The petrology of oolitic phosphorites from Esprit (Aldabra), western Indian Ocean

1980 ◽  
Vol 288 (1032) ◽  
pp. 511-540 ◽  
Keyword(s):  
Indian Ocean ◽  
Water Table ◽  
Primary Source ◽  
Western Indian Ocean ◽  
Fibrous Structure ◽  
Present Position ◽  
Fine Grained ◽  
History Of ◽  
Internal Sediments ◽  
Cubic Forms

The island of Esprit, at the western end of Aldabra lagoon, is capped by two groups of phosphorites. Near the summit, bedded deposits rest on and in cavities within the subaerially eroded surface of the limestones forming the island. The limestones themselves have not been phosphatized. On the lower slopes, and derived from the phosphorites above, are small outcrops of coarse, phosphate-cemented, bioclastic sediments and large, irregular fans of phosphoritic conglomerates. The phosphorites can be divided into five petrographic groups. Oolitic phosphorites are the most common and are apparently primary. Associated with them are lithoclast-bearing rocks, fine-grained phosphorites, bioclastic deposits and internal sediments, all of which are also wholly phosphatic. There have been numerous reworking episodes in the history of these rocks, such that large volumes now consist only of phosphatic cement sequences (the linings of former cavities) and internal sediments. Up to fourteen changes in the depositional milieu can be seen. The distribution of both cements and internal sediments is restricted, recording the paths of particular transport streams in groundwaters. The minerals identified are carbonatian hydroxyfluorapatites. Most cements are multilayer colloform crusts with a radially fibrous structure, but, in addition, crystals show a range of morphologies, including hexagonal, monoclinic and cubic forms. Some cements are carbonate, but other minerals that may have been present have been pseudomorphed by phosphates. The primary source of the phosphate in these rocks is thought to have been avian guano, deposited on a limestone surface at a time when sealevel was 7-8 m above its present position. Phosphate-rich derivatives from this were carried downwards by surface-wash processes and precipitated in a series of caves in the limestones excavated at the water table and drained as sealevel fell. Solution pipes were formed when sealevel was at least 1-2 m below its present position, but marine coquinal sediments deposited within these suggest that it was subsequently higher. Continued erosion of the host limestones, destroying the caves, released both phosphorite detritus, redeposited as the low-level sediments and transported into beach calcarenites, and phosphatic solutions for precipitation as cements. The phosphorites are tentatively dated as deposited 170-230 ka B.P .

Editorial Introduction

2020 ◽  
Vol 4 (1) ◽  
pp. 1
Author(s):  
Editors of the JIOWS
Keyword(s):  
Nineteenth Century ◽  
Indian Ocean ◽  
Western Indian Ocean ◽  
Late Nineteenth Century ◽  
Fourth Volume ◽  
History Of ◽  
The Indian Ocean ◽  
Complex Relationships ◽  
Indian Ocean World ◽  
Shed Light

The editors are proud to present the first issue of the fourth volume of the Journal of Indian Ocean World Studies. This issue contains three articles, by James Francis Warren (Murdoch University), Kelsey McFaul (University of California, Santa Cruz), and Marek Pawelczak (University of Warsaw), respectively. Warren’s and McFaul’s articles take different approaches to the growing body of work that discusses pirates in the Indian Ocean World, past and present. Warren’s article is historical, exploring the life and times of Julano Taupan in the nineteenth-century Philippines. He invites us to question the meaning of the word ‘pirate’ and the several ways in which Taupan’s life has been interpreted by different European colonists and by anti-colonial movements from the mid-nineteenth century to the present day. McFaul’s article, meanwhile, takes a literary approach to discuss the much more recent phenomenon of Somali Piracy, which reached its apex in the last decade. Its contribution is to analyse the works of authors based in the region, challenging paradigms that have mostly been developed from analysis of works written in the West. Finally, Pawelczak’s article is a legal history of British jurisdiction in mid-late nineteenth-century Zanzibar. It examines one of the facets that underpinned European influence in the western Indian Ocean World before the establishment of colonial rule. In sum, this issue uses two key threads to shed light on the complex relationships between European and other Western powers and the Indian Ocean World.

scholarly journals Bat coronavirus phylogeography in the Western Indian Ocean

2019 ◽  
Author(s):  
Léa Joffrin ◽  
Steven M. Goodman ◽  
David A. Wilkinson ◽  
Beza Ramasindrazana ◽  
Erwan Lagadec ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Phylogenetic Analyses ◽  
Strong Association ◽  
Western Indian Ocean ◽  
Reunion Island ◽  
High Genetic Diversity ◽  
Soil Fertilization ◽  
Réunion Island ◽  
History Of ◽  
Bat Coronavirus

