223.1 173.8 172.7 114.8 110.1

2.0 3.0 2.6 15 18 2.6 20 4.6 2.9 6.0 4.7 3.1 3.1 2.6 16 4.5 25 4.0 2.0 2.8 18 4.2 3.0 21 3.2 28 4.0 3.1 2.4 3.4 2.4 3.2 3.3 3.4 3.3 3.3 3.4 2.1 4.5 3.0 2.9 4.6 3.9 2.3

114.6 104.8 217.2 1578 1822 104.0 1792 110.0 181.8 342.8 111.6 219.7 221.9 178.5 1376 113.6 1609 104.3 99.0 115.7 1558 117.8 130.5 1753 166.9 1857 183.9 174.1 126.4 86.5 179.8 147.3 216.1 110.1 223.6 128.3 179.1 111.9 168.4 223.1 173.4 172.0 114.8 109.1

2.0 2.8 2.6 15 18 2.6 20 4.2 3.0 6.1 4.4 3.1 3.1 2.6 16 4.6 25 3.8 2.0 2.8 18 4.2 3.0 21 3.2 28 4.0 3.1 2.4 3.0 2.4 3.2 3.3 3.1 3.3 3.3 3.4 2.1 4.5 3.0 2.9 4.7 3.9 2.3

0.00 0.00 0.00 0.00 0.00 0.00 0.13 0.00 0.00 0.00

304 414 291 108 819 377 473 327 267 120

97 103 102 111 195 174 290 238 163 125

0.33 0.26 0.36 1.06 0.24 0.47 0.63 0.75 0.63 1.07

4.31 3.44 33.92 53.90 35.70 38.16 37.32 50.23 39.83 58.05

0.06 0.05 0.67 1.77 0.57 0.65 0.67 1.14 0.90 1.93

0.1142 0.1132 0.0538 0.0575 0.0526 0.0489 0.0477 0.0494 0.0468 0.0397

0.0017 0.0013 0.0029 0.0080 0.0020 0.0022 0.0046 0.0032 0.0031 0.0053

1346 1643 187.3 118.5 178.1 166.8 170.4 127.1 159.9 110.1

18 21 3.6 3.9 2.8 2.8 3.0 2.8 3.6 3.6

1306 1623 186.4 117.2 177.5 166.8 170.7 126.9 159.9 110.1

17 20 3.7 4.0 2.8 2.8 2.9 2.9 3.6 3.6

206

Pbc

232

Th/

238

U

238

U/

206

Pb

207

Pb/

206

Pb

238

U/

206

Pb* age

(1)

(2)

48

92 93 94 95 100 101 102 103 104 105 106 111 112 113 114 115 116 117 122 123 124 125 126 127 128 133 134 135 136 137 138 139 144 145 146 147 148 149 RX2 129 130 131 133 134 135 141 142 143 144 145 151 152 153 154 155 156 157 162 163 164 165

0.00 1.09 0.00 0.00 0.00 0.00 0.30 0.70 0.00 1.33 0.00 0.09 1.35 0.00 0.00 0.00 0.00 0.00 0.13 1.17 1.25 2.09 0.15 0.00 0.00 0.00 0.00 0.00 0.43 0.00 0.00 0.00 0.08 0.98 0.00 0.00 3.51 0.10

178 199 481 438 200 61 477 383 275 1100 561 164 339 213 554 662 460 522 471 208 212 767 1130 253 195 426 410 527 575 395 2144 685 848 240 411 591 452 560

148 51 401 29 157 37 194 136 305 140 235 51 71 139 204 284 235 376 322 264 217 290 451 90 204 316 234 280 335 16 770 218 331 149 314 381 309 523

0.85 0.26 0.86 0.07 0.81 0.62 0.42 0.36 1.14 0.13 0.43 0.32 0.22 0.67 0.38 0.44 0.52 0.74 0.70 1.30 1.05 0.39 0.41 0.37 1.07 0.76 0.59 0.55 0.60 0.04 0.37 0.33 0.40 0.64 0.78 0.66 0.70 0.96

