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                                                                    EXHIBIT 4(a)

                                    RESTATED

                          CERTIFICATE OF INCORPORATION

                                       OF

                         ANADARKO PETROLEUM CORPORATION

                     (ORIGINAL CERTIFICATE OF INCORPORATION
                     FILED IN THE OFFICE OF THE SECRETARY OF
                         STATE OF THE STATE OF DELAWARE
                         ON THE 12TH DAY OF JUNE, 1985)

         ANADARKO PETROLEUM CORPORATION, a corporation organized and existing
under and by virtue of the General Corporation Law of the State of Delaware,
hereby adopts the following Restated Certificate of Incorporation:

         FIRST. The name of the Corporation is ANADARKO PETROLEUM CORPORATION.

         SECOND. The address of the Corporation's registered office in the State
of Delaware is Corporation Trust Center, 1209 Orange Street, in the City of
Wilmington, County of New Castle. The name of its registered agent at such
address is The Corporation Trust Company.

         THIRD. The purpose of the Corporation is to engage in any lawful act or
activity for which corporations may be organized under the General Corporation
Law of the State of Delaware.

         FOURTH. The total number of shares which the Corporation shall have
authority to issue is 202,000,000 shares, of which (a) 2,000,000 shares shall be
Preferred Stock, issuable in series, of the par value of $1.00 per share and (b)
200,000,000 shares shall be Common Stock, of the par value of $0.10 per share.

         The designations, powers, preferences and rights and the
qualifications, limitations or restrictions of the Preferred Stock and the
Common Stock are as follows:

                                 PREFERRED STOCK

         1. The Preferred Stock may be issued from time to time in one or more
series and with such designations for each such series as shall be stated and
expressed in the resolution or resolutions providing for the issue of such
series adopted by the Board of Directors. The Board of Directors in any such
resolution or resolutions is expressly authorized to state and express for each
such series:

                  (i) The voting powers, if any, of the holders of stock of such
                  series;

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                  (ii) The rate per annum and the times at and conditions upon
                  which the holders of stock of such series shall be entitled to
                  receive dividends, and whether such dividends shall be
                  cumulative or noncumulative and if cumulative the terms upon
                  which such dividends shall be cumulative;

                  (iii) The price or prices and the time or times at and the
                  manner in which the stock of such series shall be redeemable;

                  (iv) The rights to which the holders of the shares of stock of
                  such series shall be entitled upon any voluntary or
                  involuntary liquidation, dissolution or winding up of the
                  Corporation;

                  (v) The terms, if any, upon which shares of stock of such
                  series shall be convertible into, or exchangeable for, shares
                  of stock of any other class or classes or of any other series
                  of the same or any other class or classes, including the price
                  or prices or the rate or rates of conversion or exchange and
                  the terms of adjustment, if any; and

                  (vi) Any other designations, powers, preferences and relative,
                  participating, optional or other special rights, and
                  qualifications, limitations or restrictions thereof, so far as
                  they are not inconsistent with the provisions of this Restated
                  Certificate of Incorporation and to the full extent now or
                  hereafter permitted by the laws of Delaware.

                                  COMMON STOCK

         1. Whenever dividends upon the Preferred Stock at the time outstanding
shall have been paid in full for all past dividend periods or declared and set
apart for payment, such dividends as may be determined by the Board of Directors
may be declared by the Board of Directors and paid from time to time to the
holders of the Common Stock.

         2. In the event of any liquidation, dissolution or winding up of the
affairs of the Corporation, whether voluntary or involuntary, all assets
remaining after the payment to the holders of the Preferred Stock at the time
outstanding of the full amounts to which they shall be entitled shall be divided
and distributed among the holders of the Common Stock according to their
respective shares.

         3. Each holder of the Common Stock shall have one vote in respect of
each share of such stock held by him.

         FIFTH. Except as otherwise restricted in the By-Laws of the
Corporation, the Board of Directors of the Corporation is expressly authorized
to adopt, amend or repeal By-Laws of the Corporation.

         SIXTH. Elections of directors need not be by written ballot except and
to the extent provided in the By-Laws of the Corporation.

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         SEVENTH. The business and affairs of the Corporation shall be managed
by or under the direction of a Board of Directors consisting of not less than
six nor more than nine directors, the exact number of directors to be determined
from time to time by resolution adopted by affirmative vote of a majority of the
entire Board of Directors. The directors shall be divided into three classes,
designated Class I, Class II and Class Ill. Each class shall consist, as nearly
as may be possible, of one-third of the total number of directors constituting
the entire Board of Directors. At a special meeting of stockholders held on
August 27, 1986, Class I directors were elected for a term ending at the 1987
Annual Meeting of Stockholders, Class II directors were elected for a term
ending at the 1988 Annual Meeting of Stockholders and Class III directors were
elected for a term ending at the 1989 Annual Meeting of Stockholders, in each
case effective as of the date of filing of this Restated Certificate of
Incorporation with the Secretary of State of the State of Delaware. At each
Annual Meeting of Stockholders beginning in 1987, successors to the class of
directors whose term expires at that Annual Meeting shall be elected for a
three-year term. If the number of directors is changed, any increase or decrease
shall be apportioned among the classes so as to maintain the number of directors
in each class as nearly equal as possible, and any additional director of any
class elected to fill a vacancy resulting from an increase in such class shall
hold office for a term that shall coincide with the remaining term of the class,
but in no case will a decrease in the number of directors shorten the term of
any incumbent director. A director shall hold office until the Annual Meeting
for the year in which his term expires and until his successor shall be elected
and shall qualify, subject, however, to prior death, resignation, retirement,
disqualification or removal from office. Any vacancy on the Board of Directors
that results from an increase in the number of directors may be filled by a
majority of the Board of Directors then in office, provided that a quorum is
present, and any other vacancy occurring on the Board of Directors may be filled
by a majority of the directors then in office, even if less than a quorum, or by
a sole remaining director. Any director elected to fill a vacancy not resulting
from an increase in the number of directors shall have the same remaining term
as that of his predecessor.

