2. School of Ocean Sciences, China University of Geosciences, Beijing 100083, China;
3. College of Earth Sciences, East China Institute of Technology, Nanchang 330013, China
Tectonic extension occurred in the East Asian continental margin since the Early Cenozoic (Ru and Piggot, 1986; Taylor and Hayes, 1983). As a part of the East Asian continental margin, South China has been dominated by this tectonic extension, which led to formation of numerous volcanic basins (Huang et al., 2018; Zou, 2001, 1995). The Sanshui Basin is one of such volcanic basins, whose volcanism was widely believed to have occurred from the Late Cretaceous to Late Paleocene (Li et al., 1989; Zhu et al., 1989).
Alkali volcanic rocks are the most important eruption in the Sanshui Basin. Although trachyte dominates most of the eruption, basalt is also a very common formation. Based on petrological and geochemical analysis, most basalts in the Sanshui Basin are tholeiitic (Chung et al., 1997; Zhu et al., 1989), while some alkali basalts are also obtained. On basis of previous studies (Dong et al., 2006; Xiao et al., 2006), the relation between trachyte and basalt was well-researched. Trachytic and basaltic samples from Sanshui Basin were erupted from the similar magma source with different crystallization processes. However, the relationship between tholeiite and alkali basalts remains unclear.
In this study, two kinds of basalts with different alkalinities were obtained. Analysis for whole-rock and mineral compositions was carried out for the difference and relation between them. The discussions on analytical results will help us to understand different formation processes of the two kinds of basalts, as well as the magmatism under the Sanshui Basin.1 GEOLOGICAL SETTINGS
The Sanshui Basin is located in South China, and its volcanism was widely believed to have occurred from 65 to 43 Ma (Hou et al., 2007; Dong et al., 2006; Zhu et al., 1989). On basis of previous studies, more than 1 500 m of volcanic rocks erupted during the Early Paleocene to Middle Eocene (Bureau of Geology and Mineralogy of Guangdong Province, 1988), and most of them are trachyte (more than 1 000 m) and tholeiite (Dong et al., 2006; Chung et al., 1997; Tang, 1994, 1984; Zhu et al., 1989). Based on major and trace element analysis, volcanism in the Sanshui Basin was widely considered to be the consequence of regional asthenospheric mantle upwelling in the continental rift environment (Dong et al., 2006; Xiao et al., 2006). This asthenospheric mantle upwelling commenced at the Lianping and Heyuan basins and migrated southward, and may have finally led to the opening of the South China Sea in Late Paleocene (Zhu et al., 2004, 1989; Chung et al., 1997).
Basalt samples from Wangjiegang (WJG) and Zidong (ZD) were both collected. WJG locates in the south of the Sanshui Basin, while ZD is only 2 km away from WJG in its west (Fig. 1). On the basis of the K-Ar geochronology, WJG basalts were erupted in the last eruption cycle with an age of 43.1±1.3 Ma (Zhu et al., 1989). Meanwhile, the ZD basalts were discovered overlaying Late Paleogene sediment, and were erupted during the same period as the WJG basalts (Dong et al., 2006). Generally speaking, it is highly probable that the ZD and WJG basalts formed in the same eruption period from a unique magma chamber.2 SAMPLES AND ANALYTICAL METHODS
Only fresh samples without significant alterations were carefully selected for analysis. These samples were ultrasonically cleaned in distilled water for 60 min, with the water changed every 15 min, and were left to dry in an oven at 60 ℃. They were then crushed into < 200 mesh particles, prior to analysis.
Eight samples (3 from the WJG basalts, 5 from the ZD basalts) were selected for major elemental analysis; and X-ray fluorescence spectrometry (XRF) on fused glass disks was conducted using a Shimadzu XRF-1500 instrument, at the Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing. Relative precision for elements present in concentrations > 1.0 wt.% was ±1.3 wt.%, and was about ±10 wt.% for elements present in concentrations < 1.0 wt.%. However, only total Fe oxide contents were obtained by the XRF analysis. FeO concentrations were obtained using the method by dissolution with HCl titration and potassium dichromate solution. This analysis was also finished at the Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing.
