SPLIT-OFF AGREEMENT

      SPLIT-OFF  AGREEMENT,  dated as of this  ________  day of ________  2005
(this  "Agreement"),  by and  among  Goldstrike  Inc.,  a  Nevada  corporation
("Seller"),  Dr.  Yenyou Zheng  ("Zheng" or  "Purchaser"),  Goldstrike  Leasco
Inc.,  a Nevada  corporation  ("Leasco"),  and Gran  Tierra  Energy  Inc.,  an
Alberta corporation ("Gran Tierra").

                               R E C I T A L S:

      WHEREAS, Seller is the owner of all of the issued and outstanding capital
stock of Leasco. Leasco is a newly-formed wholly owned subsidiary of Seller
which was organized to acquire, and has so acquired, a Mineral Property Sale
Agreement previously entered into by Seller. Seller has no other businesses or
operations;

      WHEREAS, prior to the execution of this Agreement, Seller, Gran Tierra,
and two newly-formed wholly-owned Alberta subsidiaries of Seller entered into a
series of transactions (collectively, the "Reorganization Agreements") with each
other and the former stockholders of Gran Tierra as a result of which, among
other effects, Gran Tierra became a wholly-owned subsidiary of Seller (the
"Reorganization");

      WHEREAS, the execution and delivery of this Agreement was required by Gran
Tierra as a condition subsequent to its execution of the Reorganization
Agreements. The consummation of the purchase and sale transaction contemplated
by this Agreement was also a condition subsequent to the completion of the
Reorganization pursuant to the Reorganization Agreements. Seller has represented
to Gran Tierra in the Reorganization Agreements that the purchase and sale
transaction contemplated by this Agreement would be consummated as soon as
practicable following the consummation of the Reorganization, and Gran Tierra
relied on such representation in entering into the Reorganization Agreements;

      WHEREAS, Purchaser desires to purchase the Shares (as defined in Section
1.1) from Seller, and to assume, as between Seller and Purchaser, all
responsibilities for any debts, obligations and liabilities of Leasco, on the
terms and subject to the conditions specified in this Agreement; and

      WHEREAS, Seller desires to sell and transfer the Shares to the Purchaser,
on the terms and subject to the conditions specified in this Agreement;

      NOW, THEREFORE, in consideration of the premises and the covenants,
promises, and agreements herein set forth and for other good and valuable
consideration, the receipt and sufficiency of which are hereby acknowledged, the
parties hereto, intending legally to be bound, agree as follows.

<PAGE>

I. PURCHASE AND SALE OF STOCK.

      1.1 Purchased Shares. Subject to the terms and conditions provided below,
Seller shall sell and transfer to Purchaser and Purchaser shall purchase from
Seller, on the Closing Date (as defined in Section 1.3), all the issued and
outstanding shares of capital stock of Leasco (the "Shares").

      1.2 Purchase Price. The purchase price for the Shares shall be the
transfer and delivery by Purchaser to Seller of all shares of common stock of
Seller that Purchaser owns (the "Purchase Price Shares"), as delineated below
and deliverable as provided in Section 2.2.

            Zheng                               1,565,218 shares

      1.3 Closing. The closing of the transactions contemplated in this
Agreement (the "Closing") shall take place as soon as practicable following the
execution of this Agreement. The date on which the Closing occurs shall be
referred to herein as the Closing Date (the "Closing Date").

II. CLOSING.

      2.1 Transfer of Shares. At the Closing, Seller shall deliver to Purchaser
certificates representing the Shares, duly endorsed to Purchaser or as directed
by Purchaser, which delivery shall vest Purchaser with good and marketable title
to all of the issued and outstanding shares of capital stock of Leasco, free and
clear of all liens and encumbrances. The Purchaser shall receive such number of
Shares as is set forth below:

            Zheng                               200 Shares

      2.2 Payment of Purchase Price. At the Closing, Purchaser shall deliver to
Seller a certificate or certificates representing the Purchase Price Shares duly
endorsed to Seller, which delivery shall vest Seller with good and marketable
title to the Purchase Price Shares, free and clear of all liens and
encumbrances.

      2.3 Transfer of Records. On or before the Closing, Seller shall arrange
for transfer to Leasco all existing corporate books and records in Seller's
possession relating to Leasco and its business, including but not limited to all
agreements, litigation files, real estate files, mineral leases, personnel files
and filings with governmental agencies; provided, however, when any such
documents relate to both Seller and Leasco, only copies of such documents need
be furnished. On or before the Closing, Purchaser and Leasco shall transfer to
Seller all existing corporate books and records in the possession of Purchaser
or Leasco relating to Seller, including but not limited to all corporate minute
books, stock ledgers, certificates and corporate seals of Seller and all
agreements, litigation files, real property files, personnel files and filings
with governmental agencies; provided, however, when any such documents relate to
both Seller and Leasco or its business, only copies of such documents need be
furnished.