         Subject to the rights of the holders of any series of Preferred Stock
then outstanding, any director, or the entire Board of Directors, may be removed
from office at any time, but only for cause.

         EIGHTH. No director shall be liable to the Corporation or its
stockholders for monetary damages for breach of fiduciary duty as a director,
provided that this provision shall not eliminate or limit the liability of a
director (i) for any breach of the director's duty of loyalty to the Corporation
or its stockholders, (ii) for acts or omissions not in good faith or which
involve intentional misconduct or a knowing violation of law, (iii) under
Section 174 of the General Corporation Law of the State of Delaware or (iv) for
any transaction from which the director derived an improper benefit.

         NINTH. 1. In addition to any affirmative vote required by law, this
Restated Certificate of Incorporation, the By-Laws of the Corporation or
otherwise, and except as otherwise expressly provided in Section 2 of this
Article, a Business Combination (as hereinafter defined) with any Interested
Stockholder (as hereinafter defined) or any Affiliate (as hereinafter defined)
or Associate (as hereinafter defined) of any Interested Stockholder or any
person who thereafter would be an Affiliate or Associate of any Interested
Stockholder, or in which any such Interested Stockholder, Affiliate, Associate
or person has an interest (except proportionately as a stockholder), shall
require the affirmative vote of not less than eighty percent (80%) of the

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votes entitled to be cast by the holders of all the then outstanding shares of
Voting Stock (as hereinafter defined), voting together as a single class.

         2. The provisions of Section 1 of this Article shall not be applicable
to any particular Business Combination, and such Business Combination shall
require only such affirmative vote, if any, as is required by law or by any
other provision of this Restated Certificate of Incorporation or the By-Laws of
the Corporation, if all of the conditions specified in either of the following
Paragraphs A or B are met or, in the case of a Business Combination not
involving the payment of consideration to the holders of the Corporation's
outstanding Capital Stock (as hereinafter defined), if the condition specified
in the following Paragraph A is met.

         A. The Business Combination shall have been approved, either
         specifically or as a transaction which is within a category of
         generically approved transactions, by a majority of the Continuing
         Directors (as hereinafter defined).

         B. (1) The aggregate amount of cash and the Fair Market Value (as
         hereinafter defined), as of the date of the consummation of the
         Business Combination, of consideration other than cash to be received
         per share by holders of shares of any class or series of outstanding
         Capital Stock in the Business Combination shall be at least equal to
         the highest amount determined under clauses (i), (ii) and (iii) below:

                  (i) the highest per share price (including any brokerage
                  commissions, transfer taxes and soliciting dealers' fees), if
                  any, paid by or on behalf of the Interested Stockholder for
                  any share of such class or series of Capital Stock in
                  connection with the acquisition by the Interested Stockholder
                  of beneficial ownership of shares of such class or series of
                  Capital Stock (x) within the three-year period immediately
                  prior to the first public announcement of the proposed
                  Business Combination (the "Announcement Date") or (y) in the
                  transaction in which it became an Interested Stockholder,
                  whichever is higher, in either case as adjusted for any
                  subsequent stock split, stock dividend, subdivision,
                  combination or reclassification with respect to such class or
                  series of Capital Stock;

                  (ii) the Fair Market Value per share of such class or series
                  of Capital Stock on the Announcement Date or on the date on
                  which the Interested Stockholder became an Interested
                  Stockholder (the "Determination Date"), whichever is higher,
                  as adjusted for any subsequent stock split, stock dividend,
                  subdivision, combination or reclassification with respect to
                  such class or series of Capital Stock; and

                  (iii) the highest preferential amount per share, if any, to
                  which the holders of shares of such class or series of Capital
                  Stock would be entitled in the event of any voluntary or
                  involuntary liquidation, dissolution or winding up of the
                  affairs of the Corporation regardless of whether the Business
                  Combination to be consummated constitutes such an event.

         The provisions of this Paragraph B.(1) shall be required to be met with
respect to every class or series of outstanding Capital Stock, whether or not
the Interested Stockholder has previously acquired beneficial ownership of any
shares of a particular class or series of Capital Stock.

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                  (2) The consideration to be received by holders of a
         particular class or series of outstanding Capital Stock shall be in
         cash or in the same form as previously has been paid by or on behalf of
         the Interested Stockholder in connection with its direct or indirect
         acquisition of beneficial ownership of shares of such class or series
         of Capital Stock. If the consideration so paid for shares of any class
         or series of Capital Stock varied as to form, the form of consideration
         for such class or series of Capital Stock shall be either cash or the
         form used to acquire beneficial ownership of the largest number of
         shares of such class or series of Capital Stock previously acquired by
         the Interested Stockholder.

