STRUKTUR SEDIMEN

Struktur sebelum endapan

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Struktur sebelum endapan boleh ditemui di atas lapisan, sebelum lapisan atau endapan yang muda atau baru di endapkan. Ia adalah struktur hasil hakisan seperti terusan (channel), 'scour marks', 'flutes', 'grooves', 'tool marking' dan sebagainya. Struktur-struktur ini sangat penting kerana ia juga boleh memberikan arah aliran arus.

Sharp bedding boundary between ss and sh. Borden Fm, Kentucky

Modern raindrop impressions on mudcracks

Mudcracks or synaeresis cracks? Powder River Basin

Sole marks. Miocene ss, El Tajin, Mexico

Load casts. Mississippian Borden Fm

Dinosaur tracks enhanced by yellow chalk. Triassic

Trails of Crawling organisms

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Struktur semasa endapan

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Struktur yang terbentuk semasa proses endapan sedang berlaku termasuklah lapisan mendatar (flat bedding), lapisan silang, laminasi, dan laminasi silang yang mikro (micro-crosslamination), iaitu kesan riak.

Sandstone and interbedded shale, some grading between layers. Pennsylvannian of Kentucky

Large scale cross-stratification tabular sets and cosets with tangential lower boundary. Jurassic Navajo SS, Zion Canyon

Small scale cross-stratification with tabular sets with tangential lower boundary. Cretaceous Middendorf Formation

Flow transverse section of multiple trough cross-stratification. Permian Schnebly Hlls Fm., Oak Creek Canyon, Arizona

Herringbone x-stratification

More sutle hummocky cross-stratification. Cretaceous Frontier Fm. Powder River Basin, Wyoming

Ripples or antidunes? Note steeper slope on "eroded" side and gentler slope on "depositional" slide

Wave ripples in Cretaceous ss. San Juan Basin, New Mexico

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Struktur selepas endapan

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Struktur ini terbentuk selepas sedimen terendap. Ini termasuklah struktur beban, 'pseudonodules' dimana sebahagian lapisan pasir jatuh dan masuk kedalam lapisan lumpur di bawahnya, laminasi konvolut (convolute lamination) dan sebagainya. Struktur nendatan, hasil dari pergerakan mendatar sedimen yang membentuk lipatan juga termasuk dalam struktur selepas endapan. Nendatan boleh berlaku di tebing sungai, delta dan juga laut dalan dan ianya sangat berguna untuk menentukan arah cerun kuno.

Convolute laminations.Gravity deformation aided by liquafaction

Deformed cross-bedding

Dewatering structure

Modern example of liquafaction induced deformation, Rio Grande du North, Brazil

Internal structure of liquafaction induced deformation, Rio Grande du North, Brazil

dike in a turbidite sequence injected from overpressed sand layer. Eocene of northern CA

Dish structure formed by dewatering

Partly destroyed bedding by burrowing organisms. Carboniferous of Scotland

Concretion, note bedding faintly preserved. Devonian shale, Eagle Rock