These samples were also selected for trace elemental analysis (including rare earth elements), using inductively coupled plasma mass spectrometry (ICP-MS), at the Institute of Oceanology, Chinese Academy of Sciences, Qingdao. Sample powders were weighed to be precisely 40 mg, and were transferred into teflon beakers. 1.5 mL HF and 0.5 mL HNO3 were added to the sample powders, and heated at 150 ℃ for 24 h on an electro-thermal plate. Then, at temperature of 120 ℃, 0.2 mL HClO4 was added, and after the white smoke had dissipated, 1 mL HNO3 and 1 mL H2O were added to the residue prior to sealing and heating at less than 120 ℃ for 12 h. The dissolved samples were then diluted a 1 000-fold using 2% distilled super pure HNO3. The solutions were analyzed using Re as the internal standard, and all elements have RSD < 4%.
Seven samples (four from the ZD basalts, three from the WJG basalts) were selected for Sr, Nd isotopic analysis. Sample powders were left to dry in the oven at 80 ℃ for 3 h, and diluted with relevant diluents (85Rb+84Sr or 145Nd+149Sm). Then, HF and HClO4 were added for the dissolution. Then, they were separated and purified with Dowex 50×8 cation exchange resin before the analysis on the thermal ionization mass spectrometry (Triton) at the Wuhan Center of Geological Survey, Ministry of Land and Resources of the People's Republic of China. During the whole analysis, relevant reference materials (NBS987, NBS607 and GBW04411 for Rb-Sr isotopic analysis; GBW04419 and JNdi-1 for Sm-Nd isotopic analysis) were analyzed for comparison (Table 1).
Beside geochemical analysis of whole-rock, electron probe micro analysis (EPMA) on clinopyroxene phenocrysts was also conducted using a JXA-8230(JEOL), at the EPMA Laboratory in Ocean University of China, Qingdao. Si, Na, Mg, Al, K, Ca, Ti, Fe, Mn and Cr were determined under 15 kV acceleration voltages, 20 ncA current, and a beam size of 2 μm. Peak counting times were 60 s for Fe and Mg, and 30 s for remaining elements. Abundance uncertainties were mostly < ±3%.3 RESULTS 3.1 Major and Trace Element Concentrations
The major element results of the WJG and ZD basalts are listed in Table 2. Two kinds of basalts have higher Na2O+K2O (WJG: 5.8 wt.%–6.0 wt.%; ZD: 4.8 wt.%–5.5 wt.%) and relatively higher TiO2, which is similar to typical alkali series volcanic rocks. However, they have obviously different major element concentrations. Compared with the ZD basalts, the WJG basalts have obviously lower SiO2, and higher concentrations of TiO2, Na2O+K2O, Al2O3 and CaO. The different SiO2 and total alkali between them lead to the different alkalinities. The WJG basalts have extremely high Rittmann indices of 11.5–16.2, while those of the ZD basalts are only 3.1–3.9. In this regard, the WJG basalts can be attributed to peralkaline series (Rittmann: > 9), while the ZD basalts to calc-alkaline (Rittmann: < 3.3) to alkaline series (Rittmann: 3.3–9.0). Compared with the studied basaltic samples by previous works (Dong et al., 2006; Xiao et al., 2006; Chung et al., 1997), most previously studied samples are similar to the ZD basalts with relatively low total alkali and variable SiO2 contents, while a few samples (sample Si-31 and Si-32 from Dong et al., 2006) have high total alkali contents which are similar to the WJG basalts. Such difference between the WJG and ZD samples can be observed in TAS diagram (Fig. 2), while the ZD basalts locate on the boundary line between alkaline and sub-alkaline series, the WJG basalts locate in alkaline series area.