                  (3) After the Determination Date and prior to the consummation
         of such Business Combination: (i) there shall have been no failure to
         declare and pay at the regular date therefor any full quarterly
         dividends (whether or not cumulative) payable in accordance with the
         terms of any outstanding Capital Stock, except as approved by a
         majority of the Continuing Directors; (ii) there shall have been no
         reduction in the annual rate of dividends paid on the Common Stock
         (except as necessary to reflect any stock split, stock dividend or
         subdivision of the Common Stock), except as approved by a majority of
         the Continuing Directors; (iii) there shall have been an increase in
         the annual rate of dividends paid on the Common Stock as necessary to
         reflect any combination, reclassification, recapitalization,
         reorganization or similar transaction that has the effect of reducing
         the number of outstanding shares of Common Stock. unless the failure so
         to increase such annual rate is approved by a majority of the
         Continuing Directors; and (iv) such Interested Stockholder shall not
         have become the beneficial owner of any additional shares of Capital
         Stock except as part of the transaction that results in such Interested
         Stockholder becoming an Interested Stockholder and except in a
         transaction that, after giving effect thereto, would not result in any
         increase in the Interested Stockholder's percentage beneficial
         ownership of any class or series of Capital Stock.

                  (4) A proxy or information statement describing the proposed
         Business Combination and complying with the requirements of the
         Securities Exchange Act of 1934 (the "Act") and the rules and
         regulations thereunder (or any subsequent provisions replacing such
         Act, rules or regulations) shall be mailed to all stockholders of the
         Corporation at least 30 days prior to the consummation of such Business
         Combination (whether or not such proxy or information statement is
         required to be mailed pursuant to such Act or subsequent provisions).
         The proxy or information statement shall contain on the first page
         thereof, in a prominent place, any statement as to the advisability (or
         inadvisability) of the Business Combination that the Continuing
         Directors, or any of them, may choose to make and, if deemed advisable
         by a majority of the Continuing Directors, the opinion of an investment
         banking firm selected by a majority of the Continuing Directors as to
         the fairness or adequacy (or unfairness or inadequacy) of the terms of
         the Business Combination from a financial point of view to the holders
         of the outstanding shares of Capital Stock other than the Interested
         Stockholder and its Affiliates or Associates, such investment banking
         firm to be paid a reasonable fee for its services by the Corporation.

                  (5) Such Interested Stockholder shall not have made any major
         change in the Corporation's business or equity capital structure
         without the approval of a majority of the Continuing Directors.

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         3. In any election of directors of the Corporation on or after the date
on which any 30% Stockholder (as hereinafter defined) becomes a 30% Stockholder,
and until such time as no 30% Stockholder exists, there shall be cumulative
voting for election of directors so that any holder of shares of Voting Stock
entitled to vote in such election shall be entitled to as many votes as shall
equal the number of directors to be elected multiplied by the number of votes to
which such stockholder's shares would be entitled except for the provisions of
this Section 3 and such stockholder may cast all of such votes for a single
director, or distribute such votes among as many candidates as such stockholder
sees fit. In any such election of directors, one or more candidates for the
Board of Directors may be nominated by a majority of the Continuing Directors.
With respect to any candidates nominated by a majority of the Continuing
Directors or by any person who is the beneficial owner of shares of Voting Stock
having a Fair Market Value of $100,000 or more, there shall be included in any
proxy statement or other communication with respect to such election to be sent
to holders of shares of Voting Stock by the Corporation during the period in
which there is a 30% Stockholder, at the expense of the Corporation,
descriptions and other statements of or with respect to such candidates
submitted by them or on their behalf, which shall receive equal space, coverage
and treatment as is received by candidates nominated by the Board of Directors
or management of the Corporation.

         4. The following definitions shall apply with respect to this Article:

                  A. The term "Business Combination" shall mean:

                           (1) any merger or consolidation of the Corporation or
                  any Subsidiary (as hereinafter defined) or the adoption of any
                  plan or proposal for the liquidation or dissolution of the
                  Corporation; or

                           (2) any sale, lease, exchange, mortgage, pledge,
                  transfer, other disposition, security arrangement, investment,
                  loan, advance, guarantee, agreement to purchase, agreement to
                  pay, extension of credit, joint venture participation or other
                  arrangement (in one or more related or unrelated transactions)
                  involving any assets, securities or commitments of the
                  Corporation, any Subsidiary or any Interested Stockholder or
                  any Affiliate or Associate of any Interested Stockholder which
                  have an aggregate Fair Market Value and/or involves aggregate
                  commitments of $25,000,000 or more or constitutes more than
                  five percent (5%) of the book value of the total assets (in
                  the case of transactions involving assets, commitments or
                  securities other than capital stock) or five percent (5%) of
                  the stockholders' equity (in the case of transactions
                  involving capital stock) of the entity in question (a
                  "Substantial Part"), as reflected in the most recent fiscal
                  year-end consolidated balance sheet of such entity existing at
                  the time of such transaction or transactions; or

                           (3) any amendment to the Corporation's By-Laws; or

                           (4) any reclassification of securities (including any
                  reverse stock split), or recapitalization of the Corporation,
                  or any merger or consolidation of the Corporation with any of
                  its Subsidiaries or any other transaction (whether or not with
                  or otherwise involving an Interested Stockholder), that in any
                  case has the effect, directly or indirectly, of increasing the
                  proportionate share of any class or series of Capital Stock,
                  or any securities convertible into Capital Stock or into

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                  equity securities of any Subsidiary, that is beneficially
                  owned by an Interested Stockholder or any Affiliate or
                  Associate of any Interested Stockholder; or

                           (5) any agreement, contract or other arrangement
                  providing for any one or more of the actions specified in the
                  foregoing clauses (1) to (4).

                  B. The term "Capital Stock" shall mean all capital stock of
         the Corporation authorized to be issued under this Restated Certificate
         of Incorporation, as amended from time to time, and the term "Voting
         Stock" shall mean all Capital Stock which by its terms may be voted on
         all matters submitted to stockholders of the Corporation generally.