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<PAGE>

III. PURCHASER'S REPRESENTATIONS AND WARRANTIES. The Purchaser represents and
warrants to Seller and Gran Tierra that:

      3.1 Capacity and Enforceability. Purchaser has the legal capacity to
execute and deliver this Agreement and the documents to be executed and
delivered by Purchaser at the Closing pursuant to the transactions contemplated
hereby. This Agreement and all such documents constitute valid and binding
agreements of Purchaser, enforceable in accordance with their terms.

      3.2 Compliance. Neither the execution and delivery of this Agreement nor
the consummation of the transactions contemplated hereby by Purchaser will
result in the breach of any term or provision of, or constitute a default under,
or violate any agreement, indenture, instrument, order, law or regulation to
which Purchaser is a party or by which Purchaser is bound.

Purchase for Investment. Purchaser is acquiring the Shares solely for his own
account and not with a view to or for resale in connection with any distribution
or public offering thereof, within the meaning of any applicable securities laws
and regulations, unless such distribution or offering is registered under the
Securities Act of 1933, as amended (the "Securities Act"), or an exemption from
such registration is available. Purchaser acknowledges that Purchaser is an
officer and director of Seller and Leasco and, as such, has actual knowledge of
the business, operations and financial affairs of Leasco. Purchaser has received
no public solicitation or advertisement with respect to the offer or sale of the
Shares. Purchaser realizes that the Shares are "restricted securities" as that
term is defined in Rule 144 promulgated by the Securities and Exchange
Commission under the Securities Act, the resale of the Shares is restricted by
federal and state securities laws and, accordingly, the Shares must be held
indefinitely unless their resale is subsequently registered under the Securities
Act or an exemption from such registration is available for their resale.
Purchaser understands that the Shares are being sold to him pursuant to the
exemption from registration contained in Section 4(2) of the Securities Act and
that the Seller is relying upon the representations made herein as one of the
bases for claiming the Section 4(2) exemption.

      1. Liabilities. Following the Closing, Seller will have no liability for
any debts, liabilities or obligations of Leasco or its business or activities,
and there are no outstanding guaranties, performance or payment bonds, letters
of credit or other contingent contractual obligations that have been undertaken
by Seller directly or indirectly in relation to Leasco or its business and that
may survive the Closing.

      2. Title to Purchase Price Shares. Purchaser is the sole record and
beneficial owner of the Purchase Price Shares being sold by Purchaser hereunder.
At Closing, Purchaser will have good and marketable title to the Purchase Price
Shares, which Purchase Price Shares are, and at the Closing will be, free and
clear of all options, warrants, pledges, claims, liens, and encumbrances and any
restrictions or limitations prohibiting or restricting transfer to Seller,
except for restrictions on transfer as contemplated by applicable securities
laws.


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<PAGE>

IV. SELLER'S AND LEASCO'S REPRESENTATIONS AND WARRANTIES. Seller and Leasco,
jointly and severally, represent and warrant to Purchaser that:

      4.1 Organization and Good Standing. Seller is a corporation duly
incorporated, validly existing, and in good standing under the laws of the State
of Nevada. Leasco is a corporation duly incorporated, validly existing and in
good standing under the laws of the State of Nevada.

      4.2 Authority and Enforceability. The execution and delivery of this
Agreement and the documents to be executed and delivered at the Closing pursuant
to the transactions contemplated hereby, and performance in accordance with the
terms hereof and thereof, have been duly authorized by Seller and all such
documents constitute the valid and binding agreements of Seller enforceable in
accordance with their terms.

      4.3 Title to Shares. Seller is the sole record and beneficial owner of the
Shares. At Closing, Seller will have good and marketable title to the Shares,
which Shares are, and at the Closing will be, free and clear of all options,
warrants, pledges, claims, liens and encumbrances, and any restrictions or
limitations prohibiting or restricting transfer to Purchaser, except for
restrictions on transfer as contemplated by Section 3.3 above. The Shares
constitute all of the issued and outstanding shares of capital stock of Leasco.

      4.4 Representations in Reorganization Agreement. Leasco represents and
warrants that all of the representations and warranties by Seller, insofar as
they relate to Leasco, contained in the Reorganization Agreements are true and
correct.

V. OBLIGATIONS OF PURCHASER PENDING CLOSING. Purchaser covenants and agree that
between the date hereof and the Closing:

      5.1 Not Impair Performance. Purchaser shall not take any intentional
action that would cause the conditions upon the obligations of the parties
hereto to effect the transactions contemplated hereby not to be fulfilled,
including, without limitation, taking or causing to be taken any action that
would cause the representations and warranties made by any party herein not to
be true, correct and accurate as of the Closing, or in any way impairing the
ability of Seller to satisfy its obligations as provided in Article VI.