The trace element results of the WJG and ZD basalts are also listed in Table 1. Compared with the ZD basalts, the WJG samples have higher concentrations of some large ion lithophile elements (LILE) such as Cs, Rb, Ba, Sr, etc., and some light rare earth elements (LREE) such as La, Ce, Pr and Nd (Fig. 3). Both of them are similar to alkali-basalt (Sun and McDonough, 1989) in incompatible elements concentrations. Compared with the basaltic samples from previous studies (Zhu et al., 2004; Chung et al., 1997), our samples have higher concentrations on most incompatible elements, especial in some highly incompatible elements (Th, U, Nb, K, etc.).3.2 Sr-Nd Isotopic Compositions
The Sr and Nd isotope compositions of the WJG and ZD basalts are listed in Table 2. Both the WJG and ZD basalts have high 143Nd/144Nd ratios with a limited variation ranging from 0.512 881 to 0.512 894, they also have very similar 87Sr/86Sr ratios with a relatively wider variation ranging of 0.703 9–0.704 3. Compared with the basaltic samples of previous studies (Xiao et al., 2006; Zhu et al., 2004, 1989; Chung et al., 1997), our samples have obviously limited variation in Sr-Nd isotope composition and are comparable with some samples (88-13 and 81K-40) of the last eruption period (47.57–37.98 Ma, Zhu et al., 2004) with relatively higher 143Nd/144Nd but lower 87Sr/86Sr ratios (Fig. 4). In general, the similarity of Sr and Nd isotope ratios of the WJG and ZD basalts suggest a common source for them.4 DISCUSSION 4.1 Compositional Differences and Source Characteristics of WJG and ZD Basalts
Based on previous studies (Dong et al., 2006; Xiao et al., 2006; Chung et al., 1997; Zhu et al., 1989), large quantities of volcanic rocks (basalt, trachyte, rhyolite, etc.) were found in the Sanshui Basin, and most basaltic samples are sub-alkaline.
In this study, two kinds of basalts with obviously different alkalinities are obtained with systematic differences in major and trace element concentrations. The WJG basalts have higher Na2O+K2O (~6.00 wt.%), TiO2 (> 2.50 wt.%) and significant lower SiO2 contents (45.07 wt.%–46.03 wt.%), which are similar with typical alkali basalt. On the other hand, ZD basalts have relatively lower Na2O+K2O (4.78 wt.%–5.51 wt.%), TiO2 (< 2.00 wt.%) and higher SiO2 contents (50.20 wt.%–51.20 wt.%). Nevertheless, the two kinds of basalts have higher Na2O+K2O contents than most tholeiitic basalts from the Sanshui basin (3.11 wt.%–4.70 wt.%). The different alkalinities (Rittmann indice) of the WJG and ZD basalts are mainly the consequence of different SiO2 contents, other than different total alkali contents (Na2O+K2O). On the other hand, the two kinds of basalts have differences in their trace element concentrations. The WJG basalts have higher concentrations of most highly incompatible elements (Rb, Ba, Th, Nb, Sr and LREE), but lower Zr and Hf contents than those of the ZD basalts. In addition, they also have different ratios of some higher incompatible to less incompatible elements such as Nb/Y, Ti/Zr and La/Yb (Table 1). Although there are some systematic compositional differences, the WJG and ZD basalts have very similar 143Nd/144Nd and 87Sr/86Sr ratios (Fig. 4 and Table 1), which indicates a similar source. Their 143Nd/144Nd and 87Sr/86Sr ratios are different from those of Early Cenozoic basalts from the adjacent basin (e.g., Heyuan and Maoming), but comparable with those of the alkali basalts from Leiqiong Basin formed after the expanding of the South China Sea (Zhu et al., 2004). For these basalts, their compositions are very different from basalts derived from the normal asthenospheric mantle. According to the previous studies on the Sanshui Basin, the all volcanic rocks from the Sanshui Basin exhibit a very wide variation in 87Sr/86Sr ratios, but relatively limited 143Nd/144Nd ratios (Fig. 4). As Sr is more incompatible than Nd, the concentration of Sr is obviously higher than Nd in the crust. A small amount of crustal contamination may lead to the significant shifting on Sr isotope ratios without significant changing in Nd ratios (Chung et al., 1997).
The compositional difference between the two kinds of basalts may not result from different mantle sources, but may relate to the different partial melting degrees. Elements which are more incompatible tend to enter into melt prior to less incompatible elements, and this process lead to the enrichment of highly incompatible elements in samples with low partial melting degree. In La/Sm versus La diagram (Fig. 5). La is more incompatible than Sm, and tends to enter into the melt prior to Sm. The samples with low partial melting degree (i.e., the WJG basalts) are apt to have higher La/Sm ratios and La contents than those samples with high partial melting degree (i.e., the ZD basalts and other samples).