                  C. The term "person" shall mean any individual, firm, company
         or other entity and shall include any group comprised of any person and
         any other person with whom such person or any Affiliate or Associate of
         such person has any agreement, arrangement or understanding, directly
         or indirectly, for the purpose of acquiring, holding, voting or
         disposing of Capital Stock.

                  D. The term "Interested Stockholder" shall mean any person
         (other than the Corporation or any Subsidiary and other than any
         profit-sharing, employee stock ownership or other employee benefit plan
         of the Corporation or any Subsidiary or any trustee of or fiduciary
         with respect to any such plan when acting in such capacity) who (1) is
         the beneficial owner of Voting Stock representing five percent (5%) or
         more of the votes entitled to be cast by the holders of all then
         outstanding shares of Voting Stock; or (2) at any time within the
         two-year period immediately prior to the date in question was the
         beneficial owner of Voting Stock representing five percent (5%) or more
         of the votes entitled to be cast by the holders of all then outstanding
         shares of Voting Stock.

                  E. A person shall be a "beneficial owner" of any Capital Stock
         (1) which such person or any of its Affiliates or Associates has,
         directly or indirectly, (i) the right to acquire (whether such right is
         exercisable immediately or subject only to the passage of time)
         pursuant to any agreement, arrangement or understanding or upon the
         exercise of conversion rights, exchange rights, warrants or options, or
         otherwise, or (ii) the right to vote pursuant to any agreement,
         arrangement or understanding; or (2) which is beneficially owned,
         directly or indirectly, by any other person with which such person or
         any of its Affiliates or Associates has any agreement, arrangement or
         understanding for the purpose of acquiring, holding, voting or
         disposing of any shares of Capital Stock. For the purposes of
         determining whether a person is an Interested Stockholder or a 30%
         Stockholder pursuant to Paragraphs D and J of this Section 4, the
         number of shares of Capital Stock deemed to be outstanding shall
         include shares deemed beneficially owned by such person through
         application of this Paragraph E, but shall not include any other shares
         of Capital Stock that may be issuable pursuant to any agreement,
         arrangement or understanding, or upon exercise of conversion rights,
         warrants or options, or otherwise.

                  F. The terms "Affiliate" and "Associate" shall have the
         respective meanings ascribed to such terms in Rule 12b-2 under the Act
         as in effect on the date that this Article is approved by the Board of
         Directors (the terns "registrant" in said Rule 12b-2 meaning in this
         case the Corporation).

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                  G. The term "Subsidiary" shall mean any corporation,
         partnership or other entity more than 50% of the outstanding voting
         stock or voting interest of which is owned, directly or indirectly, by
         the Corporation or by one or more other Subsidiaries, or by the
         Corporation and one or more other Subsidiaries. For the purpose of this
         definition, "voting stock" means stock which by its terms may be voted
         on all matters submitted to the stockholders of the corporation in
         question generally.

                  H. The term "Continuing Director" shall mean any member of the
         Board of Directors who is not an Affiliate or Associate or
         representative of the Interested Stockholder and who was a member of
         the Board of Directors prior to the time that the Interested
         Stockholder became an Interested Stockholder, and any successor of a
         Continuing Director who is not an Affiliate or Associate or
         representative of the Interested Stockholder and who is recommended or
         elected to succeed the Continuing Director by a majority of Continuing
         Directors.

                  I. The term "Fair Market Value" shall mean (1) in the case of
         cash, the amount of such cash; (2) in the case of stock, the highest
         closing sale price (or, if closing prices are not available and highest
         closing bid quotations are available, the highest closing bid
         quotation) during the 30-day period immediately preceding the date in
         question of a share of such stock on the Composite Tape for New York
         Stock Exchange-Listed Stocks, or, if such stock is not quoted on the
         Composite Tape, on the New York Stock Exchange, or, if such stock is
         not listed on such Exchange, on the principal United States securities
         exchange registered under the Act on which such stock is listed, or, if
         such stock is not listed on any such exchange, on the National
         Association of Securities Dealers, Inc. Automated Quotations System or
         any similar system then in use, or if no such quotations are available,
         the fair market value on the date in question of a share of such stock
         as determined by a majority of the Continuing Directors in good faith;
         and (3) in the case of property other than cash or stock, the fair
         market value of such property on the date in question as determined in
         good faith by a majority of the Continuing Directors.

                  J. The term "30% Stockholder" shall mean any person (other
         than the Corporation or any Subsidiary and other than any
         profit-sharing, employee stock ownership or other employee benefit plan
         of the Corporation or any Subsidiary or any trustee of or fiduciary
         with respect to any such plan when acting in such capacity) who (1) is
         the beneficial owner of Voting Stock representing thirty percent (30%)
         or more of the votes entitled to be cast by the holders of all then
         outstanding shares of Voting Stock; or (2) at any time within the
         two-year period immediately prior to the date in question was the
         beneficial owner of Voting Stock representing thirty percent (30%) or
         more of the votes entitled to be cast by the holders of all then
         outstanding shares of Voting Stock.

                  K. In the event of any Business Combination in which the
         Corporation survives, the phrase "consideration other than cash to be
         received" as used in Paragraph B.(1) of Section 2 of this Article shall
         include the shares of any class or series of Capital Stock retained by
         the holders of such shares.

