Abstract
This study describes the traditional Japanese Suminagashi paper marbling technique in an unusual, non-artistic way based on observations in nature (El Chichón crater lake, Chiapas, Mexico) and supported by physical processes such as wave action and Marangoni flow. It is the first time that these seemingly unrelated phenomena are linked. We show how clays floating on the surface of the El Chichón crater lake bear a strong resemblance to Suminagashi patterns. Clays rise from the lake bottom by vigorous bubbling of gases or thermal convection. After floating on the water surface due to capillary forces, the clays are transported towards the lake shore by wind-generated waves. The clay-covered lake surface is subject to Marangoni flow when the lake becomes very shallow (a few centimetres) near the lake shore. The flat lake bottom and the dynamic alternation between retreat and incurrence of the lake shore consequently result in the precipitation of the clay patterns, preserving the Suminagashi-like designs in the lake sediments. Recognition of similar patterns in the sedimentary record could indicate the presence of a shallow sedimentary environment in the past, possibly pointing to a heated crater lake.
As always occurs in science and the arts, physical laws and artistic creativity find their origin in nature. This study focuses on three main features that do not initially seem to match: the El Chichón crater lake (Chiapas, Mexico), Suminagashi and Marangoni flow.
Suminagashi means ‘spilled ink’ in Japanese, and refers to a marbling technique of decorating paper by impregnation of an ink pattern floating on a water surface (Guyot 1988; Chambers 1991; Canovi 2004) (Fig. 1a). The first Suminagashi prints were exhibited to Emperor Shirakawa in 1118, and represented a poetry anthology named Poetical Works of Thirty-Six Men or Sanjūrokunin Kashū (Chambers 1991). In this work at least four sheets of Suminagashi were recognized. Since the Heian Period (794–1185) until World War II, the secret of Suminagashi production remained strictly guarded by the Hiroba family, a father-to-son transmission method typical for Japanese arts. During the Edo Era (1603–1867), the Era of Paper, the Japanese paper industry and Suminagashi grew in importance, under the protection of the Shogun rules (Chambers 1991). Owing to the continued Hiroba monopoly, Suminagashi was never really transmitted to common artists, resulting in an almost complete disappearance to date. For this reason, contemporaneous Japanese artists, often amateurs, learned Suminagashi autodidactically by trial-and-error. While Kanji Kariya sticks more to the traditional techniques, Soseki Asami and Takaji Kuroda apply a more experimental and scientific approach to Suminagashi (Chambers 1991). Asami stressed the importance of surface tension behind the Suminagashi process (Chambers 1991).
(a) Suminagashi print (source: http://www.shodo.it/shikishi-catalogo/pagine/suminagashi.html). (b) Suminagashi-like patterns on the surface of the El Chichón crater lake.
The ink patterns are generated on thin water layers, following well-defined physical processes: wave action and the thermal Marangoni effect (Scriven & Sternling 1960; Birikh & Mazunina 2009; Tadmor 2009). Marangoni flow is the movement or surface spreading in a fluid interface caused by local variations in surface tension that are caused in turn by differences in composition or temperature (Scriven & Sternling 1960) that create gradients.
El Chichón crater lake is a large and shallow steam-heated pool, and hence is subject to thermal and density gradients (Rouwet et al. 2008; Taran & Rouwet 2008; Rouwet 2011). The resemblance between the patterns created by floating clays on the surface of El Chichón crater lake and the drawings resulting from the Suminagashi printing technique is striking (Fig. 1a, b). In this study we aim to describe the process of remobilization of clay from the bottom of the crater lake, transportation on and deposition from the surface until final sedimentation at the lake shores. Marangoni is the eventual process and the ‘glue’ between volcanology and the arts. Ideas from this study could direct future research. Following the principle of ‘the present is the key to the past’, recognizing similar patterns in the sedimentary record in a volcano crater could indicate the presence of an active crater lake in the past.
El Chichón crater lake
The chemical monitoring and understanding of mass–energy transfers of crater lakes, windows into the deeper part of volcanic-hydrothermal systems, have helped us to recognize volcanic unrest and forecast eruptions (Rowe et al. 1992; Christenson 2000; Ohba et al. 2008; Rouwet et al. 2014a, b). The El Chichón crater lake (Chiapas, Mexico; Fig. 2) appeared immediately after the March–April 1982 Plinian eruptions, and has demonstrated cyclical behaviour during the past approximately 20 years, alternating lake volume increase with shrinkage due to the periodical input of saline boiling water from a geyser-like spring north of the lake (2001, 2004, 2007, 2009–10, 2014) (Rouwet et al. 2008; Taran & Rouwet 2008; Rouwet 2011). El Chichón crater lake is one of the largest (c. 105 m3) steam-heated acid sulphate pools on Earth (240–1000 mg SO4 l−1, and pH ∼2.3) (Rouwet et al. 2008). The lake bottom is covered with clay fraction sediments, which are partly transported to the lake surface by the vigorous rise of bubbling gases (Fig. 2). The fumarolic field north of the lake is periodically flooded by the lake, and hence is subject to intense bubbling degassing during such stages. Floating clay particles are especially abundant in this area (Fig. 2).