In general, we propose that the ZD and WJG basalts were erupted from similar magma source with small amount of crustal contamination, and the compositional difference between the ZD and WJG basalts is the result of different partial melting degrees.4.2 Mineral Evidences for the Magma Mixing Processes
Most previous studies on the Sanshui Basin were based on geochemical analysis of whole-rock. The whole-rock composition is the combination of mineral phenocryst and matrix compositions, which might be affected by several different crystallization and mixing processes. However, minerals are more sensitive to sudden modifications in the melt, and may record information in their textural and compositional zoning patterns (Chen et al., 2016; Li et al., 2016; Viccaro et al., 2010; Salisbury et al., 2008; Davidson et al., 2007; Ginibre and Wӧrner, 2007; Ginibre et al., 2002a, b). On basis of the whole-rock chemical analysis above, the WJG and ZD basalts show differences in major and trace elements concentrations. These compositional differences may be generated by the different mineral constitutions. For better understanding the differences between the WJG and ZD basalts, electron probe X-ray micro-analysis (EPMA) on phenocryst compositions are conducted, which will be a powerful tool for distinguishing different processes during the crystallization.4.2.1 Different mineral compositions
On basis of EPMA analysis, the WJG and ZD basalts have different mineral compositions. All analyzed pyroxene phenocrysts in the WJG basalts are calcium-rich clinopyroxene (Cpx) (CaO: 18 wt.%–21 wt.%), and are categorized as diopside. However, two types of pyroxenes with different calcium contents are found in the ZD basalts. One is similar to the WJG basalt's Cpx, and the other is orthopyroxene (Opx) with extremely low calcium contents (CaO less than 2 wt.%).
Beside compositions, the two kinds of pyroxene phenocrysts show different mineral shapes. Using backscattered electron (BSE) image observations, it can be seen that most Opx phenocrysts in the ZD basalt develop 100 μm wide spongy textured rims (Fig. 6a), which are not observed around Cpx phenocrysts. Based on chemical analysis, these rims show high Ca and low Mg, and are comparable to the groundmass around the Opx phenocrysts. These kinds of rims were commonly found in mantle xenoliths, which were formed by magma mixing during mantle uplifting (Shaw et al., 2006). When minerals are deprived, the compositional imbalance between minerals and melt may lead to chemical reaction on the mineral surface, resulting in spongy textured rims. Thus we believe that the ZD basalts might suffered magma mixing process during crystallization, and those Opx phenocrysts might be derived from the mixed magma.4.2.2 Zoned clinopyroxene phenocryst: implications for the magma mixing processes
Beside the different mineral constitution, the magma mixing process has also been recorded by some Cpx phenocrysts in the ZD basalts. On basis of observation by BSE and polarized-light microscope, some Cpx phenocrysts with obvious zones are observed in the ZD basalts (Fig. 7), while this phenomenon is not observed in the WJG basalt.
For these zoned Cpx phenocrysts in the ZD basalts, liner scan of EPMA is conducted to obtain 57 compositions, and four zones (rim, Zone 1, Zone 2 and core) are divided by these compositions. Most of the core and rim's points have similar compositions; however, Zone 1 and Zone 2 have wide variation in compositions (Fig. 8). Compared with other zones, Zone 2 has highest MgO (13.92 wt.%–16.28 wt.%) and CaO (18.80 wt.%–20.69 wt.%) (Table S1).
On basis of comparison between these four zones, three obvious compositional variations can be distinguished. The first one (Step 1) is between the core and Zone 2. From point 17, the significant increase in MgO accompanies the decrease in CaO, FeO, and Al2O3, and their Mg# (100×MgO/(MgO+TFeO)) and Ti/Al display a rapid rise and decline, respectively. The second one (Step 2) is between Zone 2 and Zone 1. From point 26, the compositions of points exhibit rapid increase in Al2O3, FeO and CaO, but decrease in MgO. This process is also accompanied with relevant variation in their Mg# and Ti/Al. The third one is (Step 3) between Zone 1 and the Rim. The compositions of the points display slowly shifting in Zone 1, but dramatic fluctuations in the last points (37–41) with rapid decrease in FeO and TiO2. This process may be related to the crystallization of Fe-Ti oxides, which is confirmed by the observation by BSE and polarized-light microscope.