         5. A majority of the Continuing Directors shall have the power to
determine for the purposes of this Article, on the basis of information known to
them after reasonable inquiry, all questions arising under this Article,
including, without limitation, (a) whether a person is an

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Interested Stockholder or a 30% Stockholder, (b) the number of shares of Capital
Stock or other securities beneficially owned by any person, (c) whether a person
is ant Affiliate or Associate of another, (d) whether a proposed action is with
an Interested Stockholder, an Affiliate or Associate of an Interested
Stockholder or a person who after the proposed action would be an Affiliate or
Associate of an Interested Stockholder, or whether any such Interested
Stockholder, Affiliate, Associate or person would have an interest in a proposed
action, (e) whether the assets that are the subject of any Business Combination
have, or the consideration to be received for the issuance or transfer of
securities by the Corporation or any Subsidiary in any Business Combination has,
an aggregate Fair Market Value of $25,000,000 or more, and (f) whether the
assets or securities that are the subject of any Business Combination constitute
a Substantial Part. Any such determination made in good faith shall be binding
and conclusive on all parties.

         6. Nothing contained in this Article shall be construed to relieve any
Interested Stockholder from any fiduciary obligation imposed by law.

         7. The fact that any Business Combination complies with the provisions
of Section 2 of this Article shall not be construed to impose any fiduciary
duty, obligation or responsibility on the Board of Directors, or any member
thereof, to approve such Business Combination or recommend its adoption or
approval to the stockholders of the Corporation, nor shall such compliance
limit, prohibit or otherwise restrict in any manner the Board of Directors, or
any member thereof, with respect to evaluations of or actions and responses
taken with respect to such Business Combination.

         TENTH. No action required to be taken or which may be taken at any
annual or special meeting of stockholders of the Corporation may be taken
without a meeting, and the power of stockholders to consent in writing, without
a meeting, to the taking of any action is specifically denied.

         ELEVENTH. In addition to any affirmative vote required by law, this
Restated Certificate of Incorporation, the By-Laws of the Corporation or
otherwise, the affirmative vote of not less than eighty percent (80%) of the
votes entitled to be cast by the holders of all the then outstanding shares of
Voting Stock (as defined in Article NINTH), voting together as a single class,
shall be required to amend or repeal, or adopt any provisions inconsistent with,
this Article or Article SEVENTH, EIGHTH, NINTH or TENTH of this Restated
Certificate of Incorporation.

         Effective upon filing of this Restated Certificate of Incorporation
with the Secretary of State of the State of Delaware, each outstanding share of
Common Stock, par value $1.00 per share, shall be converted into one share of
Common Stock, par value $0.10 per share.

         The foregoing Restated Certificate of Incorporation has been duly
adopted by the Corporation in accordance with the applicable provisions of
Sections 242 and 245 of the General Corporation Law of the State of Delaware,
and supersedes the original Certificate of Incorporation and all amendments
thereto.

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         IN WITNESS WHEREOF, said Anadarko Petroleum Corporation has caused this
Restated Certificate of Incorporation to be executed by Robert J. Allison, Jr.,
its President, and attested by Dan A. Spencer, its Secretary, this 28th day of
August, 1986.

                                        Anadarko Petroleum Corporation

                                        By /s/ Robert J. Allison, Jr., President
                                           -------------------------------------
                                           Robert J. Allison, Jr., President

ATTEST:

By /s/ Dan A. Spencer, Secretary
   -----------------------------
   Dan A. Spencer, Secretary

                                       10<PAGE>   1
                                                                   EXHIBIT 4(d)

                                                               STATE OF DELAWARE
                                                              SECRETARY OF STATE
                                                        DIVISION OF CORPORATIONS
                                                        FILED 10:30AM 11/04/1998
                                                             981423968 - 2063991

                           CERTIFICATE OF DESIGNATIONS

                                       OF

                  SERIES C JUNIOR PARTICIPATING PREFERRED STOCK

                                       OF

                         ANADARKO PETROLEUM CORPORATION

                         (Pursuant to Section 151 of the
                        Delaware General Corporation Law)

                                   ----------

                  Anadarko Petroleum Corporation, a corporation organized and
existing under the General Corporation Law of the State of Delaware (hereinafter
called the "Corporation"), hereby certifies that the following resolution was
adopted by the Board of Directors of the Corporation as required by Section 151
of the General Corporation Law at a meeting duly called and held on October 9,
1998:

                  RESOLVED, that pursuant to the authority granted to and vested
in the Board of Directors of this Corporation (hereinafter called the "Board of
Directors" or the "Board") in accordance with the provisions of the Certificate
of Incorporation, the Board of Directors hereby creates a series of Preferred
Stock, par value $1.00 per share, of the Corporation (the "Preferred Stock"),
and hereby states the designation and number of shares, and fixes the relative
rights, preferences, and limitations thereof as follows:

                  Series C Junior Participating Preferred Stock:

                  Section 1. Designation and Amount. The shares of such series
shall be designated as "Series C Junior Participating Preferred Stock" (the
"Series C Preferred Stock") and the number of shares constituting the Series C
Preferred Stock shall be 200,000. Such number of shares may be increased or
decreased by resolution of the Board of Directors; provided, that no decrease
shall reduce the number of shares of Series C Preferred Stock to a number less
than the number of shares then outstanding plus the number of shares reserved
for issuance upon the exercise of outstanding options, rights or warrants or
upon the conversion of any outstanding securities issued by the Corporation
convertible into Series C Preferred Stock.

                  Section 2. Dividends and Distributions.