      5.2 Assist Performance. Purchaser shall exercise its reasonable best
efforts to cause to be fulfilled those conditions precedent to Seller's
obligations to consummate the transactions contemplated hereby which are
dependent upon actions of Purchaser and to make and/or obtain any necessary
filings and consents in order to consummate the sale transaction contemplated by
this Agreement.

VI. OBLIGATIONS OF SELLER PENDING CLOSING. Seller covenants and agrees that
between the date hereof and the Closing:

      6.1 Business as Usual. Leasco shall operate and Seller shall cause Leasco
to operate in accordance with past practices and shall use best efforts to
preserve its goodwill and the goodwill of its employees, customers and others
having business dealings with Leasco. Without limiting the generality of the
foregoing, from the date of this Agreement until the Closing Date, Leasco shall
(a) make all normal and customary repairs to its equipment, assets and
facilities, (b) keep in force all insurance, (c) preserve in full force and
effect all material franchises, licenses, contracts and real property interests
and comply in all material respects with all laws and regulations, (d) collect
all accounts receivable and pay all trade creditors in the ordinary course of
business at intervals historically experienced, and (e) preserve and maintain
Leasco's assets in their current operating condition and repair, ordinary wear
and tear excepted. Leasco shall not (i) amend, terminate or surrender any
material franchise, license, contract or real property interest, or (ii) sell or
dispose of any of its assets except in the ordinary course of business. Neither
Leasco nor Purchaser shall take or omit to take any action that results in
Seller incurring any liability or obligation prior to or in connection with the
Closing.


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<PAGE>

      6.2 Not Impair Performance. Seller shall not take any intentional action
that would cause the conditions upon the obligations of the parties hereto to
effect the transactions contemplated hereby not to be fulfilled, including,
without limitation, taking or causing to be taken any action which would cause
the representations and warranties made by any party herein not to be materially
true, correct and accurate as of the Closing, or in any way impairing the
ability of Purchaser to satisfy its obligations as provided in Article V.

      6.3 Assist Performance. Seller shall exercise its reasonable best efforts
to cause to be fulfilled those conditions precedent to Purchaser's obligations
to consummate the transactions contemplated hereby which are dependent upon the
actions of Seller and to work with Purchaser to make and/or obtain any necessary
filings and consents. Seller shall cause Leasco to comply with its obligations
under this Agreement.

VII. SELLER'S AND LEASCO'S CONDITIONS PRECEDENT TO CLOSING. The obligations of
Seller and Leasco to close the transactions contemplated by this Agreement are
subject to the satisfaction at or prior to the Closing of each of the following
conditions precedent (any or all of which may be waived by Seller and Gran
Tierra in writing):

      7.1 Representations and Warranties; Performance. All representations and
warranties of Purchaser contained in this Agreement shall have been true and
correct, in all material respects, when made and shall be true and correct, in
all material respects, at and as of the Closing, with the same effect as though
such representations and warranties were made at and as of the Closing.
Purchaser shall have performed and complied with all covenants and agreements
and satisfied all conditions, in all material respects, required by this
Agreement to be performed or complied with or satisfied by Purchaser at or prior
to the Closing.

      7.2 Additional Documents. Purchaser shall deliver or cause to be delivered
such additional documents as may be necessary in connection with the
consummation of the transactions contemplated by this Agreement and the
performance of its obligations hereunder.

      7.3 Release by Leasco. At the Closing, Leasco shall execute and deliver to
Seller and Gran Tierra a general release which in substance and effect releases
Seller and Gran Tierra from any and all liabilities and obligations that Seller
and Gran Tierra may owe to Leasco in any capacity and from any and all claims
that Leasco may have against Seller, Gran Tierra, or their respective officers,
directors, stockholders, employees and agents (other than those arising pursuant
to this Agreement or any document delivered in connection with this Agreement).


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<PAGE>

VIII. PURCHASER'S CONDITIONS PRECEDENT TO CLOSING. The obligation of Purchaser
to close the transactions contemplated by this Agreement is subject to the
satisfaction at or prior to the Closing of each of the following conditions
precedent (any and all of which may be waived by Purchaser in writing):

      8.1 Representations and Warranties; Performance. All representations and
warranties of Seller and Leasco contained in this Agreement shall have been true
and correct, in all material respects, when made and shall be true and correct,
in all material respects, at and as of the Closing with the same effect as
though such representations and warranties were made at and as of the Closing.
Seller and Leasco shall have performed and complied with all covenants and
agreements and satisfied all conditions, in all material respects, required by
this Agreement to be performed or complied with or satisfied by them at or prior
to the Closing.

IX. OTHER AGREEMENTS.

      9.1 Expenses. Each party hereto shall bear its expenses separately
incurred in connection with this Agreement and with the performance of its
obligations hereunder.