57.11 4.61 56.63 3.50 55.50 50.18 30.86 36.19 60.70 8.39 36.13 36.42 38.22 52.75 36.39 28.17 27.58 51.71 27.96 52.51 55.24 4.99 27.94 36.21 49.13 52.93 3.51 5.64 28.56 69.34 39.96 35.31 35.68 54.43 60.33 36.39 36.82 52.01

1.63 0.10 1.10 0.04 1.30 2.29 0.51 0.62 1.21 0.11 0.55 0.93 0.84 1.40 0.52 0.43 0.46 1.02 0.45 1.57 1.78 0.09 0.43 0.95 1.37 1.09 0.05 0.08 0.44 1.51 0.90 0.63 0.53 1.31 1.36 0.68 0.85 1.05

0.0450 0.1269 0.0471 0.1089 0.0568 0.0402 0.0494 0.0528 0.0458 0.0888 0.0532 0.0536 0.0441 0.0446 0.0467 0.0510 0.0505 0.0439 0.0487 0.0365 0.0438 0.0908 0.0524 0.0492 0.0475 0.0496 0.1146 0.1086 0.0457 0.0470 0.0487 0.0480 0.0469 0.0469 0.0417 0.0514 0.0377 0.0527

0.0046 0.0029 0.0029 0.0012 0.0048 0.0071 0.0037 0.0039 0.0034 0.0015 0.0020 0.0060 0.0037 0.0044 0.0022 0.0019 0.0021 0.0029 0.0040 0.0142 0.0126 0.0020 0.0023 0.0031 0.0038 0.0031 0.0017 0.0017 0.0032 0.0038 0.0011 0.0016 0.0025 0.0089 0.0027 0.0024 0.0101 0.0065

111.9 1265 112.8 1622 115.1 127.2 205.6 175.7 105.3 726.2 176.0 174.6 166.5 121.1 174.8 224.9 229.6 123.5 226.5 121.6 115.6 1177 226.7 175.6 129.9 120.6 1616 1052 221.8 92.3 159.3 180.0 178.2 117.4 106.0 174.7 172.8 122.8

3.2 26 2.2 18 2.7 5.8 3.3 3.0 2.1 9.1 2.6 4.4 3.6 3.2 2.5 3.4 3.8 2.4 3.6 3.6 3.7 19 3.4 4.5 3.6 2.5 20 14 3.4 2.0 3.5 3.2 2.6 2.8 2.4 3.2 3.9 2.5

111.9 1206 112.8 1607 113.9 127.2 205.8 175.0 105.3 705.3 175.2 173.7 167.6 121.1 174.8 224.8 229.6 123.5 226.8 123.0 116.3 1164 226.2 175.6 129.9 120.5 1591 1012 222.8 92.3 159.3 180.0 178.3 117.6 106.0 174.3 175.3 122.1

3.2 25 2.2 18 2.7 5.8 3.3 3.0 2.1 8.9 2.7 4.4 3.6 3.2 2.5 3.4 3.8 2.4 3.5 3.1 3.5 19 3.4 4.5 3.6 2.5 19 13 3.3 2.0 3.5 3.2 2.6 2.7 2.4 3.2 3.8 2.3

1.64 0.00 0.37 0.49 0.65 0.00 0.00 0.23 0.00 0.26 2.39 0.25 0.00 0.00 0.08 0.00 2.03 0.30 0.02 0.00 0.00 0.00

180 510 707 211 196 173 99 207 212 670 131 231 532 295 291 1273 143 356 514 245 141 284

152 204 251 165 108 153 112 140 178 276 183 180 435 213 97 944 89 118 244 235 118 234

0.87 0.41 0.36 0.80 0.57 0.91 1.15 0.69 0.86 0.42 1.44 0.80 0.84 0.74 0.34 0.76 0.64 0.34 0.49 0.98 0.86 0.85

54.72 84.32 42.11 55.08 7.60 43.56 56.77 52.47 14.50 57.32 61.34 9.97 59.96 47.20 38.34 49.79 48.55 55.17 42.78 43.47 58.50 46.03

1.78 1.86 0.74 1.98 0.14 1.20 2.95 1.71 0.26 1.21 2.94 0.18 1.18 1.14 0.90 0.87 1.90 1.41 0.86 1.19 2.25 1.03