                  (A) Subject to the rights of the holders of any shares of any
         series of Preferred Stock (or any similar stock) ranking prior and
         superior to the Series C Preferred Stock with respect to dividends, the
         holders of shares of Series C Preferred Stock, in preference to the
         holders of Common Stock, par value $0.10 per share (the "Common
         Stock"), of the Corporation, and of any other junior stock, shall be
         entitled to receive,

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<PAGE>   2

         when, as and if declared by the Board of Directors out of funds legally
         available for the purpose, quarterly dividends payable in cash on the
         last day of September, December, March and June in each year (each such
         date being referred to herein as a "Quarterly Dividend Payment Date"),
         commencing on the first Quarterly Dividend Payment Date after the first
         issuance of a share or fraction of a share of Series C Preferred Stock,
         in an amount per share (rounded to the nearest cent) equal to the
         greater of (a) $1 or (b) subject to the provision for adjustment
         hereinafter set forth, 1,000 times the aggregate per share amount of
         all cash dividends, and 1,000 times the aggregate per share amount
         (payable in kind) of all non-cash dividends or other distributions,
         other than a dividend payable in shares of Common Stock or a
         subdivision of the outstanding shares of Common Stock (by
         reclassification or otherwise), declared on the Common Stock since the
         immediately preceding Quarterly Dividend Payment Date or, with respect
         to the first Quarterly Dividend Payment Date, since the first issuance
         of any share or fraction of a share of Series C Preferred Stock. In the
         event the Corporation shall at any time declare or pay any dividend on
         the Common Stock payable in shares of Common Stock, or effect a
         subdivision or combination or consolidation of the outstanding shares
         of Common Stock (by reclassification or otherwise than by payment of a
         dividend in shares of Common Stock) into a greater or lesser number of
         shares of Common Stock, then in each such case the amount to which
         holders of shares of Series C Preferred Stock were entitled immediately
         prior to such event under clause (b) of the preceding sentence shall be
         adjusted by multiplying such amount by a fraction, the numerator of
         which is the number of shares of Common Stock outstanding immediately
         after such event and the denominator of which is the number of shares
         of Common Stock that were outstanding immediately prior to such event.

                  (B) The Corporation shall declare a dividend or distribution
         on the Series C Preferred Stock as provided in paragraph (A) of this
         Section immediately after it declares a dividend or distribution on the
         Common Stock (other than a dividend payable in shares of Common Stock);
         provided that, in the event no dividend or distribution shall have been
         declared on the Common Stock during the period between any Quarterly
         Dividend Payment Date and the next subsequent Quarterly Dividend
         Payment Date, a dividend of $1 per share on the Series C Preferred
         Stock shall nevertheless be payable on such subsequent Quarterly
         Dividend Payment Date.

                  (C) Dividends shall begin to accrue and be cumulative on
         outstanding shares of Series C Preferred Stock from the Quarterly
         Dividend Payment Date next preceding the date of issue of such shares,
         unless the date of issue of such shares is prior to the record date for
         the first Quarterly Dividend Payment Date, in which case dividends on
         such shares shall begin to accrue from the date of issue of such
         shares, or unless the date of issue is a Quarterly Dividend Payment
         Date or is a date after the record date for the determination of
         holders of shares of Series C Preferred Stock entitled to receive a
         quarterly dividend and before such Quarterly Dividend Payment Date, in
         either of which events such dividends shall begin to accrue and be
         cumulative from such Quarterly Dividend Payment Date. Accrued but
         unpaid dividends shall not bear interest. Dividends paid on the shares
         of Series C Preferred Stock in an amount less than the total amount of
         such dividends at the time accrued and payable on such shares shall be
         allocated pro rata on a share-by-share basis among all such shares at
         the time outstanding. The Board of Directors may fix a record date for
         the determination of holders of shares of Series C Preferred Stock
         entitled to receive payment of a dividend or distribution declared
         thereon, which record date shall be not more than 60 days prior to the
         date fixed for the payment thereof.

                                      -2-
<PAGE>   3

                  Section 3. Voting Rights. The holders of shares of Series C
Preferred Stock shall have the following voting rights:

                  (A) Subject to the provision for adjustment hereinafter set
         forth, each share of Series C Preferred Stock shall entitle the holder
         thereof to 1,000 votes on all matters submitted to a vote of the
         stockholders of the Corporation. In the event the Corporation shall at
         any time declare or pay any dividend on the Common Stock payable in
         shares of Common Stock, or effect a subdivision or combination or
         consolidation of the outstanding shares of Common Stock (by
         reclassification or otherwise than by payment of a dividend in shares
         of Common Stock) into a greater or lesser number of shares of Common
         Stock, then in each such case the number of votes per share to which
         holders of shares of Series C Preferred Stock were entitled immediately
         prior to such event shall be adjusted by multiplying such number by a
         fraction, the numerator of which is the number of shares of Common
         Stock outstanding immediately after such event and the denominator of
         which is the number of shares of Common Stock that were outstanding
         immediately prior to such event.

                  (B) Except as otherwise provided herein, in any other
         Certificate of Designations creating a series of Preferred Stock or any
         similar stock, or by law, the holders of shares of Series C Preferred
         Stock and the holders of shares of Common Stock and any other capital
         stock of the Corporation having general voting rights shall vote
         together as one class on all matters submitted to a vote of
         stockholders of the Corporation.

                  (C) Except as set forth herein, or as otherwise provided by
         law, holders of Series C Preferred Stock shall have no special voting
         rights and their consent shall not be required (except to the extent
         they are entitled to vote with holders of Common Stock as set forth
         herein) for taking any corporate action.

                  Section 4. Certain Restrictions.