      9.2 Confidentiality. The parties hereto shall not make any public
announcements concerning this transaction other than in accordance with mutual
agreement reached prior to any such announcement(s) and other than as may be
required by applicable law or judicial process. If for any reason the
transactions contemplated hereby are not consummated, then Purchaser shall
return any information received by Purchaser from Seller or Leasco, and
Purchaser shall cause all confidential information obtained by Purchaser
concerning Leasco and its business to be treated as such.

      9.3 Brokers' Fees. No party to this Agreement has employed the services of
a broker and each agrees to indemnify the other against all claims of any third
parties for fees and commissions of any brokers claiming a fee or commission
related to the transactions contemplated hereby.

      9.4 Access to Information Post-Closing; Cooperation.

            (a) Following the Closing, Purchaser and Leasco shall afford to
      Seller and its authorized accountants, counsel, and other designated
      representatives reasonable access (and including using reasonable efforts
      to give access to persons or firms possessing information) and duplicating
      rights during normal business hours to allow records, books, contracts,
      instruments, computer data and other data and information (collectively,
      "Information") within the possession or control of Purchaser or Leasco
      insofar as such access is reasonably required by Seller. Information may
      be requested under this Section 9.4(a) for, without limitation, audit,
      accounting, claims, litigation and tax purposes, as well as for purposes
      of fulfilling disclosure and reporting obligations and performing this
      Agreement and the transactions contemplated hereby. No files, books or
      records of Leasco existing at the Closing Date shall be destroyed by
      Purchaser or Leasco after Closing but prior to the expiration of any
      period during which such files, books or records are required to be
      maintained and preserved by applicable law without giving the Seller at
      least 30 days' prior written notice, during which time Seller shall have
      the right to examine and to remove any such files, books and records prior
      to their destruction.


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<PAGE>

            (b) Following the Closing, Seller shall afford to Leasco and its
      authorized accountants, counsel and other designated representatives
      reasonable access (including using reasonable efforts to give access to
      persons or firms possessing information) duplicating rights during normal
      business hours to Information within Seller's possession or control
      relating to the business of Leasco. Information may be requested under
      this Section 9.4(b) for, without limitation, audit, accounting, claims,
      litigation and tax purposes as well as for purposes of fulfilling
      disclosure and reporting obligations and for performing this Agreement and
      the transactions contemplated hereby. No files, books or records of Leasco
      existing at the Closing Date shall be destroyed by Seller after Closing
      but prior to the expiration of any period during which such files, books
      or records are required to be maintained and preserved by applicable law
      without giving the Purchaser at least 30 days prior written notice, during
      which time Purchaser shall have the right to examine and to remove any
      such files, books and records prior to their destruction.

            (c) At all times following the Closing, Seller, Purchaser and Leasco
      shall use reasonable efforts to make available to the other party on
      written request, the current and former officers, directors, employees and
      agents of Seller or Leasco for any of the purposes set forth in Section
      9.4(a) or (b) above or as witnesses to the extent that such persons may be
      reasonably be required in connection with any legal, administrative or
      other proceedings in which Seller or Leasco may from time to be involved.

            (d) The party to whom any Information or witnesses are provided
      under this Section 9.4 shall reimburse the provider thereof for all
      out-of-pocket expenses actually and reasonably incurred in providing such
      Information or witnesses.

            (e) Seller, Purchaser, Leasco and their respective employees and
      agents shall each hold in strict confidence all Information concerning the
      other party in their possession or furnished by the other or the other's
      representative pursuant to this Agreement with the same degree of care as
      such party utilizes as to such party's own confidential information
      (except to the extent that such Information is (i) in the public domain
      through no fault of such party or (ii) later lawfully acquired from any
      other source by such party), and each party shall not release or disclose
      such Information to any other person, except such party's auditors,
      attorneys, financial advisors, bankers, other consultants and advisors or
      persons with whom such party has a valid obligation to disclose such
      Information, unless compelled to disclose such Information by judicial or
      administrative process or, as advised by its counsel, by other
      requirements of law.

            (f) Seller, Purchaser and Leasco shall each use their best efforts
      to forward promptly to the other party all notices, claims, correspondence
      and other materials which are received and determined to pertain to the
      other party.


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<PAGE>

      9.5 Guarantees, Surety Bonds and Letter of Credit Obligations. In the
event that Seller is obligated for any debts, obligations or liabilities of
Leasco by virtue of any outstanding guarantee, performance or surety bond or
letter of credit provided or arranged by Seller on or prior to the Closing Date,
Purchaser and Leasco shall use best efforts to cause to be issued replacements
of such bonds, letters of credit and guarantees and to obtain any amendments,
novations, releases and approvals necessary to release and discharge fully
Seller from any liability thereunder following the Closing. Purchaser and
Leasco, jointly and severally, shall be responsible for, and shall indemnify,
hold harmless and defend Seller from and against, any costs or losses incurred
by Seller arising from such bonds, letters of credits and guarantees and any
liabilities arising therefrom and shall reimburse Seller for any payments that
Seller may be required to pay pursuant to enforcement of its obligations
relating to such bonds, letters of credit and guarantees.

