Foundation Unit A.M. THURSDAY, 20 May hour

Transcription

1 Candidate Name Centre Number 2 Candidate Number GCE AS/A level 1211/01 GEOLOGY - GL1 Foundation Unit A.M. THURSDAY, 20 May hour Question 1 Question Question 3 Question 4 Total 60 ADDITIONAL MATERIALS In addition to this examination paper, you will need a copy of the Mineral Data Sheet. INSTRUCTIONS TO CANDIDATES Write your name, centre number and candidate number in the spaces at the top of this page. Answer all questions in the spaces provided in this booklet. INFORMATION FOR CANDIDATES The number of marks is given in brackets at the end of each question or part-question. You are reminded that marking will take into account the use of examples and the quality of communication used in your answers. LH*(S )

2 2 GL1 FOUNDATION GEOLOGY Answer all questions. 1. Figure 1a shows a field sketch of the geology of a cliff face. Figure 1b shows the detail of the fossil coral referred to in Figure 1a. S N rock B rock B deposited A 1 in a desert A fossil plant remains rock sequence C sandstone coal seam Figure 1a location of fossil coral (see Figure 1b) feature D Refer to Figure 1a. Figure 1b (a) Describe the surface A-A 1. [2] (b) (i) Describe the texture of rock B. [3] (ii) Name rock type B. [1]

3 3 (c) (i) Identify feature D shown in the coral in Figure 1b. [1] (ii) Account for the presence of the fossil coral in the desert deposit rock B. [3] (d) A student has incorrectly concluded that the plant fossils in Figure 1a represent a death assemblage. (i) Explain what is meant by a death assemblage. [2] (ii) Explain the evidence which indicates that the student s conclusion is incorrect. [2] (e) Evaluate the statement the fossil coral was originally deposited within rock sequence C. Give reasons for your answer. [3] [Total 17 marks] Turn over.

4 4 2. Figure 2 shows a cross-section of the Grand Canyon in the USA. North Coconino Sandstone South Permian Key: unmetamorphosed Precambrian rocks sandstone shale Redwall Limestone Carboniferous limestone schist and gneiss Q Q 1 F-F fault P Colorado River Cambrian P 1 Not to scale Vishnu Group Precambrian F Figure 2 (a) Many of the rocks in Figure 2 can be dated using their fossil content. The Vishnu Group (schist and gneiss) cannot be dated in this way because it lacks fossils. (i) State two reasons why the Vishnu Group lacks fossils. [2] (ii) With reference to Figure 2, state which one of the following cephalopods (goniatite, ceratite or ammonite) is most likely to be of use in dating the Carboniferous Redwall Limestone. Give a reason for your answer. [2] Cephalopod... Reason......

5 5 (b) Identify the type of dip-slip fault (normal, reverse or thrust) shown in the Precambrian rocks in Figure 2. Give a reason for your answer. [2] Type of fault... Reason... (c) Two geological boundaries P-P 1 and Q-Q 1 are marked on Figure 2. Both are unconformities. (i) State two pieces of evidence which indicate that boundary P-P 1 is an unconformity. [2] (ii)... Describe the evidence in Figure 2 which indicates that boundary Q-Q 1 is an unconformity. Give a reason for your answer. [2] (d) The Coconino Sandstone has a texture and cross bedding which indicates that it is the deposit of aeolian sand dunes blown from the North. (i) Describe the texture of the Coconino Sandstone which would lead geologists to conclude that it is the deposit of aeolian sand dunes. [2] (ii) Explain how aeolian conditions cause this texture. [2] Turn over.

6 6 (iii) Draw in the space below, a sketch of the cross bedding which would lead geologists to conclude that it is the deposit of aeolian sand dunes blown from the North. Add a scale to your sketch. [3] North South [Total 17 marks]

7 7 BLANK PAGE Turn over.

8 8 3. Figure 3 shows a cross-section of the Earth through an oceanic spreading centre and an island arc. 2 A 3 1 B C source of magma supplying volcano 2 source of magma supplying volcano 3 Not to scale oceanic crust mantle rocks of the island arc volcano earthquake focus Figure 3 Refer to Figure 3. (a) (i) Draw an arrow in each of the blank boxes in Figure 3 to show the relative direction of movement at the Earth s surface at localities A, B and C. [2] (ii) Show with an arrow labelled T (T ) the location of an oceanic trench in Figure 3. [1] (b) Explain the pattern of earthquake foci shown in Figure 3. [4]

9 9 (c) The rocks at locality 1 on Figure 3 have been formed by regional metamorphism. (i) Name a metamorphic rock which might have formed at locality 1. [1] (ii) Explain why regional metamorphism occurs at locality 1. [2] (d) Andesite lava is erupted at locality 2 on Figure 3. However at locality 3 basalt lava is erupted. (i) Explain the origin of the andesitic magma beneath locality 2. [2] (ii) Explain why the lava erupting at locality 3 has a different composition from the lava at locality 2. [2] [Total 14 marks] Turn over.