It is widely believed that clinopyroxene's composition varies with the chemistry of its host lava (Leterrier et al., 1982), and the Ti versus Ca+Na discrimination diagram (Fig. 9) is conducted for distinguishing the characteristics of their host lava. Almost all Zone 2 points locate in the tholeiite area with low Ti and low Ca+Na, while points from the other three zones locate in alkaline area. In this regards, the ZD magma commenced crystallization in alkali-basaltic magma, and shifted composition to tholeiite in step 1. Then it turned back to alkaline from Zone 2 to the Rim, in steps 2 and 3. The similar variation is also observed in SiO2 versus Al2O3 diagram (Fig. 10) for distinguishing the alkalinity changing of their host lavas (Nisbet and Pearce, 1977). From the core to Zone 2, the alkalinity shows a sustained decline from alkaline to sub-alkaline. However, it returns to per-alkaline from point 27, and go back to the beginning in Step 3.
Generally speaking, all of these evidences above suggest a similar chemical variation for the formation of the ZD basalts. It started at alkali basaltic core with low MgO and high Ti/Al. Then it influenced by a less alkali magma with higher MgO and lower Ti/Al in Step 1, which lead to the compositional and alkalinity shifting. However, it turned back in steps 2 and 3, which explained the compositional similarity of the core and the Rim.4.3 Magma Chamber under the Sanshui Basin
On basis of the previous studies, plenty of basaltic samples with different ages were collected in a large area in the Sanshui Basin. In this study, the ZD and WJG basalts were collected in two places only 2 km away from each other. On basis of chronology research, they were both erupted in a similar period (57.1–59.7 Ma). In other words, they were highly probably erupted from a unique magma chamber at the similar eruption period, and that explain the similarity in their isotopic ratios (143Nd/144Nd and 87Sr/86Sr). However, these two kinds of basalts have different chemical compositions and mineral constitutions. Furthermore, the zoned Cpx and rimy Opx in the ZD basalt reveal that it experienced the mixing between magmas with different alkalinities, while this mixing process did not occur for the WJG basalt. How could these happen in one magma chamber at the similar time?
Chung et al. (1997) assumed a "double diffusive" magma chamber model, which explains the generation of the Sanshui bimodal volcanism. We believed that this model can also explain the ZD and WJG basalts' contemporary eruption, as well as the zoned Cpx and Opx with spongy-textured rim (Fig. 11).
Firstly, an interface formed in the magma chamber, which generated relatively independent differentiations in the upper and lower chambers, respectively. Two types of magma with different density accumulated in the upper and lower chambers, forming alkaline series and calc-alkaline series rocks (Chung et al., 1997). It is proposed that not only trachyte and rhyolite, but also a small amount of alkali basalt, crystallized in the upper chamber. On the other hand, a huge amount of tholeiitic magma crystallized in the lower chamber. This explains why most of basalts in the Sanshui Basin are tholeiitic, other than alkali.
Following this, small amount of magma mixing occurred between the upper and lower chambers though the interface, which lead to compositional shifting and different mineral constitution in the ZD basalt. This mixing process was recorded by zoned Cpx, and some Opx xenoliths were also captured. These Opx formed the spongy textural rims due to reaction with surrounding alkali-basaltic melt. However, the WJG basalt is irrelevant to this mixing process, whose composition represents typical products in the upper chamber.
Generally speaking, although the ZD and WJG basalts were formed by similar source, and crystallized in the same magma chamber, they show different chemical composition and mineral constitution, which is mainly the consequence of different magmatism processes.5 CONCLUSIONS
(1) Although the Sanshui Basin's ZD and WJG basalts show systematic difference in their chemical compositions, the similarity of their isotopic ratios suggests that they were derived from a similar magma source.
(2) The ZD and WJG basalts have different mineral constitutions. Pyroxene phenocrysts in the WJG basalt are all calcium-rich type, while those in the ZD basalt can be divided into two types with different calcium concentrations.
(3) Opx with spongy textured rim and zoned Cpx are observed in the ZD basalt, which indicates mixing between magmas with different alkalinities.