      3. Filings and Consents. Purchaser, at its risk, shall determine what, if
any, filings and consents must be made and/or obtained prior to Closing to
consummate the purchase and sale of the Shares. Purchaser shall indemnify the
Seller Indemnified Parties (as defined in Section 11.1 below) against any Losses
(as defined in Section 11.1 below) incurred by any Seller Indemnified Parties by
virtue of the failure to make and/or obtain any such filings or consents.
Recognizing that the failure to make and/or obtain any filings or consents may
cause Seller to incur Losses or otherwise adversely affect Seller, Purchaser and
Leasco confirm that the provisions of this Section 9.6 will not limit Seller's
right to treat such failure as the failure of a condition precedent to Seller's
obligation to close pursuant to Article VII above.

      4. Insurance. Purchaser acknowledges that on the Closing Date, effective
as of the Closing, all insurance coverage and bonds provided by Seller for
Leasco, and all certificates of insurance evidencing that Leasco maintains any
required insurance by virtue of insurance provided by Seller, will terminate
with respect to any insured damages resulting from matters occurring subsequent
to Closing.

      5. Agreements Regarding Taxes.

            6. Tax Sharing Agreements. Any tax sharing agreement between Seller
      and Leasco is terminated as of the Closing Date and will have no further
      effect for any taxable year (whether the current year, a future year, or a
      past year).

            7. Returns for Periods Through the Closing Date. Seller will include
      the income and loss of Leasco (including any deferred income triggered
      into income by Reg. ss.1.1502-13 and any excess loss accounts taken into
      income under Reg. ss.1.1502-19) on Seller's consolidated federal income
      tax returns for all periods through the Closing Date and pay any federal
      income taxes attributable to such income. Seller and Leasco agree to
      allocate income, gain, loss, deductions and credits between the period up
      to Closing (the "Pre-Closing Period") and the period after Closing (the
      "Post-Closing Period") based on a closing of the books of Leasco and both
      Seller and Leasco agree not to make an election under Reg.
      ss.1.1502-76(b)(2)(ii) to ratably allocate the year's items of income,
      gain, loss, deduction and credit. Seller, Leasco and Purchaser agree to
      report all transactions not in the ordinary course of business occurring
      on the Closing Date after Purchaser's purchase of the Shares on Leasco's
      tax returns to the extent permitted by Reg. ss.1.1502-76(b)(1)(ii)(B).
      Purchaser agrees to indemnify Seller for any additional tax owed by Seller
      (including tax owned by Seller due to this indemnification payment)
      resulting from any transaction engaged in by Leasco during the Pre-Closing
      Period or on the Closing Date after Purchaser's purchase of the Shares.
      Leasco will furnish tax information to Seller for inclusion in Seller's
      consolidated federal income tax return for the period which includes the
      Closing Date in accordance with Leasco's past custom and practice.


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<PAGE>

            8. Audits. Seller will allow Leasco and its counsel to participate
      at Leasco's expense in any audits of Seller's consolidated federal income
      tax returns to the extent that such audit raises issues that relate to and
      increase the tax liability of Leasco. Seller shall have the absolute
      right, in its sole discretion, to engage professionals and direct the
      representation of Seller in connection with any such audit and the
      resolution thereof, without receiving the consent of Purchaser or Leasco
      or any other party acting on behalf of Purchaser or Leasco, provided that
      Seller will not settle any such audit in a manner which would materially
      adversely affect Leasco after the Closing Date unless such settlement
      would be reasonable in the case of a person that owned Leasco both before
      and after the Closing Date. In the event that after Closing any tax
      authority informs the Purchaser or Leasco of any notice of proposed audit,
      claim, assessment, or other dispute concerning an amount of taxes which
      pertain to the Seller, or to Leasco during the period prior to Closing,
      Purchaser or Leasco must promptly notify the Seller of the same within 15
      calendar days of the date of the notice from the tax authority. In the
      event Purchaser or Leasco does not notify the Seller within such 15 day
      period, Purchaser and Leasco, jointly and severally, will indemnify the
      Seller for any incremental interest, penalty or other assessments
      resulting from the delay in giving notice. To the extent of any conflict
      or inconsistency, the provisions of this Section 9.8 shall control over
      the provisions of Section 11.2 below.