AbstractBats provide key ecosystem services such as crop pest regulation, pollination, seed dispersal, and soil fertilization. Bats are also major hosts for biological agents responsible for zoonoses, such as coronaviruses (CoVs). The islands of the Western Indian Ocean are identified as a major biodiversity hotspot, with more than 50 bat species. In this study, we tested 1,013 bats belonging to 36 species from Mozambique, Madagascar, Mauritius, Mayotte, Reunion Island and Seychelles, based on molecular screening and partial sequencing of the RNA-dependent RNA polymerase gene. In total, 88 bats (8.7%) tested positive for coronaviruses, with higher prevalence in Mozambican bats (20.5% ± 4.9%) as compared to those sampled on islands (4.5% ± 1.5%). Phylogenetic analyses revealed a large diversity of α- and β-CoVs and a strong signal of co-evolution between CoVs and their bat host species, with limited evidence for host-switching, except for bat species sharing day roost sites.ImportanceThis is the first study to report the presence of coronaviruses (CoVs) in bats in Mayotte, Mozambique and Reunion Island, and in insectivorous bats in Madagascar. Eight percent of the tested bats were positive for CoVs, with higher prevalence in continental Africa than on islands. A high genetic diversity of α- and β-CoVs was found, with strong association between bat host and virus phylogenies, supporting a long history of co-evolution between bats and their associated CoVs in the Western Indian Ocean. These results highlight that strong variation between islands does exist and is associated with the composition of the bat species community on each island. Future studies should investigate whether CoVs detected in these bats have a potential for spillover in other hosts.

Gujarat in the History of the Indian Ocean

2019 ◽  
pp. 52-67
Author(s):  
Lakshmi Subramanian
Keyword(s):  
Indian Ocean ◽  
Western Indian Ocean ◽  
Maritime History ◽  
Historical Knowledge ◽  
History Writing ◽  
New Methods ◽  
History Of ◽  
The Indian Ocean

This chapter takes a stock taking exercise of the history writing on Gujarat and Indian maritime history over the last five decades. It identifies the major shifts and emphases that mark the nature of historical knowledge. What these hold for the discipline of history in general and how these inflect the case study of Gujarat in particular are examined. The intention of such a stock taking exercise is also to consider the importance of recovering and reading new and local archives and of incorporating new methods into standard historical work. The author also explores the most significant shifts that have emerged in the recent historiography of the Indian Ocean and of maritime Gujarat: study of law and piracy and Muslim seafaring and sailing practices in the western Indian Ocean.

Gene flow and demographic history of the mangrove crab Neosarmatium meinerti: A case study from the western Indian Ocean

2010 ◽  
Vol 86 (2) ◽  
pp. 179-188 ◽  
Author(s):  
Lapo Ragionieri ◽  
Stefano Cannicci ◽  
Christoph D. Schubart ◽  
Sara Fratini
Keyword(s):  
Gene Flow ◽  
Indian Ocean ◽  
Demographic History ◽  
Western Indian Ocean ◽  
Mangrove Crab ◽  
History Of

Phylogeography of the introduced speciesRattus rattusin the western Indian Ocean, with special emphasis on the colonization history of Madagascar

2010 ◽  
Vol 37 (3) ◽  
pp. 398-410 ◽  
Author(s):  
Charlotte Tollenaere ◽  
Carine Brouat ◽  
Jean-Marc Duplantier ◽  
Lila Rahalison ◽  
Soanandrasana Rahelinirina ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Western Indian Ocean ◽  
Colonization History ◽  
History Of

Indian Merchants and the Western Indian Ocean: The Early Seventeenth Century

1985 ◽  
Vol 19 (3) ◽  
pp. 481-499 ◽  
Author(s):  
Ashin Das Gupta
Keyword(s):  
Seventeenth Century ◽  
Indian Ocean ◽  
Economic History ◽  
Western Indian Ocean ◽  
Ocean Area ◽  
European Expansion ◽  
History Of ◽  
The Indian Ocean ◽  
Work Done

Researches in Indian economic history have stimulated curiosity about India's connections with the Indian Ocean area. Work done on European expansion in the non-European world has also contributed to the development of this area of enquiry. Recent writings on the Indian Ocean and the Indian maritime merchant have indicated important possibilities of further research. I shall first briefly consider some of these, and then pass on to an examination of a concrete historical problem where Indian economic history meets the history of European expansion and the two themes are held together by the Indian Ocean.

scholarly journals Negotiating Identity and Belonging in the Western Indian Ocean: Fluid Enabling Spaces in M.G. Vassanji’s Uhuru Street

2021 ◽  
pp. 27-46
Author(s):  
Dolors Ortega ◽  
Keyword(s):  
Short Stories ◽  
Indian Ocean ◽  
Short Story ◽  
Western Indian Ocean ◽  
Cross Cultural ◽  
Short Story Cycle ◽  
Indian Community ◽  
History Of ◽  
Story Cycle

This article analyses the short story cycle Uhuru Street, which describes the life of the members of the minority Ismaili community, whom Vassanji fictionalises as Shamsis, in the context of crucial changes in the history of Tanzania. Diaspora, fragmentation and ethnic multiplicity in a really hierarchical tripartite society will be studied within the framework of cross-cultural networking in the Western Indian Ocean, where complex identity relations are established. Our discussion stems from a brief historical genealogy of the Indian community in Tanzania, it analyses the complex identity relations and affiliations among Tanzanian citizens of Indian descent, and moves on to the analysis of Vassanji’s short stories in order to explore those fluid and enabling spaces where identity and belonging are to be negotiated.