0.0286 0.0382 0.0473 0.0432 0.0611 0.0568 0.0391 0.0570 0.0543 0.0540 0.0457 0.0579 0.0494 0.0437 0.0436 0.0473 0.0483 0.0458 0.0434 0.0500 0.0566 0.0435

0.0139 0.0030 0.0036 0.0110 0.0043 0.0057 0.0092 0.0086 0.0027 0.0049 0.0233 0.0039 0.0032 0.0035 0.0046 0.0016 0.0135 0.0054 0.0038 0.0034 0.0082 0.0028

116.7 76.0 151.3 116.0 797.3 146.3 112.6 121.7 429.8 111.5 104.2 616.1 106.6 135.2 166.0 128.2 131.4 115.8 149.0 146.6 109.3 138.6

3.8 1.7 2.6 4.1 14.1 4.0 5.8 3.9 7.5 2.3 5.0 10.5 2.1 3.2 3.8 2.2 5.1 2.9 2.9 4.0 4.2 3.1

118.7 76.0 151.6 116.6 801.6 144.9 112.6 120.4 429.8 110.7 104.6 617.6 106.5 135.2 166.1 128.2 131.5 116.1 149.0 146.4 108.1 138.6

3.4 1.7 2.6 4.0 14.0 4.1 5.8 3.8 7.5 2.3 4.3 10.2 2.1 3.2 3.8 2.2 4.9 2.9 2.9 4.0 4.3 3.1

49

166 167 168 173 174 175 176 177 178 179 187 189 190 191 192 193 198 200 201 202 203 209 210 212 213 215 220 222 223 224 226 232 233 234 235 236 237 242 243 244 245 246 247 253 254 256 257 258 259 264 266 267 268 269 270 275 276 277 278 280 281

0.00 0.26 0.00 0.00 3.33 1.55 0.00 0.86 0.63 0.00 0.00 0.70 0.41 0.15 0.35 7.97 0.00 0.47 0.00 0.55 0.69 0.97 0.55 0.15 0.00 0.05 0.00 0.00 0.43 0.00 1.57 0.00 0.47 0.00 1.69 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.42 0.00 0.09 0.00 0.33 0.00 0.00 0.00 0.00 0.00 3.31 0.17 0.00 0.00 0.00 0.00 0.62 0.84

262 428 139 1072 221 131 518 193 225 193 416 604 817 480 322 484 288 1145 694 259 158 145 207 178 985 115 318 142 260 297 118 316 248 61 156 271 124 204 70 123 277 250 97 225 187 406 208 1352 728 220 323 183 176 195 162 207 221 40 157 325 162

237 334 145 596 212 148 158 125 223 220 270 472 194 350 170 485 157 527 354 195 66 129 157 99 282 83 192 130 198 286 72 681 271 27 44 344 103 95 50 83 144 159 109 129 186 246 204 522 820 253 458 201 124 119 72 174 136 17 408 245 133

0.93 0.80 1.07 0.57 0.98 1.16 0.31 0.67 1.02 1.17 0.67 0.80 0.24 0.75 0.54 1.03 0.56 0.47 0.52 0.77 0.43 0.92 0.78 0.57 0.29 0.74 0.62 0.94 0.78 0.99 0.62 2.21 1.12 0.45 0.29 1.30 0.85 0.48 0.74 0.69 0.54 0.65 1.16 0.59 1.02 0.62 1.01 0.40 1.15 1.18 1.45 1.13 0.73 0.63 0.45 0.86 0.63 0.44 2.67 0.77 0.84

51.99 62.64 44.05 41.01 62.31 53.60 47.80 59.61 54.56 68.94 52.21 49.63 39.02 2.54 44.19 63.90 30.82 62.48 60.54 3.57 31.71 46.85 64.30 49.04 36.16 69.71 53.88 52.39 47.94 45.09 37.42 70.81 58.13 55.14 49.56 56.45 39.36 31.39 58.44 71.85 38.61 60.77 3.13 58.08 54.15 28.53 44.58 66.39 66.42 45.05 45.19 54.72 47.56 50.89 62.51 48.46 46.80 57.60 27.87 63.14 58.85