      9. Cooperation on Tax Matters. Purchaser, Seller and Leasco shall
cooperate fully, as and to the extent reasonably requested by the other party,
in connection with the filing of tax returns pursuant to this Section and any
audit, litigation or other proceeding with respect to taxes. Such cooperation
shall include the retention and (upon the other party's request) the provision
of records and information which are reasonably relevant to any such audit,
litigation or other proceeding and making employees available on a mutually
convenient basis to provide additional information and explanation of any
material provided hereunder. Leasco shall (i) retain all books and records with
respect to tax matters pertinent to Leasco relating to any taxable period
beginning before the Closing Date until the expiration of the statute of
limitations (and, to the extent notified by Seller, any extensions thereof) of
the respective taxable periods, and to abide by all record retention agreements
entered into with any taxing authority, and (ii) give Seller reasonable written
notice prior to transferring, destroying or discarding any such books and
records and, if the Seller so requests, Purchaser agrees to cause Leasco to
allow Seller to take possession of such books and records.


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<PAGE>

X. TERMINATION. This Agreement may be terminated at, or at any time prior to,
the Closing by mutual written consent of Seller, Purchaser and Gran Tierra.

      If this Agreement is terminated as provided herein, it shall become wholly
void and of no further force and effect and there shall be no further liability
or obligation on the part of any party except to pay such expenses as are
required of such party.

XI. INDEMNIFICATION.

      11.1 Indemnification by Purchaser. Purchaser covenants and agrees to
indemnify, defend, protect and hold harmless Seller, and its officers,
directors, employees, stockholders, agents, representatives and affiliates
(collectively, together with Seller, the "Seller Indemnified Parties") at all
times from and after the date of this Agreement from and against all losses,
liabilities, damages, claims, actions, suits, proceedings, demands, assessments,
adjustments, costs and expenses (including specifically, but without limitation,
reasonable attorneys' fees and expenses of investigation), whether or not
involving a third party claim and regardless of any negligence of any Seller
Indemnified Party (collectively, "Losses"), incurred by any Seller Indemnified
Party as a result of or arising from (i) any breach of the representations and
warranties of Purchaser set forth herein or in certificates delivered in
connection herewith, (ii) any breach or nonfulfillment of any covenant or
agreement (including any other agreement of Purchaser to indemnify Seller set
forth in this Agreement) on the part of Purchaser under this Agreement, (iii)
any debt, liability or obligation of Leasco, (iv) the conduct and operations of
the business of Leasco whether before or after Closing, (v) claims asserted
against Leasco whether before or after Closing, or (vi) any federal or state
income tax payable by Seller and attributable to the transaction contemplated by
this Agreement.

      11.2 Third Party Claims.

            (a) Defense. If any claim or liability (a "Third-Party Claim")
      should be asserted against any of the Seller Indemnified Parties (the
      "Indemnitee") by a third party after the Closing for which Purchaser have
      an indemnification obligation under the terms of Section 11.1, then the
      Indemnitee shall notify Purchaser and Leasco (the "Indemnitor") within 20
      days after the Third-Party Claim is asserted by a third party (said
      notification being referred to as a "Claim Notice") and give the
      Indemnitor a reasonable opportunity to take part in any examination of the
      books and records of the Indemnitee relating to such Third-Party Claim and
      to assume the defense of such Third-Party Claim and in connection
      therewith and to conduct any proceedings or negotiations relating thereto
      and necessary or appropriate to defend the Indemnitee and/or settle the
      Claim. The expenses (including reasonable attorneys' fees) of all
      negotiations, proceedings, contests, lawsuits or settlements with respect
      to any Third-Party Claim shall be borne by the Indemnitor. If the
      Indemnitor agrees to assume the defense of any Third-Party Claim in
      writing within 20 days after the Claim Notice of such Third-Party Claim
      has been delivered, through counsel reasonably satisfactory to Indemnitee,
      then the Indemnitor shall be entitled to control the conduct of such
      defense, and any decision to settle such Third-Party Claim, and shall be
      responsible for any expenses of the Indemnitee in connection with the
      defense of such Third-Party Claim so long as the Indemnitor continues such
      defense until the final resolution of such Third-Party Claim. The
      Indemnitor shall be responsible for paying all settlements made or
      judgments entered with respect to any Third-Party Claim the defense of
      which has been assumed by the Indemnitor. Except as provided on subsection
      (b) below, both the Indemnitor and the Indemnitee must approve any
      settlement of a Third Party Claim. A failure by the Indemnitee to timely
      give the Claim Notice shall not excuse Indemnitor from any indemnification
      liability except only to the extent that the Indemnitor is materially and
      adversely prejudiced by such failure.


