Green Grotto Caves EarthCache

Located on Jamaica’s north coast between two towns with the romantic names of Runaway Bay and Discovery Bay, lies the Green Grotto Caves. Named for the green algae that cover its walls, the caves have a long connection with Jamaican history. With a length of 1,525 metres and a depth of 12 metres the cave is character by numerous chambers and light holes and a subterranean lake.

Jamaica first formed 80 -100 million years ago through a series of volcanic activities that laid down the oldest igneous and metamorphic rocks of the Inliers. Gradual subsidence during the Eocene marked the deposition of shale, sand, clay and impure limestone, identified as Yellow Limestone. As subsidence continued, shallow submarine banks encouraged the growth of coral reefs and the subsequent deposition of the very pure White Limestone Group. It is generally accepted that the Jamaican landmass was completely submerged from the mid-Eocene to the late Oligocene or early Miocene (40-25 million years ago). The island reemerged by tectonic uplift of the Caribbean Plate and the geology stabilised at its present size 10-12 million years ago.

Various blocks and belts have been recognised in Jamaica and are mainly based on the different rocks that comprise the White Limestone Group. The blocks are composed of shallow-water White Limestone rocks and the belts by deep-water White Limestone rocks; the different rocks can be identified based on the fossils that they contain. The shallow-water White Limestone contains abundant larger benthic foraminifers together with

corals, algae and molluscs, which lived within the photic zone. The deep-water White Limestone contains planktic foraminifers and radiolarians. Smaller benthic foraminifers, ostracods and fish teeth demonstrate that the deep-water White Limestone was deposited in water depths of 2,000 m or more.

What do you have to do? Answer the 3 questions and send them via e-mail (Heidschnucke43@outlook.de) at FIRST to me!

First: At stage 1 you see which form of the limestone is responsible for the formation of the cave. Is it the shallow-water White Limestone or the deep-water White Limestone? And second: What type of fossil can you see? Write it to me!

The History of Jamaica is everywhere. Between two anchors you see ..... what? (You find the answer outside of the cave!)

Optional: Take a picture of you and your GPS at the entrance or at the "limbo hole" (Please with distance to the rocks!)

You can log immediately. Should something not correct I will contact you promptly then we can remove the mistake together......

Have Fun!

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