Cretaceous-Tertiary boundary sequence in the Cacarajicara Formation, western Cuba: An impact-related, high-energy, gravity-flow deposit

Shoichi Kiyokawa, Ryuji Tada, Manuel Iturralde-Vinent, Eiichi Tajika, Shinji Yamamoto, Tetsuo Oji, Youichiro Nakano, Kazuhisa Goto, Hideo Takayama, Dora Garcia Delgado, Consuelo Diaz Otero, Reinaldo Rojas-Consuegra, Takafumi Matsui

研究成果: ジャーナルへの寄稿学術誌査読

26 被引用数 (Scopus)


The Cacarajicara Formation of western Cuba is a more than 700-m-thick calcareous clastic sequence that contains shocked quartz throughout, and spherules. Three members are recognized. The lower member consists of limestone and chert boulders, and disconformably overlies Cretaceous deep-water turbidite. It is characterized by: (1) a grain-supported fabric with only a small amount of matrix, (2) 5-15 cm, well-sorted clasts and occasional boulders, (3) reversely graded, discoidal or rectangular boulders showing a preferred orientation, (4) abundant shallow- and deep-water carbonate clasts in a well-mixed fabric, (5) direct contact between adjacent clasts, and (6) hydrostatic deformation within a black clay matrix. This evidence suggests that the lower member was deposited under conditions of high-density and high-speed laminar flow. The middle member consists of upward graded, massive to well-bedded, homogeneous calcarenite. Unusual fluid-escape structures in the thick calcarenite suggest that this member formed by high-density turbidity suspension. The upper member consists of fine calcarenite mudstone; there is no evidence of bioturbation. We infer that it was deposited from a dilute, low-density suspension. On the basis of these criteria, the Cacarajicara Formation is interpreted to be a single hyperconcentrated flow that was formed by high-energy and high-speed concentrated flow. The south-southeast paleocurrent direction suggests that this high-energy flow originated on the Yucatan platform and was triggered by the Chicxulub impact.We propose that a gigantic flow deposit was induced by earthquake-generated collapse of the Yucatan platform margin owing to ballistic flow from the Chicxulub impact.

ジャーナルSpecial Paper of the Geological Society of America
出版ステータス出版済み - 1月 1 2002

!!!All Science Journal Classification (ASJC) codes

  • 地質学


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