![]() The matrix is micritic, organic rich, and shows calcite sparitization. Very few micritized echinoderm fragments are also observed. The peloids are subangular to subrounded and are poorly to moderately sorted. They show mouldic nature and are filled with fine to medium sized spar. Other bioclasts are lath shaped and angular. The bioclasts, particularly finer ones, show completely micritized character. The monocrystalline quartz silt is randomly oriented, lenticular and equant in shape, angular, sorted, and confined within fine to very fine silt size classes. ![]() The bioclastic arenaceous packstones are composed of 50% grains and 50% argillaceous and micritic matrix. In the LDS, this member is represented by very finely laminated, marly/argillaceous very fine silt. Bedding parallel dark insoluble residue/organic matter, lenticular quartz grains, and angular bioclasts are observed frequently. The rock shows discontinuous, but bedding parallel quartz rich (<40%) and mud-rich layers. These interlayers are found without any break in sedimentation and resulted by increased influx of bioclasts of bivalves and echinoderms. The Gypsiferous Shale Member is composed of bioclastic calcareous very fine silt interspersed with bioclastic arenaceous packstone and occasional arenaceous peloidal bioclastic packstone. (A) Lodai section (B) Fakirwari section (C) Jumara section (D) Jara dome Tr. Lithologs of the three studied sections and position of geochemical samples. The Jumara section (JMS) is located at about 20 km northeast of Matanomadh close to the Jumara village and exposes the DOM and basal part of the Katrol Formation ( Fig. The Fakirwari section (FWS) is located at about 6 km south of Bhuj, along the road to Mundra, exposing the DOM and other members of the Chari Formation ( Fig. The rocks are exposed close to the road 3 km south of Lodai, over a lateral distance of 320 m, showing the occurrences of the Gypsiferous Shale, Dhosa Sandstone, and DOMs of the Chari Formation and basal part of the Katrol Formation ( Fig. The Lodai section (LDS) is a composite section located at northeast of Bhuj in the Habo dome ( Fig. Among various exposures examined, three sections located in Lodai, Fakirwara, and Jumara that contain condensed sections of the DOM are discussed in this paper. This surface is a chronological boundary between Callovian-Oxfordian ( Fürsich et al., 2001) and also a transgressive systems tract surface ( Pandey et al., 2009). The DOM rests over the Dhosa Sandstone Member with a distinct erosional/nondepositional surface. Good exposures are found in Jara, Jumara, Keera, Jhura, and Habo domes/areas, located between southeast of Lakhpat and east of Bhuj ( Fig. It is easily recognizable in the field by its red-colored, well-cemented cap rock and massive amorphous iron crusts at top. As glaciers and polar ice caps started melting 15,000 years ago, flooding of land combined with tidal influence changed the geography of the Keys and their surrounding areas.The DOM is exposed for about 100 km along its strike direction in the Kachchh mainland. The two dominate rock formations in the Keys are Key Largo Limestone and Miami Oolite.ĭuring this time of lower sea levels, the Florida land mass was much larger than it is today and the area now referred to as Florida Bay was forested. They are island remnants of ancient coral reefs (Upper Keys) and sand bars (Lower Keys) that flourished during a period of higher sea levels approximately 125,000 years ago (a period of geologic time known as the Pleistocene Epoch).ĭuring the last ice age (100,000 years ago) sea level dropped, exposing the ancient coral reefs and sand bars which became fossilized over time to form the rock that makes up the island chain today. The Florida Keys are a chain of limestone islands that extend from the southern tip of the Florida mainland southwest to the Dry Tortugas, a distance of approximately 220 miles.
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