                                       10
<PAGE>

            (b) Failure to Defend. If the Indemnitor shall not agree to assume
      the defense of any Third-Party Claim in writing within 20 days after the
      Claim Notice of such Third-Party Claim has been delivered, or shall fail
      to continue such defense until the final resolution of such Third-Party
      Claim, then the Indemnitee may defend against such Third-Party Claim in
      such manner as it may deem appropriate and the Indemnitee may settle such
      Third-Party Claim on such terms as it may deem appropriate. The Indemnitor
      shall promptly reimburse the Indemnitee for the amount of all settlement
      payments and expenses, legal and otherwise, incurred by the Indemnitee in
      connection with the defense or settlement of such Third-Party Claim. If no
      settlement of such Third-Party Claim is made, then the Indemnitor shall
      satisfy any judgment rendered with respect to such Third-Party Claim
      before the Indemnitee is required to do so, and pay all expenses, legal or
      otherwise, incurred by the Indemnitee in the defense against such
      Third-Party Claim.

      11.3 Non-Third-Party Claims. Upon discovery of any claim for which
Purchaser have an indemnification obligation under the terms of Section 11.1
which does not involve a claim by a third party against the Indemnitee, the
Indemnitee shall give prompt notice to Purchaser of such claim and, in any case,
shall give Purchaser such notice within 30 days of such discovery. A failure by
Indemnitee to timely give the foregoing notice to Purchaser shall not excuse
Purchaser from any indemnification liability except to the extent that Purchaser
is materially and adversely prejudiced by such failure.

      10. Survival. Except as otherwise provided in this Section 11.4, all
representations and warranties made by Purchaser, Leasco and Seller in
connection with this Agreement shall survive the Closing. Anything in this
Agreement to the contrary notwithstanding, the liability of all Indemnitors
under this Article XI shall terminate on the third (3rd) anniversary of the
Closing Date, except with respect to (a) liability for any item as to which,
prior to the third (3rd) anniversary of the Closing Date, any Indemnitee shall
have asserted a Claim in writing, which Claim shall identify its basis with
reasonable specificity, in which case the liability for such Claim shall
continue until it shall have been finally settled, decided or adjudicated, (b)
liability of any party for Losses for which such party has an indemnification
obligation, incurred as a result of such party's breach of any covenant or
agreement to be performed by such party after the Closing, (c) liability of
Purchaser for Losses incurred by a Seller Indemnified Party due to breaches of
their representations and warranties in Article III of this Agreement, and (d)
liability of Purchaser for Losses arising out of Third-Party Claims for which
Purchaser have an indemnification obligation, which liability shall survive
until the statute of limitation applicable to any third party's right to assert
a Third-Party Claim bars assertion of such claim.


                                       11
<PAGE>

XII. MISCELLANEOUS.

12.1 Notices. All notices and communications required or permitted hereunder
shall be in writing and deemed given when received by means of the United States
mail, addressed to the party to be notified, postage prepaid and registered or
certified with return receipt requested, or personal delivery, or overnight
courier, as follows:

            (a)   If to Seller, addressed to:

                  Goldstrike Inc.
                  1055 West Hastings Street, Suite 1980, Vancouver,
                  British Columbia, Canada V6E 2E9
                  Attn: Dr. Yenyou Zheng

            With a copy to (which shall not constitute notice hereunder):

                  Gottbetter & Partners LLP
                  488 Madison Avenue, 12th Floor
                  New York, NY 10022
                  Attn: Kenneth S. Goodwin, Esq.

            (b)   If to Purchaser or Leasco, addressed to:

                  Dr. Dr. Yenyou Zheng
                  1055 West Hastings Street, Suite 1980, Vancouver,
                  British Columbia, Canada V6E 2E9

            With a copy to (which shall not constitute notice hereunder):

                  Gregory S. Yanke, Law Corporation
                  200 - 675 West Hastings Street, Vancouver
                  British Columbia, Canada V7L 3G8
                  Attention:  Gregory S. Yanke, Esq.

            (c)   If to Gran Tierra, addressed to:

                  Gran Tierra Energy Inc.
                  Tenth Floor, 10 - 8th Avenue S.W.
                  Calgary, Alberta, Canada T2P 1G5
                  Attention: Dana Coffield


                                       12
<PAGE>

            With a copy to (which shall not constitute notice hereunder):

                  McGuireWoods LLP
                  1345 Avenue of the Americas
                  New York, NY 10105
                  Attention: Louis W. Zehil, Esq.

or to such other address as any party hereto shall specify pursuant to this
Section 12.1 from time to time.

      12.2 Exercise of Rights and Remedies. Except as otherwise provided herein,
no delay of or omission in the exercise of any right, power or remedy accruing
to any party as a result of any breach or default by any other party under this
Agreement shall impair any such right, power or remedy, nor shall it be
construed as a waiver of or acquiescence in any such breach or default, or of
any similar breach or default occurring later; nor shall any waiver of any
single breach or default be deemed a waiver of any other breach or default
occurring before or after that waiver.