1.38 1.40 1.57 0.92 1.91 2.15 1.03 2.00 1.85 2.29 1.28 0.90 0.58 0.03 0.88 1.46 0.67 0.89 0.97 0.05 0.79 1.40 1.69 1.35 0.59 2.60 1.06 1.38 0.99 0.92 1.13 1.75 1.70 2.56 1.74 1.37 1.17 0.72 2.78 2.51 0.80 1.75 0.06 1.59 1.53 0.58 0.95 0.99 1.33 1.10 0.97 1.36 1.35 1.43 2.01 1.27 1.17 3.21 0.72 1.51 2.13

0.0541 0.0475 0.0528 0.0541 0.0363 0.0506 0.0492 0.0314 0.0456 0.0476 0.0544 0.0450 0.0489 0.1494 0.0489 0.0586 0.0568 0.0459 0.0504 0.1093 0.0549 0.0469 0.0493 0.0429 0.0496 0.0564 0.0591 0.0532 0.0452 0.0557 0.0418 0.0522 0.0450 0.0470 0.0380 0.0535 0.0453 0.0588 0.0563 0.0528 0.0511 0.0421 0.1132 0.0429 0.0552 0.0499 0.0463 0.0451 0.0463 0.0474 0.0410 0.0503 0.0554 0.0372 0.0534 0.0504 0.0453 0.0605 0.0518 0.0425 0.0426

0.0039 0.0075 0.0046 0.0022 0.0138 0.0176 0.0028 0.0116 0.0122 0.0057 0.0031 0.0057 0.0028 0.0021 0.0060 0.0156 0.0028 0.0028 0.0020 0.0027 0.0056 0.0111 0.0106 0.0080 0.0016 0.0130 0.0035 0.0049 0.0056 0.0026 0.0094 0.0037 0.0100 0.0098 0.0088 0.0030 0.0043 0.0040 0.0095 0.0079 0.0033 0.0043 0.0026 0.0077 0.0049 0.0036 0.0032 0.0028 0.0022 0.0033 0.0024 0.0037 0.0042 0.0100 0.0101 0.0037 0.0069 0.0125 0.0034 0.0076 0.0125

122.8 102.1 144.7 155.3 102.6 119.2 133.5 107.2 117.1 92.8 122.3 128.6 163.1 2139 144.2 100.1 205.8 102.4 105.6 1594 200.1 136.2 99.5 130.1 175.8 91.8 118.5 121.9 133.1 141.4 170.0 90.4 110.0 115.9 128.8 113.2 161.7 202.1 109.4 89.1 164.8 105.2 1788 110.1 118.0 222.1 143.0 96.4 96.3 141.5 141.1 116.7 134.1 125.4 102.3 131.7 136.3 111.0 227.3 101.3 108.6

3.2 2.3 5.1 3.4 3.1 4.7 2.8 3.6 3.9 3.1 3.0 2.3 2.4 23 2.8 2.3 4.4 1.5 1.7 19 4.9 4.0 2.6 3.6 2.8 3.4 2.3 3.2 2.7 2.9 5.0 2.2 3.2 5.3 4.5 2.7 4.8 4.6 5.2 3.1 3.4 3.0 32 3.0 3.3 4.5 3.0 1.4 1.9 3.4 3.0 2.9 3.8 3.5 3.3 3.4 3.4 6.1 5.8 2.4 3.9

122.0 102.2 144.0 154.3 104.2 118.8 133.4 108.2 117.5 92.8 121.4 129.2 163.2 2106 144.3 98.8 204.2 102.6 105.3 1576 199.0 136.5 99.3 130.3 175.8 90.8 117.0 121.2 133.6 140.2 171.6 89.9 110.4 115.9 130.5 112.5 161.7 200.0 108.3 88.5 164.5 105.2 1781 110.5 117.0 222.3 143.0 96.7 96.3 141.5 141.1 116.5 133.0 127.2 101.6 131.4 136.3 109.3 227.0 101.9 109.4