(4) A magma chamber under the Sanshui Basin is proposed with alkaline and calc-alkaline magma accumulating in upper and lower chambers, and formed alkali-basalt and tholeiite, respectively. Furthermore, small amount of magma mixing occurred between these two magmas, which lead to the different chemical compositions and mineral constitutions of the ZD and WJG basalts.ACKNOWLEDGMENTS
We thank Prof. Qi Li, Drs. Shu-Ying Yang, Ye Jin, and Jun-Jie Hu for helping us to collect samples. We also appreciate many suggestions from anonymous reviewers. This study was financial supported by the National Natural Science Foundation of China (Nos. 41276047, 41030853, 41572207, 41440041) and the Special and Frontier Foundation for the Twelve Five Plan of the China Ocean Mineral Resources Research and Development Association (No. DY125-22-QY-21). The final publication is available at Springer via https://doi.org/10.1007/s12583-019-1208-y.
Electronic Supplementary Material: Supplementary material (Table S1) is available in the online version of this article at https://doi.org/10.1007/s12583-019-1208-y.
Bureau of Geology and Mineralogy of Guangdong Province, 1988. Regional Geology of the Guangdong Province. Geology Publishing House, Beijing. 941 (in Chinese)
Chung, S. L., Cheng, H., Jahn, B. M., et al., 1997. Major and Trace Element, and Sr-Nd Isotope Constraints on the Origin of Paleogene Volcanism in South China Prior to the South China Sea Opening. Lithos, 40: 203-220. DOI:10.1016/S0024-4937(97)00028-5
Davidson, J. P., Morgan, D. J., et al., 2007. Microsampling and Isotopic Analysis of Igneous Rocks: Implications for the Study of Magmatic Systems. Annual Review of Earth and Planetary Sciences, 35(1): 273-311. DOI:10.1146/annurev.earth.35.031306.140211
Dong, Y. X., Xiao, L., Zhou, H. N., et al., 2006. Spatial Distribution and Petrological Characteristics of the Bimodal Volcanic Rocks from Sanshui Basin, Guangdong Province: Implication for Basin Dynamics. Geotectonica et Metallogenia, 30: 82-92.
Ginibre, C., Wörner, G., Kronz, A., 2002a. Minor- and Trace-Element Zoning in Plagioclase: Implications for Magma Chamber Processes at Parinacota Volcano, Northern Chile. Contributions to Mineralogy and Petrology, 143(3): 300-315. DOI:10.1007/s00410-002-0351-z
Ginibre, C., Kronz, A., Wörner, G., 2002b. High-Resolution Quantitative Imaging of Plagioclase Composition Using Accumulated Backscattered Electron Images: New Constraints on Oscillatory Zoning. Contributions to Mineralogy and Petrology, 142(4): 436-448. DOI:10.1007/s004100100298
Ginibre, C., Wörner, G., 2007. Variable Parent Magmas and Recharge Regimes of the Parinacota Magma System (N. Chile) Revealed by Fe, Mg and Sr Zoning in Plagioclase. Lithos, 98(1-4): 118-140. DOI:10.1016/j.lithos.2007.03.004
Hou, M. C., Chen, H. D., Tian, J. C., et al., 2007. The Lithofacies-Paleogeographic Character and Evolution of the Sanshui Basin during Cretaceous in Guangdong, China. Journal of Chengdu University of Technology (Science & Technology Edition), 34: 238-244.
Hou, M. C., Lin, L. B., Chen, H. D., 2010. Sedimentary and Tectonic Evolution of Sanshui Basin, Guandong Province. Geology Publishing House, Beijing. 88 (in Chinese)
Huang, Y., Liang, W., Zhang, L. K., et al., 2018. The Initial Break-up between Tethyan-Himalaya and Indian Terrane: Evidences from Late Cretaceous OIB-Type Basalt in Southern Tibet. Earth Science, 43(8): 2651-2663. DOI:10.3799/dqkx.2017.573
Le Maitre, R. W., Streckeisen, A., Zanettin, B., et al., 2002. Igneous Rocks: A Classification and Glossary of Terms. Cambridge University Press, Cambridge
Leterrier, J., Maury, R. C., Thonon, P., et al., 1982. Clinopyroxene Composition as a Method of Identification of the Magmatic Affinities of Paleo-Volcanic Series. Earth and Planetary Science Letters, 59(1): 139-154. DOI:10.1016/0012-821x(82)90122-4
Li, D. M., Chen, W. J., Wang, X., et al., 1989. 40Ar-39Ar Age of Trachyte ZGC from Zoumaying, Nanhaicounty, Guangdong Province. Seismology and Geology, 11: 82-84.