The northern shore of El Chichón crater lake, where Suminagashi patterns are most abundant. Intense bubbling degassing (lower picture) is located by the blue arrow. Note the macro-scale Suminagashi patterns in the top centre of the upper picture. Inset: location map of El Chichón volcano. Vi, Villahermosa; TG, Tuxtla Gutiérrez; SC, San Cristóbal de Las Casas; CAVA, Central American Volcanic Arc.
Suminagashi
The technique of Suminagashi consists of dropping sumi, Chinese ink, on a still water plane in a shallow tray (Fig. 3a). The floating ink is moved by breathing or blowing on the water surface (Canovi 2004). The colours used in Suminagashi are the classic black and red, sometimes combined with indigo and orange. While the water should be as pure as possible, inks are mixed with additives (e.g. fish glue), fixatives (such as ferrous sulphates, aluminium chloride or aluminium acetate) and dispersants (e.g. lotions, pine resin), to control the spreading, solidification and surface tension of the inks. After the desired pattern appears, hand-made Japanese paper (washi) is carefully placed on top of the water surface, transferring the pattern into the paper fibres (Fig. 3b). Each Suminagashi print is unexpected, unique, even mystical (Figs 1a and 3c). Kuroda (2000) mentioned for the first time the effect of Marangoni flow on the floating inks utilized in Suminagashi.
The Suminagashi technique of paper decoration. (a) Sumi is dropped on a still water plane in a shallow tray; (b) Washi is carefully posed on top of the decorated water surface. The paper fibres are impregnated with the ink. (c) The Suminagashi print is cleaned and dried. Pictures are used with permission of Hiromi Miyazaki (Kamism, Kawashima Planning Company).
Marangoni flow
Marangoni flow on the surface of a thin fluid layer results from a surface tension gradient at the interface between two liquids, which originates from a gradient in temperature or chemical composition (Scriven & Sternling 1960; Birikh & Mazunina 2009; Tadmor 2009). If a fluid layer is thin, buoyancy effects become negligible and motion on the fluid surface depends on the thermocapillary or thermal Marangoni effect (Fournier & Cazabat 1992).
The Marangoni effect naturally produces streamer-like patterns, such as observed when wine moves on the inner wall of a glass (tears of wine; Fournier & Cazabat 1992). In this case, the effect results from the lower surface tension of alcohol with respect to water during evaporation when moving as a thin layer on the wall of the glass. When an external temperature gradient is applied to the thin layer, the liquid is forced to convect under non-equilibrium conditions. A heated water layer that evaporates reflects an endothermic condition resulting in vertical thermal stratification, which enhances Marangoni flow on the cooling surface (Borcia & Bestehorn 2005; Dondlinger et al. 2005; Haut & Colinet 2005). This intertwining of processes creates a constantly varying physical state at the liquid surface, emphasized by the surface Marangoni flow.
Marangoni flow is usually mentioned in industrial physics of liquid surfaces. It is clearly manifested when non-soluble surfactants contaminate the liquid surface, which leads to a variety of applications in the dyeing, paint and coating industry, artificial or natural crystal growth, quartz displays and solar cells (wafer drying), space engineering under microgravitational conditions, bacteria movement on liquid surfaces and ophthalmology (Cazabat et al. 1990; Ball 1991; Sazaki et al. 2002; Zhang et al. 2003; Tsai et al. 2010).
Results and discussion
Clay rises towards the lake surface with bubbles
In contrast to Suminagashi, the ‘ink’ at El Chichón crater lake comes from below. Clays sedimented at the lake bottom are transported to the surface by rising bubbles (Fig. 4a). Bubbles often do not break open due to the more viscous clay coating (Fig. 4b, c), even amalgamating into a foam-like mass (Fig. 4c, d) (Kitchener 1962; Bikerman 1973; Yaminsky 2006). Moving Suminagashi-like patterns can be observed on the surfaces of the bubbles (Fig. 4b, c): the rising gas bubble is initially hotter than the surrounding air while it cools at the lake surface, creating differences in surface tension at the bubble surface, generating Marangoni flow on the bubble sphere.