3.3 2.2 5.2 3.4 2.9 4.4 2.9 3.4 3.7 3.1 3.0 2.2 2.4 23 2.8 2.3 4.4 1.4 1.7 19 4.8 3.8 2.5 3.4 2.8 3.3 2.3 3.2 2.6 2.9 5.0 2.2 3.0 5.3 4.5 2.7 4.8 4.6 5.3 3.2 3.5 3.0 32 2.9 3.4 4.5 3.0 1.4 1.9 3.4 3.0 2.9 3.8 3.4 3.3 3.5 3.2 6.3 5.8 2.3 3.7

50

RX7 4 0.00 382 369 0.99 7.87 0.11 0.0652 0.0012 5 2.04 640 191 0.31 34.47 0.73 0.0515 0.0054 6 0.77 211 236 1.15 42.11 1.17 0.0514 0.0103 9 0.74 109 82 0.77 69.19 2.67 0.0386 0.0119 10 0.00 217 195 0.92 41.66 0.88 0.0470 0.0038 15 0.03 375 226 0.62 27.99 0.54 0.0511 0.0044 16 0.00 352 97 0.28 47.43 0.90 0.0522 0.0029 18 0.66 218 227 1.07 45.22 1.15 0.0414 0.0093 19 0.00 524 169 0.33 2.87 0.04 0.1141 0.0011 20 0.18 103 48 0.47 2.18 0.03 0.1517 0.0028 21 0.01 413 208 0.52 56.57 1.19 0.0496 0.0052 26 0.00 191 159 0.85 56.52 1.61 0.0473 0.0047 27 0.00 135 145 1.11 57.96 1.61 0.0428 0.0050 28 0.00 922 802 0.89 48.44 1.05 0.0455 0.0020 29 0.00 447 224 0.52 36.01 0.71 0.0522 0.0026 30 0.00 244 420 1.77 67.94 2.09 0.0473 0.0048 37 0.00 161 49 0.31 32.29 0.81 0.0497 0.0038 38 1.11 231 184 0.82 59.84 1.68 0.0496 0.0092 39 1.18 385 533 1.42 45.98 1.01 0.0428 0.0094 40 0.16 1211 376 0.32 25.71 0.32 0.0493 0.0017 41 1.98 263 182 0.71 29.09 0.65 0.0439 0.0065 42 0.00 787 633 0.83 28.15 0.39 0.0513 0.0015 43 0.00 233 197 0.87 56.19 1.22 0.0518 0.0041 48 0.04 249 309 1.27 41.14 1.03 0.0487 0.0102 49 0.00 353 137 0.40 33.61 0.60 0.0474 0.0023 51 0.03 413 398 0.99 60.93 1.35 0.0431 0.0088 52 0.00 1217 475 0.40 24.59 0.28 0.0513 0.0012 53 0.00 256 116 0.46 7.11 0.10 0.0671 0.0017 54 0.00 147 90 0.63 58.80 1.47 0.0520 0.0052 60 0.00 93 90 1.00 60.75 1.98 0.0548 0.0068 61 0.00 125 76 0.62 35.32 0.93 0.0457 0.0040 62 0.00 740 813 1.13 61.51 1.05 0.0528 0.0021 65 0.31 299 180 0.62 64.38 1.79 0.0481 0.0069 75 0.00 164 128 0.80 49.77 1.34 0.0407 0.0039 77 3.59 171 92 0.56 52.83 1.45 0.0353 0.0107 78 0.00 192 106 0.57 33.31 0.71 0.0525 0.0035 85 0.05 210 97 0.47 24.15 0.57 0.0484 0.0055 86 0.24 138 56 0.41 23.10 0.68 0.0513 0.0055 87 0.86 401 354 0.90 66.05 1.52 0.0409 0.0080 88 0.09 352 141 0.41 35.34 0.63 0.0501 0.0040 89 0.00 175 206 1.21 48.93 1.23 0.0434 0.0039 90 0.13 289 206 0.73 58.72 1.49 0.0514 0.0075 91 0.97 349 297 0.87 58.63 1.62 0.0396 0.0080 97 0.00 133 90 0.70 50.14 1.61 0.0423 0.0051 98 0.08 370 237 0.66 55.57 1.26 0.0438 0.0061 99 1.23 298 52 0.18 45.08 0.99 0.0499 0.0050 100 0.18 785 150 0.20 34.76 0.61 0.0489 0.0024 101 1.00 275 169 0.63 52.18 1.28 0.0386 0.0064 108 0.00 411 171 0.43 31.56 0.53 0.0529 0.0025 109 0.00 308 297 0.99 27.54 0.50 0.0525 0.0026 110 0.00 185 143 0.79 54.23 1.62 0.0522 0.0042 111 0.10 195 220 1.16 45.82 1.26 0.0538 0.0097 112 1.04 238 170 0.73 49.47 1.42 0.0384 0.0072 113 0.00 86 128 1.54 7.53 0.16 0.0659 0.0032 119 0.05 579 783 1.39 29.61 0.56 0.0507 0.0064 120 0.24 782 549 0.72 44.96 0.89 0.0472 0.0043 122 0.00 171 98 0.58 52.77 1.67 0.0452 0.0046 123 0.00 722 368 0.52 33.22 0.54 0.0517 0.0023 124 0.00 652 298 0.47 27.77 0.46 0.0535 0.0018 Errors are 1-sigma; Pbc and Pb* indicate the common and radiogenic portions, respectively.

