This book presents basic knowledge and key objectives of research of geological, geochemical, and microbial properties and processes in travertines, carbonate deposits precipitated from calcareous hot springs. Much of the contents are based on the authors' researches performed in Japan and Indonesia over the last decade. Travertine is one of the most active sedimentary systems, which have a potential impact on the Earth's environment. It is also an accessible epitome of the Earth's history, cultivating ancestral bacteria and representing a modern analog for ancient stromatolites. Readers can learn how integration of various scopes and methods unveils mysterious phenomena in travertine and can find clues for considering the early history of the Earth and life. This book includes a monographic chapter on Japanese onsens, or hot springs, which may help tourists to select the best places to enjoy the unique features of travertine.
About the Author:

Professor Akihiro Kano is the head of the Laboratory of Historical Geology in the Department of Earth and Planetary Science, The University of Tokyo. He researched carbonate sedimentology during his master's degree study at Tohoku University and his doctoral study at Stockholm University in 1990. While he was working at Hiroshima University (1990-2008), he did intensive research of the sedimentology and geochemistry of freshwater carbonate deposits, or tufas. He started his research on travertines in 2003, and one of his early studies with Dr. C. Takashima successfully revealed that travertine lamination occurred daily. His appointment at Kyushu University in 2008 activated his travertine studies on the island of Kyushu, where a number of hydrothermal sites produce travertine. He moved to The University of Tokyo in December 2016. In addition to travertines and tufas, he is currently working with projects on stalagmite paleoclimatology, gas hydrates in the Japan Sea, and Ediacaran carbonate deposits in China and Brazil.

Dr. Tomoyo Okumura is an assistant professor at the Center for Advanced Marine Core Research, Kochi University. Before taking up her current position, she worked at Kyushu University, The University of Tokyo, and the Japan Agency for Marine-Earth Science and Technology (JAMSTEC) as a postdoctoral fellow. She has made significant contributions in the geomicrobiology of modern carbonate sediments at hot springs in Japan, Indonesia, and the U.S.A. Dr. Okumura is interested in understanding how microbes contribute to or are associated with microbialites such as stromatolites, thrombolites, and fenestrate microbialites. She applied molecular biological techniques, geochemical analysis, and fluorescence staining for the carbonates. Her current research topics extend to deep-sea sediments in order to understand microbe-sediment interaction in aphotic chemosynthetic environments.

Dr. Chizuru Takashima is an associate professor at the School of Education (earth science) at Saga University. Her specialties are carbonate sedimentology and geomicrobiology. Her background study was in the sedimentology of microfossils in limestone and deep-sea coral mounds, and she has extended her research topics to hydrothermal iron deposits resembling Precambrian banded iron formations (BIFs). Recently, she investigated the interaction of spring water, mineral precipitates, and microbes in domestic and foreign hydrothermal environments with sedimentological, geochemical, and biological approaches to elucidate the processes of Precambrian deposits. With the co-authors of this book, she has published articles related to the process of daily lamination in travertines contributed by cyanobacterial metabolism and laminations in iron-rich travertines induced by iron-oxidizing bacteria.

Dr. Fumito Shiraishi is an assistant professor in the Department of Earth and Planetary Systems Science, Graduate School of Science, Hiroshima University. He received his bachelor's and master's degrees in geology at Hiroshima University, studying Japanese Mesozoic limestones using paleontological and geochemical techniques. He received a Dr. rer. nat. under the supervision of Professor Gernot Arp at the University of Göttingen (Germany) in 2008, studying German recent tufa deposits, using geochemical and microbiological techniques. Thereafter, he worked as a postdoctoral fellow at Hiroshima University, then as a Japan Society for the Promotion of Science (JSPS) research fellow at Kyushu University, and continued studying recent calcified biofilms in these positions. Since November 2011, he has been an assistant professor at Hiroshima University. His present research also focuses on non-carbonatemicrobial deposits (including phosphate iron oxides, manganese oxides, and siliciclastics) to elucidate Earth and life evolutions. He has published several papers in established science journals, and he has co-authored a book on travertine, GEOBIOCAL Atlas (Brazil Publishing 2016).