Transportation of clays from the lake bottom toward the lake surface by rising bubbles: (a) vigorous bubble rise at the El Chichón crater lake surface; (b) clay-coated bubbles featuring Marangoni flow at their surfaces; (c) amalgamation of clay-coated bubbles; (d) amalgamation of clay-coated bubbles into a foamy mass. White scale bars indicate approximately 10 cm.
Wind transportation of clays on the lake surface and near-shore Marangoni flow
Bubbles less charged with clays can easily break open from numerous upwellings in the lake (near-shore and centrally), leaving the clay floating on the lake surface (Fig. 5a–c). The first agent to transport the clays on the lake surface is the wind, similar to the blowing or breathing on top of the water surface during Suminagashi printing. As the crater lake is heated from below (Tlake∼30°C) and inevitably cooled at the lake–air interface (Tambient ∼20°C), and the clay is blown toward the shore, the thermal Marangoni effect inevitably becomes dominant when the water depth decreases (Figs 1b & 5b) (Scriven & Sternling 1960). In its turn, the northern shore of the El Chichón crater lake is strongly affected by heat input and bubbles degassing from the submerged fumaroles (Taran & Rouwet 2008), creating the ideal combination of thin water layers, heat and clay input by bubbling (Fig. 2). The gently floating Suminagashi-like patterns are disturbed by larger-scale features such as rising bubbles (Fig. 5b) and touching rocks or grass (Fig. 5c), which generates second-order patterns, such as in the broken Suminagashi patterns by Takaji Kuroda (Chambers 1991). Density and colour differences in the clays create horizontal banded laminations when the clay reaches the lake shore (Fig. 5c).
Wind transportation of clays on the lake surface and Marangoni flow: (a) Marangoni flow patterns interrupted by rising gas bubbles; (b) banded clays reaching the lake shore by wind transportation (note how stones and grass interfere with the clay laminations); (c) banded clays reaching the lake shore by wind transportation. White scale bars indicate approximately 10 cm.
Sedimentation of clays in Suminagashi-like patterns
The natural system of El Chichón crater lake is far from physico-chemical equilibrium and lacks well-controlled conditions strived for during laboratory experiments to ideally describe the Marangoni flow. For the majority of the lake Marangoni flow is overwhelmed by the effect of wind blowing over the lake surface, convection by heat and fluid input from below the lake, intense upwelling, inflow of warm and more saline geyser waters and irregularities of the bottom substrate (e.g. a rocky bottom with sedimentation ripples and funnel-shaped bubble pits) (Rouwet et al. 2008; Taran & Rouwet 2008). Despite the impossibility of quantifying the influence of each of these highly variable factors, Marangoni flow on the clay-coated lake surface becomes visible near the lake shore. Owing to the flat-bottomed shape of the El Chichón lake basin (Rouwet 2011), the near-shore lake water becomes very shallow (in the order of a few centimetres) making Marangoni flow more dominant with respect to the large-scale features observable more centrally in the deeper (several metres) portions of the lake.
In analogy, in the Sanjūrokunin Kashū micas were added to the ink (Chambers 1991). The alteration products in hydrothermal environments are clay minerals. As for micas, the laminar crystal structure (phylosilicates) causes clays to float on liquid surfaces, subject to capillary forces and the thermal and chemical surface gradients affecting Marangoni flow. The micro-scale feature visually demonstrates the endothermic process occurring at evaporating crater lakes, which leads to the lower temperature of the ‘skin’ of the lake surface with respect to the temperature a few centimetres deeper (Oppenheimer 1997). Besides its gracefulness, the ‘Suminagashi-effect’ could thus influence the thermal and evaporative regime of clay-laden crater lakes.
When the lake becomes too shallow (e.g. after the geyser input ceased; Rouwet et al. 2008), it retreats rapidly and clays are forced to deposit (Fig. 6a, b). This process is analogous to the ink impregnation in the washi of Suminagashi, but in the downward direction: the unique clay pattern is ‘frozen’ at the lake shore with the same design as was floating on the lake surface. This creates concentric or laminar patterns as a relict in the sediments (Fig. 6c, d). The semi-regular forms (Fig. 6b, c) are not accidental during Marangoni flow in thin layers (Cazabat et al. 1990; Fournier & Cazabat 1992; Yerushalmi-Rozen et al. 1999; Bestehorn & Colinet 2000). With the alternation between lake shrinkage and growth (Rouwet et al. 2008; Rouwet 2011), this creates laminar sedimentary sequences (varves; Mingram et al. 2004), each stratum topped with its own ‘fossilized’ Suminagashi-like pattern (Fig. 6c). After the formation of desiccation cracks, strata of earlier-deposited sediments become visible (Fig. 6d).