10 10 4. Figure 4a shows the temperatures to which shale, surrounding a pluton with a surface diameter of 1km, was heated. Temperature ( C) Distance from edge of intrusion (m) Refer to Figure 4a. Figure 4a (a) The mineral andalusite is formed by contact metamorphism of shale. In this case andalusite exists in shale that has been heated to temperatures between 620 C and 340 C. (i) State the distance from the edge of the intrusion at which shale was heated to 620 C. [1]... m (ii) Calculate the width of the zone surrounding the intrusion which would contain the mineral andalusite. [1]... m (b) Sketch a line on Figure 4a to show the temperatures to which shale surrounding a smaller pluton of the same initial temperature would have been heated. [2]

11 (c) 11 Figure 4b shows the texture of a metaquartzite. mm Figure 4b Describe the texture of this metaquartzite. [3] (d) Figure 4c is a geological map. The pluton, with a surface diameter of 1 km, heated the surrounding rocks to the temperatures shown on Figure 4a. Key: horizontal beds dip direction lava flow pluton sandstone limestone N shale km Figure 4c (i) (ii) Refer to Figure 4a. Indicate on Figure 4c with an X the most likely location of a rock containing the mineral andalusite. [2] Indicate on Figure 4c with an arrow labelled M (M ) the most likely location of metaquartzite. Give reasons for your answer. [3] [Total 12 marks]

12 GCE AS/A level 1211/01-A 1212/01-A GEOLOGY MINERAL DATA SHEET FOR USE WITH GL1 or GL2a LH*(S A)

13 Quartz Name Cleavage/Fracture Hardness RF Feldspar Orthoclase RF Feldspar Plagioclase RF Mica-muscovite RF Mica-biotite RF *none/conchoidal scratches streak *2 good, 90 *6 2.6 scratches streak *2 good, 90 *6 2.7 scratches streak Density gcm 3 Streak Lustre Colour vitreous colourless, milky but variable vitreous flesh, pink, white *simple twin Other diagnostic properties hexagonal prisms terminated by pyramids vitreous creamy-white, grey, colourless *repeated multiple twin *1 perfect (basal) * white pearly colourless or pale yellow, green or brown *1 perfect (basal) * white pearly brown/black *flaky *flaky Hornblende RF Augite RF Olivine RF Chiastolite/ Andalusite Garnet Chlorite Calcite RF Fluorite Halite Gypsum *2 good, 60/120 * scratches streak *2 good, 90 * scratches streak none/conchoidal * scratches streak poor 1/ uneven fracture none * good (basal) * *3 good, not at 90, perfect rhombs *4 good, parallel to octahedron scratches streak * * good, 90 cubic * good (basal) * scratches streak white white white white white vitreous black, dark green prismatic crystals vitreous greenish black prismatic crystals vitreous *olive green vitreous pearl grey/pink needle crystals with square x- sections, black centre vitreous red/brown *12 sided crystals - each face rhomb shaped pearly green fibrous/flaky as massive, tabular crystals vitreous colourless, white, tints *effervesces with 0.5M HCl, rhombic shape vitreous colourless fluoresces in u v light, purple/green/yellow cubic or octahedral crystals vitreous colourless, white, often stained *salty taste cubic crystals, often stained silky, pearly colourless, white, often stained fibrous, or twinned crystals white Barites 2 good, 90 *3-3.5 *4.5 vitreous, resinous white, pink bladed crystals poor/conchoidal *black metallic bronze yellow *tarnished to peacock colours Chalcopyrite *greenish black Pyrite none/conchoidal *6 5 metallic brass yellow crystals often striated cubes *lead grey Galena *3 good, 90 cubic *2.5 *7.5 metallic lead grey cubic crystals *cherry red Haematite poor/subconchoidal * metallic-dull red/black skin/steel grey kidney shaped masses, fibrous * - Useful property for diagnosis RF - Common rock-forming mineral This table should not be memorised. Marks in the examinations will be awarded for description of the outcomes of tests on minerals and, on some occasions, identification from test results.