      12.3 Time. Time is of the essence with respect to this Agreement.

      12.4 Reformation and Severability. In case any provision of this Agreement
shall be invalid, illegal or unenforceable, it shall, to the extent possible, be
modified in such manner as to be valid, legal and enforceable but so as to most
nearly retain the intent of the parties, and if such modification is not
possible, such provision shall be severed from this Agreement, and in either
case the validity, legality and enforceability of the remaining provisions of
this Agreement shall not in any way be affected or impaired thereby.

      12.5 Further Acts. Seller, Purchaser and Leasco shall execute any and all
documents and perform such other acts which may be reasonably necessary to
effectuate the purposes of this Agreement.

      12.6 Entire Agreement; Amendments. This Agreement contains the entire
understanding of the parties relating to the subject matter contained herein.
This Agreement cannot be amended or changed except through a written instrument
signed by all of the parties hereto, including Gran Tierra. No provisions of
this Agreement or any rights hereunder may be waived by any party without the
prior written consent of Gran Tierra.

      12.7 Assignment. No party may assign his or its rights or obligations
hereunder, in whole or in part, without the prior written consent of the other
parties.

      12.8 Governing Law. This Agreement shall be governed by and construed in
accordance with the laws of the State of Nevada, without giving effect to
principles of conflicts or choice of laws thereof.

      12.9 Counterparts. This Agreement may be executed in one or more
counterparts, with the same effect as if all parties had signed the same
document. Each such counterpart shall be an original, but all such counterparts
taken together shall constitute a single agreement. In the event that any
signature is delivered by facsimile transmission, such signature shall create a
valid and binding obligation of the party executing (or on whose behalf such
signature is executed) the same with the same force and effect as if such
facsimile signature page was an original thereof.


                                       13
<PAGE>

      12.10 Section Headings and Gender. The Section headings used herein are
inserted for reference purposes only and shall not in any way affect the meaning
or interpretation of this Agreement. All personal pronouns used in this
Agreement shall include the other genders, whether used in the masculine,
feminine or neuter, and the singular shall include the plural, and vice versa,
whenever and as often as may be appropriate.

      12.11 Specific Performance; Remedies. Each of Seller, Purchaser and Leasco
acknowledges and agrees that Gran Tierra would be damaged irreparably if any
provision of this Agreement is not performed in accordance with its specific
terms or is otherwise breached. Accordingly, each of Seller, Purchaser and
Leasco agrees that Gran Tierra will be entitled to seek an injunction or
injunctions to prevent breaches of the provisions of this Agreement and to
enforce specifically this Agreement and its terms and provisions in any action
instituted in any court of the United States or any state thereof having
jurisdiction over the parties and the matter, subject to Section 12.8, in
addition to any other remedy to which they may be entitled, at law or in equity.
Except as expressly provided herein, the rights, obligations and remedies
created by this Agreement are cumulative and in addition to any other rights,
obligations or remedies otherwise available at law or in equity, and nothing
herein will be considered an election of remedies.

      12.12 Construction. The parties hereto have participated jointly in the
negotiation and drafting of this Agreement. If an ambiguity or question of
intent or interpretation arises, this Agreement will be construed as if drafted
jointly by the parties hereto and no presumption or burden of proof will arise
favoring or disfavoring any party because of the authorship of any provision of
this Agreement. Any reference to any federal, state, local, or foreign law will
be deemed also to refer to law as amended and all rules and regulations
promulgated thereunder, unless the context requires otherwise. The words
"include," "includes," and "including" will be deemed to be followed by "without
limitation." The words "this Agreement," "herein," "hereof," "hereby,"
"hereunder," and words of similar import refer to this Agreement as a whole and
not to any particular subdivision unless expressly so limited. The parties
hereto intend that each representation, warranty, and covenant contained herein
will have independent significance. If any party hereto has breached any
representation, warranty, or covenant contained herein in any respect, the fact
that there exists another representation, warranty or covenant relating to the
same subject matter (regardless of the relative levels of specificity) which
that party has not breached will not detract from or mitigate the fact that such
party is in breach of the first representation, warranty, or covenant.



                        [Signature page follows this page.]


                                       14
<PAGE>

      IN WITNESS WHEREOF, the parties hereto have hereunto set their hands as of
the day and year first above written.


                                      GOLDSTRIKE INC.


                                      By:
                                         -----------------------------------
                                      Name:
                                           ---------------------------------
                                      Title:
                                            --------------------------------


                                      LEASCO, INC.


                                      By:
                                         -----------------------------------
                                      Name:
                                           ---------------------------------
                                      Title:
                                            --------------------------------


                                      PURCHASER


                                      Dr. Yenyou Zheng




                                      GRAN TIERRA ENERGY INC.


                                      By:
                                         -----------------------------------
                                      Name:
                                           ---------------------------------
                                      Title:
                                            --------------------------------






                                       15