Carbonate Petrography

Carbonate petrography is the study of limestones, dolomites and associated deposits under optical or electron microscopes greatly enhances field studies or core observations and can provide a frame of reference for geochemical studies.

25 strangest Geologic Formations on Earth

The strangest formations on Earth.

What causes Earthquake?

Of these various reasons, faulting related to plate movements is by far the most significant. In other words, most earthquakes are due to slip on faults.

The Geologic Column

As stated earlier, no one locality on Earth provides a complete record of our planet’s history, because stratigraphic columns can contain unconformities. But by correlating rocks from locality to locality at millions of places around the world, geologists have pieced together a composite stratigraphic column, called the geologic column, that represents the entirety of Earth history.

Folds and Foliations

Geometry of Folds Imagine a carpet lying flat on the floor. Push on one end of the carpet, and it will wrinkle or contort into a series of wavelike curves. Stresses developed during mountain building can similarly warp or bend bedding and foliation (or other planar features) in rock. The result a curve in the shape of a rock layer is called a fold.

Equipment for Geological Field Work

Following is a list of all equipment that is likely to be needed in the field:

1. Adhesive tape
2. Aerial photographs
3. Altimeter
4. Binoculars
5. Calculator
6. Camera, tripod, film, etc
7. Chemicals for staining rocks
8. Cold chisel
9. Color pencils
10. Colored tape or paint for marking localities
11. Brunton compass or other
12. Drawing Board
13. Erasers
14. Field case for maps and photographs
15. Field glasses
16. First aid kit
17. Flashlight
18. Gloves
19. Gold pan
20. Grain-size card
21. Geologists Hammer
22. Hand lens
23. Dilute Hydrochloric Acid
24. Ink, waterproof; black, brown, blue, red and green
25. Insect repellent
26. Jacob staff
27. Knapsack
28. Lettering set
29. Loose-leaf blinder
30. Magnet
31. Maps, topographic, geologic
32. Microscope
33. Mineral hardness set
34. Field notebooks
35. Paper, lined
36. Paper, quadrille
37. Paper, scratch
38. Pen, drop circle
39. Pen, holders
40. Pen, ruling
41. Pens, ballpoint
42. Pen, inkflow, for photographs
43. Pencils, 3B to 9H
44. Pencil pointer
45. Pick or mattock
46. Pocket knife
47. Protractors
48. Rain gears
49. Rangefinder, Camera
50. Reference library
51. Sample bags
52. Scale, plotting, 6 in.
53. Shovel
54. Stereo-graphic net
55. Tally counter
56. Tape, 6-ft
57. Tape, 100-ft
58. Triangles, drawing
59. Satellite phone
60. Watch

Estwing Hammer and Hand lens

A hammer with a pick or chisel end is used for cleaning exposures, for digging, for breaking rocks, and for trimming samples. Standard geologists hammer have heads weighing 1.5 to 2 lb (0.68 to 0.9 kg) and are adequate for most geologic work. A small sledge--- for example a 2 or 3 lb head on a 14-in. handle may be needed to collect fresh  samples of especially hard rocks.
While using hammer, it is important,
1. to wear safety goggles
2. not to strike heavy blows when people are nearby
3. never to strike one angular rock edges

A cold chisel maybe used with a hammer to split rocks parallel to bedding or foliation and to free fossils or specific mineral samples from unfoliated rocks.

A map holder must be large enough to carry 9*9 in. aerial photographs and should be made of masonite rather than metal( which in uncomfortable to carry) or plastic (which may break when cold).

A scale, used for measuring features or laying off distances on maps and photographs, should have fine, distinct graduation marks that are equivalent to even increments at the map scale used.

A protractor is used for plotting structural symbol maps and for measuring angles between structures in rocks.

A camera, for, photo-geologic interpretation, is an important equipment for geological field work and should be compact and strong. All 35 mm cameras have a great depth of focus than cameras with longer focal length and this is a decided advantage in photographing irregular outcrops at closer range.

Samples bags of cloth or plastic maybe obtained through most suppliers, or bags maybe of extra heavy paper, the variety often used as nail bags.

Hydrochloric acid will be needed and should be diluted just to the strength that causes effervescence of calcite but not dolomite (except when powdered).

Of the hand lenses, 10X and 14X lenses are used most widely. The depth of focus of the 14X lens, however, is only 0.8 mm, whereas that of 10X lens is 2.5 mm.
Good quality triplet lenses typically give excellent images. In testing a lens, and in all other viewing, the following are important:

1. Hold the sample so that the area being viewed is in full light --- in sunlight, if possible.
2. Hold the lens exactly at the distance of sharp focus, with its optical axis perpendicular to the surface being viewed
3. Bring the eye to the point where the eyelashes are mostly touching the lens (this is the only position from which the entire field of view will be sharply and comfortably in focus)