771.0 184.3 151.3 92.5 152.9 226.3 134.5 141.0 1925 2431 113.0 113.1 110.3 131.7 176.6 94.2 196.6 106.8 138.7 246.0 217.9 225.0 113.7 154.8 189.0 104.9 257.0 848.2 108.7 105.2 180.0 104.0 99.4 128.2 120.9 190.7 261.5 273.2 96.9 179.9 130.4 108.9 109.0 127.3 115.0 141.4 182.8 122.4 201.1 229.9 117.8 139.2 129.0 804.3 214.1 141.8 121.0 191.2 228.0

9.9 3.8 4.1 3.5 3.2 4.3 2.5 3.6 21 31 2.4 3.2 3.0 2.8 3.4 2.9 4.9 3.0 3.0 3.0 4.8 3.1 2.4 3.8 3.3 2.3 2.8 11.2 2.7 3.4 4.7 1.8 2.7 3.4 3.3 4.0 6.1 7.8 2.2 3.2 3.2 2.7 3.0 4.0 2.6 3.1 3.2 3.0 3.3 4.1 3.5 3.8 3.7 15.6 4.0 2.8 3.8 3.1 3.7

770.8 184.0 150.9 93.2 152.9 226.2 133.9 141.9 1925 2434 112.8 113.1 110.3 131.7 176.0 94.2 196.6 106.6 139.7 246.3 219.7 224.9 113.2 154.9 189.0 105.0 257.0 848.2 108.2 104.4 180.0 103.3 99.4 128.2 122.9 190.1 261.6 273.3 97.7 179.8 130.4 108.4 110.1 127.3 115.1 141.3 183.0 123.6 200.4 229.4 117.2 138.3 130.3 804.3 214.0 142.1 121.0 190.8 227.3

9.9 3.8 3.8 3.4 3.2 4.2 2.6 3.3 21 31 2.3 3.2 3.0 2.8 3.5 2.9 4.9 2.9 2.7 3.0 4.8 3.1 2.5 3.4 3.3 2.1 2.8 11.2 2.8 3.5 4.7 1.8 2.7 3.4 3.2 4.1 5.9 7.8 2.1 3.1 3.2 2.7 2.9 4.0 2.5 3.1 3.2 2.9 3.4 4.2 3.5 3.6 3.6 15.6 3.7 2.7 3.8 3.1 3.7

51

(1) Common Pb corrected by assuming

206

(2) Common Pb corrected by assuming

206

Pb/

238

Pb/

238

U-

208

U-

207

Pb/

232

Pb/

235

Th age-concordance U age-concordance

Graphical abstract

52

Highlights 

Recognition of the Late Cretaceous Daroctan Granite in the Palawan Continental Block.



Late Cretaceous maximum age of deposition of the magmatic minerals.



Tectono-magmatic events prior to the translation of the PCB is presented.

53