Nisbet, E. G., Pearce, J. A., 1977. Clinopyroxene Composition in Mafic Lavas from Different Tectonic Settings. Contributions to Mineralogy and Petrology, 63(2): 149-160. DOI:10.1007/bf00398776
Ru, K., Piggot, J. D., 1986. Episodic Rifting and Subsidence in the South China Sea. AAPG Bulletin, 70(9): 1136-1155. DOI:10.1029/jb091ib10p10513
Salisbury, M. J., Bohrson, W. A., Clynne, M. A., et al., 2008. Multiple Plagioclase Crystal Populations Identified by Crystal Size Distribution and in-situ Chemical Data: Implications for Timescales of Magma Chamber Processes Associated with the 1915 Eruption of Lassen Peak, CA. Journal of Petrology, 49(10): 1755-1780. DOI:10.1093/petrology/egn045
Shaw, C. S. J., Heidelbach, F., Dingwell, D. B., 2006. The Origin of Reaction Textures in Mantle Peridotite Xenoliths from Sal Island, Cape Verde: The Case for "Metasomatism" by the Host Lava. Contributions to Mineralogy and Petrology, 151(6): 681-697. DOI:10.1007/s00410-006-0087-2
Sun, S. S., McDonough, W. F., 1989. Chemical and Isotopic Systematics of Oceanic Basalts: Implications for Mantle Composition and Processes. Geological Society, London, Special Publications, 42(1): 313-345. DOI:10.1144/gsl.sp.1989.042.01.19
Tang, Z. Y., 1984. Relationship of Oil and Gas with Volcanism in Sanshui Basin. Oil & Gas Geology, 5: 89-100.
Tang, Z. Y., 1994. Cretaceous-Eogene Rift Valley-Type Volcanism in Sanshui Basin, Guangdong. Guangdong Geology, 9: 49-54.
Taylor, B., Hayes, D. E., 1983. Origin and History of the South China Basin. In: Hayes, D. E., ed., The Tectonic and Geologic Evolution of Southeast Asian Seas and Islands: Part 2. AGU Geophyscal Monograph Series, 27: 23–56
Viccaro, M., Giacomoni, P. P., Ferlito, C., et al., 2010. Dynamics of Magma Supply at Mt. Etna Volcano (Southern Italy) as Revealed by Textural and Compositional Features of Plagioclase Phenocrysts. Lithos, 116(1/2): 77-91. DOI:10.1016/j.lithos.2009.12.012
Xiao, L., Zhou, H. N., Dong, Y. X., et al., 2006. Geochemistry and Petrogenesis of Cenozoic Volcanic Rocks from Sanshui Basin: Implications for Spatial and Temporal Variation of Rock Types and Constraints on the Formation of South China Sea. Geotectonica et Metallogenia, 30: 72-81.
Zhu, B. Q., Wang, H. F., Chen, Y. W., et al., 2004. Geochronological and Geochemical Constraint on the Cenozoic Extension of Cathaysian Lithosphere and Tectonic Evolution of the Border Sea Basins in East Asia. Journal of Asian Earth Sciences, 24(2): 163-175. DOI:10.1016/j.jseaes.2003.10.006
Zhu, B. Q., Wang, H. F., Mao, C. X., et al., 1989. Geochronology of and Nd-Sr-Pb Isotopic Evidence for Mantle Source in the Ancient Subduction Zone beneath Sanshui Basin, Guangdong Province, China. Chinese Journal of Geochemistry, 8(1): 65-71. DOI:10.1007/BF02842215
Zou, H. P., 1995. On the Diwa Basin System of Continental Margin Spreading Type and Its Genetic Mechanism. Geotectonica et Metallogenia, 19: 303-313.
Zou, H. P., 2001. Continental Marginal Rifting along the Northern South China Sea: The Crustal Response to the Lower Lithospheric Delamination. Martin Geology & Quaternary Geology, 21: 39-44.