Historical records of Indian Ocean giant tortoise populations

1979 ◽  
Vol 286 (1011) ◽  
pp. 147-161 ◽  
Keyword(s):  
Indian Ocean ◽  
Western Indian Ocean ◽  
Historical Records ◽  
History Of ◽  
Ocean Islands

Historical records from the seventeenth to the nineteenth centuries indicate that giant tortoises became extinct on many western Indian Ocean islands during this period, and that by 1900 the surviving population on Aldabra was very small. These data are reviewed, the causes of decline and extinction discussed, and the implications for the history of the Aldabra population are considered.

New Thoughts on the Use of Chinese Documents in the Reconstruction of Early Swahili History

1995 ◽  
Vol 22 ◽  
pp. 349-358 ◽  
Author(s):  
John Shen
Keyword(s):  
East Africa ◽  
Ming Dynasty ◽  
Primary Source ◽  
Western Indian Ocean ◽  
Potential Contribution ◽  
Original Text ◽  
East African ◽  
Long Time ◽  
History Of ◽  
Chinese Texts

For a long time, scholars have known that the ancient Sino-East Africantrade relationship produced valuable accounts of East Africa in the Chinese imperial archives. Particularly, the historical documents compiled during the T'ang, Sung, and Ming dynasties contain several insightful snapshots of East Africa over the span of 800 years. Unfortunately, due to the difficulty of translating ancient Chinese texts, scholars have not been able to utilize these documents fully. In other cases, scholars have misused the translations to derive conclusions that may not be supported by the original text. In this essay I propose to re-examine the original Chinese sources and the way these sources have been used by subsequent scholars. Furthermore, I shall explore the real or potential contribution of these texts to our understanding of East African coastal history.The primary source of Chinese knowledge about East Africa during the T'ang dynasty (618-907) comes from Ching–hsing Chi (“Record of Travels”) and Yu–yang Tsa–tsu (“Assorted Dishes from Yu–yang”). During the Sung dynasty (960-1279), most of the information is recorded in Chu-fan-chih (“Gazetteer of Foreigners”) and Ling–wai Tai–ta (“Information from Beyond the Mountains”). Finally, the record of the Ming (1368-1644) naval expedition into the western Indian Ocean is preserved in Wu–pei–chih (“Notes on Military Preparedness”), Hsing–ch'a Sheng–lan (“Triumphant Vision of the Starry Raft”), and Ming Shih (“History of the Ming Dynasty”).

scholarly journals The genetic history of Mayotte and Madagascar cattle breeds mirrors the complex pattern of human exchanges in Western Indian Ocean

2021 ◽  
Author(s):  
Jessica Magnier ◽  
Tom Druet ◽  
Michel Naves ◽  
Melissa Ouvrard ◽  
Solene Raoul ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Western Indian Ocean ◽  
Physiological Adaptation ◽  
12Th Century ◽  
Tropical Conditions ◽  
African Populations ◽  
Population Sizes ◽  
History Of ◽  
And Behavior ◽  
Ocean Islands

Despite their central economic and cultural role, the origin of cattle populations living in Indian Ocean islands still remains poorly documented. Here, we unravel the demographic and adaptive histories of the extant Zebus from the Mayotte and Madagascar islands using high-density SNP genotyping data. We found that these populations are very closely related and both display a predominant indicine ancestry. They diverged in the 16th century at the arrival of European people who transformed the trade network in the area. Their common ancestral cattle population originates from an admixture between an admixed African zebu population and an Indian zebu that occurred around the 12th century at the time of the earliest contacts between human African populations of the Swahili corridor and Austronesian people from Southeast Asia in Comoros and Madagascar. A steep increase of the estimated population sizes from the beginning of the 16th to the 17th century coincides with the expansion of the cattle trade. By carrying out genome scans for recent selection in the two cattle populations from Mayotte and Madagascar, we identified sets of candidate genes involved in biological functions (cancer, skin structure and UV-protection, nervous system and behavior, organ development, metabolism and immune response) broadly representative of the physiological adaptation to tropical conditions. Overall, the origin of the cattle populations from Western Indian Ocean islands mirrors the complex history of human migrations and trade in this area.

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