                  (A) Whenever quarterly dividends or other dividends or
         distributions payable on the Series C Preferred Stock as provided in
         Section 2 are in arrears, thereafter and until all accrued and unpaid
         dividends and distributions, whether or not declared, on shares of
         Series C Preferred Stock outstanding shall have been paid in full, the
         Corporation shall not:

                           (i) declare or pay dividends, or make any other
                  distributions, on any shares of stock ranking junior (either
                  as to dividends or upon liquidation, dissolution or winding
                  up) to the Series C Preferred Stock;

                           (ii) declare or pay dividends, or make any other
                  distributions, on any shares of stock ranking on a parity
                  (either as to dividends or upon liquidation, dissolution or
                  winding up) with the Series C Preferred Stock, except
                  dividends paid ratably on the Series C Preferred Stock and all
                  such parity stock on which dividends are payable or in arrears
                  in proportion to the total amounts to which the holders of all
                  such shares are then entitled;

                           (iii) redeem or purchase or otherwise acquire for
                  consideration shares of any stock ranking junior (either as to
                  dividends or upon liquidation, dissolution or winding up) to
                  the Series C Preferred Stock, provided that the Corporation
                  may at any time redeem, purchase or otherwise acquire shares
                  of any

                                      -3-
<PAGE>   4
                  such junior stock in exchange for shares of any stock of the
                  Corporation ranking junior (either as to dividends or upon
                  dissolution, liquidation or winding up) to the Series C
                  Preferred Stock; or

                           (iv) redeem or purchase or otherwise acquire for
                  consideration any shares of Series C Preferred Stock, or any
                  shares of stock ranking on a parity with the Series C
                  Preferred Stock, except in accordance with a purchase offer
                  made in writing or by publication (as determined by the Board
                  of Directors) to all holders of such shares upon such terms as
                  the Board of Directors, after consideration of the respective
                  annual dividend rates and other relative rights and
                  preferences of the respective series and classes, shall
                  determine in good faith will result in fair and equitable
                  treatment among the respective series or classes.

                  (B) The Corporation shall not permit any subsidiary of the
         Corporation to purchase or otherwise acquire for consideration any
         shares of stock of the Corporation unless the Corporation could, under
         paragraph (A) of this Section 4, purchase or otherwise acquire such
         shares at such time and in such manner.

                  Section 5. Reacquired Shares. Any shares of Series C Preferred
Stock purchased or otherwise acquired by the Corporation in any manner
whatsoever shall be retired and cancelled promptly after the acquisition
thereof. All such shares shall upon their cancellation become authorized but
unissued shares of Preferred Stock and may be reissued as part of a new series
of Preferred Stock subject to the conditions and restrictions on issuance set
forth herein, in the Certificate of Incorporation, or in any other Certificate
of Designations creating a series of Preferred Stock or any similar stock or as
otherwise required by law.

                  Section 6. Liquidation, Dissolution or Winding Up. Upon any
liquidation, dissolution or winding up of the Corporation, no distribution shall
be made (1) to the holders of shares of stock ranking junior (either as to
dividends or upon liquidation, dissolution or winding up) to the Series C
Preferred Stock unless, prior thereto, the holders of shares of Series C
Preferred Stock shall have received $1,000 per share, plus an amount equal to
accrued and unpaid dividends and distributions thereon, whether or not declared,
to the date of such payment, provided that the holders of shares of Series C
Preferred Stock shall be entitled to receive an aggregate amount per share,
subject to the provision for adjustment hereinafter set forth, equal to 1,000
times the aggregate amount to be distributed per share to holders of shares of
Common Stock, or (2) to the holders of shares of stock ranking on a parity
(either as to dividends or upon liquidation, dissolution or winding up) with the
Series C Preferred Stock, except distributions made ratably on the Series C
Preferred Stock and all such parity stock in proportion to the total amounts to
which the holders of all such shares are entitled upon such liquidation,
dissolution or winding up. In the event the Corporation shall at any time
declare or pay any dividend on the Common Stock payable in shares of Common
Stock, or effect a subdivision or combination or consolidation of the
outstanding shares of Common Stock (by reclassification or otherwise than by
payment of a dividend in shares of Common Stock) into a greater or lesser number
of shares of Common Stock, then in each such case the aggregate amount to which
holders of shares of Series C Preferred Stock were entitled immediately prior to
such event under the proviso in clause (1) of the preceding sentence shall be
adjusted by multiplying such amount by a fraction the numerator of which is the
number of shares of Common Stock outstanding immediately after such event and
the denominator of which is the number of shares of Common Stock that were
outstanding immediately prior to such event.

                  Section 7. Consolidation, Merger, etc. In case the Corporation
shall enter into any consolidation, merger, combination or other transaction in
which the shares of Common

                                      -4-
<PAGE>   5

Stock are exchanged for or changed into other stock or securities, cash and/or
any other property, then in any such case each share of Series C Preferred Stock
shall at the same time be similarly exchanged or changed into an amount per
share, subject to the provision for adjustment hereinafter set forth, equal to
1,000 times the aggregate amount of stock, securities, cash and/or any other
property (payable in kind), as the case may be, into which or for which each
share of Common Stock is changed or exchanged. In the event the Corporation
shall at any time declare or pay any dividend on the Common Stock payable in
shares of Common Stock, or effect a subdivision or combination or consolidation
of the outstanding shares of Common Stock (by reclassification or otherwise than
by payment of a dividend in shares of Common Stock) into a greater or lesser
number of shares of Common Stock, then in each such case the amount set forth in
the preceding sentence with respect to the exchange or change of shares of
Series C Preferred Stock shall be adjusted by multiplying such amount by a
fraction, the numerator of which is the number of shares of Common Stock
outstanding immediately after such event and the denominator of which is the
number of shares of Common Stock that were outstanding immediately prior to such
event.