Various Suminagashi-like patterns observed at the El Chichón crater lake shore: (a) concentric laminations; (b) circular laminations around stones; (c) concentric laminations within the dried-out shore sediments; (d) piled sediment layers. White scale bars indicate approximately 10 cm.
Sedimentation rate
Kusakabe et al. (1986) described alternate layers of yellowish, fine-grained sulphur and dark grey clays for an extinct crater lake at Tateyama volcano (Honshu, Japan). They estimated a sedimentation rate for the various layers between 1.3 and 2 mm a−1, which is one order of magnitude higher than for non-volcanic lakes. A different sequence of banded sediments is observed for El Chichón (Fig. 7): no extreme colour difference exists between the various layers, consistent with no observed change in magmatic activity and thus chemistry throughout the young history of the lake; and different strata are distinguished by different grain sizes of the sediments, reflecting varying sedimentary environments (∼lake depth).
Sediment layers at the El Chichón lake shore.
Separate strata are 1–2 cm thick. Considering the extremely fast dynamics of the El Chichón crater lake, with shrinking–growing sequences of 2–3 months (Rouwet 2011) and residence times of lake water of 2 months (Taran & Rouwet 2008) sedimentation rates of 4–12 cm a−1 are estimated (i.e. 4–6 strata per year with each stratum 1–2 cm thick). Rouwet et al. (2008) pointed out that the fast alternation between large (c. 105 m3) and small (c. 104 m3) lake volumes depends on the geyser-like behaviour of the boiling springs feeding the lake in cycles of several months, rather than being related to the difference in seasonal rainfall (the rainy season lasts from June to October, with a total yearly rainfall of about 4000 mm). Sediments from the inner crater walls were only washed into the lake during the first rainy season after the lake formation, right after the March–April 1982 eruptions. Since then, the lake remained an endorheic basin, with its specific internal sedimentation regime (Rouwet 2011). The sedimentation rate for El Chichón is one order of magnitude higher than the estimate for the Tateyama paleo-lake, which probably results from this fast fluid cycling of the boiling spring waters feeding the crater lake (Rouwet et al. 2008), rather than seasonal repetition of environmental conditions of the lake water.
Conclusions
This study combines two non-familiar processes to better describe the sedimentation regime of the dynamic crater lake of El Chichón volcano (Chiapas, Mexico): (1) the Japanese paper technique of Suminagashi; and (2) Marangoni flow, the streamer-like mass movement on the surface of a thin water layer due to a surface tension gradient. Clay-fraction minerals are transported to the lake surface by intense bubbling degassing from the submerged fumarolic field near the shore and from upwellings more centrally in the lake. Wind and waves move the floating clays toward the lake shore, where Marangoni flow takes over to weave patterns of clays on the lake surface. These clay patterns show a very strong resemblance to Suminagashi prints. Subsequent to the frequent retreats of the crater lake, due to the peculiar lake–geyser dynamics of El Chichón hydrothermal system (Rouwet et al. 2008), the Suminagashi-like patterns are quenched in the sediment strata. Sedimentation rates at El Chichón are an order of magnitude higher than at other volcanic lakes (e.g. Kusakabe et al. 1986). The recognition of similar patterns in the sedimentary record of other geological environments might indicate the existence of shallow water bodies (lakes) in the past, occasionally affected by thermal input (volcanic lakes). We hope to have provided an example on how arts can increase alternative, creative thinking that could lead to new scientific insights.
Acknowledgments
We are grateful to Minoru Kusakabe, Yuri Taran and Clive Oppenheimer to encourage us to share this artistic curiosity with the scientific community. Luisa Canovi is thanked for fruitful discussions on the Suminagashi technique. Hiromi Miyazaki (Kamism, Kawashima Planning Co., Ltd) is acknowledged for permission to publish the Suminagashi pictures (Fig. 1). 2006–07 research funding for DR came from Belgische Stichting Roeping; 2012–14 funding for DR came from VUELCO (FP7 Theme: ENV.2011.1.3.3-1; Grant 282759: ‘VUELCO’). Four anonymous reviewers helped to improve the manuscript.
- © 2017 The Author(s). Published by The Geological Society of London. All rights reserved
References
The sedimentation of Suminagashi-like floating clay patterns at El Chichón crater lake (Chiapas, Mexico)