                  Section 8. Redemption. (A) The Corporation shall have the
option to redeem in whole, but not in part, the Series C Preferred Stock at any
time at a redemption price equal to, subject to the provisions for adjustment
hereinafter set forth, 1,000 times the "current per share market price" of the
Common Stock on the date of the mailing of the notice of redemption, together
with unpaid accumulated dividends to the date of such redemption. In the event
the Corporation shall at any time after November 10, 1998, (i) declare any
dividend on Common Stock payable in shares of Common Stock, (ii) subdivide the
outstanding Common Stock or (ii) combine the outstanding Common Stock into a
smaller number of shares, then in each such case the amount to which holders of
shares of Series C Preferred Stock were otherwise entitled immediately prior to
such event under the preceding sentence shall be adjusted by multiplying such
amount by a fraction the numerator of which is the number of shares of Common
Stock outstanding immediately after such event and the denominator of which is
the number of shares of Common Stock that were outstanding immediately prior to
such event. The "current per share market price" on any date shall be deemed to
be the average of the closing price per share of such Common Stock for the 10
consecutive Trading Days (as such term is hereinafter defined) immediately prior
to such date. The closing price for each day shall be the last sale price,
regular way, or, in case no such sale takes place on such day, the average of
the closing bid and asked prices, regular way, in either case as reported in the
principal consolidated transaction reporting system with respect to securities
listed or admitted to trading on the New York Stock Exchange or, if the Common
Stock is not listed or admitted to trading on the New York Stock Exchange, as
reported in the principal consolidated transaction reporting system with respect
to securities listed or admitted to trading on the principal national securities
exchange on which the Common Stock is listed or admitted to trading or, if the
Common Stock is not listed or admitted to trading on any national securities
exchange, the last quoted price or, if not so quoted the average of the high bid
and low asked prices in the over-the-counter market, as reported by the National
Association of Securities Dealers, Inc. Automated Quotation System ("NASDAQ") or
such other system then in use or, if on any such date the Common Stock is not
quoted by any such organization, the average of the closing bid and asked prices
as furnished by a professional market maker making a market in the Common Stock
selected by the Board of Directors of the Corporation. If on such date no such
market maker is making a market in the Common Stock, the fair value of the
Common Stock on such date as determined shall be used. The term "Trading Day"
shall mean a day on which the principal national securities exchange on which
the Common Stock is listed or admitted to trading is open for the transaction of
business or, if the Common Stock is not listed or admitted to trading on any
national securities exchange, a Monday, Tuesday, Wednesday, Thursday or Friday
on which banking institutions in the State of New York are not authorized or
obligated by law or executive order to close.

                                      -5-
<PAGE>   6

                  (B) Notice of any such redemption shall be given by mailing to
the holders of the Series C Preferred Stock a notice of such redemption, first
class postage prepaid, not later than the thirtieth day and not earlier than the
sixtieth day before the date fixed for redemption, at their last address as the
same shall appear upon the books of the Corporation. Any notice which is mailed
in the manner herein provided shall be conclusively presumed to have been duly
given, whether or not the stockholder received such notice, and failure duly to
give such notice by mail, or any defect in such notice, to any holder of Series
C Preferred Stock shall not affect the validity of the proceedings for the
redemption of such Series C Preferred Stock.

                  (C) If any such notice of redemption shall have been duly
given or if the Corporation shall have given to the bank or trust company
hereinafter referred to irrevocable written authorization promptly to give or
complete such notice, and if on or before the redemption date specified therein
the funds necessary for such redemption shall have been deposited by the
Corporation with the bank or trust company designated in such notice, doing
business in the United States of America and having a capital, surplus and
undivided profits aggregating at least $50,000,000 according to its last
published statement of condition, in trust for the benefit of the holders of
Series C Preferred Stock called for redemption, then, notwithstanding that any
certificate for such shares so called for redemption shall not have been
surrendered for cancellation, from and after the time of such deposit all such
shares called for redemption shall no longer be deemed outstanding and all
rights with respect to such shares shall no longer be deemed outstanding and all
rights with respect to such shares shall forthwith cease and terminate, except
the rights of the holders thereof to receive from such bank or trust company at
any time after the time of such deposit the funds so deposited, without
interest. Any interest accrued on such funds shall be paid to the Corporation
from time to time. Any funds so deposited and unclaimed at the end of six years
from such redemption date shall be repaid to the Corporation, after which the
holders of shares of Series C Preferred Stock called for redemption shall look
only to the Corporation for payment thereof.

                  Section 9. Rank. The Series C Preferred Stock shall rank, with
respect to the payment of dividends and the distribution of assets, junior to
all series of any other class of the Corporation's Preferred Stock.

                  Section 10. Amendment. The Certificate of Incorporation of the
Corporation shall not be amended in any manner which would materially alter or
change the powers, preferences or special rights of the Series C Preferred Stock
so as to affect them adversely without the affirmative vote of the holders of at
least two-thirds of the outstanding shares of Series C Preferred Stock, voting
together as a single class.

                                      -6-
<PAGE>   7

         IN WITNESS WHEREOF, this Certificate of Designations is executed on
behalf of the Corporation by its Executive Vice President and attested by its
Secretary this 29th day of October, 1998.

                                                /s/ John N. Seitz
                                                ------------------------
                                                Executive Vice President
                                                John N. Seitz
Attest:

/s/ Suzanne Suter
-------------------
Corporate Secretary
Suzanne Suter

                                      -7-

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